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The document outlines various aspects of the Base Station Subsystem (BSS) optimization, including idle parameter optimization, power control, handover control, and radio resource administration. It covers technical configurations, channel mapping, TDMA frame structures, and signaling parameters essential for effective communication in mobile networks. Additionally, it discusses traffic channel configurations, frequency allocation, and the process of cell selection and reselection within the network for optimal performance.

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1 © Nokia Siemens Networks BSS Optimisation Workshop Denpasar Bali Oct 21-25, 2013 NSN – TSEL
2 © Nokia Siemens Networks Idle Parameter Optimization Power Control Parameter Handover Control parameter Radio Resource Administration Radio resource Management KPI case Measurement processing
3 © Nokia Siemens Networks Radio Resource Administration
4 © Nokia Siemens Networks TDMA frame = 8 timeslots ( 0.577ms * 8 = 4.615 ms) 0 1 3 4 5 7 6 0 1 2 3 4 5 7 6 0 1 2 3 4 5 200 kHz Physical channel e.g. allocated to one subscriber with FR voice and no frequency hopping frequency t i m e TDMA frame 2 2 2 2 Basic TDMA Structure
5 © Nokia Siemens Networks Base Station Subsystem Logical Channels for transport of specific content Physical Channels transport medium MS mapping Physical channel parameters ARFCN Time slot number Frequency hopping algorithm GSM Channel Organization
6 © Nokia Siemens Networks SCH FCCH PCH BCCH AGCH RACH SDCCH SACCH FACCH Stand alone Dedicated Control Channel Frequency Correction Channel Synchronisation Channel Broadcast Control Channel Paging Channel Slow Associated Control Channel Fast Associated Control Channel Paging Channel Random Access Channel Access Grant Channel BCH CCCH DCCH TCH DL DL DL UL Common Channels Dedicated Channels UL/DL UL/DL CBCH Cell Broadcast Channel Logical Channels FR/HR Full rate / Halft rate TCH EFR Enhanced Full rate TCH AMR FR/HR Adaptive multirate TCH (FR/HR)
7 © Nokia Siemens Networks f s f f s f s Downlink 51 TDMA frames = 235 ms - Uplink BCCH CCCH f s f s CCCH CCCH r r f r r r r r r r f r r r r r r r r r r f r r r r r r f r r 1 51 CCCH CCCH CCCH CCCH CCCH CCCH r r r r r r r r r r r r r r r r r r r r r r r r f = FCCH, s = SCH, r = RACH TDMA frame - = dummy burst 51 TDMA frames = 235 ms 1 51 Signalling Channel Mapping (BCCH +CCCH/9)
8 © Nokia Siemens Networks f s f f s f s Downlink 51 TDMA frames = 235 ms - Uplink BCCH CCCH f s f s CCCH CCCH SDCCH 0 SDCCH 1 SDCCH 2 SDCCH 3 SACCH 0/2 SACCH 1/3 r r f r r r r r r r f r r r r r r r r r r f r r r r r r f r r 1 51 SACCH 2/0 SACCH 3/1 SDCCH 0 SDCCH 1 SDCCH 3 SDCCH 2 f = FCCH, s = SCH, r = RACH TDMA frame - = dummy burst 51 TDMA frames = 235 ms 1 51 Signalling Channel Mapping (BCCH + SDCCH/4 + SACCH/C4)
9 © Nokia Siemens Networks ... 26 TDMA frames = 120 ms 1 26 t t t t t t t f t t t t t t t t t t t f t t t t t t s i Full Rate Traffic Channel Configuration (UL & DL) Half Rate Traffic Channel Configuration (UL & DL) 26 TDMA frames = 120 ms 1 26 t T T t t T t f t t T T T T t t T t T f T t T t t T s S t = full rate TCH, s = SACCH/T, i = idle TDMA frame t = half rate TCH, s = SACCH/T (first user) T = half rate TCH, S = SACCH/T (second user) TDMA frame Traffic Channel Mapping
10 © Nokia Siemens Networks f f i = idle TDMA frame f 51 TDMA frames = 235 ms i i i i i i SDCCH 0 SDCCH 1 SDCCH 2 SDCCH 3 SDCCH 4 SDCCH 5 SDCCH 6 SDCCH 7 SDCCH 1 SDCCH 2 SDCCH 3 SDCCH 4 SDCCH 5 SDCCH 6 SDCCH 7 SDCCH 0 Downlink Uplink SACCH 0/4 SACCH 1/5 SACCH 2/6 SACCH 3/7 SACCH 6/2 SACCH 7/3 SACCH 4/0 SACCH 5/1 51 TDMA frames = 235 ms 1 51 1 51 Signalling Channel Mapping (SDCCH/8 +SACCH/C4)
11 © Nokia Siemens Networks Signalling Channel Mapping New improved CCCH features in RG10 •BSS20738 CS Paging Coordination in NMO II •BSS21538 Extended CCCH – Extended CCCH can be allocated to timeslot 2,4,6 •BSS101411 Extended BCCH – For example Uncombined BCCH
12 © Nokia Siemens Networks Channel configuration defined by parameter channelType TCHF (0) = full rate traffic channel TCHH (1) = half rate traffic channel TCHD (2) = dual rate traffic channel SDCCH (3) = standalone (SDCCH/8) MBCCH (4) = broadcast control channel MBCCHC (5) = BCCH + SDCCH/4 MBCCB (7) = BCCH + SDCCH/3 with CBCH SDCCB (8) = SDCCH/7 with CBCH NOTUSED (9) = timeslot has no radio definition or Abis allocation ERACH (10) = random access channel of extended area EGTCH (14) = EGPRS packed data traffic channel for extended area LRTCH (15) = long reach traffic channel Channel Mapping Parameter Setting Note: • Some values not allowed in certain tsl (e.g. TSL0 can’t have value 8) • PBCCH is not supported in S13 and onwards MO Class TR/RTSL Parameter channelxType (CHx) where x = 0…7
13 © Nokia Siemens Networks Mobile terminating call -> MSC performs paging MS identifies paging message with the IMSI/TMSI MS listens to own paging group only SEG-BTS parameters MSC parameters Repaging Interval (INT) 0.5s…10s Time between consecutive paging attempts Repaging Attempts (AT) 0…5 Number of paging repetitions Buffering BTS stores up to 8 paging messages of the MSC in page group buffer BTS sends paging messages to MS according noOfMultiframesBetweenPaging Paging Channel (PCH) Parameters MO Class Abbreviated Name Range And Step Description Default value BSC - MML Name BTS noOfMFramesB etweenPaging 2...9, step 1 Defines the number of multiframes between two transmissions of the same paging message to the MSs of the same paging group. 4 MFR
14 © Nokia Siemens Networks Mobile sends channel requests to BTS separated by random time intervals in case of no answer! Parameters Random time interval between consecutive retransmissions t = S + random [0,.. numberOfSlotsSpreadTrans – 1] RACH slots S depends on numberOfSlotsSpreadTrans signalling channel mapping (CCCH + SDCCH combined or not in one multi frame) numberOfSlotsSpreadTrans = 10 signalling channel mapping = not combined  S = 58 Therefore t = 58..to..67 RACH slots time channel requests RACH Parameters MO Class Abbreviated Name Range And Step Description Default value BSC - MML Name BTS maxNumberRetra nsmission 1,2,4,7 Maximum number of retransmissions on the RACH that the MS can perform. 4 RET BTS nbrOfSlotsSpread Trans MML Range: 3..12, 14, 16, 20, 25, 32, 50 The number of TDMA frames over which retransmission is spread on the RACH (random access channel) 10 SLO
15 © Nokia Siemens Networks Network gives the MS dedicated resources Downlink CCCH blocks • PCH can be used for AGCH messages • AGCH cannot be used for PCH messages Reservation of CCCH blocks for AGCH noOfBlocksForAccessGrant (AG) 0..7 possible number, if CCCH and SDCCH are not combined 1..7 possible number, if CBCH is used in non combined configuration 0..2 possible number, if CCCH and SDCCH are combined Preference of AGCH messages on PCH noOfBlocksForAccessGrant  0 PCH can be used only, if no paging messages have to be send = 0 AGCH messages have higher priority than PCH ones Number of paging groups N = (number of CCCH blocks – noOfBlocksForAccessGrant) * noOfMultiframesBetweenPaging AGCH Parameters
16 © Nokia Siemens Networks Combined CCCH / SDCCH configuration noOfBlocksForAccessGrant = 1  2 CCCH blocks for PCH 3 MSs paged per paging message  3 pages per block 2 blocks per multi frame  3 * 2 = 6 pages per multiframe Number of pages per hour  3600 s / 0.235 s * 6 = 91915 Avg of 2 pages required per MS  91915 / 2 = 45957 MSs per hour BTS 3 MS Paging_Request BTS 3 MS Paging_Request Paging Capacity Example
17 © Nokia Siemens Networks Cell with 325 subscribers 1 call per subscriber once in a hour 1 location update (LU) per subscriber once in 2 hours Duration of call assignment = 4 s  4 s / 3600 s = 1.11 mErl on SDCCH per subscriber 325 subscribers  325 * 1.11 mErl = 0.3607 Erl on SDCCH Reservation time for LU = 5s 5 s / 7200 s = 0.69 mErl on SDCCH per subscriber 325 subscribers  0.2242 Erl on SDCCH Total SDCCH traffic  0.3607 Erl + 0.2242 Erl = 0.5849 Erl Blocking probability = 1%  4 SDCCHs required  SDCCH combined with CCCH can be used (MBCCHC) SDCCH Signalling Capacity Example with call Establishment & Location Update
18 © Nokia Siemens Networks Same cell with 325 subscribers Additional SMS traffic of 1 mErl per subscriber 325 subscribers  325 * 1 mErl = 0.325 Erl on SDCCH Total SDCCH traffic  0.5849 + 0.325 Erl = 0.9099 Erl Blocking probability = 1%  5 SDCCHs required  not combined with CCCH (MBCCH) SDCCH Signalling Capacity Example including SMS
19 © Nokia Siemens Networks Base Station Identity Code BSIC = Network Colour Code NCC + Base Station Colour Code BCC bsIdentityCode Setting of BSIC NCC 0..7, distinguishes between PLMNs BCC 0..7, distinguishes between clusters BSIC + frequency channel  unique identity of adjacent cell f1 f2 f3 f1 f1 bcc = 1 bcc = 2 bcc = 3 Base Station Identity Code
20 © Nokia Siemens Networks 200 kHz 890 915 935 960 1 2 3 4 124 123 1 2 3 4 124 123 duplex distance Absolute radio frequency carrier number ARFCN uplink direction downlink direction Example: GSM 900 Defining Frequency carrier number
21 © Nokia Siemens Networks Frequency to be used by TRX (must be unique within a BTS) initialFrequency (FREQ) 1…1023 Setting of ARFCNs GSM 800: 128 .. 251 GSM 900: 1..124 and 975..1023, 0 GSM 1800: 512..885 GSM 1900: 512..810 f1 f2 f3 f4 f5 f6 f7 f1 f2 f3 f4 f5 f6 f7 f1 f2 f3 f4 f5 f6 f7 Frequency Reuse
22 © Nokia Siemens Networks Frequency Time F1 F2 F3 Call is transmitted through several frequencies to • average the interference (interference diversity) • minimise the impact of fading (frequency diversity) Frequency hopping techniques hoppingMode (HOP) BB,RF,N BB = base band hopping (1) RF = RF hopping (2) N = no frequency hopping at all (0) Principle of Frequency Hopping
23 © Nokia Siemens Networks Baseband Hopping TRX 1 TRX 2 TRX 3 0 1 7 2 Timeslot TRX 4 BC CH f 1 f 2 f 3 f 4 HSN1 (BB hopping group 1 and RF hopping) Timeslot 0 hops over TRXs 2-4 only BCCH does not hop HSN2 (BB hopping group 2) Timeslots 1-7 hop over all TRXs TRXs do not hop Physical channels moved from one TRX to another Hopping sequence hoppingSequenceNumber (HSN) 0..63 0 = cyclic hopping 1..63 = pseudorandom hopping Base Band Hopping
24 © Nokia Siemens Networks RF Hopping Standard technique TRX 1 TRX 2 TRX 3 0 1 7 2 Timeslot TRX 4 BC CH f1 – no hopping f2,f3..fn – hopping according mobile allocation list One hopping sequence number only All TRXs hop except TRX1 (provides BCCH) Up to 63 frequencies available defined by mobile allocation list -> better hopping gain mobileAllocationList Setting of ARFCN values usedMobileAllocation (MAL) 0,1...2000 0 = BTS detached from any list 1..2000 = indicates list which shall be used
25 © Nokia Siemens Networks Standard technique 9 hopping hopping frequencies MAI = 0..8 But 3 frequencies available for every TRX only Freeform hopping For every sector same mobile allocation list hopping sequence number frame number (frame synchronization) For every sector different starting points for hopping sequence possible by mobile allocation index offset maioOffset (MO) 0..62 setting of MAIO 9 hopping hopping frequencies MAI = 0..8 9 frequencies available for every TRX RF Hopping Freeform Hopping
26 © Nokia Siemens Networks Freeform hopping • Not adequate for MA list with consecutive ARFCN values • Avoids co-channel interference but not adjacent channel interference Flexible MAIO management MAIO increases with constant step size from one TRX to the next one maioStep (MS) 1..62 maioOffset = 0, 6, 12 for sector 1, 2, 3 maioStep = 2 18 frequencies required (2 * number of hopping TRXs) RF Hopping Flexible MAIO Management
27 © Nokia Siemens Networks BCCH Band allocation: MA list Consecutive ARFCN Only BCCH frequency planning required Flexible MAIO management MAIO Offset + MAIO Step BCCH Band allocation: MA list Non-adjacent ARFCN Freeform hopping MAIO Offset MA list and BCCH frequency planning required RF Hopping (Tight Frequency Reuse)
28 © Nokia Siemens Networks Changing Frequency Plan BSIC / TSC Frequencies Frequency hopping setting Intelligent underlay overlay TRX settings • Plan downloaded to BSC/BTSs via MML or GUI • File-based plan provisioning • Immediate Plan activation method
29 © Nokia Siemens Networks Idle Mode Operation
30 © Nokia Siemens Networks • When the MS is switched ON • When there is no dedicated connection When? • To camp on the best suitable cell Why? • For MS to receive system info from the NW on DL • For MS to be able to initiate a call whenever needed • For the NW to be able to locate the MS when there is a MT call/SMS Why to camp on a specific cell? • PLMN selection • Cell selection & re-selection • Location updates Idle Mode Tasks Idle Mode Operation I MS switched ON Search RF channels to find BCCH carrier Check that the PLMN & cell is allowed MS camps on the best suitable cell See slide 10 for detail
31 © Nokia Siemens Networks Value LAI (locationAreaId) • NCC (Network Colour Code) 0 … 7 • BCC (BTS Colour Code) 0 … 7 BSIC (bsIdentityCode) CI (cell-ID 0 … 65535 Parameter TSC (trainingSequenceCode) 0 … 7 • MCC (Mobile Country Code) 0 … 999 • MNC (Mobile Network Code) 0 … 99, 0… 999 (optional 3-digit MNC) • LAC (Location Area Code) 1 … 65533 CGI (Cell Global Identity) MCC + MNC + LAC + CI ID’s and ID Codes
32 © Nokia Siemens Networks Any cell selection Camped on any cell Choose cell cell found no suitable cell found suitable cell found leave idle mode return to idle mode Connected mode (emergency call only) Any cell re- selection trigger cell re-selected no suitable cell found go here when no SIM in MS SIM inserted in MS 1 2 cell found on selected PLMN (adopted from TS 43.022 V5.1.0 chap. States and State Transition for Cell Selection
33 © Nokia Siemens Networks Camped normally (adopted from TS 43.022 V5.1.0 chap. 6 Connected mode Normal cell selection Stored list cell selection Choose cell Normal cell re-selection go here whenever a new PLMN is selected BA list stored for PLMN no BA list stored for PLMN 1 no suitable cell found suitable cell found suitable cell found trigger Suitable cell re-selected no suitable cell found suitable cell found leave idle mode return to idle mode no suitable cell found no suitable cell found • IMSI unknown • Illegal MS • PLMN not allowed 2 2 States and State Transition for Cell Selection
34 © Nokia Siemens Networks Normal Cell Selection Search all the RF channels, take samples during 3-5 s and calculate averages. And put them in ascending order with respect to signal level. Then tune to the strongest RF channel. Search for the frequency correction burst in that carrier in order to verify if it is a BCCH carrier Camp on the cell Try to synchronize to the carrier and read the BCCH data Is it a BCCH carrier? Is it a correct PLMN ? Is the cell barred? Is C1>0 Tune to the next highest RF channel which is not tried before No No No No Yes Yes Yes Yes
35 © Nokia Siemens Networks I am outside I am inside, but have not enough power C1 = A – max(B,0) = RLA_C – RXLEV_ACCESS_MIN – max(MS_TXPWR_MAX_CCH – P , 0) RLA_C = avg received RxLev on BCCH P = MS max output power max(B,0) 0..63 0..31 Pathloss Criterion C1 for Cell Selection and Reselection
36 © Nokia Siemens Networks Cell1 LAC1 C1 ( Cell1) C1 (Cell2) A B C A= 4 dB B= 6 dB C= 8 dB Cell2 LAC2 In case the neighbouring cells belong to different Location Area, a hysteresis is applied with C1 criteria • minimizing ping-pong cell reselections • cellReselectHysteresis (HYS)(BTS) (0…14 dB) Cell Selection with C1
37 © Nokia Siemens Networks C1 + CELL_RESELECT_OFFSET – (TEMPORARY OFFSET * H(PENALTY_TIME - T)) for PENALTY_TIME  640 s < C1 if temporary offset big for PENALTY_TIME = 640 s C2 = serving cell: • C2: List of 6 strongest carriers: • C2: • C2: • C2: • C2: • C2: • C2: 0 .. 126 dB step size: 2 dB 0, 10, 20, 30, 40, 50, 60,  dB 20 .. 640 s step size: 20 s PENALTY_TIME TEMPORARY OFFSET CELL_RESELECT_OFFSET C1 C2 T new candidate = formerly non- serving cell CELL_RESELECT_OFFSET C1 C2 T new candidate = former serving cell no TEMPORARY OFFSET Pathloss Criterion C2
38 © Nokia Siemens Networks cell 1 cell 2 cell 3 C2 time 5 seconds cell reselection 5 seconds CELL_RESELECT_ HYSTERESIS (HYS) LAC = A LAC = B cell reselection & location update Cell Reselection Based on Pathloss Criterion C2
39 © Nokia Siemens Networks Cell "A" Cell "B" Cell "C" Cell "D" cellReselectOffset 0 dB 20 dB 0 dB 0 dB temporaryOffset 0 dB 30 dB 0 dB 30 dB penaltyTime 20 s 20 s 20 s 40 s Micro 900 "D" Macro 1800 "B" Macro 900 "A" Macro 900 "C" Road Parameters =30 Cell "A" (Serving Cell) =25 Cell "B" =5 Cell "C" =50 Cell "D" =30 + 0 (H(x)=0, serving cell) Cell "A" =25 + 20 - 30*H(20 - T) Cell "B" =5 + 0 - 0*H(20 - T) Cell "C" =50 + 0 - 30*H(40 - T) Cell "D" C1 C2 = C1 + cellReselectOffset - temporaryOffset*H(penaltyTime-T) C2 Time T: (0 - 19 s) C2 =30 Cell "A" C2 =15 Cell "B" C2 =5 Cell "C" C2 =20 Cell "D" Time T: (20 - 39 s) C2 =30 Cell "A" C2 =45 Cell "B" C2 =5 Cell "C" C2 =20 Cell "D" Time T: (> 40 s) C2 =30 Cell "A" C2 =45 Cell "B" C2 =5 Cell "C" C2 =50 Cell "D" Cell Reselection Based on Pathloss Criterion C2
