SlideShare a Scribd company logo

Wcdma physical layer

Download as PPT, PDF
R
rajibratan

The document discusses the physical layer design of WCDMA networks. It provides an overview of WCDMA network architecture and the UMTS network model. It then describes the physical channels, transport formats, channel coding, spreading techniques and code types used in the WCDMA uplink and downlink. Key aspects covered include dedicated and common physical channels, orthogonal variable spreading factor channelization codes, scrambling codes, and transport block sets.

EducationTechnologyEntertainment & Humor
1 of 59
Downloaded 697 times
1
2
3
4
5
6
Most read
7
8
9
10
11
12
Most read
13
Most read
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
WCDMA Physical Layer Design A. Chockalingam Assistant Professor Indian Institute of Science, Bangalore-12 [email_address] http://ece.iisc.ernet.in/~achockal
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Outline WCDMA Network Architecture WCDMA Physical Layer Physical / Transport / Logical Channels Uplink Spreading - Channelisation / Scrambling Transport Formats and Configuration Multiplexing and Channel Coding Downlink Spreading / Scrambling / Channelisation Multiplexing and Channel Coding
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore 2G to 3G Evolution IS-95A IS-95B cdma2000 IMT2000 IMT2000: ITU’s Standardization Effort towards 3G (IMT-2000 previously termed as FPLMTS) UMTS: European Effort (Specified by 3G Partnership Project 3GPP) GSM GPRS WCDMA EDGE D A T A I S 9 9
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore UMTS NW Model USIM Mobile Equipment Access Network Serving Network PS/CS Transit Network Cu Uu Iu Yu User Equipment Access Network Core Network Infrastructure Home Network Access Stratum (Protocols between UE and Access NW) Non-access Stratum (Protocols between UE and Core NW) Zu Stratum: Refers to a way of grouping protocols handling activities
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore UMTS NW Architecture Node B UE UE UE Node B Node B Node B RNC RNC UTRAN RNS RNS CN CN (CS Domain) CN (PS Domain) SGSN GGSN Registers HLR/AuC/EIR (Home Network) 3G MSC / VLR 3G GMSC Uu Iu Iur Iub
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore WCDMA System Features UTRA FDD mode and TDD mode UTRA FDD features Multiple Access: CDMA Channel Spacing: 5 MHz Chip Rate: 3.84 Mcps Frame Length: 10 msec Time Slots: 15 slots per 10 msec frame Spreading Factor: 4 to 512 Multi-rate: Through Multi-code or Orthogonal Variable Spreading
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore UTRA FDD Features FEC Codes: Rate 1/2, 1/3 convolutional code with constraint length K = 9 Rate 1/3, 8-state Turbo coding Interleaving: Intra- or Inter-frame interleaving (10, 20 40, 80 msec) Modulation: QPSK Detection: Coherent based on pilot symbols Micro diversity: RAKE in BS and UE Power Control: Fast closed-loop at 1500 Hz rate Intra-frequency HO: Soft / Softer Handover Inter-frequency HO: Hard Handover Interference Cancellation: Support for multiuser detection
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Radio Interface Protocol Model PHY MAC RLC Transport Channels Logical Channels User Plane Radio Bearers Signalling Radio Bearers PDCP BMC RRC USER PLANE CONTROL PLANE Control L1 (Radio Physical Layer) L2 (Radio Link Layer) L3 (Radio Network Layer) U-Plane Radio Bearers
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore WCDMA Radio Channels Physical Channels Transmission media. Two types of physical channels defined in L1; FDD and TDD. FDD is characterized by frequency, code, I/Q phase Follow a layered structure of “radio frames” and “time slots” Transport Channels describes the way information is transferred over the radio interface Logical Channels the type of information transferred characterizes a logical channel UE BS RNC Logical Channels Transport Channels Physical Channels
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Physical Channels Corresponds to a specific carrier frequency, code, relative phase in I and Q branches Dedicated and Common Physical Channels Layered structure of radio frames and time slots A radio frame = 10 msec = 15 slots/frame 1 frame = 38400 chips, 1 slot = 2560 chips Slot configuration varies depending on the channel bit rate of the physical channel # bits/slot different for different physical channels may vary with time (on a frame by frame basis)
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore U/L Physical Channels Dedicated U/L Channels DPDCH DPCCH Common U/L Channels PRACH Preamble part Message part PCPCH Preamble part Message part