40 © Nokia Siemens Networks When shall I select a new cell? Pathloss Criterion C1 C1  0 for a period of 5 s Pathloss Criterion C2 • neighbour‘s C2 value > current cell‘s C2 value (same LA) • neighbour‘s C2 value > current cell‘s C2 value + HYS (new LA) for a period of 5 s. Downlink Signalling Failure DSC  0 RACH Failure MAX RETRANS + 1 times Authentication Failure notification by upper layers Cell has been barred CELL_BAR_ACCESS & CELL_BAR_QUALIFY Cell Reselection Events
41 © Nokia Siemens Networks Location Update Procedure BSS MSC VLR HLR REQUEST SUBSCRIBER INFO ALL OK - HLR UPDATE MS LOCATION UPDATE REQUEST SEND SUBSCRIBER ID REQUEST SUBSCRIBER ID SEND SUBSCRIBER INFO AUTHENTICATION AUTHENTICATION RESPONSE
42 © Nokia Siemens Networks Paging LocUp # of cells in Loc. area signalling traffic optimum number of cells in Loc. area function of user density, cell size, call arrival rate ... function of user mobility Trade-off between Location Update and Paging Traffic
43 © Nokia Siemens Networks Location Updates • MS location & status flag => MSC / VLR • Mobile Station switched ON mode – IMSI Attach / Detach – Same Location Area => No Location Update – Different Location Area => Location Update • Change of the Location Area – Location Area under the same MSC / VLR – Location Area under another MSC / VLR => HLR will be updated • Service is rejected (MS unknown in VLR) • Time-Periodic LU (MS -> MSC/VLR) MO Class Abbreviated Name Range And Step Description Default value BSC - MML Name BTS allowIMSIAtt achDetach Yes/No Defines whether IMSI attach/detach is used in the cell. Yes ATT BTS timerPeriodic UpdateMs 0...25.5 h, step 0.1 h Defines the interval between periodic MS location updates. The value 0 means that the periodic location update is not used. 0.5 h PER
44 © Nokia Siemens Networks IDLE MODE OPERATION Idle Mode Controls Parameter Value Access Parameters notAllowedAccessClasses 0 ... 9, 11 ... 15 emergencyCallRestricted Yes/No msTxPwrMaxCCH 13 ... 43 (dBm) rxLevAccessMin -110 ... -47 (dBm) msMaxDistanceInCallSetup 0 ... 255 radiusExtension 0 ... 67 (Km) cellBarred Yes/No plmn-permitted 0 ... 7 cellReselectHysteresis 0 ... 14 (dB) Mobility Parameters cellReselectOffset (REO) 0 ... 126 (dB) cell reselection parameter index (PI) (N/Y)
45 © Nokia Siemens Networks IDLE MODE OPERATION Idle Mode Controls definitions • RxLevAccessmin : With this parameter you define the minimum power level an MS has to receive before it is allowed to access the cell. • MsTxPwrMaxCCH : With this parameter you define the maximum transmission power an MS may use when accessing a CCH in the cell. • notAllowedAccessClasses With this parameter you define the MS access classes that are not allowed to access a cell. • Emergency Call Restricted With this parameter you define if an emergency call in the cell is allowed to all MSs or only to the MSs which belong to one of the classes between 11 to 15. Value ’Y’ means the latter case. • MsMaxDistancein CallSetup With this parameter you define the maximum distance between the BTS and the MS in call setup. The maximum distance is expressed as an access delay. Within the range of 0...62, one step correlates to a distance of 550 meters. If the access delay of the channel request message exceeds the given maximum, the call attempt is rejected. When the parameter is given a value from 63 to 255, call attempts are never rejected • radiusExtention With this parameter you define the radius extension of an extended cell
46 © Nokia Siemens Networks Radio Resource management
47 © Nokia Siemens Networks Channel request (RACH) MS NETWORK Immediate assignment Immediate assignment (AGCH) Service request (SDCCH) Service request Authentication request (SDCCH) Authentication response (SDCCH) Authentication Ciphering mode command (SDCCH) Ciphering mode complete (SDCCH) Ciphering mode setting Setup (SDCCH) Call initiation Call proceeding (SDCCH) Assignment command (SDCCH) Assignment complete (FACCH) Assignment of traffic channel Alert (FACCH) Call confirmation Connect (FACCH) Connect acknowledged (FACCH) Call accepted Signalling (Mobile Originating Call) Idle parameter Dedicated parameter
48 © Nokia Siemens Networks Page request (PCH) MS NETWORK Immediate assignment Channel request (RACH) Page response (SDCCH) Service request Authentication request (SDCCH) Authentication response (SDCCH) Authentication Ciphering mode command (SDCCH) Ciphering mode complete (SDCCH) Ciphering mode setting Setup (SDCCH) Call initiation Call confirmation (SDCCH) Assignment command (SDCCH) Assignment complete (FACCH) Assignment of traffic channel Alert (FACCH) Call confirmation Connect (FACCH) Connect acknowledged (FACCH) Call accepted Immediate assignment (AGCH) Signalling (Mobile Terminating Call) Idle parameter Dedicated parameter
49 © Nokia Siemens Networks Disconnect MS NETWORK Call clearing Release Channel release Release Release complete Disconnect MS NETWORK Call clearing Release Channel release Release Release complete Network initiated MS initiated Signalling (Call Release)
50 © Nokia Siemens Networks MS capabilities Channel rate : full, half, dual, multi rate Speech codecs : normal FR, normal HR, EFR, AMR FR, AMR HR, doubleHR(OSC) MSC demands A interface circuit allocated for call BTS demands Speech codec capabilities TCH configuration Current resources Homogeneous use of TRXs and radio time slots Large free groups of radio time slots for high loaded HSCSD BTS Standard TCH Allocation (General Criteria)
51 © Nokia Siemens Networks TCH Allocation 2 TRX=16 channels 0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 12:00:00 AM 2:00:00 AM 4:00:00 AM 6:00:00 AM 8:00:00 AM 10:00:00 AM 12:00:00 PM 2:00:00 PM 4:00:00 PM 6:00:00 PM 8:00:00 PM 10:00:00 PM RTSL SDCCH BCCH PEAK_PERMANENT_GPRS_CH AVE_GPRS_CHANNELS AVE_TCH_BUSY_FULL 0 1 2 3 4 5 6 7 TRX1 BCCH SDCCH SDCCH V/D V/D V/D V/D V/D TRX2 SDCCH SDCCH V/D V/D V/D V/D D D TIME AVE_SDCCH (SDCCH/8) AVE_BUSY_SDCCH PEAK_BUSY_SDCCH AVE_AVAIL_FULL_TCH AVE_TCH_BUSY_FULL PEAK_BUSY_TCH TCH_PEAK_BUSY_FULL TCH_PEAK_BUSY_HALF SDCCH_CONG_TIME(sec) TCH_FR_RADIO_CONGESTION_TIME (sec) TCH_HR_RADIO_CONGESTION_TIME (sec) AVE_GPRS_CHANNELS PEAK_GPRS_CHANNELS PEAK_PERMANENT_GPRS_CH 12:00:00 AM 32 5.0 18 6.3 4.0 9 9 0 0 8.48 0 4.7 8 2 1:00:00 AM 32 3.1 13 6.8 3.4 9 9 0 0 1.41 0 4.2 9 2 2:00:00 AM 32 1.7 12 5.2 2.9 7 7 0 0 0 0 5.8 9 2 3:00:00 AM 32 1.5 12 6.2 1.4 7 7 0 0 0 0 4.8 9 2 4:00:00 AM 32 1.6 10 8.0 1.7 5 5 0 0 0 0 3.0 9 2 5:00:00 AM 32 8.8 32 5.7 0.8 6 6 0 559 0 0 5.3 9 2 6:00:00 AM 32 5.2 18 4.3 1.1 6 6 0 0 0 0 6.7 9 2 7:00:00 AM 32 6.5 23 8.5 2.6 8 8 0 0 0 0 2.5 6 2 8:00:00 AM 32 4.8 20 6.6 2.2 7 7 0 0 0 0 4.4 9 2 9:00:00 AM 32 4.3 20 6.8 2.4 8 8 0 0 0 0 4.3 9 2 10:00:00 AM 32 5.2 32 7.5 2.6 9 9 0 2 0.21 0 3.5 9 2 11:00:00 AM 32 5.9 18 6.3 2.9 9 9 0 0 8.98 0 4.7 9 2 12:00:00 PM 32 5.9 19 6.8 3.9 9 9 0 0 13.52 0 4.2 8 2 1:00:00 PM 32 7.3 24 6.4 3.4 9 9 0 0 8.96 0 4.6 9 2 2:00:00 PM 32 6.8 30 6.2 3.9 9 9 0 0 44.05 0 4.8 8 2 3:00:00 PM 32 7.1 21 6.7 4.7 9 9 0 0 64.18 0 4.3 9 2 4:00:00 PM 32 7.7 23 6.6 3.9 9 9 0 0 25.61 0 4.4 8 2 5:00:00 PM 32 8.5 23 6.7 3.9 9 9 0 0 34.51 0 4.3 9 2 6:00:00 PM 32 10.7 27 8.3 5.9 9 9 0 0 320.58 0 2.7 7 2 7:00:00 PM 32 11.1 28 8.4 5.6 9 9 0 0 217.77 0 2.6 9 2 8:00:00 PM 32 10.4 30 7.8 5.5 9 9 0 0 284.15 0 3.2 8 2 9:00:00 PM 32 9.3 26 7.5 5.3 9 9 0 0 217.65 0 3.5 8 2 10:00:00 PM 32 8.3 22 7.5 5.2 9 9 0 0 185.36 0 3.5 9 2 11:00:00 PM 32 5.8 21 6.8 4.6 9 9 0 0 89.61 0 4.2 9 2 How can be optimized?
52 © Nokia Siemens Networks Channel allocation ( For each TS) Each TRX – have its own Quality both DL and UL and TRX with bad quality (UL and DL) will result bad KPI on respective TRX Placing each Time Slot (BCCH, SDCCH, TCH and PDTCH) properly will result good KPI (SDSR, DCR, HOSR TBF Completion rate) Shitting SDCCH, BCCH can improve SDSR and DCR
53 © Nokia Siemens Networks Measurement of uplink receive level on idle channels = uplink interference Averaging over interferenceAveragingProcessAverPeriod (AP) = 1..32 SACCH periods Classification into interference bands based on interferenceAveragingProcess (BO1..BO4) = -110..-47 dBm BSC tries to allocate TCH from best interference band (can be requested by MSC) If not available, BSC tries to take TCH from next band 0 7 1 2 3 4 5 6 rxLevUL = -75 dBm BO5 –47 (fixed) BO0 –110 (fixed) BO4 -90 BO3 -95 BO1 -105 BO2 -100 Standard TCH Allocation (Interference Bands)
54 © Nokia Siemens Networks Priority for TCH from BCCH TRX BCCH transmitted permanently -> no additional interference in network Planned to be least interfered channels Priority for TCH from other TRX BCCH TRX does not hop in case of RF hopping -> hopping gain only for other TRX Parameter trxPriorityInTCHAlloc (TRP) 0 = no priority 1 = priority for BCCH TRX 2 = priority for other TRX 3 = priority for BCCH TRX for non-AMR users, priority for other TRX for AMR users Prioritized TCH Allocation (TRP) Whole band , 50 channels 1 ch=200kHz BCCH, 30 channels TCH, 20 channels All 50 channels for BCCH and TCH Case1 Case2
55 © Nokia Siemens Networks Enables to differentiate Rx level requirement for: • MS camping to the network /RxLev Access Min • MS accessing to TCH /RX level based TCH access RX level based TCH allocation method • RX Level measured by the MS is used to determine whether the BTS is acceptable for TCH allocation • TCH allocation for emergency calls is not restricted due to low RX level Provides better drop call meters and better performance of MSs • MSs having too low Rx levels are not allowed to camp the network By separating camping and TCH access thresholds the operator will be able to provide the maximum camping footprint RX level based TCH Allocation (RXP) Note! RG20 feature – Energy optimized TCH allocation
56 © Nokia Siemens Networks Allows to define minimum C/N ratios separately for each call type (AMR FR, AMR HR, EFR/FR, HR and 14.4 data) Parameter values ‘RX level based TCH access’: 0: RX level based TCH access is not used (C/N definitions not in use) 1: RX level based TCH access is used in call setup 2: RX level based TCH access is used in call setup and in handovers Downlink RX Level -> TCH Access Soft blocking C/N FR: 0…63dB/ def: 12dB Soft Blocking C/N HR: 0…63dB/ def: 14dB Soft blocking C/N AMR FR: 0…63dB/ def: 7dB Soft blocking C/N AMR HR: 0…63dB/ def: 12dB Soft blocking C/N 14.4 : 0…63dB/ def: 14dB RX level based TCH Allocation (RXTA)
57 © Nokia Siemens Networks Priorities No TCH available for call set up / handover -> request put into queue Different kinds of requests can have different priorities queuePriorityUsed (QPU) Y/N enables use of priorities queueingPriorityCall (QPC) 1..14 priority for call set up request queuePriorityNonUrgentHo (QPN) 1..14 priority for non urgent handover (power budget, umbrella, slow moving MS, traffic reason) request queueingPriorityHandover (QPH) 1..14 priority for urgent handover (all other) request Queue length and time maxQueueLength (MQL) 0..100% percentage of number of TCHs handled by BTS timeLimitCall (TLC) 0..15 s time a call set up request is kept in the queue 0 = queuing is disabled timeLimitHandover (TLH) 0..10 s time a handover request is kept in the queue 0 = queuing is disabled Queuing (Parameters)
58 © Nokia Siemens Networks Conditions Timers set to values > 0 User of priorities enabled Queue not full with requests of equal or higher priority than the current one Queuing of call set up requests Reservation of SDCCH resources -> SDCCH easily overbooked -> blocking of services like SMS or location update Queuing (Entering the Queue)
59 © Nokia Siemens Networks Handover request queued by target BTS Handover timers hoPeriodPBGT and hoPeriodUmbrella stopped Measurement processing and averaging continues as usual Intra BSC handover Inter BSC handover Queuing possibility checked for all possible target cells Order according conventional ranking Target BTS given by MSC by handover request message Queuing (Handover)
60 © Nokia Siemens Networks With TCH allocation Release of busy TCH  Check of queue from top to bottom for best matching request  If TCH allocation possible, request removed from queue Without TCH allocation Queuing timer expires Request of higher priority enters full queue Queuing (Leaving the Queue)
61 © Nokia Siemens Networks Directed Retry Timer maxTimeLimitDirectedRetry expires  call cleared, even if still in queue Queuing timer expires  target cell evaluation continues, if directed retry timer is still running Queuing (Together with Directed Retry)
62 © Nokia Siemens Networks BTS does not receive measurement report on SACCH for running call for the first time Counter initialised with value of radioLinkTimeout (4,8,..64 SACCH periods) SACCH not received again Counter decremented by 1 SACCH received again Counter incremented by 2 (but not beyond initial value) Counter has value 0 Call release due to radio link time out Example: short tunnel Dropped Call Control Radio Link Timeout
63 © Nokia Siemens Networks • RLT is based on SACCH deletion but SACCH is though not using a dynamic codec like voice in AMR, which means: • Using the EFR RLT value an AMR customer can have the call dropped because RLT = 0 when still the FER is good • RLT is not anymore reliable with the same value in AMR than in EFR • Due to the fact that the FER performance is different when comparing AMR calls to EFR calls, the Radio Link Timeout need to be defined separately for AMR • The Radio Link Timeout parameters for AMR are ARLT and AHRLT. The principle of these is the same than in the RLT but it is used only for the AMR capable mobile stations. ARLT & AHRLT are not supported in Talk Family base stations. Dropped Call Control Radio Link Timeout
64 © Nokia Siemens Networks Radio link timeout occurs callReestablishmentAllowed (RE) set to Y Receive level of BCCH measured for serving and adjacent cell Averaged over 5 s Strongest cell considered BCCH decoded C1 cell selection criterion fulfilled Cell not barred Cell belongs to selected PLMN Attempt to re-establish call Successful within 20s *  call re-established Not successful within 20s *  call released Example: long tunnel Dropped Call Control Call Reestablishment * MAX WAIT TIME OF RE-ESTAB REQ is a modifiable timer in MSC
65 © Nokia Siemens Networks NPT parameter related (Idle Parameter)
66 © Nokia Siemens Networks Measurement Processing
67 © Nokia Siemens Networks Measurement Report Standard • Rx level • Rx quality • Level & BSIC of up to 6 neighbours • 3G cells Enhanced Standard + following: • DL frame erasure rate • DTX bit error probability • Real time difference serving – adjacent cell • 3G cells • Control over reporting priority Measurements Idle mode • MS listens to BCCH Dedicated mode • MS sends DL measurement report on SACCH • BTS performs UL measurements Introduction
68 © Nokia Siemens Networks Measurement Report Standard • Rx level • Rx quality • Level & BSIC of up to 6 neighbours • 3G cells Enhanced Standard + following: • DL frame erasure rate • DTX bit error probability • Real time difference serving – adjacent cell • 3G cells • Control over reporting priority Measurements Idle mode • MS listens to BCCH Dedicated mode • MS sends DL measurement report on SACCH • BTS performs UL measurements Introduction
69 © Nokia Siemens Networks P (dBm) P (dBm) LEV No offset 10 dB offset -110 -100 0 -109 -99 1 -108 -98 2 . . . . . . . . . -49 -39 61 -48 -38 62 -47 -37 63 Activation of offset to code high levels scaleOrd (SCO)(SEG)(0,1,2)(0) 0 = no offset used 1 = offset used in general 2 = MS decides automatically about offset Coding of Rx Level
70 © Nokia Siemens Networks BER (%) BER (%) QUAL RANGE MEAN < 0.2 0.14 0 0.2-0.4 0.28 1 0.4-0.8 0.57 2 0.8-1.6 1.13 3 1.6-3.2 2.26 4 3.2-6.4 4.53 5 6.4-12.8 9.05 6 > 12.8 18.1 7 Coding of Rx Quality Average window = 4 Quality samples 0,0,7,0 WRONG!!: (0+0+7+0)/4 = 1.75 (wrong!!) RIGHT: (0.14+0.14.+18.1+0.14)/4 = 4.63 (right!!) => corresponds to Qual5
71 © Nokia Siemens Networks BEP BER (%) QUAL VALUE RANGE 22..31 < 0.2 0 19..21 0.2-0.4 1 16..18 0.4-0.8 2 13..15 0.8-1.6 3 10..12 1.6-3.2 4 7..9 3.2-6.3 5 4..6 6.3-12.6 6 0..3 > 12.6 7 Mapping of BEP to RX Quality
72 © Nokia Siemens Networks X axis: frame erasure rate (< 1%, 1-5 %, 5-10 %, 10-15 %, > 15 %) Y axis: RX quality (0..7) Z axis: Percentage of measurements for each FER category Frame Erasure Rate for Handover / Power Control Decision fepInPcHoUse (FPHO)(BSC)(Y,N)(N) Mapping of FER to RX Quality
73 © Nokia Siemens Networks • Decoding of BCCH • for serving (camped) cell every 30 s • for adjacent cells every 5 min • Pre-synchronization and decoding of BSIC • for adjacent cells every 30 s • Adjacent cell list • Updating every 60 s • BCCH decoding of new cell in 30 s MS Measurement Execution Idle Mode
74 © Nokia Siemens Networks • Measures RX level and quality for serving cell • Detects whether DTX is used 26 FRAME MULTIFRAME = 120 ms TDMA FRAMES TCH SACCH IDLE • Measures frequencies of adjacent cells • BSIC decoding for at least one adjacent cell • Pre-synchronization on SCH TDMA FRAMES 4.615 ms SACCH PERIOD = 480 ms RX TX RX TX RX TX MEAS MEAS MEAS MS Measurement Execution Dedicated Mode I
75 © Nokia Siemens Networks Power Control
76 © Nokia Siemens Networks • Longer service time of battery • Realization of power class • Supported by default on UL Reduced interference on DL/UL Activation of DL power control powerCtrlEnabled (PENA) Y,N Power control independent • for DL and UL • for each call Power Control Motivation
77 © Nokia Siemens Networks 30 dB Range Power class dependent range Attenuations Power Values Maximum MS output power msTxPwrMaxGSM (PMAX1) 5..39 dBm GSM 900 TCH msTxPwrMaxGSM1x00 0..36/32,33 dBm GSM 1800/1900 TCH (PMAX2) msTxPwrMaxCCH (TXP1) 5..39 dBm GSM 900 CCH msTxPwrMaxCCH1x00 0..30 dBm GSM 1800 CCH (TXP2) 0..32 dBm GSM 1900 CCH Minimum MS output power minMSTxPower (PMIN) 5..39 dBm GSM 900 0..36 dBm GSM 1800 0..32 dBm GSM 1900 Maximum BTS output power (by minimum attenuation) bsTxPwrMax (PMAX1) 0..30 dB GSM 900 bsTxPwrMax1x00 (PMAX2) 0..30 dB GSM 1800/1900 Minimum MS output power (by maximum attenuation) bsTxPowerMin 0..30 dB Power Control Parameter Output Power Limits
78 © Nokia Siemens Networks Fixed increment step size • pcIncrStepSize (INC) 2,4,6 dB Fixed decrement step size • pcRedStepSize (RED) 2,4,6 dB Desired power level can be achieved in 1 or 2 commands Yes Fixed step size No Variable step size Power Control Parameters Power Change Step Sizes
79 © Nokia Siemens Networks UL Level UL Quality <Av_RXQUAL_UL> <Av_RXLEV_UL> DL Level DL Quality <Av_RXQUAL_DL> <Av_RXLEV_DL> POWER CONTROL UPLINK THRESHOLD COMPARISON POWER CONTROL DOWNLINK Power control interval powerCtrlInterval (INT) 0..31 s Power Control Strategy Measurement Averaging
80 © Nokia Siemens Networks threshold Actual average samples Nx samples Less than Px samples exceed threshold No power change triggered Nx samples Px samples are equal to or exceed threshold Power change triggered Signal level thresholds pcUpperThresholdLevelDL/UL (UDR/UUR) -110..-47 dBm pcLowerThresholdLevelDL/UL (LDR/LUR) -110..-47 dBm Signal quality thresholds pcUpperThresholdQualDL/UL (UDR/UUR) 0..7 pcLowerThresholdQualDL/UL (LDR/LUR) 0..7 Number of average samples (for each threshold) Nx 1..32 Px 1..32 Power change step size estimation Power Control Strategy Triggering
81 © Nokia Siemens Networks Exceeded threshold Action Reason pcUpperThresholdLevelDL BTS power decrease Signal level pcLowerThresholdLevelDL BTS power increase Signal level pcUpperThresholdLevelUL MS power decrease Signal level pcLowerThresholdLevelUL MS power increase Signal level pcUpperThresholdQualDL BTS power decrease Signal quality pcLowerThresholdQualDL BTS power increase Signal quality pcUpperThresholdQualUL MS power decrease Signal quality pcLowerThresholdQualUL MS power increase Signal quality Power Control Strategy Scenarios
82 © Nokia Siemens Networks AMR Power Control Exceeded threshold Action Reason AMR Power Control FR PC Lower Threshold DL Rx Qual BTS power increase Poor DL signal quality AMR Power Control FR PC Lower Threshold UL Rx Qual MS power increase Poor UL signal quality AMR Power Control FR PC Upper Threshold DL Rx Qual BTS power decrease Good DL signal quality AMR Power Control FR PC Upper Threshold UL Rx Qual MS power decrease Good UL signal quality AMR Power Control HR PC Lower Threshold DL Rx Qual BTS power increase Poor DL signal quality AMR Power Control HR PC Lower Threshold UL Rx Qual MS power increase Poor UL signal quality AMR Power Control HR PC Upper Threshold DL Rx Qual BTS power decrease Good DL signal quality AMR Power Control HR PC Upper Threshold UL Rx Qual MS power decrease Good UL signal quality AMR FR AMR HR Details in chapter on AMR
83 © Nokia Siemens Networks POC Quality Signal level Increase due to bad Signal level Decrease Due to good Signal level Increase due to Bad quality Decrease due to good quality Qual 0 Qual 7 -110 dB -47 dB Lower Level(-90) Upper Level(-80) Upper Quality(1) Lower Quality(3) No action Ping pong effect
84 © Nokia Siemens Networks POC Quality Signal level Increase due to level Decrease Due to level Increase due to quality Decrease due to quality Qual 0 Qual 7 -110 dB -47 dB Lower Level Upper Level Upper Quality Lower Quality 6dB No action
85 © Nokia Siemens Networks POC and HOC (UL) Quality Signal level Qual 0 Qual 7 -110 dB -47 dB UL Level HO Threshold No action UL Quality HO Threshold When UL quality HO is triggered • Should MS be sent full power? •What about UL level
86 © Nokia Siemens Networks Power Control Summary Lower Level Upper Level Upper Quality Lower Quality No action Power decrease due to level Power increase due to quality Power increase due to level or quality Power increase due to quality Power decrease due to level or quality Power increase due to level Power decrease due to quality 6 dB Power increase due to level Qual 0 Qual 7 -110 dBm -47 dBm
87 © Nokia Siemens Networks pcLowerThresholdsLevelDL/UL Power control triggered UL: Power increase of MS DL: Power increase of BTS RXLEV_DL/UL > pcLowerThresholdLevelDL/UL - 2 powerIncrStepSize Yes Fixed step size PWR_INCR_STEP = powerIncrStepSize No Variable step size PWR_INCR_STEP = pcLowerThresholdLevelDL/UL – RXLEV_UL/DL Actual receive level RXLEV_DL/UL Power Increase Due to Signal Level For MS & BTS
88 © Nokia Siemens Networks pcUpperThresholdsLevelDL Power control triggered Power decrease Yes Fixed step size PWR_DECR_STEP = powerDecrStepSize No Variable step size PWR_DECR_STEP = Min (RXLEV_DL – pcUpperThresholdLevelDL, 10) Actual received level RXLEV_DL RXLEV_DL < pcUpperThresholdLevelDL + 2 powerDecrStepSize OR variableDLStepUse (VDLS) = No Power Decrease Due to Signal Level For BTS
89 © Nokia Siemens Networks pcUpperThresholdsLevelUL Power control triggered Power decrease Yes Fixed step size PWR_DECR_STEP = powerDecrStepSize No Variable step size PWR_DECR_STEP = RXLEV_UL – pcUpperThresholdLevelUL Actual received level RXLEV_UL RXLEV_UL < pcUpperThresholdLevelUL + 2 powerDecrStepSize Power Decrease Due to Signal Level For MS
90 © Nokia Siemens Networks pcLowerThresholdsQualDL/UL Power control triggered UL: Power increase of MS DL: Power increase of BTS Actual receive quality RXQUAL_DL/UL Variable step size based on actual quality PWR_INCR_STEP = (1 + Max (0,QUAL)) * powerIncrStepSize QUAL = RXQUAL_DL/UL – pcLowerThresholdQualDL/UL Step size based on actual level Take algorithm for power increase due to signal level Take largest step size Power Increase Due to Signal Quality For MS & BTS
91 © Nokia Siemens Networks pcUpperThresholdsQualDL/UL Power control triggered Actual received quality RXQUAL_DL/UL Actual RXLEV_DL/UL – pcLowerThresholdLevelDL/UL < 6 dB Yes No No power decrease Avoid ping pong effect Power decrease Take algorithm for power decrease due to signal level (different for MS & BTS power decrease) Power Decrease Due to Signal Quality For MS & BTS with No Power Optimization
92 © Nokia Siemens Networks NPT parameter related (POC Parameter) Should be greater than HOC
93 © Nokia Siemens Networks Handover Control
94 © Nokia Siemens Networks Intra cell Only other carrier / timeslot Inter cell Intra BSC Inter BSC Intra MSC Inter MSC Inter PLMN Global Cell ID required MCC + MNC + LAC + CI Germany Czech Republic Intra PLMN Simple Cell ID required LAC + CI Handover Types
95 © Nokia Siemens Networks Multi Layer Network Types Coverage Layer: Gives access to the network Capacity Layer: Provides additional capacity and allows traffic distribution Macro cells Micro cells Intelligent Underlay Overlay Different frequencies for high / low power TRx Normal frequency Super reuse frequency GSM 900 cell GSM 1800 cell
96 © Nokia Siemens Networks threshold Actual average samples Nx samples Less than Px samples >= threshold No handover triggered Nx samples Px samples are >= threshold handover triggered Signal interference thresholds hoThresholdsInterferenceDL/UL (IDR/IUR) -110..-47 dBm Signal quality thresholds hoThresholdsQualDL/UL (QDR/QUR) 0..7 Signal level thresholds hoThresholdLevelDL/UL (LDR/LUR) -110..-47 dBm hoThresholdRapidLevelUL (RPD) -110..-47 dBm MS speed thresholds upper/lowerSpeedLimit (USL/LSL) 0..255 (unit = 2km/h) Number of average samples Nx 1..32 Px 1..32 Target cell selection Handover Strategy Triggering Trigger Point – When the set threshold has been met or exceeded Px times of Nx times
97 © Nokia Siemens Networks More than one handover criterion fulfilled -> process of higher priority performed Handover and power control criteria fulfilled -> handover performed 1) Interference (uplink or downlink) 2) Intra-segment inter-band because of downlink level (from higher to lower frequency band) 3) Uplink quality 4) Downlink quality 5) AMR unpacking (uplink level and also uplink unpacking quality triggers) 6) Uplink level 7) AMR unpacking (downlink level and also downlink unpacking quality triggers) 8) Downlink level 9) Coverage based inter-system handover to WCDMA RAN 10) IMSI-based inter-system handover to WCDMA RAN 11) IMSI-based handover 12) DTM-based handover to WCDMA RAN 13) Inter-system handover to WCDMA RAN 14) MS-BS distance (maximum or minimum) 15) Turn-around-corner MS 16) Rapid field drop 17) Slow/fast-moving MS 18) Umbrella 19) Power budget 20) DTM-based handover to a GSM DTM cell 21) BSC-initiated TRHO 22) IUO 23) Intra-segment HO based on load 24) AMR packing because of good uplink and downlink quality 25) AMR unpacking because of bad uplink or downlink quality 26) PC because of lower quality thresholds (uplink and downlink) 27) PC because of lower level thresholds (uplink and downlink) 28) PC because of upper quality thresholds (uplink and downlink) 29) PC because of upper level thresholds (uplink and downlink) Handover Strategy (Priorities) Exercise: Whu UL has many times higher priority than DL?
98 © Nokia Siemens Networks HO due to UL/DL Quality IF AV_RXQUAL_DL_HO >= HoThresholdsQualDL THEN Handover cause Downlink quality IF AV_RXQUAL_UL_HO >= HoThresholdsQualUL THEN Handover cause Uplink quality Target cells is listed based on below criteria 1. AV_RXLEV_NCELL(n) > RxLevMinCell(n) + MAX(0,Pa) 2.AND IF EnableHoMarginLevQual(n)= Yes THEN AV_RXLEV_NCELL(n) > AV_RXLEV_DL_HO + (BsTxPwrMax - BS_TXPWR) + HoMarginQual(n) 3. ELSE PBGT(n) > HoMarginPBGT(n) (2) Order of preference of target cells PRIORITY(n) = HoPriorityLevel(n) - HoLoadFactor(n) HoLoadFactor value is taken into account when BTSLoadThreshold is exceeded. Interval between handovers and handover attempts Listing set of target cell Priority of target cell Timer of source cell
99 © Nokia Siemens Networks HO due to UL/DL LEVEL IF AV_RXLEV_DL_HO<= HoThresholdsLevDL THEN Handover cause Downlink level IF AV_RXLEV_UL_HO<= HoThresholdsLevUL THEN Handover cause Uplink level Target cells is listed based on below criteria 1. AV_RXLEV_NCELL(n) > RxLevMinCell(n) + MAX(0,Pa) 2.AND IF EnableHoMarginLevQual(n)= Yes THEN AV_RXLEV_NCELL(n) > AV_RXLEV_DL_HO + (BsTxPwrMax - BS_TXPWR) + HoMarginLev(n) 3. ELSE PBGT(n) > HoMarginPBGT(n) (2) Order of preference of target cells PRIORITY(n) = HoPriorityLevel(n) - HoLoadFactor(n) HoLoadFactor value is taken into account when BTSLoadThreshold is exceeded. GUARD_TIME = 2 * HoPeriodPBGT (Ho Due PBGT) GUARD_TIME = 2 * HoPeriodUmbrella (HO Due to Umbrella) Listing set of target cell Priority of target cell Timer of source cell
100 © Nokia Siemens Networks HO due to Fast/Slow moving MS MS speed in relation to cell size: IF MsSpeedDetectionState= 0 AdjCellLayer(n) = Lower FastMovingThreshold(n)> 0 Measured MS speed: IF AV_MS_SPEED <= LowerSpeedLimit THEN MS is slow-moving IF AV_MS_SPEED >= UpperSpeedLimit THEN MS is fast-moving AV_RXLEV_NCELL(n) > RxLevMinCell(n) + MAX (0, Pa) THEN RXLEV_CNT(n) = RXLEV_CNT(n) + 2 ELSE RXLEV_CNT(n) = RXLEV_CNT(n) - 1 IF RXLEV_CNT(n) >= FastMovingThreshold(n) THEN Handover cause Slow-moving MS Target cell evaluation: AdjCellLayer(n) = Lower/Upper AND AV_RXLEV_NCELL(n) > HoLevelUmbrella(n) (1') Handover to low layer cell is not possible if maximum power capability of MS exceeds gsm/dcsMicrocellThreshold IF MsSpeedDetectionState= 0 THEN Handover Cause Fast/Slow-moving MS ELSE Scale averaging parameters
101 © Nokia Siemens Networks HO due to Fast/Slow moving MS (Count) Target cell evaluation: AdjCellLayer(n) = Lower/Upper AND AV_RXLEV_NCELL(n) > HoLevelUmbrella(n) (1') Handover to low layer cell is not possible if maximum power capability of MS exceeds gsm/dcsMicrocellThreshold Order of preference of target cells PRIORITY(n) = HoPriorityLevel(n) - HoLoadFactor(n) HoLoadFactor value is taken into account when BTSLoadThreshold is exceeded Interval between handovers and handover attempts
102 © Nokia Siemens Networks HO due to Umbrella IF EnableUmbrellaHO= Yes HoPeriodUmbrella - interval between the umbrella handover threshold comparisons Umbrella handover and target cell evaluation: AV_RXLEV_NCELL(n) > HoLevelUmbrella(n) (1') AND ( [(P >= macro_thr) AND (pwr(n) >= macro_thr)] OR [(P <= micro_thr) AND (pwr(n) <= micro_thr)] OR [(P < macro_thr) AND (pwr(n) < macro_thr) AND (P > micro_thr) AND (pwr(n) > micro_thr)] ) Interval between handovers and handover attempts Order of preference of target cells PRIORITY (n) = HoPriorityLevel(n) - HoLoadFactor(n) HoLoadFactor value is taken into account when BTSLoadThreshold is exceeded.
103 © Nokia Siemens Networks Umbrella handover to 1800 cell A B 900 ‘Macro’ hoLevelUmbrella = -85 dBm gsmMacrocellThreshold = 33 dBm dcsMacrocellThreshold = 33 dBm Threshold RX level handover –95 dBm Threshold umbrella handover –85 dBm PTCH (msTxPwrMax(n)) = 30 dBm -> micro cell PMAX = 30 dBm -> handover to micro cell only hoThresholdLevelDL = -95 dBm 1800 ‘Micro’ RX level handover back to 900 cell Umbrella +FMT Handover Example After FMT>1 (example)
104 © Nokia Siemens Networks HO due to PBGT IF EnablePowerBudgetHO= Yes HoPeriodPBGT - interval between the power budget threshold comparisons Power budget and target cell evaluation: AV_RXLEV_NCELL(n) > RxLevMinCell(n) + MAX(0, Pa) (1) AND PBGT(n) > HoMarginPBGT(n) (2) PBGT(n) = (B - AV_RXLEV_DL_HO - (BsTxPwrMax - BS_TXPWR)) - (A - AV_RXLEV_NCELL(n)) Interval between handovers and handover attempts Order of preference of target cells PRIORITY (n) = HoPriorityLevel(n) - HoLoadFactor(n) HoLoadFactor value is taken into account when BTSLoadThreshold is exceeded.
105 © Nokia Siemens Networks Serving cell: A HO candidate target cells: B, C, D All cells have the following parameter set: rxLevMinCell= -99 dBm msTxPwrMax= 33 dBm btsTxPwrMax= 42 dBm hoMarginPBGT= 6 dB Target cell ‘hoPriorityLevel’: B priority: 4 C priority: 3 D priority: 3 Target cell ‘HOLoadFactor’: B load factor: 2 C load factor: 1 D load factor: 1 Target cell B is considered overloaded BTS BTS BTS BTS BSC A B C D Which cell (B/C/D) will be chosen as target for the Power Budget HO? AV_RXLEV_NCELL (B)= -80 dBm AV_RXLEV_NCELL (C)= -83 dBm AV_RXLEV_NCELL (D)= -85 dBm Serving cell A: AV_RXLEV_DL_HO= -92 dBm BTS_TX_PWR= 42 dBm Exercise Solution Power Budget Handover Exercise
106 © Nokia Siemens Networks enablePowerBudgetHo = Yes & enableUmbrellaHo = Yes Power budget handover to cells of the same layer Umbrella and FMT handover to cells of different layer Combined Umbrella & Power Budget HO Overview macrocells microcells RR PBGT,RR PBGT,RR UMBR+FMT UMBR umbrella HO RR radio reason HO PBGT power budget HO
107 © Nokia Siemens Networks UPPER layer (macro) SAME layer (serving layer) LOWER layer (micro) Predefinition of layer possible by adjCellLayer (ACL) Three layers visible relative to serving cell Used for target cell evaluation • Combined umbrella and power budget • Handover based on MS speed • Fast moving MS handling in macro cell N (no predefinition) Combined Umbrella & Power Budget HO Adjacent Cell Classification
108 © Nokia Siemens Networks HO due to Directed Retry IF DirectedRetryUsed = Yes Handover from SDCCH of serving cell to TCH of adjacent cell due to congestion minTimeLimitDR – Target cell evaluation started MaxTimeLimitDR - Target cell evaluation stopped Target Cell evaluation IF DirectedRetryMethod = 1 THEN AV_RXLEV_NCELL(n) > RxLevMinCell(n) + MAX(0, Pa) (1) AND AV_RXLEV_NCELL(n) > DRThreshold ELSE AV_RXLEV_NCELL(n) >RxLevMinCell(n) + MAX (0,Pa) Interval between handovers and handover attempts
109 © Nokia Siemens Networks No TCH available during call set up in serving cell -> handover to TCH of other cell Must be enabled with drInUse (DR) Y/N Thresholds to be exceeded by target cell according condition (1a) drMethod (DRM) 0/1 Defined type of threshold rxLevMinCell -110..-47 dBm Used if drMethod = 0 drThreshold (DRT) -110..-47 dBm Used if drMethod = 1 and drThreshold > rxLevMin Cell Timers (to be counted from TCH assignment) minTimeLimitDirectedRetry (MIDR) 0..14 s No target cell evaluation allowed maxTimeLimitDirectedRetry (MADR) 1..15 s Target cell evaluation allowed SDCCH TCH congested Time Assignment Request minTimeLimitDR maxTimeLimitDR DR not allowed DR allowed Directed Retry Parameters
110 © Nokia Siemens Networks HO due to Rapid Field Drop IF HoThresholdsRapidLevUL/Px > 0 IF Px number of RXLEV_UL measurement < HoThresholdsRapidLevUL THEN Handover cause Rapid field drop Target cell evaluation IF ChainedAdjacentCell(n) = Yes AND AV_RXLEV_NCELL(n) > RxLevMinCell(n) + MAX(0, Pa) (1) Order of preference of target cells: The target cells are ranked according to radio link properties (equation 1).
111 © Nokia Siemens Networks Chained Cell 1st 2nd Serving cell hoThresholdRapidLevUL = -93 dBm hoThresholdRapidLevUlN = 2 chainedAdjacentCell = Y Threshold rapid field drop handover –93 dBm Handover triggered Serving Cell Rapid Field Drop Handover Example
112 © Nokia Siemens Networks NPT parameter related (HOC Parameter) Should be lower than POC
113 © Nokia Siemens Networks NPT parameter related (ADCE Parameter)
114 © Nokia Siemens Networks NPT parameter related (ADCE Parameter)
115 © Nokia Siemens Networks KPI case
116 © Nokia Siemens Networks Optimization Principle service quality cell coverage cell capacity Optimization and Tailoring Optimization process is a way to do changes in a network so that those network have maximum on Capacity, Coverage and Quality Excessive value RxLevAmi will improve KPI but coverage and quality will reduce Site with height >40m with total tilt =2 will have wide coverage but KPI will bad Site with FRL/FRU = 100% will have max capacity but have lower Quality
117 © Nokia Siemens Networks KPI- Rules, SDCCH Blocking SDCCH Blocking >X% Is dynamic sddch active Is dynamic sdcch reaching max values in some moment Is combined sdcch used yes yes Check unavailability in the cells, averarage available sdcch Availability OK Check sdcch blocking. Can sdcch capacity be added without tch blocking SDCCH blocking is high yes No Yes, remove combined sdcch No, check parameter Values and make corrections No, activate Dynamic sdcch Yes, make corrections Case closed No Yes, add sdcch capacity Add TRX and add Sdcch capacity sdcch Blocking is still high No Yes Is high sdcch traffic due to Location updates. If yes, can LU area be optimized? Check also PRAU parameter, can the value be increased? no Yes, Optimize LU area border no ND_211 ND_130 Cngt_2 Blck_5 Blck_5b ND_139,ND_131 ND_130, uav_22 csf_1a,csf_11 Ava_45a ND_211 c1154 ND_211 c2032 NetAct Planner P_nbcs_cc_pm ND_211 If SDCCH block high please check: 1.TCH/SDCCH availability 2.LOC design (SDCCH traffic profile) 3.Parameter (CRO, CRH, RxLevAmi)
118 © Nokia Siemens Networks KPI- Rules, SDCCH Drop SD DCR > 2% and SD DCRnum > 10 Drops due to RF Reasons Drops due to Abis Reasons No Drops due to A-interface Reasons No Drops due to other Reasons No Case Closed No RF Abis A Other Yes Yes Yes Yes Yes No ND_166 If SDCCH drop high please check: 1.DL/UL Quality 2.CRO/CRH, TRP setting 3.TA profile – overshooting possibility 4.SDCCH TS location
119 © Nokia Siemens Networks KPI- Rules, SDCCH Drop due to RF/Abis
120 © Nokia Siemens Networks KPI- Rules, SDCCH Drop due to Aif
121 © Nokia Siemens Networks KPI- Rules, SDCCH Drop (A) A >X% A interface problems. Alarms are checked and A interface trace is done Investigate alarms.If problems are not solved, activate A trace Any improvements Any problems found. Trace was long enough Make corrections Check ET lines in the BSC and transcoders /TCSM. Any problems Repair ET lines Still A drops or problems No Activate No No Yes Yes Alarms Are Solved Yes Trace was not long enough Case Closed Yes No Trace was Long enough. Not An problem was found Investigate log files. Check DX causes, see document Call related DX causes in BSC No alarms
122 © Nokia Siemens Networks KPI- Rules, SDCCH Drop (other) Other Lapd fails BTS fails Netw Act Fails User Act, bcsu, resets Still lots of other drops Check all the alarms signalling fails or PCM fails. Check transmissio / parameters Yes No TRX or BTS fails. Check that BTS/ TRX are working properly Yes No Configuration problems, check configurations Yes No Resets or act fail channel failures Yes No Case Closed No Yes
123 © Nokia Siemens Networks KPI- Rules, TCH Block
124 © Nokia Siemens Networks TCH SEIZURES FOR NEW CALL tch_norm_seiz /c1009 +tch_seiz_due_sdcch_con /c1099 (S5) +msc_i_sdcch_tch /c4044 +bsc_i_sdcch_tch /c4057 +cell_sdcch_tch /c4074 -tch_succ_seiz_for_dir_acc /c1165 (S7) -tch_re_est_assign /c57032 (S7) TCH DROPS AFTER SEIZURE TCH_RADIO_FAIL /c1013 +TCH_RF_OLD_HO /c1014 +TCH_ABIS_FAIL_CALL /c1084 +TCH_ABIS_FAIL_OLD /c1085 +TCH_A_IF_FAIL_CALL /c1087 +TCH_A_IF_FAIL_OLD /c1088 +TCH_TR_FAIL /c1029 +TCH_TR_FAIL_OLD /c1030 +TCH_LAPD_FAIL /c1046 +TCH_BTS_FAIL /c1047 +TCH_USER_ACT /c1048 +TCH_BCSU_RESET /c1049 +TCH_NETW_ACT /c1050 +TCH_ACT_FAIL_CALL /c1081 -tch_re_est_assign /c57032 (S7) DROPS CALLS 100 * % STARTED CONVERSATIONS conver_started /c57015 - msc_i_tch_tch /c4043 CONVERSATION DROPS dropped_calls /c57007 TCH DROPS AFTER ASSIGNMENT tch_new_call_assign /c57033 +tch_ho_assign /c57034 -tch_norm_release /c57035 -tch_ho_release /c57036 -tch_re_est_assign /c57032 TCH ASSIGNMENTS FOR NEW CALL tch_new_call_assign /c57033 -tch_re_est_assign /c57032 TCH RELEASE Disconnect from MS RF CHN RELEASE Rf_channel_release_ack from BTS CONVERSATION STARTED conn_ack to BTS TCH ASSIGNED Assignment_complete from BTS TCH SEIZED BSC allocates a TCH as a response to TCH request (Channel Activation) Dcr_8h Dcr_5a Dcr_3j KPI- Rules, TCH Drop Call Ratios
125 © Nokia Siemens Networks KPI- Rules, TCH Drop due to RF/Abis
126 © Nokia Siemens Networks KPI- Rules, TCH Drop due to RF Old
127 © Nokia Siemens Networks How unnecessary HO happened?? GSM DCS RxLev = -80dBm CRO=0 RxLev = -95dBm CRO=23 HO threshold = 20 On idle mode received level for GSM is -80 dBm while DCS can be (-95 dBm + (2 x 23) -49dBm On dedicated mode user will move from DCS to GSM due to DCS level already too low Unecessary HO can lead to DCR due to RF Old and HO fail (ex. Due to GSM blocking)
128 © Nokia Siemens Networks How unnecessary HO happened?? GSM/DCS A GSM/DCS B Call establish on cell A, then received level drop below HO threshold. User will move from cell A to cell B After user serve by cell B, cell B will ask user to do handover as received level on cell B already below HO threshold. RxLev = -95dBm HO threshold = 20 RxLevmin from A to B = 12 RxLev = -92dBm HO threshold = 20 RxLevmin from A to B = 12
129 © Nokia Siemens Networks KPI- Rules, TCH Drop due to Aif
130 © Nokia Siemens Networks KPI- Rules, TCH Drop due to Transcoder
131 © Nokia Siemens Networks KPI- Rules, TCH Drop DCR > X% and DCRnum > XX Drops due to RF Reasons Drops due to Abis Reasons No Drops due to A-interface Reasons No Drops due to Transcoder Reasons No Drops due to other Reasons No Case Closed No RF Abis A TR Other Yes Yes Yes Yes Yes Yes No ND_163
132 © Nokia Siemens Networks KPI- Rules, TCH Drop (Other) Other Lapd fails BTS fails Netw Act Fails User Act, bcsu, act fails Still lots of other drops Check all the alarms signalling fails or PCM fails. Check transmissio / parameters Yes No TRX or BTS fails. Check that BTS/ TRX are working properly Yes No Configuration problems, check configurations Yes No Resets or act fail channel failures Yes No Case Closed No Yes
133 © Nokia Siemens Networks KPI- Rules, coverage problems (dlq_2a and ulq_2a) Here are some examples how different kind of problems can be found Like Normal distribution HW Problem, TRX/combiner etc is broken Q0 Q1 Q2 Q3 Q4 Q5 Q6 Q7 Q0 Q1 Q2 Q3 Q4 Q5 Q6 Q7 CL10 10645 8516 6813 5450 4360 3488 2791 2232 CL10 5323 4258 3406 2725 2180 1744 4563 9765 CL15 47043 37634 30108 24086 9865 7543 5643 2345 CL15 11761 9409 7527 6022 9383 1886 65432 7675 CL20 56204 44963 35971 28776 6574 10324 345 65 CL20 14051 11241 8993 7194 18271 2581 65438 63562 CL30 200863 160690 128552 102842 17654 9876 145 28 CL30 33772 27017 21614 17291 75037 2469 18765 14523 CL40 12785 10228 8182 6546 456 112 24 23 CL40 3196 2557 2046 1636 4938 28 3659 2648 CL63 4583 1123 583 452 261 76 26 2 CL63 1146 281 146 113 3378 19 100 174 HW problem, Q4 amount of samples is strange Interference problem Q0 Q1 Q2 Q3 Q4 Q5 Q6 Q7 Q0 Q1 Q2 Q3 Q4 Q5 Q6 Q7 CL10 5323 4258 3406 2725 2180 1744 1395 1116 CL10 5323 4258 3406 2725 2180 1744 1395 1116 CL15 23522 18817 15054 12043 18765 3772 2822 1173 CL15 23522 13234 10588 8470 13234 10588 8470 6776 CL20 28102 22482 17985 14388 36542 5162 173 33 CL20 28102 2123 1699 1359 2123 1699 1359 1087 CL30 67544 54035 43228 34582 150073 4938 73 14 CL30 67544 3634 2908 2326 3634 2908 2326 1861 CL40 6393 5114 4091 3273 9876 56 12 12 CL40 6393 4091 3273 2618 4091 3273 2618 4532 CL63 2292 562 292 226 6756 38 13 1 CL63 9987 7543 4323 3454 2275 1187 876 654 HW Problem, TRX/combiner etc is broken Q0 Q1 Q2 Q3 Q4 Q5 Q6 Q7 CL10 200863 160690 128552 102842 17654 9876 7865 6543 CL15 16543 13234 10588 8470 6776 2822 1173 234 CL20 2654 2123 1699 1359 1087 173 33 65 CL30 4543 3634 2908 2326 1861 73 14 28 CL40 5114 4091 3273 2618 2095 12 12 23 CL63 24 54 8 87 7 0 0 0 1 2 3 1. Lots of Q4 samples. Distribution is not OK  HW problem. Site reset will help 2. Lots of bad signal level samples. TRX/Combiner is broken. If no HW problem  Site is totally in wrong place, site is like transferring traffic to another cell ( cause level HO). Typically a HW problem 3. Lots of Q6 and Q7 samples. Distribution is not OK, no Q5 samples  HW problems. Site reset or broken TRX 4. Typical normal interference problem. Here are some examples how different kind of HW problems can be found 4
134 © Nokia Siemens Networks KPI- Rules, Interference analysis DL /UL RxQualityxRxLevel Coverage Problem: Bad quality and Low Rx Level Interference Problem: Bad quality and High Rx Level Good Quality High Rv Level HW Problem: Bad Quality for all Rx Levels NWD report 204 model HW Problem All samples below - 100dBm CL10  <-100dBm Same level – quality distribution for both UL and DL
135 © Nokia Siemens Networks KPI- Rules, Interference, UL q0 q1 q2 q3 q4 q5 q6 q7 -100dBm 10645 8516 6813 5450 4360 3488 2791 2232 -95dBm 47043 37634 30108 24086 9865 7543 5643 2345 -90dBm 56204 44963 35971 28776 16574 5676 845 65 -80dBm 200863 160690 128552 102842 17654 3653 145 28 -70dBm 1234 987 790 632 505 404 323 259 -47dBm 24 19 15 12 10 8 6 5 MS power control can be seen here. If Power is reduced → no bad UL problems. BSC border is increasing good level samples q0 q1 q2 q3 q4 q5 q6 q7 -100dBm 10645 8516 6813 5450 4360 3488 2791 2232 -95dBm 47043 37634 30108 24086 9865 7543 5643 2345 -90dBm 56204 44963 35971 28776 16574 5676 845 65 -80dBm 200863 160690 128552 102842 17654 3653 145 28 -70dBm 1234 987 790 632 505 404 323 259 -47dBm 24 19 15 12 10 8 6 5 Bad interference problems. By POC parameter interference can be decreased, how power is adjusted etc. Also optimum MS power feature improves UL interference, no full power is sent after HO. q0 q1 q2 q3 q4 q5 q6 q7 -100dBm 10645 8516 6813 5450 4360 3488 2791 2232 -95dBm 47043 37634 30108 24086 9865 7543 5643 2345 -90dBm 56204 44963 35971 28776 16574 5676 845 65 -80dBm 200863 160690 128552 102842 17654 3653 145 28 -70dBm 1234 987 790 632 505 404 323 259 -47dBm 24 19 15 12 10 8 6 5 Bad quality sample due to signal level problems. Diversity should be checked, also possibilities to use LNA to improve UL signal level. Antenna place should be also checked if there are some obstacles near the antenna.
136 © Nokia Siemens Networks KPI- Rules, Interference, UL, examples UL_q0 UL_q1 UL_q2 UL_q3 UL_q4 UL_q5 UL_q6 UL_q7 DL_q0 DL_q1 DL_q2 DL_q3 DL_q4 DL_q5 DL_q6 DL_q7 -100dBm 251992 30668 20552 18417 18156 18286 16983 12478 27862 5537 5529 6069 6109 6107 5389 4119 -95dBm 123653 1151 403 692 519 351 221 72 89094 4236 3853 3576 2893 2264 1372 584 -90dBm 62938 247 144 288 353 129 62 29 142228 2732 2550 2356 1510 1114 774 404 -80dBm 27005 51 65 149 177 82 40 16 222462 1523 1355 1552 716 812 1081 343 -70dBm 2831 3 9 28 87 10 6 0 44504 91 123 151 81 101 191 88 -47dBm 751 0 4 10 25 1 0 0 5994 49 17 17 12 29 65 10 Huge amount of UL bad samples. Cells is not working properly, it is like transferring traffic, UL quality/ UL level HO’s are triggering immediately. These kind of cells must be investigated. UL_q0 UL_q1 UL_q2 UL_q3 UL_q4 UL_q5 UL_q6 UL_q7 -100dBm 490 137 368 605 1014 1378 1830 2586 -95dBm 8410 3768 3225 3023 2767 2304 1561 1859 -90dBm 38512 5249 3066 2323 1692 1570 1191 1268 -80dBm 219137 4600 2453 2311 1470 1724 1864 1221 -70dBm 509591 2504 1812 3050 1271 1465 1649 337 -47dBm 244302 582 711 1363 1713 873 671 87 UL_q0 UL_q1 UL_q2 UL_q3 UL_q4 UL_q5 UL_q6 UL_q7 -100dBm 70004 5020 3500 2564 2232 1946 2190 2579 -95dBm 80339 392 286 461 328 250 275 92 -90dBm 106883 233 318 602 199 146 234 64 -80dBm 246892 227 314 860 298 338 395 60 -70dBm 254875 155 298 935 203 135 166 15 -47dBm 23288 21 27 103 109 11 41 0 Some UL interference in good signal level. UL power control is not working properly. Ul power control is good indicator, if power is adjusted, there are no big problems in UL direction There is no UL interference, or just a little. MS is adjusting power properly, there are only little samples in good UL signal level.
137 © Nokia Siemens Networks q0 q1 q2 q3 q4 q5 q6 q7 -100dBm 10645 8516 6813 5450 4360 3488 2791 2232 -95dBm 47043 37634 30108 24086 9865 7543 5643 2345 -90dBm 56204 44963 35971 28776 16574 5676 845 65 -80dBm 200863 160690 128552 102842 17654 3653 145 28 -70dBm 12785 10228 8182 6546 456 112 24 23 -47dBm 4583 1123 583 452 261 76 26 2 KPI- Rules, Interference, DL Bad interference problem → signal level good (<-80dBm) and sometimes no better cell available. If better cell available and quality samples are 4 or worse → HO (reason quality or interference, depends on the parameter) Interference is causing drops. Really bad interference problem → signal level is really good (<-70dBm) and usually no better cell available → no HO → samples can be seen in the table. Interference is causing drops. Situation is “network is working properly” If there are quality 4 or worse samples → quality HO. Most of the samples are q4 samples. If lots of q5..q7 samples → interference problem and interference must be analyzed / removed. If quality HOs but no q5..q7 samples → better cell is available → no interference problems. In these signal levels overlapping exists and if handover reason is no PBGT, it will be quality HO. By parameter amount of quality HOs can be adjusted q0 q1 q2 q3 q4 q5 q6 q7 -100dBm 10645 8516 6813 5450 4360 3488 2791 2232 -95dBm 47043 37634 30108 24086 9865 7543 5643 2345 -90dBm 56204 44963 35971 28776 16574 5676 845 65 -80dBm 200863 160690 128552 102842 17654 3653 145 28 -70dBm 12785 10228 8182 6546 456 112 24 23 -47dBm 4583 1123 583 452 261 76 26 2 q0 q1 q2 q3 q4 q5 q6 q7 -100dBm 10645 8516 6813 5450 4360 3488 2791 2232 -95dBm 47043 37634 30108 24086 9865 7543 5643 2345 -90dBm 56204 44963 35971 28776 16574 5676 845 65 -80dBm 200863 160690 128552 102842 17654 3653 145 28 -70dBm 12785 10228 8182 6546 456 112 24 23 -47dBm 4583 1123 583 452 261 76 26 2 q0 q1 q2 q3 q4 q5 q6 q7 -100dBm 10645 8516 6813 5450 4360 3488 2791 2232 -95dBm 47043 37634 30108 24086 9865 7543 5643 2345 -90dBm 56204 44963 35971 28776 16574 5676 845 65 -80dBm 200863 160690 128552 102842 17654 3653 145 28 -70dBm 12785 10228 8182 6546 456 112 24 23 -47dBm 4583 1123 583 452 261 76 26 2 Bad quality samples due to signal level problems. If PBGT overlapping is not existing → lots of quality HOs + level HOs (margin are lower than in PBGT). Not interference problem, more signal level problem. Check how much samples vs. HOs → are better cells available or not.
138 © Nokia Siemens Networks KPI- Rules, Interference, DL, examples DL_q0 DL_q1 DL_q2 DL_q3 DL_q4 DL_q5 DL_q6 DL_q7 -100dBm 12057 2827 3108 3952 4783 6200 7013 8156 -95dBm 44818 4811 5041 5866 6587 7223 7259 6781 -90dBm 98587 7107 7400 8334 8470 8781 7825 6162 -80dBm 225919 7450 7731 8445 7726 7441 5695 3369 -70dBm 88708 1014 971 998 751 688 689 367 -47dBm 15881 84 109 122 104 167 199 184 DL_q0 DL_q1 DL_q2 DL_q3 DL_q4 DL_q5 DL_q6 DL_q7 -100dBm 8006 1636 1681 2197 2379 2510 2025 1290 -95dBm 24951 1636 1627 1767 1037 431 175 53 -90dBm 57559 2171 1884 1651 781 330 161 47 -80dBm 200602 5771 4686 4130 1736 566 254 97 -70dBm 304206 5464 4310 3796 1315 350 153 105 -47dBm 108047 2134 1908 1623 689 230 129 64 There are almost as much samples Q5 and Q7 samples as Q 4 samples → even interference is really bad or there is no better cell available ( no ho’s after bad quality samples). These kind of interference cells should be optimized, otherwise there are lots of drops etc There are no as much Q5…Q7 samples as Q4 samples → after interference samples Quality HO is done or the interference situation is not so bad, for example sampling is Q0,Q2,Q4,Q2,Q5,Q0,Q2,Q3,Q4,Q2 → quality HO is not triggering DL_q0 DL_q1 DL_q2 DL_q3 DL_q4 DL_q5 DL_q6 DL_q7 -100dBm 7055 1398 1374 1906 2163 2003 1468 832 -95dBm 20109 1307 1274 1161 694 332 211 84 -90dBm 34531 1053 745 587 273 131 94 41 -80dBm 107539 875 518 630 161 98 113 47 -70dBm 177614 283 316 663 61 32 29 9 -47dBm 58718 78 91 198 54 40 54 32 There are bad quality samples only due to signal level problems.
139 © Nokia Siemens Networks KPI- Rules, Interference (internal / external) •Internal Interference – Interference can be seen from stats or can be measured by scanner. – Neighbor cells (DL) or mobiles (UL) are causing interference. – By frequency / network planning interference can be decreased. •External Interference – Interference can be seen from stats or can be measured by scanner. – External radio frequencies are causing interference  Military use  In the border area, interference is coming from other country.  Some external wireless system (for example some wireless industry system) is causing interference  Increased I level can be also due to external interference
140 © Nokia Siemens Networks KPI- Rules, HOSR
141 © Nokia Siemens Networks KPI- Rules, HO fail sum(msc_o_succ_ho + bsc_o_succ_ho + cell_succ_ho) Total HO success ratio = 100 * (-------------------------------------------------------------------------------- ) (ho_65) sum(msc_o_ho_cmd + bsc_o_ho_cmd_assgn + bts_ho_assgn) sum(a.msc_o_succ_ho + a.bsc_o_succ_ho + a.cell_succ_ho + a.msc_to_wcdma_ran_succ_tch_ho) Total HO failure ratio = 100 * (1- -------------------------------------------------------------------------------------) (hfr_2b) sum(b.msc_o_ho_cmd + b.bsc_o_ho_cmd_assgn + b.bts_ho_assgn+a.msc_gen_sys_wcdma_ran_ho_com) /* handovers failing due to blocking */ sum(a.msc_o_fail_lack + a.bsc_o_fail_lack + a.cell_fail_lack + a.msc_to_wcdma_ran_fail_lack) HO failure ratio due to RF blocking = 100 * --------------------------------------------------------------------------------------- /* all HO attempts */ sum(b.msc_o_ho_cmd + b.bsc_o_ho_cmd_assgn + b.bts_ho_assgn + a.msc_gen_sys_wcdma_ran_ho_com) (hfr_55a)

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2gtrainingoptimization-150301041427-conversion-gate02.ppt

  • 1. 1 © Nokia Siemens Networks BSS Optimisation Workshop Denpasar Bali Oct 21-25, 2013 NSN – TSEL
  • 2. 2 © Nokia Siemens Networks Idle Parameter Optimization Power Control Parameter Handover Control parameter Radio Resource Administration Radio resource Management KPI case Measurement processing
  • 3. 3 © Nokia Siemens Networks Radio Resource Administration
  • 4. 4 © Nokia Siemens Networks TDMA frame = 8 timeslots ( 0.577ms * 8 = 4.615 ms) 0 1 3 4 5 7 6 0 1 2 3 4 5 7 6 0 1 2 3 4 5 200 kHz Physical channel e.g. allocated to one subscriber with FR voice and no frequency hopping frequency t i m e TDMA frame 2 2 2 2 Basic TDMA Structure
  • 5. 5 © Nokia Siemens Networks Base Station Subsystem Logical Channels for transport of specific content Physical Channels transport medium MS mapping Physical channel parameters ARFCN Time slot number Frequency hopping algorithm GSM Channel Organization
  • 6. 6 © Nokia Siemens Networks SCH FCCH PCH BCCH AGCH RACH SDCCH SACCH FACCH Stand alone Dedicated Control Channel Frequency Correction Channel Synchronisation Channel Broadcast Control Channel Paging Channel Slow Associated Control Channel Fast Associated Control Channel Paging Channel Random Access Channel Access Grant Channel BCH CCCH DCCH TCH DL DL DL UL Common Channels Dedicated Channels UL/DL UL/DL CBCH Cell Broadcast Channel Logical Channels FR/HR Full rate / Halft rate TCH EFR Enhanced Full rate TCH AMR FR/HR Adaptive multirate TCH (FR/HR)
  • 7. 7 © Nokia Siemens Networks f s f f s f s Downlink 51 TDMA frames = 235 ms - Uplink BCCH CCCH f s f s CCCH CCCH r r f r r r r r r r f r r r r r r r r r r f r r r r r r f r r 1 51 CCCH CCCH CCCH CCCH CCCH CCCH r r r r r r r r r r r r r r r r r r r r r r r r f = FCCH, s = SCH, r = RACH TDMA frame - = dummy burst 51 TDMA frames = 235 ms 1 51 Signalling Channel Mapping (BCCH +CCCH/9)
  • 8. 8 © Nokia Siemens Networks f s f f s f s Downlink 51 TDMA frames = 235 ms - Uplink BCCH CCCH f s f s CCCH CCCH SDCCH 0 SDCCH 1 SDCCH 2 SDCCH 3 SACCH 0/2 SACCH 1/3 r r f r r r r r r r f r r r r r r r r r r f r r r r r r f r r 1 51 SACCH 2/0 SACCH 3/1 SDCCH 0 SDCCH 1 SDCCH 3 SDCCH 2 f = FCCH, s = SCH, r = RACH TDMA frame - = dummy burst 51 TDMA frames = 235 ms 1 51 Signalling Channel Mapping (BCCH + SDCCH/4 + SACCH/C4)
  • 9. 9 © Nokia Siemens Networks ... 26 TDMA frames = 120 ms 1 26 t t t t t t t f t t t t t t t t t t t f t t t t t t s i Full Rate Traffic Channel Configuration (UL & DL) Half Rate Traffic Channel Configuration (UL & DL) 26 TDMA frames = 120 ms 1 26 t T T t t T t f t t T T T T t t T t T f T t T t t T s S t = full rate TCH, s = SACCH/T, i = idle TDMA frame t = half rate TCH, s = SACCH/T (first user) T = half rate TCH, S = SACCH/T (second user) TDMA frame Traffic Channel Mapping
  • 10. 10 © Nokia Siemens Networks f f i = idle TDMA frame f 51 TDMA frames = 235 ms i i i i i i SDCCH 0 SDCCH 1 SDCCH 2 SDCCH 3 SDCCH 4 SDCCH 5 SDCCH 6 SDCCH 7 SDCCH 1 SDCCH 2 SDCCH 3 SDCCH 4 SDCCH 5 SDCCH 6 SDCCH 7 SDCCH 0 Downlink Uplink SACCH 0/4 SACCH 1/5 SACCH 2/6 SACCH 3/7 SACCH 6/2 SACCH 7/3 SACCH 4/0 SACCH 5/1 51 TDMA frames = 235 ms 1 51 1 51 Signalling Channel Mapping (SDCCH/8 +SACCH/C4)
  • 11. 11 © Nokia Siemens Networks Signalling Channel Mapping New improved CCCH features in RG10 •BSS20738 CS Paging Coordination in NMO II •BSS21538 Extended CCCH – Extended CCCH can be allocated to timeslot 2,4,6 •BSS101411 Extended BCCH – For example Uncombined BCCH
  • 12. 12 © Nokia Siemens Networks Channel configuration defined by parameter channelType TCHF (0) = full rate traffic channel TCHH (1) = half rate traffic channel TCHD (2) = dual rate traffic channel SDCCH (3) = standalone (SDCCH/8) MBCCH (4) = broadcast control channel MBCCHC (5) = BCCH + SDCCH/4 MBCCB (7) = BCCH + SDCCH/3 with CBCH SDCCB (8) = SDCCH/7 with CBCH NOTUSED (9) = timeslot has no radio definition or Abis allocation ERACH (10) = random access channel of extended area EGTCH (14) = EGPRS packed data traffic channel for extended area LRTCH (15) = long reach traffic channel Channel Mapping Parameter Setting Note: • Some values not allowed in certain tsl (e.g. TSL0 can’t have value 8) • PBCCH is not supported in S13 and onwards MO Class TR/RTSL Parameter channelxType (CHx) where x = 0…7
  • 13. 13 © Nokia Siemens Networks Mobile terminating call -> MSC performs paging MS identifies paging message with the IMSI/TMSI MS listens to own paging group only SEG-BTS parameters MSC parameters Repaging Interval (INT) 0.5s…10s Time between consecutive paging attempts Repaging Attempts (AT) 0…5 Number of paging repetitions Buffering BTS stores up to 8 paging messages of the MSC in page group buffer BTS sends paging messages to MS according noOfMultiframesBetweenPaging Paging Channel (PCH) Parameters MO Class Abbreviated Name Range And Step Description Default value BSC - MML Name BTS noOfMFramesB etweenPaging 2...9, step 1 Defines the number of multiframes between two transmissions of the same paging message to the MSs of the same paging group. 4 MFR
  • 14. 14 © Nokia Siemens Networks Mobile sends channel requests to BTS separated by random time intervals in case of no answer! Parameters Random time interval between consecutive retransmissions t = S + random [0,.. numberOfSlotsSpreadTrans – 1] RACH slots S depends on numberOfSlotsSpreadTrans signalling channel mapping (CCCH + SDCCH combined or not in one multi frame) numberOfSlotsSpreadTrans = 10 signalling channel mapping = not combined  S = 58 Therefore t = 58..to..67 RACH slots time channel requests RACH Parameters MO Class Abbreviated Name Range And Step Description Default value BSC - MML Name BTS maxNumberRetra nsmission 1,2,4,7 Maximum number of retransmissions on the RACH that the MS can perform. 4 RET BTS nbrOfSlotsSpread Trans MML Range: 3..12, 14, 16, 20, 25, 32, 50 The number of TDMA frames over which retransmission is spread on the RACH (random access channel) 10 SLO
  • 15. 15 © Nokia Siemens Networks Network gives the MS dedicated resources Downlink CCCH blocks • PCH can be used for AGCH messages • AGCH cannot be used for PCH messages Reservation of CCCH blocks for AGCH noOfBlocksForAccessGrant (AG) 0..7 possible number, if CCCH and SDCCH are not combined 1..7 possible number, if CBCH is used in non combined configuration 0..2 possible number, if CCCH and SDCCH are combined Preference of AGCH messages on PCH noOfBlocksForAccessGrant  0 PCH can be used only, if no paging messages have to be send = 0 AGCH messages have higher priority than PCH ones Number of paging groups N = (number of CCCH blocks – noOfBlocksForAccessGrant) * noOfMultiframesBetweenPaging AGCH Parameters
  • 16. 16 © Nokia Siemens Networks Combined CCCH / SDCCH configuration noOfBlocksForAccessGrant = 1  2 CCCH blocks for PCH 3 MSs paged per paging message  3 pages per block 2 blocks per multi frame  3 * 2 = 6 pages per multiframe Number of pages per hour  3600 s / 0.235 s * 6 = 91915 Avg of 2 pages required per MS  91915 / 2 = 45957 MSs per hour BTS 3 MS Paging_Request BTS 3 MS Paging_Request Paging Capacity Example
  • 17. 17 © Nokia Siemens Networks Cell with 325 subscribers 1 call per subscriber once in a hour 1 location update (LU) per subscriber once in 2 hours Duration of call assignment = 4 s  4 s / 3600 s = 1.11 mErl on SDCCH per subscriber 325 subscribers  325 * 1.11 mErl = 0.3607 Erl on SDCCH Reservation time for LU = 5s 5 s / 7200 s = 0.69 mErl on SDCCH per subscriber 325 subscribers  0.2242 Erl on SDCCH Total SDCCH traffic  0.3607 Erl + 0.2242 Erl = 0.5849 Erl Blocking probability = 1%  4 SDCCHs required  SDCCH combined with CCCH can be used (MBCCHC) SDCCH Signalling Capacity Example with call Establishment & Location Update
  • 18. 18 © Nokia Siemens Networks Same cell with 325 subscribers Additional SMS traffic of 1 mErl per subscriber 325 subscribers  325 * 1 mErl = 0.325 Erl on SDCCH Total SDCCH traffic  0.5849 + 0.325 Erl = 0.9099 Erl Blocking probability = 1%  5 SDCCHs required  not combined with CCCH (MBCCH) SDCCH Signalling Capacity Example including SMS
  • 19. 19 © Nokia Siemens Networks Base Station Identity Code BSIC = Network Colour Code NCC + Base Station Colour Code BCC bsIdentityCode Setting of BSIC NCC 0..7, distinguishes between PLMNs BCC 0..7, distinguishes between clusters BSIC + frequency channel  unique identity of adjacent cell f1 f2 f3 f1 f1 bcc = 1 bcc = 2 bcc = 3 Base Station Identity Code
  • 20. 20 © Nokia Siemens Networks 200 kHz 890 915 935 960 1 2 3 4 124 123 1 2 3 4 124 123 duplex distance Absolute radio frequency carrier number ARFCN uplink direction downlink direction Example: GSM 900 Defining Frequency carrier number
  • 21. 21 © Nokia Siemens Networks Frequency to be used by TRX (must be unique within a BTS) initialFrequency (FREQ) 1…1023 Setting of ARFCNs GSM 800: 128 .. 251 GSM 900: 1..124 and 975..1023, 0 GSM 1800: 512..885 GSM 1900: 512..810 f1 f2 f3 f4 f5 f6 f7 f1 f2 f3 f4 f5 f6 f7 f1 f2 f3 f4 f5 f6 f7 Frequency Reuse
  • 22. 22 © Nokia Siemens Networks Frequency Time F1 F2 F3 Call is transmitted through several frequencies to • average the interference (interference diversity) • minimise the impact of fading (frequency diversity) Frequency hopping techniques hoppingMode (HOP) BB,RF,N BB = base band hopping (1) RF = RF hopping (2) N = no frequency hopping at all (0) Principle of Frequency Hopping
  • 23. 23 © Nokia Siemens Networks Baseband Hopping TRX 1 TRX 2 TRX 3 0 1 7 2 Timeslot TRX 4 BC CH f 1 f 2 f 3 f 4 HSN1 (BB hopping group 1 and RF hopping) Timeslot 0 hops over TRXs 2-4 only BCCH does not hop HSN2 (BB hopping group 2) Timeslots 1-7 hop over all TRXs TRXs do not hop Physical channels moved from one TRX to another Hopping sequence hoppingSequenceNumber (HSN) 0..63 0 = cyclic hopping 1..63 = pseudorandom hopping Base Band Hopping
  • 24. 24 © Nokia Siemens Networks RF Hopping Standard technique TRX 1 TRX 2 TRX 3 0 1 7 2 Timeslot TRX 4 BC CH f1 – no hopping f2,f3..fn – hopping according mobile allocation list One hopping sequence number only All TRXs hop except TRX1 (provides BCCH) Up to 63 frequencies available defined by mobile allocation list -> better hopping gain mobileAllocationList Setting of ARFCN values usedMobileAllocation (MAL) 0,1...2000 0 = BTS detached from any list 1..2000 = indicates list which shall be used
  • 25. 25 © Nokia Siemens Networks Standard technique 9 hopping hopping frequencies MAI = 0..8 But 3 frequencies available for every TRX only Freeform hopping For every sector same mobile allocation list hopping sequence number frame number (frame synchronization) For every sector different starting points for hopping sequence possible by mobile allocation index offset maioOffset (MO) 0..62 setting of MAIO 9 hopping hopping frequencies MAI = 0..8 9 frequencies available for every TRX RF Hopping Freeform Hopping
  • 26. 26 © Nokia Siemens Networks Freeform hopping • Not adequate for MA list with consecutive ARFCN values • Avoids co-channel interference but not adjacent channel interference Flexible MAIO management MAIO increases with constant step size from one TRX to the next one maioStep (MS) 1..62 maioOffset = 0, 6, 12 for sector 1, 2, 3 maioStep = 2 18 frequencies required (2 * number of hopping TRXs) RF Hopping Flexible MAIO Management
  • 27. 27 © Nokia Siemens Networks BCCH Band allocation: MA list Consecutive ARFCN Only BCCH frequency planning required Flexible MAIO management MAIO Offset + MAIO Step BCCH Band allocation: MA list Non-adjacent ARFCN Freeform hopping MAIO Offset MA list and BCCH frequency planning required RF Hopping (Tight Frequency Reuse)
  • 28. 28 © Nokia Siemens Networks Changing Frequency Plan BSIC / TSC Frequencies Frequency hopping setting Intelligent underlay overlay TRX settings • Plan downloaded to BSC/BTSs via MML or GUI • File-based plan provisioning • Immediate Plan activation method
  • 29. 29 © Nokia Siemens Networks Idle Mode Operation
  • 30. 30 © Nokia Siemens Networks • When the MS is switched ON • When there is no dedicated connection When? • To camp on the best suitable cell Why? • For MS to receive system info from the NW on DL • For MS to be able to initiate a call whenever needed • For the NW to be able to locate the MS when there is a MT call/SMS Why to camp on a specific cell? • PLMN selection • Cell selection & re-selection • Location updates Idle Mode Tasks Idle Mode Operation I MS switched ON Search RF channels to find BCCH carrier Check that the PLMN & cell is allowed MS camps on the best suitable cell See slide 10 for detail
  • 31. 31 © Nokia Siemens Networks Value LAI (locationAreaId) • NCC (Network Colour Code) 0 … 7 • BCC (BTS Colour Code) 0 … 7 BSIC (bsIdentityCode) CI (cell-ID 0 … 65535 Parameter TSC (trainingSequenceCode) 0 … 7 • MCC (Mobile Country Code) 0 … 999 • MNC (Mobile Network Code) 0 … 99, 0… 999 (optional 3-digit MNC) • LAC (Location Area Code) 1 … 65533 CGI (Cell Global Identity) MCC + MNC + LAC + CI ID’s and ID Codes
  • 32. 32 © Nokia Siemens Networks Any cell selection Camped on any cell Choose cell cell found no suitable cell found suitable cell found leave idle mode return to idle mode Connected mode (emergency call only) Any cell re- selection trigger cell re-selected no suitable cell found go here when no SIM in MS SIM inserted in MS 1 2 cell found on selected PLMN (adopted from TS 43.022 V5.1.0 chap. States and State Transition for Cell Selection
  • 33. 33 © Nokia Siemens Networks Camped normally (adopted from TS 43.022 V5.1.0 chap. 6 Connected mode Normal cell selection Stored list cell selection Choose cell Normal cell re-selection go here whenever a new PLMN is selected BA list stored for PLMN no BA list stored for PLMN 1 no suitable cell found suitable cell found suitable cell found trigger Suitable cell re-selected no suitable cell found suitable cell found leave idle mode return to idle mode no suitable cell found no suitable cell found • IMSI unknown • Illegal MS • PLMN not allowed 2 2 States and State Transition for Cell Selection
  • 34. 34 © Nokia Siemens Networks Normal Cell Selection Search all the RF channels, take samples during 3-5 s and calculate averages. And put them in ascending order with respect to signal level. Then tune to the strongest RF channel. Search for the frequency correction burst in that carrier in order to verify if it is a BCCH carrier Camp on the cell Try to synchronize to the carrier and read the BCCH data Is it a BCCH carrier? Is it a correct PLMN ? Is the cell barred? Is C1>0 Tune to the next highest RF channel which is not tried before No No No No Yes Yes Yes Yes
  • 35. 35 © Nokia Siemens Networks I am outside I am inside, but have not enough power C1 = A – max(B,0) = RLA_C – RXLEV_ACCESS_MIN – max(MS_TXPWR_MAX_CCH – P , 0) RLA_C = avg received RxLev on BCCH P = MS max output power max(B,0) 0..63 0..31 Pathloss Criterion C1 for Cell Selection and Reselection
  • 36. 36 © Nokia Siemens Networks Cell1 LAC1 C1 ( Cell1) C1 (Cell2) A B C A= 4 dB B= 6 dB C= 8 dB Cell2 LAC2 In case the neighbouring cells belong to different Location Area, a hysteresis is applied with C1 criteria • minimizing ping-pong cell reselections • cellReselectHysteresis (HYS)(BTS) (0…14 dB) Cell Selection with C1
  • 37. 37 © Nokia Siemens Networks C1 + CELL_RESELECT_OFFSET – (TEMPORARY OFFSET * H(PENALTY_TIME - T)) for PENALTY_TIME  640 s < C1 if temporary offset big for PENALTY_TIME = 640 s C2 = serving cell: • C2: List of 6 strongest carriers: • C2: • C2: • C2: • C2: • C2: • C2: 0 .. 126 dB step size: 2 dB 0, 10, 20, 30, 40, 50, 60,  dB 20 .. 640 s step size: 20 s PENALTY_TIME TEMPORARY OFFSET CELL_RESELECT_OFFSET C1 C2 T new candidate = formerly non- serving cell CELL_RESELECT_OFFSET C1 C2 T new candidate = former serving cell no TEMPORARY OFFSET Pathloss Criterion C2
  • 38. 38 © Nokia Siemens Networks cell 1 cell 2 cell 3 C2 time 5 seconds cell reselection 5 seconds CELL_RESELECT_ HYSTERESIS (HYS) LAC = A LAC = B cell reselection & location update Cell Reselection Based on Pathloss Criterion C2
  • 39. 39 © Nokia Siemens Networks Cell "A" Cell "B" Cell "C" Cell "D" cellReselectOffset 0 dB 20 dB 0 dB 0 dB temporaryOffset 0 dB 30 dB 0 dB 30 dB penaltyTime 20 s 20 s 20 s 40 s Micro 900 "D" Macro 1800 "B" Macro 900 "A" Macro 900 "C" Road Parameters =30 Cell "A" (Serving Cell) =25 Cell "B" =5 Cell "C" =50 Cell "D" =30 + 0 (H(x)=0, serving cell) Cell "A" =25 + 20 - 30*H(20 - T) Cell "B" =5 + 0 - 0*H(20 - T) Cell "C" =50 + 0 - 30*H(40 - T) Cell "D" C1 C2 = C1 + cellReselectOffset - temporaryOffset*H(penaltyTime-T) C2 Time T: (0 - 19 s) C2 =30 Cell "A" C2 =15 Cell "B" C2 =5 Cell "C" C2 =20 Cell "D" Time T: (20 - 39 s) C2 =30 Cell "A" C2 =45 Cell "B" C2 =5 Cell "C" C2 =20 Cell "D" Time T: (> 40 s) C2 =30 Cell "A" C2 =45 Cell "B" C2 =5 Cell "C" C2 =50 Cell "D" Cell Reselection Based on Pathloss Criterion C2
  • 40. 40 © Nokia Siemens Networks When shall I select a new cell? Pathloss Criterion C1 C1  0 for a period of 5 s Pathloss Criterion C2 • neighbour‘s C2 value > current cell‘s C2 value (same LA) • neighbour‘s C2 value > current cell‘s C2 value + HYS (new LA) for a period of 5 s. Downlink Signalling Failure DSC  0 RACH Failure MAX RETRANS + 1 times Authentication Failure notification by upper layers Cell has been barred CELL_BAR_ACCESS & CELL_BAR_QUALIFY Cell Reselection Events
  • 41. 41 © Nokia Siemens Networks Location Update Procedure BSS MSC VLR HLR REQUEST SUBSCRIBER INFO ALL OK - HLR UPDATE MS LOCATION UPDATE REQUEST SEND SUBSCRIBER ID REQUEST SUBSCRIBER ID SEND SUBSCRIBER INFO AUTHENTICATION AUTHENTICATION RESPONSE
  • 42. 42 © Nokia Siemens Networks Paging LocUp # of cells in Loc. area signalling traffic optimum number of cells in Loc. area function of user density, cell size, call arrival rate ... function of user mobility Trade-off between Location Update and Paging Traffic
  • 43. 43 © Nokia Siemens Networks Location Updates • MS location & status flag => MSC / VLR • Mobile Station switched ON mode – IMSI Attach / Detach – Same Location Area => No Location Update – Different Location Area => Location Update • Change of the Location Area – Location Area under the same MSC / VLR – Location Area under another MSC / VLR => HLR will be updated • Service is rejected (MS unknown in VLR) • Time-Periodic LU (MS -> MSC/VLR) MO Class Abbreviated Name Range And Step Description Default value BSC - MML Name BTS allowIMSIAtt achDetach Yes/No Defines whether IMSI attach/detach is used in the cell. Yes ATT BTS timerPeriodic UpdateMs 0...25.5 h, step 0.1 h Defines the interval between periodic MS location updates. The value 0 means that the periodic location update is not used. 0.5 h PER
  • 44. 44 © Nokia Siemens Networks IDLE MODE OPERATION Idle Mode Controls Parameter Value Access Parameters notAllowedAccessClasses 0 ... 9, 11 ... 15 emergencyCallRestricted Yes/No msTxPwrMaxCCH 13 ... 43 (dBm) rxLevAccessMin -110 ... -47 (dBm) msMaxDistanceInCallSetup 0 ... 255 radiusExtension 0 ... 67 (Km) cellBarred Yes/No plmn-permitted 0 ... 7 cellReselectHysteresis 0 ... 14 (dB) Mobility Parameters cellReselectOffset (REO) 0 ... 126 (dB) cell reselection parameter index (PI) (N/Y)
  • 45. 45 © Nokia Siemens Networks IDLE MODE OPERATION Idle Mode Controls definitions • RxLevAccessmin : With this parameter you define the minimum power level an MS has to receive before it is allowed to access the cell. • MsTxPwrMaxCCH : With this parameter you define the maximum transmission power an MS may use when accessing a CCH in the cell. • notAllowedAccessClasses With this parameter you define the MS access classes that are not allowed to access a cell. • Emergency Call Restricted With this parameter you define if an emergency call in the cell is allowed to all MSs or only to the MSs which belong to one of the classes between 11 to 15. Value ’Y’ means the latter case. • MsMaxDistancein CallSetup With this parameter you define the maximum distance between the BTS and the MS in call setup. The maximum distance is expressed as an access delay. Within the range of 0...62, one step correlates to a distance of 550 meters. If the access delay of the channel request message exceeds the given maximum, the call attempt is rejected. When the parameter is given a value from 63 to 255, call attempts are never rejected • radiusExtention With this parameter you define the radius extension of an extended cell
  • 46. 46 © Nokia Siemens Networks Radio Resource management
  • 47. 47 © Nokia Siemens Networks Channel request (RACH) MS NETWORK Immediate assignment Immediate assignment (AGCH) Service request (SDCCH) Service request Authentication request (SDCCH) Authentication response (SDCCH) Authentication Ciphering mode command (SDCCH) Ciphering mode complete (SDCCH) Ciphering mode setting Setup (SDCCH) Call initiation Call proceeding (SDCCH) Assignment command (SDCCH) Assignment complete (FACCH) Assignment of traffic channel Alert (FACCH) Call confirmation Connect (FACCH) Connect acknowledged (FACCH) Call accepted Signalling (Mobile Originating Call) Idle parameter Dedicated parameter
  • 48. 48 © Nokia Siemens Networks Page request (PCH) MS NETWORK Immediate assignment Channel request (RACH) Page response (SDCCH) Service request Authentication request (SDCCH) Authentication response (SDCCH) Authentication Ciphering mode command (SDCCH) Ciphering mode complete (SDCCH) Ciphering mode setting Setup (SDCCH) Call initiation Call confirmation (SDCCH) Assignment command (SDCCH) Assignment complete (FACCH) Assignment of traffic channel Alert (FACCH) Call confirmation Connect (FACCH) Connect acknowledged (FACCH) Call accepted Immediate assignment (AGCH) Signalling (Mobile Terminating Call) Idle parameter Dedicated parameter
  • 49. 49 © Nokia Siemens Networks Disconnect MS NETWORK Call clearing Release Channel release Release Release complete Disconnect MS NETWORK Call clearing Release Channel release Release Release complete Network initiated MS initiated Signalling (Call Release)
  • 50. 50 © Nokia Siemens Networks MS capabilities Channel rate : full, half, dual, multi rate Speech codecs : normal FR, normal HR, EFR, AMR FR, AMR HR, doubleHR(OSC) MSC demands A interface circuit allocated for call BTS demands Speech codec capabilities TCH configuration Current resources Homogeneous use of TRXs and radio time slots Large free groups of radio time slots for high loaded HSCSD BTS Standard TCH Allocation (General Criteria)
  • 51. 51 © Nokia Siemens Networks TCH Allocation 2 TRX=16 channels 0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 12:00:00 AM 2:00:00 AM 4:00:00 AM 6:00:00 AM 8:00:00 AM 10:00:00 AM 12:00:00 PM 2:00:00 PM 4:00:00 PM 6:00:00 PM 8:00:00 PM 10:00:00 PM RTSL SDCCH BCCH PEAK_PERMANENT_GPRS_CH AVE_GPRS_CHANNELS AVE_TCH_BUSY_FULL 0 1 2 3 4 5 6 7 TRX1 BCCH SDCCH SDCCH V/D V/D V/D V/D V/D TRX2 SDCCH SDCCH V/D V/D V/D V/D D D TIME AVE_SDCCH (SDCCH/8) AVE_BUSY_SDCCH PEAK_BUSY_SDCCH AVE_AVAIL_FULL_TCH AVE_TCH_BUSY_FULL PEAK_BUSY_TCH TCH_PEAK_BUSY_FULL TCH_PEAK_BUSY_HALF SDCCH_CONG_TIME(sec) TCH_FR_RADIO_CONGESTION_TIME (sec) TCH_HR_RADIO_CONGESTION_TIME (sec) AVE_GPRS_CHANNELS PEAK_GPRS_CHANNELS PEAK_PERMANENT_GPRS_CH 12:00:00 AM 32 5.0 18 6.3 4.0 9 9 0 0 8.48 0 4.7 8 2 1:00:00 AM 32 3.1 13 6.8 3.4 9 9 0 0 1.41 0 4.2 9 2 2:00:00 AM 32 1.7 12 5.2 2.9 7 7 0 0 0 0 5.8 9 2 3:00:00 AM 32 1.5 12 6.2 1.4 7 7 0 0 0 0 4.8 9 2 4:00:00 AM 32 1.6 10 8.0 1.7 5 5 0 0 0 0 3.0 9 2 5:00:00 AM 32 8.8 32 5.7 0.8 6 6 0 559 0 0 5.3 9 2 6:00:00 AM 32 5.2 18 4.3 1.1 6 6 0 0 0 0 6.7 9 2 7:00:00 AM 32 6.5 23 8.5 2.6 8 8 0 0 0 0 2.5 6 2 8:00:00 AM 32 4.8 20 6.6 2.2 7 7 0 0 0 0 4.4 9 2 9:00:00 AM 32 4.3 20 6.8 2.4 8 8 0 0 0 0 4.3 9 2 10:00:00 AM 32 5.2 32 7.5 2.6 9 9 0 2 0.21 0 3.5 9 2 11:00:00 AM 32 5.9 18 6.3 2.9 9 9 0 0 8.98 0 4.7 9 2 12:00:00 PM 32 5.9 19 6.8 3.9 9 9 0 0 13.52 0 4.2 8 2 1:00:00 PM 32 7.3 24 6.4 3.4 9 9 0 0 8.96 0 4.6 9 2 2:00:00 PM 32 6.8 30 6.2 3.9 9 9 0 0 44.05 0 4.8 8 2 3:00:00 PM 32 7.1 21 6.7 4.7 9 9 0 0 64.18 0 4.3 9 2 4:00:00 PM 32 7.7 23 6.6 3.9 9 9 0 0 25.61 0 4.4 8 2 5:00:00 PM 32 8.5 23 6.7 3.9 9 9 0 0 34.51 0 4.3 9 2 6:00:00 PM 32 10.7 27 8.3 5.9 9 9 0 0 320.58 0 2.7 7 2 7:00:00 PM 32 11.1 28 8.4 5.6 9 9 0 0 217.77 0 2.6 9 2 8:00:00 PM 32 10.4 30 7.8 5.5 9 9 0 0 284.15 0 3.2 8 2 9:00:00 PM 32 9.3 26 7.5 5.3 9 9 0 0 217.65 0 3.5 8 2 10:00:00 PM 32 8.3 22 7.5 5.2 9 9 0 0 185.36 0 3.5 9 2 11:00:00 PM 32 5.8 21 6.8 4.6 9 9 0 0 89.61 0 4.2 9 2 How can be optimized?
  • 52. 52 © Nokia Siemens Networks Channel allocation ( For each TS) Each TRX – have its own Quality both DL and UL and TRX with bad quality (UL and DL) will result bad KPI on respective TRX Placing each Time Slot (BCCH, SDCCH, TCH and PDTCH) properly will result good KPI (SDSR, DCR, HOSR TBF Completion rate) Shitting SDCCH, BCCH can improve SDSR and DCR
  • 53. 53 © Nokia Siemens Networks Measurement of uplink receive level on idle channels = uplink interference Averaging over interferenceAveragingProcessAverPeriod (AP) = 1..32 SACCH periods Classification into interference bands based on interferenceAveragingProcess (BO1..BO4) = -110..-47 dBm BSC tries to allocate TCH from best interference band (can be requested by MSC) If not available, BSC tries to take TCH from next band 0 7 1 2 3 4 5 6 rxLevUL = -75 dBm BO5 –47 (fixed) BO0 –110 (fixed) BO4 -90 BO3 -95 BO1 -105 BO2 -100 Standard TCH Allocation (Interference Bands)
  • 54. 54 © Nokia Siemens Networks Priority for TCH from BCCH TRX BCCH transmitted permanently -> no additional interference in network Planned to be least interfered channels Priority for TCH from other TRX BCCH TRX does not hop in case of RF hopping -> hopping gain only for other TRX Parameter trxPriorityInTCHAlloc (TRP) 0 = no priority 1 = priority for BCCH TRX 2 = priority for other TRX 3 = priority for BCCH TRX for non-AMR users, priority for other TRX for AMR users Prioritized TCH Allocation (TRP) Whole band , 50 channels 1 ch=200kHz BCCH, 30 channels TCH, 20 channels All 50 channels for BCCH and TCH Case1 Case2
  • 55. 55 © Nokia Siemens Networks Enables to differentiate Rx level requirement for: • MS camping to the network /RxLev Access Min • MS accessing to TCH /RX level based TCH access RX level based TCH allocation method • RX Level measured by the MS is used to determine whether the BTS is acceptable for TCH allocation • TCH allocation for emergency calls is not restricted due to low RX level Provides better drop call meters and better performance of MSs • MSs having too low Rx levels are not allowed to camp the network By separating camping and TCH access thresholds the operator will be able to provide the maximum camping footprint RX level based TCH Allocation (RXP) Note! RG20 feature – Energy optimized TCH allocation
  • 56. 56 © Nokia Siemens Networks Allows to define minimum C/N ratios separately for each call type (AMR FR, AMR HR, EFR/FR, HR and 14.4 data) Parameter values ‘RX level based TCH access’: 0: RX level based TCH access is not used (C/N definitions not in use) 1: RX level based TCH access is used in call setup 2: RX level based TCH access is used in call setup and in handovers Downlink RX Level -> TCH Access Soft blocking C/N FR: 0…63dB/ def: 12dB Soft Blocking C/N HR: 0…63dB/ def: 14dB Soft blocking C/N AMR FR: 0…63dB/ def: 7dB Soft blocking C/N AMR HR: 0…63dB/ def: 12dB Soft blocking C/N 14.4 : 0…63dB/ def: 14dB RX level based TCH Allocation (RXTA)
  • 57. 57 © Nokia Siemens Networks Priorities No TCH available for call set up / handover -> request put into queue Different kinds of requests can have different priorities queuePriorityUsed (QPU) Y/N enables use of priorities queueingPriorityCall (QPC) 1..14 priority for call set up request queuePriorityNonUrgentHo (QPN) 1..14 priority for non urgent handover (power budget, umbrella, slow moving MS, traffic reason) request queueingPriorityHandover (QPH) 1..14 priority for urgent handover (all other) request Queue length and time maxQueueLength (MQL) 0..100% percentage of number of TCHs handled by BTS timeLimitCall (TLC) 0..15 s time a call set up request is kept in the queue 0 = queuing is disabled timeLimitHandover (TLH) 0..10 s time a handover request is kept in the queue 0 = queuing is disabled Queuing (Parameters)
  • 58. 58 © Nokia Siemens Networks Conditions Timers set to values > 0 User of priorities enabled Queue not full with requests of equal or higher priority than the current one Queuing of call set up requests Reservation of SDCCH resources -> SDCCH easily overbooked -> blocking of services like SMS or location update Queuing (Entering the Queue)
  • 59. 59 © Nokia Siemens Networks Handover request queued by target BTS Handover timers hoPeriodPBGT and hoPeriodUmbrella stopped Measurement processing and averaging continues as usual Intra BSC handover Inter BSC handover Queuing possibility checked for all possible target cells Order according conventional ranking Target BTS given by MSC by handover request message Queuing (Handover)
  • 60. 60 © Nokia Siemens Networks With TCH allocation Release of busy TCH  Check of queue from top to bottom for best matching request  If TCH allocation possible, request removed from queue Without TCH allocation Queuing timer expires Request of higher priority enters full queue Queuing (Leaving the Queue)
  • 61. 61 © Nokia Siemens Networks Directed Retry Timer maxTimeLimitDirectedRetry expires  call cleared, even if still in queue Queuing timer expires  target cell evaluation continues, if directed retry timer is still running Queuing (Together with Directed Retry)
  • 62. 62 © Nokia Siemens Networks BTS does not receive measurement report on SACCH for running call for the first time Counter initialised with value of radioLinkTimeout (4,8,..64 SACCH periods) SACCH not received again Counter decremented by 1 SACCH received again Counter incremented by 2 (but not beyond initial value) Counter has value 0 Call release due to radio link time out Example: short tunnel Dropped Call Control Radio Link Timeout
  • 63. 63 © Nokia Siemens Networks • RLT is based on SACCH deletion but SACCH is though not using a dynamic codec like voice in AMR, which means: • Using the EFR RLT value an AMR customer can have the call dropped because RLT = 0 when still the FER is good • RLT is not anymore reliable with the same value in AMR than in EFR • Due to the fact that the FER performance is different when comparing AMR calls to EFR calls, the Radio Link Timeout need to be defined separately for AMR • The Radio Link Timeout parameters for AMR are ARLT and AHRLT. The principle of these is the same than in the RLT but it is used only for the AMR capable mobile stations. ARLT & AHRLT are not supported in Talk Family base stations. Dropped Call Control Radio Link Timeout
  • 64. 64 © Nokia Siemens Networks Radio link timeout occurs callReestablishmentAllowed (RE) set to Y Receive level of BCCH measured for serving and adjacent cell Averaged over 5 s Strongest cell considered BCCH decoded C1 cell selection criterion fulfilled Cell not barred Cell belongs to selected PLMN Attempt to re-establish call Successful within 20s *  call re-established Not successful within 20s *  call released Example: long tunnel Dropped Call Control Call Reestablishment * MAX WAIT TIME OF RE-ESTAB REQ is a modifiable timer in MSC
  • 65. 65 © Nokia Siemens Networks NPT parameter related (Idle Parameter)
  • 66. 66 © Nokia Siemens Networks Measurement Processing
  • 67. 67 © Nokia Siemens Networks Measurement Report Standard • Rx level • Rx quality • Level & BSIC of up to 6 neighbours • 3G cells Enhanced Standard + following: • DL frame erasure rate • DTX bit error probability • Real time difference serving – adjacent cell • 3G cells • Control over reporting priority Measurements Idle mode • MS listens to BCCH Dedicated mode • MS sends DL measurement report on SACCH • BTS performs UL measurements Introduction
  • 68. 68 © Nokia Siemens Networks Measurement Report Standard • Rx level • Rx quality • Level & BSIC of up to 6 neighbours • 3G cells Enhanced Standard + following: • DL frame erasure rate • DTX bit error probability • Real time difference serving – adjacent cell • 3G cells • Control over reporting priority Measurements Idle mode • MS listens to BCCH Dedicated mode • MS sends DL measurement report on SACCH • BTS performs UL measurements Introduction
  • 69. 69 © Nokia Siemens Networks P (dBm) P (dBm) LEV No offset 10 dB offset -110 -100 0 -109 -99 1 -108 -98 2 . . . . . . . . . -49 -39 61 -48 -38 62 -47 -37 63 Activation of offset to code high levels scaleOrd (SCO)(SEG)(0,1,2)(0) 0 = no offset used 1 = offset used in general 2 = MS decides automatically about offset Coding of Rx Level
  • 70. 70 © Nokia Siemens Networks BER (%) BER (%) QUAL RANGE MEAN < 0.2 0.14 0 0.2-0.4 0.28 1 0.4-0.8 0.57 2 0.8-1.6 1.13 3 1.6-3.2 2.26 4 3.2-6.4 4.53 5 6.4-12.8 9.05 6 > 12.8 18.1 7 Coding of Rx Quality Average window = 4 Quality samples 0,0,7,0 WRONG!!: (0+0+7+0)/4 = 1.75 (wrong!!) RIGHT: (0.14+0.14.+18.1+0.14)/4 = 4.63 (right!!) => corresponds to Qual5
  • 71. 71 © Nokia Siemens Networks BEP BER (%) QUAL VALUE RANGE 22..31 < 0.2 0 19..21 0.2-0.4 1 16..18 0.4-0.8 2 13..15 0.8-1.6 3 10..12 1.6-3.2 4 7..9 3.2-6.3 5 4..6 6.3-12.6 6 0..3 > 12.6 7 Mapping of BEP to RX Quality
  • 72. 72 © Nokia Siemens Networks X axis: frame erasure rate (< 1%, 1-5 %, 5-10 %, 10-15 %, > 15 %) Y axis: RX quality (0..7) Z axis: Percentage of measurements for each FER category Frame Erasure Rate for Handover / Power Control Decision fepInPcHoUse (FPHO)(BSC)(Y,N)(N) Mapping of FER to RX Quality
  • 73. 73 © Nokia Siemens Networks • Decoding of BCCH • for serving (camped) cell every 30 s • for adjacent cells every 5 min • Pre-synchronization and decoding of BSIC • for adjacent cells every 30 s • Adjacent cell list • Updating every 60 s • BCCH decoding of new cell in 30 s MS Measurement Execution Idle Mode
  • 74. 74 © Nokia Siemens Networks • Measures RX level and quality for serving cell • Detects whether DTX is used 26 FRAME MULTIFRAME = 120 ms TDMA FRAMES TCH SACCH IDLE • Measures frequencies of adjacent cells • BSIC decoding for at least one adjacent cell • Pre-synchronization on SCH TDMA FRAMES 4.615 ms SACCH PERIOD = 480 ms RX TX RX TX RX TX MEAS MEAS MEAS MS Measurement Execution Dedicated Mode I
  • 75. 75 © Nokia Siemens Networks Power Control
  • 76. 76 © Nokia Siemens Networks • Longer service time of battery • Realization of power class • Supported by default on UL Reduced interference on DL/UL Activation of DL power control powerCtrlEnabled (PENA) Y,N Power control independent • for DL and UL • for each call Power Control Motivation
  • 77. 77 © Nokia Siemens Networks 30 dB Range Power class dependent range Attenuations Power Values Maximum MS output power msTxPwrMaxGSM (PMAX1) 5..39 dBm GSM 900 TCH msTxPwrMaxGSM1x00 0..36/32,33 dBm GSM 1800/1900 TCH (PMAX2) msTxPwrMaxCCH (TXP1) 5..39 dBm GSM 900 CCH msTxPwrMaxCCH1x00 0..30 dBm GSM 1800 CCH (TXP2) 0..32 dBm GSM 1900 CCH Minimum MS output power minMSTxPower (PMIN) 5..39 dBm GSM 900 0..36 dBm GSM 1800 0..32 dBm GSM 1900 Maximum BTS output power (by minimum attenuation) bsTxPwrMax (PMAX1) 0..30 dB GSM 900 bsTxPwrMax1x00 (PMAX2) 0..30 dB GSM 1800/1900 Minimum MS output power (by maximum attenuation) bsTxPowerMin 0..30 dB Power Control Parameter Output Power Limits
  • 78. 78 © Nokia Siemens Networks Fixed increment step size • pcIncrStepSize (INC) 2,4,6 dB Fixed decrement step size • pcRedStepSize (RED) 2,4,6 dB Desired power level can be achieved in 1 or 2 commands Yes Fixed step size No Variable step size Power Control Parameters Power Change Step Sizes
  • 79. 79 © Nokia Siemens Networks UL Level UL Quality <Av_RXQUAL_UL> <Av_RXLEV_UL> DL Level DL Quality <Av_RXQUAL_DL> <Av_RXLEV_DL> POWER CONTROL UPLINK THRESHOLD COMPARISON POWER CONTROL DOWNLINK Power control interval powerCtrlInterval (INT) 0..31 s Power Control Strategy Measurement Averaging
  • 80. 80 © Nokia Siemens Networks threshold Actual average samples Nx samples Less than Px samples exceed threshold No power change triggered Nx samples Px samples are equal to or exceed threshold Power change triggered Signal level thresholds pcUpperThresholdLevelDL/UL (UDR/UUR) -110..-47 dBm pcLowerThresholdLevelDL/UL (LDR/LUR) -110..-47 dBm Signal quality thresholds pcUpperThresholdQualDL/UL (UDR/UUR) 0..7 pcLowerThresholdQualDL/UL (LDR/LUR) 0..7 Number of average samples (for each threshold) Nx 1..32 Px 1..32 Power change step size estimation Power Control Strategy Triggering
  • 81. 81 © Nokia Siemens Networks Exceeded threshold Action Reason pcUpperThresholdLevelDL BTS power decrease Signal level pcLowerThresholdLevelDL BTS power increase Signal level pcUpperThresholdLevelUL MS power decrease Signal level pcLowerThresholdLevelUL MS power increase Signal level pcUpperThresholdQualDL BTS power decrease Signal quality pcLowerThresholdQualDL BTS power increase Signal quality pcUpperThresholdQualUL MS power decrease Signal quality pcLowerThresholdQualUL MS power increase Signal quality Power Control Strategy Scenarios
  • 82. 82 © Nokia Siemens Networks AMR Power Control Exceeded threshold Action Reason AMR Power Control FR PC Lower Threshold DL Rx Qual BTS power increase Poor DL signal quality AMR Power Control FR PC Lower Threshold UL Rx Qual MS power increase Poor UL signal quality AMR Power Control FR PC Upper Threshold DL Rx Qual BTS power decrease Good DL signal quality AMR Power Control FR PC Upper Threshold UL Rx Qual MS power decrease Good UL signal quality AMR Power Control HR PC Lower Threshold DL Rx Qual BTS power increase Poor DL signal quality AMR Power Control HR PC Lower Threshold UL Rx Qual MS power increase Poor UL signal quality AMR Power Control HR PC Upper Threshold DL Rx Qual BTS power decrease Good DL signal quality AMR Power Control HR PC Upper Threshold UL Rx Qual MS power decrease Good UL signal quality AMR FR AMR HR Details in chapter on AMR
  • 83. 83 © Nokia Siemens Networks POC Quality Signal level Increase due to bad Signal level Decrease Due to good Signal level Increase due to Bad quality Decrease due to good quality Qual 0 Qual 7 -110 dB -47 dB Lower Level(-90) Upper Level(-80) Upper Quality(1) Lower Quality(3) No action Ping pong effect
  • 84. 84 © Nokia Siemens Networks POC Quality Signal level Increase due to level Decrease Due to level Increase due to quality Decrease due to quality Qual 0 Qual 7 -110 dB -47 dB Lower Level Upper Level Upper Quality Lower Quality 6dB No action
  • 85. 85 © Nokia Siemens Networks POC and HOC (UL) Quality Signal level Qual 0 Qual 7 -110 dB -47 dB UL Level HO Threshold No action UL Quality HO Threshold When UL quality HO is triggered • Should MS be sent full power? •What about UL level
  • 86. 86 © Nokia Siemens Networks Power Control Summary Lower Level Upper Level Upper Quality Lower Quality No action Power decrease due to level Power increase due to quality Power increase due to level or quality Power increase due to quality Power decrease due to level or quality Power increase due to level Power decrease due to quality 6 dB Power increase due to level Qual 0 Qual 7 -110 dBm -47 dBm
  • 87. 87 © Nokia Siemens Networks pcLowerThresholdsLevelDL/UL Power control triggered UL: Power increase of MS DL: Power increase of BTS RXLEV_DL/UL > pcLowerThresholdLevelDL/UL - 2 powerIncrStepSize Yes Fixed step size PWR_INCR_STEP = powerIncrStepSize No Variable step size PWR_INCR_STEP = pcLowerThresholdLevelDL/UL – RXLEV_UL/DL Actual receive level RXLEV_DL/UL Power Increase Due to Signal Level For MS & BTS
  • 88. 88 © Nokia Siemens Networks pcUpperThresholdsLevelDL Power control triggered Power decrease Yes Fixed step size PWR_DECR_STEP = powerDecrStepSize No Variable step size PWR_DECR_STEP = Min (RXLEV_DL – pcUpperThresholdLevelDL, 10) Actual received level RXLEV_DL RXLEV_DL < pcUpperThresholdLevelDL + 2 powerDecrStepSize OR variableDLStepUse (VDLS) = No Power Decrease Due to Signal Level For BTS
  • 89. 89 © Nokia Siemens Networks pcUpperThresholdsLevelUL Power control triggered Power decrease Yes Fixed step size PWR_DECR_STEP = powerDecrStepSize No Variable step size PWR_DECR_STEP = RXLEV_UL – pcUpperThresholdLevelUL Actual received level RXLEV_UL RXLEV_UL < pcUpperThresholdLevelUL + 2 powerDecrStepSize Power Decrease Due to Signal Level For MS
  • 90. 90 © Nokia Siemens Networks pcLowerThresholdsQualDL/UL Power control triggered UL: Power increase of MS DL: Power increase of BTS Actual receive quality RXQUAL_DL/UL Variable step size based on actual quality PWR_INCR_STEP = (1 + Max (0,QUAL)) * powerIncrStepSize QUAL = RXQUAL_DL/UL – pcLowerThresholdQualDL/UL Step size based on actual level Take algorithm for power increase due to signal level Take largest step size Power Increase Due to Signal Quality For MS & BTS
  • 91. 91 © Nokia Siemens Networks pcUpperThresholdsQualDL/UL Power control triggered Actual received quality RXQUAL_DL/UL Actual RXLEV_DL/UL – pcLowerThresholdLevelDL/UL < 6 dB Yes No No power decrease Avoid ping pong effect Power decrease Take algorithm for power decrease due to signal level (different for MS & BTS power decrease) Power Decrease Due to Signal Quality For MS & BTS with No Power Optimization
  • 92. 92 © Nokia Siemens Networks NPT parameter related (POC Parameter) Should be greater than HOC
  • 93. 93 © Nokia Siemens Networks Handover Control
  • 94. 94 © Nokia Siemens Networks Intra cell Only other carrier / timeslot Inter cell Intra BSC Inter BSC Intra MSC Inter MSC Inter PLMN Global Cell ID required MCC + MNC + LAC + CI Germany Czech Republic Intra PLMN Simple Cell ID required LAC + CI Handover Types
  • 95. 95 © Nokia Siemens Networks Multi Layer Network Types Coverage Layer: Gives access to the network Capacity Layer: Provides additional capacity and allows traffic distribution Macro cells Micro cells Intelligent Underlay Overlay Different frequencies for high / low power TRx Normal frequency Super reuse frequency GSM 900 cell GSM 1800 cell
  • 96. 96 © Nokia Siemens Networks threshold Actual average samples Nx samples Less than Px samples >= threshold No handover triggered Nx samples Px samples are >= threshold handover triggered Signal interference thresholds hoThresholdsInterferenceDL/UL (IDR/IUR) -110..-47 dBm Signal quality thresholds hoThresholdsQualDL/UL (QDR/QUR) 0..7 Signal level thresholds hoThresholdLevelDL/UL (LDR/LUR) -110..-47 dBm hoThresholdRapidLevelUL (RPD) -110..-47 dBm MS speed thresholds upper/lowerSpeedLimit (USL/LSL) 0..255 (unit = 2km/h) Number of average samples Nx 1..32 Px 1..32 Target cell selection Handover Strategy Triggering Trigger Point – When the set threshold has been met or exceeded Px times of Nx times
  • 97. 97 © Nokia Siemens Networks More than one handover criterion fulfilled -> process of higher priority performed Handover and power control criteria fulfilled -> handover performed 1) Interference (uplink or downlink) 2) Intra-segment inter-band because of downlink level (from higher to lower frequency band) 3) Uplink quality 4) Downlink quality 5) AMR unpacking (uplink level and also uplink unpacking quality triggers) 6) Uplink level 7) AMR unpacking (downlink level and also downlink unpacking quality triggers) 8) Downlink level 9) Coverage based inter-system handover to WCDMA RAN 10) IMSI-based inter-system handover to WCDMA RAN 11) IMSI-based handover 12) DTM-based handover to WCDMA RAN 13) Inter-system handover to WCDMA RAN 14) MS-BS distance (maximum or minimum) 15) Turn-around-corner MS 16) Rapid field drop 17) Slow/fast-moving MS 18) Umbrella 19) Power budget 20) DTM-based handover to a GSM DTM cell 21) BSC-initiated TRHO 22) IUO 23) Intra-segment HO based on load 24) AMR packing because of good uplink and downlink quality 25) AMR unpacking because of bad uplink or downlink quality 26) PC because of lower quality thresholds (uplink and downlink) 27) PC because of lower level thresholds (uplink and downlink) 28) PC because of upper quality thresholds (uplink and downlink) 29) PC because of upper level thresholds (uplink and downlink) Handover Strategy (Priorities) Exercise: Whu UL has many times higher priority than DL?
  • 98. 98 © Nokia Siemens Networks HO due to UL/DL Quality IF AV_RXQUAL_DL_HO >= HoThresholdsQualDL THEN Handover cause Downlink quality IF AV_RXQUAL_UL_HO >= HoThresholdsQualUL THEN Handover cause Uplink quality Target cells is listed based on below criteria 1. AV_RXLEV_NCELL(n) > RxLevMinCell(n) + MAX(0,Pa) 2.AND IF EnableHoMarginLevQual(n)= Yes THEN AV_RXLEV_NCELL(n) > AV_RXLEV_DL_HO + (BsTxPwrMax - BS_TXPWR) + HoMarginQual(n) 3. ELSE PBGT(n) > HoMarginPBGT(n) (2) Order of preference of target cells PRIORITY(n) = HoPriorityLevel(n) - HoLoadFactor(n) HoLoadFactor value is taken into account when BTSLoadThreshold is exceeded. Interval between handovers and handover attempts Listing set of target cell Priority of target cell Timer of source cell
  • 99. 99 © Nokia Siemens Networks HO due to UL/DL LEVEL IF AV_RXLEV_DL_HO<= HoThresholdsLevDL THEN Handover cause Downlink level IF AV_RXLEV_UL_HO<= HoThresholdsLevUL THEN Handover cause Uplink level Target cells is listed based on below criteria 1. AV_RXLEV_NCELL(n) > RxLevMinCell(n) + MAX(0,Pa) 2.AND IF EnableHoMarginLevQual(n)= Yes THEN AV_RXLEV_NCELL(n) > AV_RXLEV_DL_HO + (BsTxPwrMax - BS_TXPWR) + HoMarginLev(n) 3. ELSE PBGT(n) > HoMarginPBGT(n) (2) Order of preference of target cells PRIORITY(n) = HoPriorityLevel(n) - HoLoadFactor(n) HoLoadFactor value is taken into account when BTSLoadThreshold is exceeded. GUARD_TIME = 2 * HoPeriodPBGT (Ho Due PBGT) GUARD_TIME = 2 * HoPeriodUmbrella (HO Due to Umbrella) Listing set of target cell Priority of target cell Timer of source cell
  • 100. 100 © Nokia Siemens Networks HO due to Fast/Slow moving MS MS speed in relation to cell size: IF MsSpeedDetectionState= 0 AdjCellLayer(n) = Lower FastMovingThreshold(n)> 0 Measured MS speed: IF AV_MS_SPEED <= LowerSpeedLimit THEN MS is slow-moving IF AV_MS_SPEED >= UpperSpeedLimit THEN MS is fast-moving AV_RXLEV_NCELL(n) > RxLevMinCell(n) + MAX (0, Pa) THEN RXLEV_CNT(n) = RXLEV_CNT(n) + 2 ELSE RXLEV_CNT(n) = RXLEV_CNT(n) - 1 IF RXLEV_CNT(n) >= FastMovingThreshold(n) THEN Handover cause Slow-moving MS Target cell evaluation: AdjCellLayer(n) = Lower/Upper AND AV_RXLEV_NCELL(n) > HoLevelUmbrella(n) (1') Handover to low layer cell is not possible if maximum power capability of MS exceeds gsm/dcsMicrocellThreshold IF MsSpeedDetectionState= 0 THEN Handover Cause Fast/Slow-moving MS ELSE Scale averaging parameters
  • 101. 101 © Nokia Siemens Networks HO due to Fast/Slow moving MS (Count) Target cell evaluation: AdjCellLayer(n) = Lower/Upper AND AV_RXLEV_NCELL(n) > HoLevelUmbrella(n) (1') Handover to low layer cell is not possible if maximum power capability of MS exceeds gsm/dcsMicrocellThreshold Order of preference of target cells PRIORITY(n) = HoPriorityLevel(n) - HoLoadFactor(n) HoLoadFactor value is taken into account when BTSLoadThreshold is exceeded Interval between handovers and handover attempts
  • 102. 102 © Nokia Siemens Networks HO due to Umbrella IF EnableUmbrellaHO= Yes HoPeriodUmbrella - interval between the umbrella handover threshold comparisons Umbrella handover and target cell evaluation: AV_RXLEV_NCELL(n) > HoLevelUmbrella(n) (1') AND ( [(P >= macro_thr) AND (pwr(n) >= macro_thr)] OR [(P <= micro_thr) AND (pwr(n) <= micro_thr)] OR [(P < macro_thr) AND (pwr(n) < macro_thr) AND (P > micro_thr) AND (pwr(n) > micro_thr)] ) Interval between handovers and handover attempts Order of preference of target cells PRIORITY (n) = HoPriorityLevel(n) - HoLoadFactor(n) HoLoadFactor value is taken into account when BTSLoadThreshold is exceeded.
  • 103. 103 © Nokia Siemens Networks Umbrella handover to 1800 cell A B 900 ‘Macro’ hoLevelUmbrella = -85 dBm gsmMacrocellThreshold = 33 dBm dcsMacrocellThreshold = 33 dBm Threshold RX level handover –95 dBm Threshold umbrella handover –85 dBm PTCH (msTxPwrMax(n)) = 30 dBm -> micro cell PMAX = 30 dBm -> handover to micro cell only hoThresholdLevelDL = -95 dBm 1800 ‘Micro’ RX level handover back to 900 cell Umbrella +FMT Handover Example After FMT>1 (example)
  • 104. 104 © Nokia Siemens Networks HO due to PBGT IF EnablePowerBudgetHO= Yes HoPeriodPBGT - interval between the power budget threshold comparisons Power budget and target cell evaluation: AV_RXLEV_NCELL(n) > RxLevMinCell(n) + MAX(0, Pa) (1) AND PBGT(n) > HoMarginPBGT(n) (2) PBGT(n) = (B - AV_RXLEV_DL_HO - (BsTxPwrMax - BS_TXPWR)) - (A - AV_RXLEV_NCELL(n)) Interval between handovers and handover attempts Order of preference of target cells PRIORITY (n) = HoPriorityLevel(n) - HoLoadFactor(n) HoLoadFactor value is taken into account when BTSLoadThreshold is exceeded.
  • 105. 105 © Nokia Siemens Networks Serving cell: A HO candidate target cells: B, C, D All cells have the following parameter set: rxLevMinCell= -99 dBm msTxPwrMax= 33 dBm btsTxPwrMax= 42 dBm hoMarginPBGT= 6 dB Target cell ‘hoPriorityLevel’: B priority: 4 C priority: 3 D priority: 3 Target cell ‘HOLoadFactor’: B load factor: 2 C load factor: 1 D load factor: 1 Target cell B is considered overloaded BTS BTS BTS BTS BSC A B C D Which cell (B/C/D) will be chosen as target for the Power Budget HO? AV_RXLEV_NCELL (B)= -80 dBm AV_RXLEV_NCELL (C)= -83 dBm AV_RXLEV_NCELL (D)= -85 dBm Serving cell A: AV_RXLEV_DL_HO= -92 dBm BTS_TX_PWR= 42 dBm Exercise Solution Power Budget Handover Exercise
  • 106. 106 © Nokia Siemens Networks enablePowerBudgetHo = Yes & enableUmbrellaHo = Yes Power budget handover to cells of the same layer Umbrella and FMT handover to cells of different layer Combined Umbrella & Power Budget HO Overview macrocells microcells RR PBGT,RR PBGT,RR UMBR+FMT UMBR umbrella HO RR radio reason HO PBGT power budget HO
  • 107. 107 © Nokia Siemens Networks UPPER layer (macro) SAME layer (serving layer) LOWER layer (micro) Predefinition of layer possible by adjCellLayer (ACL) Three layers visible relative to serving cell Used for target cell evaluation • Combined umbrella and power budget • Handover based on MS speed • Fast moving MS handling in macro cell N (no predefinition) Combined Umbrella & Power Budget HO Adjacent Cell Classification
  • 108. 108 © Nokia Siemens Networks HO due to Directed Retry IF DirectedRetryUsed = Yes Handover from SDCCH of serving cell to TCH of adjacent cell due to congestion minTimeLimitDR – Target cell evaluation started MaxTimeLimitDR - Target cell evaluation stopped Target Cell evaluation IF DirectedRetryMethod = 1 THEN AV_RXLEV_NCELL(n) > RxLevMinCell(n) + MAX(0, Pa) (1) AND AV_RXLEV_NCELL(n) > DRThreshold ELSE AV_RXLEV_NCELL(n) >RxLevMinCell(n) + MAX (0,Pa) Interval between handovers and handover attempts
  • 109. 109 © Nokia Siemens Networks No TCH available during call set up in serving cell -> handover to TCH of other cell Must be enabled with drInUse (DR) Y/N Thresholds to be exceeded by target cell according condition (1a) drMethod (DRM) 0/1 Defined type of threshold rxLevMinCell -110..-47 dBm Used if drMethod = 0 drThreshold (DRT) -110..-47 dBm Used if drMethod = 1 and drThreshold > rxLevMin Cell Timers (to be counted from TCH assignment) minTimeLimitDirectedRetry (MIDR) 0..14 s No target cell evaluation allowed maxTimeLimitDirectedRetry (MADR) 1..15 s Target cell evaluation allowed SDCCH TCH congested Time Assignment Request minTimeLimitDR maxTimeLimitDR DR not allowed DR allowed Directed Retry Parameters
  • 110. 110 © Nokia Siemens Networks HO due to Rapid Field Drop IF HoThresholdsRapidLevUL/Px > 0 IF Px number of RXLEV_UL measurement < HoThresholdsRapidLevUL THEN Handover cause Rapid field drop Target cell evaluation IF ChainedAdjacentCell(n) = Yes AND AV_RXLEV_NCELL(n) > RxLevMinCell(n) + MAX(0, Pa) (1) Order of preference of target cells: The target cells are ranked according to radio link properties (equation 1).
  • 111. 111 © Nokia Siemens Networks Chained Cell 1st 2nd Serving cell hoThresholdRapidLevUL = -93 dBm hoThresholdRapidLevUlN = 2 chainedAdjacentCell = Y Threshold rapid field drop handover –93 dBm Handover triggered Serving Cell Rapid Field Drop Handover Example
  • 112. 112 © Nokia Siemens Networks NPT parameter related (HOC Parameter) Should be lower than POC
  • 113. 113 © Nokia Siemens Networks NPT parameter related (ADCE Parameter)
  • 114. 114 © Nokia Siemens Networks NPT parameter related (ADCE Parameter)
  • 115. 115 © Nokia Siemens Networks KPI case
  • 116. 116 © Nokia Siemens Networks Optimization Principle service quality cell coverage cell capacity Optimization and Tailoring Optimization process is a way to do changes in a network so that those network have maximum on Capacity, Coverage and Quality Excessive value RxLevAmi will improve KPI but coverage and quality will reduce Site with height >40m with total tilt =2 will have wide coverage but KPI will bad Site with FRL/FRU = 100% will have max capacity but have lower Quality
  • 117. 117 © Nokia Siemens Networks KPI- Rules, SDCCH Blocking SDCCH Blocking >X% Is dynamic sddch active Is dynamic sdcch reaching max values in some moment Is combined sdcch used yes yes Check unavailability in the cells, averarage available sdcch Availability OK Check sdcch blocking. Can sdcch capacity be added without tch blocking SDCCH blocking is high yes No Yes, remove combined sdcch No, check parameter Values and make corrections No, activate Dynamic sdcch Yes, make corrections Case closed No Yes, add sdcch capacity Add TRX and add Sdcch capacity sdcch Blocking is still high No Yes Is high sdcch traffic due to Location updates. If yes, can LU area be optimized? Check also PRAU parameter, can the value be increased? no Yes, Optimize LU area border no ND_211 ND_130 Cngt_2 Blck_5 Blck_5b ND_139,ND_131 ND_130, uav_22 csf_1a,csf_11 Ava_45a ND_211 c1154 ND_211 c2032 NetAct Planner P_nbcs_cc_pm ND_211 If SDCCH block high please check: 1.TCH/SDCCH availability 2.LOC design (SDCCH traffic profile) 3.Parameter (CRO, CRH, RxLevAmi)
  • 118. 118 © Nokia Siemens Networks KPI- Rules, SDCCH Drop SD DCR > 2% and SD DCRnum > 10 Drops due to RF Reasons Drops due to Abis Reasons No Drops due to A-interface Reasons No Drops due to other Reasons No Case Closed No RF Abis A Other Yes Yes Yes Yes Yes No ND_166 If SDCCH drop high please check: 1.DL/UL Quality 2.CRO/CRH, TRP setting 3.TA profile – overshooting possibility 4.SDCCH TS location
  • 119. 119 © Nokia Siemens Networks KPI- Rules, SDCCH Drop due to RF/Abis
  • 120. 120 © Nokia Siemens Networks KPI- Rules, SDCCH Drop due to Aif
  • 121. 121 © Nokia Siemens Networks KPI- Rules, SDCCH Drop (A) A >X% A interface problems. Alarms are checked and A interface trace is done Investigate alarms.If problems are not solved, activate A trace Any improvements Any problems found. Trace was long enough Make corrections Check ET lines in the BSC and transcoders /TCSM. Any problems Repair ET lines Still A drops or problems No Activate No No Yes Yes Alarms Are Solved Yes Trace was not long enough Case Closed Yes No Trace was Long enough. Not An problem was found Investigate log files. Check DX causes, see document Call related DX causes in BSC No alarms
  • 122. 122 © Nokia Siemens Networks KPI- Rules, SDCCH Drop (other) Other Lapd fails BTS fails Netw Act Fails User Act, bcsu, resets Still lots of other drops Check all the alarms signalling fails or PCM fails. Check transmissio / parameters Yes No TRX or BTS fails. Check that BTS/ TRX are working properly Yes No Configuration problems, check configurations Yes No Resets or act fail channel failures Yes No Case Closed No Yes
  • 123. 123 © Nokia Siemens Networks KPI- Rules, TCH Block
  • 124. 124 © Nokia Siemens Networks TCH SEIZURES FOR NEW CALL tch_norm_seiz /c1009 +tch_seiz_due_sdcch_con /c1099 (S5) +msc_i_sdcch_tch /c4044 +bsc_i_sdcch_tch /c4057 +cell_sdcch_tch /c4074 -tch_succ_seiz_for_dir_acc /c1165 (S7) -tch_re_est_assign /c57032 (S7) TCH DROPS AFTER SEIZURE TCH_RADIO_FAIL /c1013 +TCH_RF_OLD_HO /c1014 +TCH_ABIS_FAIL_CALL /c1084 +TCH_ABIS_FAIL_OLD /c1085 +TCH_A_IF_FAIL_CALL /c1087 +TCH_A_IF_FAIL_OLD /c1088 +TCH_TR_FAIL /c1029 +TCH_TR_FAIL_OLD /c1030 +TCH_LAPD_FAIL /c1046 +TCH_BTS_FAIL /c1047 +TCH_USER_ACT /c1048 +TCH_BCSU_RESET /c1049 +TCH_NETW_ACT /c1050 +TCH_ACT_FAIL_CALL /c1081 -tch_re_est_assign /c57032 (S7) DROPS CALLS 100 * % STARTED CONVERSATIONS conver_started /c57015 - msc_i_tch_tch /c4043 CONVERSATION DROPS dropped_calls /c57007 TCH DROPS AFTER ASSIGNMENT tch_new_call_assign /c57033 +tch_ho_assign /c57034 -tch_norm_release /c57035 -tch_ho_release /c57036 -tch_re_est_assign /c57032 TCH ASSIGNMENTS FOR NEW CALL tch_new_call_assign /c57033 -tch_re_est_assign /c57032 TCH RELEASE Disconnect from MS RF CHN RELEASE Rf_channel_release_ack from BTS CONVERSATION STARTED conn_ack to BTS TCH ASSIGNED Assignment_complete from BTS TCH SEIZED BSC allocates a TCH as a response to TCH request (Channel Activation) Dcr_8h Dcr_5a Dcr_3j KPI- Rules, TCH Drop Call Ratios
  • 125. 125 © Nokia Siemens Networks KPI- Rules, TCH Drop due to RF/Abis
  • 126. 126 © Nokia Siemens Networks KPI- Rules, TCH Drop due to RF Old
  • 127. 127 © Nokia Siemens Networks How unnecessary HO happened?? GSM DCS RxLev = -80dBm CRO=0 RxLev = -95dBm CRO=23 HO threshold = 20 On idle mode received level for GSM is -80 dBm while DCS can be (-95 dBm + (2 x 23) -49dBm On dedicated mode user will move from DCS to GSM due to DCS level already too low Unecessary HO can lead to DCR due to RF Old and HO fail (ex. Due to GSM blocking)
  • 128. 128 © Nokia Siemens Networks How unnecessary HO happened?? GSM/DCS A GSM/DCS B Call establish on cell A, then received level drop below HO threshold. User will move from cell A to cell B After user serve by cell B, cell B will ask user to do handover as received level on cell B already below HO threshold. RxLev = -95dBm HO threshold = 20 RxLevmin from A to B = 12 RxLev = -92dBm HO threshold = 20 RxLevmin from A to B = 12
  • 129. 129 © Nokia Siemens Networks KPI- Rules, TCH Drop due to Aif
  • 130. 130 © Nokia Siemens Networks KPI- Rules, TCH Drop due to Transcoder
  • 131. 131 © Nokia Siemens Networks KPI- Rules, TCH Drop DCR > X% and DCRnum > XX Drops due to RF Reasons Drops due to Abis Reasons No Drops due to A-interface Reasons No Drops due to Transcoder Reasons No Drops due to other Reasons No Case Closed No RF Abis A TR Other Yes Yes Yes Yes Yes Yes No ND_163
  • 132. 132 © Nokia Siemens Networks KPI- Rules, TCH Drop (Other) Other Lapd fails BTS fails Netw Act Fails User Act, bcsu, act fails Still lots of other drops Check all the alarms signalling fails or PCM fails. Check transmissio / parameters Yes No TRX or BTS fails. Check that BTS/ TRX are working properly Yes No Configuration problems, check configurations Yes No Resets or act fail channel failures Yes No Case Closed No Yes
  • 133. 133 © Nokia Siemens Networks KPI- Rules, coverage problems (dlq_2a and ulq_2a) Here are some examples how different kind of problems can be found Like Normal distribution HW Problem, TRX/combiner etc is broken Q0 Q1 Q2 Q3 Q4 Q5 Q6 Q7 Q0 Q1 Q2 Q3 Q4 Q5 Q6 Q7 CL10 10645 8516 6813 5450 4360 3488 2791 2232 CL10 5323 4258 3406 2725 2180 1744 4563 9765 CL15 47043 37634 30108 24086 9865 7543 5643 2345 CL15 11761 9409 7527 6022 9383 1886 65432 7675 CL20 56204 44963 35971 28776 6574 10324 345 65 CL20 14051 11241 8993 7194 18271 2581 65438 63562 CL30 200863 160690 128552 102842 17654 9876 145 28 CL30 33772 27017 21614 17291 75037 2469 18765 14523 CL40 12785 10228 8182 6546 456 112 24 23 CL40 3196 2557 2046 1636 4938 28 3659 2648 CL63 4583 1123 583 452 261 76 26 2 CL63 1146 281 146 113 3378 19 100 174 HW problem, Q4 amount of samples is strange Interference problem Q0 Q1 Q2 Q3 Q4 Q5 Q6 Q7 Q0 Q1 Q2 Q3 Q4 Q5 Q6 Q7 CL10 5323 4258 3406 2725 2180 1744 1395 1116 CL10 5323 4258 3406 2725 2180 1744 1395 1116 CL15 23522 18817 15054 12043 18765 3772 2822 1173 CL15 23522 13234 10588 8470 13234 10588 8470 6776 CL20 28102 22482 17985 14388 36542 5162 173 33 CL20 28102 2123 1699 1359 2123 1699 1359 1087 CL30 67544 54035 43228 34582 150073 4938 73 14 CL30 67544 3634 2908 2326 3634 2908 2326 1861 CL40 6393 5114 4091 3273 9876 56 12 12 CL40 6393 4091 3273 2618 4091 3273 2618 4532 CL63 2292 562 292 226 6756 38 13 1 CL63 9987 7543 4323 3454 2275 1187 876 654 HW Problem, TRX/combiner etc is broken Q0 Q1 Q2 Q3 Q4 Q5 Q6 Q7 CL10 200863 160690 128552 102842 17654 9876 7865 6543 CL15 16543 13234 10588 8470 6776 2822 1173 234 CL20 2654 2123 1699 1359 1087 173 33 65 CL30 4543 3634 2908 2326 1861 73 14 28 CL40 5114 4091 3273 2618 2095 12 12 23 CL63 24 54 8 87 7 0 0 0 1 2 3 1. Lots of Q4 samples. Distribution is not OK  HW problem. Site reset will help 2. Lots of bad signal level samples. TRX/Combiner is broken. If no HW problem  Site is totally in wrong place, site is like transferring traffic to another cell ( cause level HO). Typically a HW problem 3. Lots of Q6 and Q7 samples. Distribution is not OK, no Q5 samples  HW problems. Site reset or broken TRX 4. Typical normal interference problem. Here are some examples how different kind of HW problems can be found 4
  • 134. 134 © Nokia Siemens Networks KPI- Rules, Interference analysis DL /UL RxQualityxRxLevel Coverage Problem: Bad quality and Low Rx Level Interference Problem: Bad quality and High Rx Level Good Quality High Rv Level HW Problem: Bad Quality for all Rx Levels NWD report 204 model HW Problem All samples below - 100dBm CL10  <-100dBm Same level – quality distribution for both UL and DL
  • 135. 135 © Nokia Siemens Networks KPI- Rules, Interference, UL q0 q1 q2 q3 q4 q5 q6 q7 -100dBm 10645 8516 6813 5450 4360 3488 2791 2232 -95dBm 47043 37634 30108 24086 9865 7543 5643 2345 -90dBm 56204 44963 35971 28776 16574 5676 845 65 -80dBm 200863 160690 128552 102842 17654 3653 145 28 -70dBm 1234 987 790 632 505 404 323 259 -47dBm 24 19 15 12 10 8 6 5 MS power control can be seen here. If Power is reduced → no bad UL problems. BSC border is increasing good level samples q0 q1 q2 q3 q4 q5 q6 q7 -100dBm 10645 8516 6813 5450 4360 3488 2791 2232 -95dBm 47043 37634 30108 24086 9865 7543 5643 2345 -90dBm 56204 44963 35971 28776 16574 5676 845 65 -80dBm 200863 160690 128552 102842 17654 3653 145 28 -70dBm 1234 987 790 632 505 404 323 259 -47dBm 24 19 15 12 10 8 6 5 Bad interference problems. By POC parameter interference can be decreased, how power is adjusted etc. Also optimum MS power feature improves UL interference, no full power is sent after HO. q0 q1 q2 q3 q4 q5 q6 q7 -100dBm 10645 8516 6813 5450 4360 3488 2791 2232 -95dBm 47043 37634 30108 24086 9865 7543 5643 2345 -90dBm 56204 44963 35971 28776 16574 5676 845 65 -80dBm 200863 160690 128552 102842 17654 3653 145 28 -70dBm 1234 987 790 632 505 404 323 259 -47dBm 24 19 15 12 10 8 6 5 Bad quality sample due to signal level problems. Diversity should be checked, also possibilities to use LNA to improve UL signal level. Antenna place should be also checked if there are some obstacles near the antenna.
  • 136. 136 © Nokia Siemens Networks KPI- Rules, Interference, UL, examples UL_q0 UL_q1 UL_q2 UL_q3 UL_q4 UL_q5 UL_q6 UL_q7 DL_q0 DL_q1 DL_q2 DL_q3 DL_q4 DL_q5 DL_q6 DL_q7 -100dBm 251992 30668 20552 18417 18156 18286 16983 12478 27862 5537 5529 6069 6109 6107 5389 4119 -95dBm 123653 1151 403 692 519 351 221 72 89094 4236 3853 3576 2893 2264 1372 584 -90dBm 62938 247 144 288 353 129 62 29 142228 2732 2550 2356 1510 1114 774 404 -80dBm 27005 51 65 149 177 82 40 16 222462 1523 1355 1552 716 812 1081 343 -70dBm 2831 3 9 28 87 10 6 0 44504 91 123 151 81 101 191 88 -47dBm 751 0 4 10 25 1 0 0 5994 49 17 17 12 29 65 10 Huge amount of UL bad samples. Cells is not working properly, it is like transferring traffic, UL quality/ UL level HO’s are triggering immediately. These kind of cells must be investigated. UL_q0 UL_q1 UL_q2 UL_q3 UL_q4 UL_q5 UL_q6 UL_q7 -100dBm 490 137 368 605 1014 1378 1830 2586 -95dBm 8410 3768 3225 3023 2767 2304 1561 1859 -90dBm 38512 5249 3066 2323 1692 1570 1191 1268 -80dBm 219137 4600 2453 2311 1470 1724 1864 1221 -70dBm 509591 2504 1812 3050 1271 1465 1649 337 -47dBm 244302 582 711 1363 1713 873 671 87 UL_q0 UL_q1 UL_q2 UL_q3 UL_q4 UL_q5 UL_q6 UL_q7 -100dBm 70004 5020 3500 2564 2232 1946 2190 2579 -95dBm 80339 392 286 461 328 250 275 92 -90dBm 106883 233 318 602 199 146 234 64 -80dBm 246892 227 314 860 298 338 395 60 -70dBm 254875 155 298 935 203 135 166 15 -47dBm 23288 21 27 103 109 11 41 0 Some UL interference in good signal level. UL power control is not working properly. Ul power control is good indicator, if power is adjusted, there are no big problems in UL direction There is no UL interference, or just a little. MS is adjusting power properly, there are only little samples in good UL signal level.
  • 137. 137 © Nokia Siemens Networks q0 q1 q2 q3 q4 q5 q6 q7 -100dBm 10645 8516 6813 5450 4360 3488 2791 2232 -95dBm 47043 37634 30108 24086 9865 7543 5643 2345 -90dBm 56204 44963 35971 28776 16574 5676 845 65 -80dBm 200863 160690 128552 102842 17654 3653 145 28 -70dBm 12785 10228 8182 6546 456 112 24 23 -47dBm 4583 1123 583 452 261 76 26 2 KPI- Rules, Interference, DL Bad interference problem → signal level good (<-80dBm) and sometimes no better cell available. If better cell available and quality samples are 4 or worse → HO (reason quality or interference, depends on the parameter) Interference is causing drops. Really bad interference problem → signal level is really good (<-70dBm) and usually no better cell available → no HO → samples can be seen in the table. Interference is causing drops. Situation is “network is working properly” If there are quality 4 or worse samples → quality HO. Most of the samples are q4 samples. If lots of q5..q7 samples → interference problem and interference must be analyzed / removed. If quality HOs but no q5..q7 samples → better cell is available → no interference problems. In these signal levels overlapping exists and if handover reason is no PBGT, it will be quality HO. By parameter amount of quality HOs can be adjusted q0 q1 q2 q3 q4 q5 q6 q7 -100dBm 10645 8516 6813 5450 4360 3488 2791 2232 -95dBm 47043 37634 30108 24086 9865 7543 5643 2345 -90dBm 56204 44963 35971 28776 16574 5676 845 65 -80dBm 200863 160690 128552 102842 17654 3653 145 28 -70dBm 12785 10228 8182 6546 456 112 24 23 -47dBm 4583 1123 583 452 261 76 26 2 q0 q1 q2 q3 q4 q5 q6 q7 -100dBm 10645 8516 6813 5450 4360 3488 2791 2232 -95dBm 47043 37634 30108 24086 9865 7543 5643 2345 -90dBm 56204 44963 35971 28776 16574 5676 845 65 -80dBm 200863 160690 128552 102842 17654 3653 145 28 -70dBm 12785 10228 8182 6546 456 112 24 23 -47dBm 4583 1123 583 452 261 76 26 2 q0 q1 q2 q3 q4 q5 q6 q7 -100dBm 10645 8516 6813 5450 4360 3488 2791 2232 -95dBm 47043 37634 30108 24086 9865 7543 5643 2345 -90dBm 56204 44963 35971 28776 16574 5676 845 65 -80dBm 200863 160690 128552 102842 17654 3653 145 28 -70dBm 12785 10228 8182 6546 456 112 24 23 -47dBm 4583 1123 583 452 261 76 26 2 Bad quality samples due to signal level problems. If PBGT overlapping is not existing → lots of quality HOs + level HOs (margin are lower than in PBGT). Not interference problem, more signal level problem. Check how much samples vs. HOs → are better cells available or not.
  • 138. 138 © Nokia Siemens Networks KPI- Rules, Interference, DL, examples DL_q0 DL_q1 DL_q2 DL_q3 DL_q4 DL_q5 DL_q6 DL_q7 -100dBm 12057 2827 3108 3952 4783 6200 7013 8156 -95dBm 44818 4811 5041 5866 6587 7223 7259 6781 -90dBm 98587 7107 7400 8334 8470 8781 7825 6162 -80dBm 225919 7450 7731 8445 7726 7441 5695 3369 -70dBm 88708 1014 971 998 751 688 689 367 -47dBm 15881 84 109 122 104 167 199 184 DL_q0 DL_q1 DL_q2 DL_q3 DL_q4 DL_q5 DL_q6 DL_q7 -100dBm 8006 1636 1681 2197 2379 2510 2025 1290 -95dBm 24951 1636 1627 1767 1037 431 175 53 -90dBm 57559 2171 1884 1651 781 330 161 47 -80dBm 200602 5771 4686 4130 1736 566 254 97 -70dBm 304206 5464 4310 3796 1315 350 153 105 -47dBm 108047 2134 1908 1623 689 230 129 64 There are almost as much samples Q5 and Q7 samples as Q 4 samples → even interference is really bad or there is no better cell available ( no ho’s after bad quality samples). These kind of interference cells should be optimized, otherwise there are lots of drops etc There are no as much Q5…Q7 samples as Q4 samples → after interference samples Quality HO is done or the interference situation is not so bad, for example sampling is Q0,Q2,Q4,Q2,Q5,Q0,Q2,Q3,Q4,Q2 → quality HO is not triggering DL_q0 DL_q1 DL_q2 DL_q3 DL_q4 DL_q5 DL_q6 DL_q7 -100dBm 7055 1398 1374 1906 2163 2003 1468 832 -95dBm 20109 1307 1274 1161 694 332 211 84 -90dBm 34531 1053 745 587 273 131 94 41 -80dBm 107539 875 518 630 161 98 113 47 -70dBm 177614 283 316 663 61 32 29 9 -47dBm 58718 78 91 198 54 40 54 32 There are bad quality samples only due to signal level problems.
  • 139. 139 © Nokia Siemens Networks KPI- Rules, Interference (internal / external) •Internal Interference – Interference can be seen from stats or can be measured by scanner. – Neighbor cells (DL) or mobiles (UL) are causing interference. – By frequency / network planning interference can be decreased. •External Interference – Interference can be seen from stats or can be measured by scanner. – External radio frequencies are causing interference  Military use  In the border area, interference is coming from other country.  Some external wireless system (for example some wireless industry system) is causing interference  Increased I level can be also due to external interference
  • 140. 140 © Nokia Siemens Networks KPI- Rules, HOSR
  • 141. 141 © Nokia Siemens Networks KPI- Rules, HO fail sum(msc_o_succ_ho + bsc_o_succ_ho + cell_succ_ho) Total HO success ratio = 100 * (-------------------------------------------------------------------------------- ) (ho_65) sum(msc_o_ho_cmd + bsc_o_ho_cmd_assgn + bts_ho_assgn) sum(a.msc_o_succ_ho + a.bsc_o_succ_ho + a.cell_succ_ho + a.msc_to_wcdma_ran_succ_tch_ho) Total HO failure ratio = 100 * (1- -------------------------------------------------------------------------------------) (hfr_2b) sum(b.msc_o_ho_cmd + b.bsc_o_ho_cmd_assgn + b.bts_ho_assgn+a.msc_gen_sys_wcdma_ran_ho_com) /* handovers failing due to blocking */ sum(a.msc_o_fail_lack + a.bsc_o_fail_lack + a.cell_fail_lack + a.msc_to_wcdma_ran_fail_lack) HO failure ratio due to RF blocking = 100 * --------------------------------------------------------------------------------------- /* all HO attempts */ sum(b.msc_o_ho_cmd + b.bsc_o_ho_cmd_assgn + b.bts_ho_assgn + a.msc_gen_sys_wcdma_ran_ho_com) (hfr_55a)

Editor's Notes

  • #33: (continued on the next page)
  • #44: Two slides put together notAllowedAccessClasses :Mobile Subscribers are uniformly distributed among 10 "access classes" coded 0 … 9. This information is stored in the SIM. To control the load of the RACH (slotted Alhoa) the operator can forbid some classes to access the cell. Additional VIP classes are coded between 11 and 15. emergencyCallRestricted : Tells if MS with access classes between 0 and 9 are forbidden emergency calls in the cell. This is independent from the access classes being allowed or not. It corresponds to access class 10 being forbidden access. plmnPermitted tells the Mobile Station which neighbouring cells to report to the Network. Only those with NCC among the ones indicated by plmnPermitted are reported. NCC is a part of the BSIC and is decoded in the SCH cellReselectHysteresis when cell reselection involves a change in the Location Area, an hysteresis is used to limit the amount of signalling that would derive from the Location Updates. msMaxDistanceInCallSetup The parameter is expressed as an access delay timing advance. In range from 0 to 62 one step size correlates with the distance of 550 meters. If the value of the parameter is above 63 the access is never rejected. In fact, even with Extended Cell, the RACH is received either by the Normal TRX or by the Extended TRXs. However it never exceeds 35 km for the TRX that receives it. RadiusExtension is the distance from the BTS where the extended part of the Cell begins.
  • #45: Two slides put together notAllowedAccessClasses :Mobile Subscribers are uniformly distributed among 10 "access classes" coded 0 … 9. This information is stored in the SIM. To control the load of the RACH (slotted Alhoa) the operator can forbid some classes to access the cell. Additional VIP classes are coded between 11 and 15. emergencyCallRestricted : Tells if MS with access classes between 0 and 9 are forbidden emergency calls in the cell. This is independent from the access classes being allowed or not. It corresponds to access class 10 being forbidden access. plmnPermitted tells the Mobile Station which neighbouring cells to report to the Network. Only those with NCC among the ones indicated by plmnPermitted are reported. NCC is a part of the BSIC and is decoded in the SCH cellReselectHysteresis when cell reselection involves a change in the Location Area, an hysteresis is used to limit the amount of signalling that would derive from the Location Updates. msMaxDistanceInCallSetup The parameter is expressed as an access delay timing advance. In range from 0 to 62 one step size correlates with the distance of 550 meters. If the value of the parameter is above 63 the access is never rejected. In fact, even with Extended Cell, the RACH is received either by the Normal TRX or by the Extended TRXs. However it never exceeds 35 km for the TRX that receives it. RadiusExtension is the distance from the BTS where the extended part of the Cell begins.
  • #51: Dynamic SDCCH HR can be added
  • #97: Answer: Power control might be the reason. If more UL reason, check that POC is working rapidly enough
  • #124: Dcr 3j – does not have HO into account. You can know the cause of drops but your are taking into account some drops before you have the traffic channel under use. Some failures in the release phase are included in this formula (tch_abis_fail_call) but are, in fact, not perceived as dropped calls by users. “tch_norm_seiz” does not mean that the user is on TCH. Dcr 8a – does not allow to know the drops cause. Calculated in the instant where the MS has the TCH. Good at cluster level but not at BTS level because the denominator counts only started new calls (there can be a lot of HOs in too) In the denominator you never have HO realted actions (only new calls)