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Dedicated U/L Physical Channels Two types Dedicated Physical Data CHannel (DPDCH) Dedicated Physical Control CHannel (DPCCH) Both are I/Q code multiplexed within each radio frame U/L DPDCH carries the DCH transport channel U/L DPCCH carries L1 control bits such as Pilot bits (to enable channel estimation for coherent detection at BS) Transmit power control (TPC) commands Feedback Information (FBI) used for CL transmit diversity and Site Selection Diversity Transmission (SDTC) Transport Format Combination Indicator (TFCI) for several simultaneous services. Informs the rx of the transport format combination of the transport channels mapped to DPDCH
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore U/L Frame Structure There is only one U/L DPCCH on each radio link There can be 0, 1, or several DPDCHs on each radio link 10 msec frames divided into 15 slots S0 S1 S2 S3 S13 S14 1 Frame = 15 slots = 10 msec DATA 1 time slot = 2/3 msec DPDCH (on I-Chl) Pilot DPCCH (on Q-Chl) TFCI FBI TPC 10 bits = 2560 chips => SF = 256 (N data bits)
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore I, Q Spreading for DPDCH, DPCCH DPDCH-1 DPDCH-3 C d,1 C d,3 B d B d I DPDCH-2 DPCCH-2 C d,2 C c B c B d Q I+jQ S dpch,n C c, C d,n: Channelization codes Sdpch,n: Scrambling code B d, B c: Gain factors Up to 6 DPDCHs in parallel j
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore WCDMA Transmission Rates (U/L) System Chip Rate : 3.84 Mcps Symbol Rates on Uplink Chl Symb Rate Chl Bit Rate SF Bits/frame N data 15 Ks/s 15 Kb/s 256 150 10 30 Ks/s 30 Kb/s 128 300 20 60 Ks/s 60 Kb/s 64 600 40 120 Ks/s 120 Kb/s 32 1200 80 240 Ks/s 240 Kb/s 16 2400 160 480 Ks/s 480 Kb/s 8 4800 320 960 Ks/s 960 Kb/s 4 9600 640
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore WCDMA Channelisation Codes Orthogonal codes Used for channel separation both in U/L and D/L directions Can have different spreading factor values (thus support different symbol rates) C ch,SF,k : SF - Spreading Factor, k is the code number 0<=k<= SF-1 Spreading factor value indicates how many bits of those codes are used in a connection
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore U/L Channelization Codes Orthogonal Variable Spreading Factor (OVSF) channelization codes Separates data / control channels from same UE Preserves orthogonality between these channels (1) (1,1) (1,-1) (1,1,1,1) (1,1,-1,-1) (1,-1,1,-1) (1,-1,-1,1) SF=1 SF=2 SF=4 C(SF,k) SF: Spreading Factor k: code number 0<k<=SF-1
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore U/L Scrambling Codes Use complex valued scrambling code Long scrambling sequences (2^24) Gold sequences (linear combination of two m-sequences) Short scrambling sequences (2^24) from a family sequence of periodically extended S(2) codes Long or short sequences for DPCCH / DPDCH Only long sequences for message parts of PRACH and PCPCH
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore WCDMA Code Types Scrambling Codes, Channelisation Codes Uplink Downlink Scrambling codes User separation Cell separation Channelisation Data and Control Users within a codes channels from the cell same terminal Spreading code = Scrambling code x Channelisation code
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Common U/L Physical Channels Two Types Physical Random Access CHannel (PRACH) Physical Common Packet CHannel (PCPCH) Physical Random Access CHannel (PRACH) carries RACH Uses S-ALOHA technique with fast Acquisition Indication Access slots (15 access slots per 2 frames) RA transmission consists of several 4096 chip preambles (uses 256 repetitions of 16 chips signature sequence) and 1or 2 frame message Preamble Message Part (1 or 2 frames) 4096 Chips Preamble
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Random Access UE BS PRACH: Preamble sent (initial access) No detection on AICH PRACH: Preamble sent (initial access) AICH: Preamble sent detected PRACH: Random Access Info sent
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Common U/L Physical Channels Physical Common Packet CHannel (PCPCH) Carries CPCH CPCH is based on DSMA-CD technique with fast Acquisition Indication Access slot timing and structure are identical to those defined for RACH Transmission consists of Access preamble(s) - one or several each 4096 chips Collision Detection preamble DPCCH Power Control Preamble (0 or 8 slots) Message of variable length (Nx10 msec) PCPCH good for carrying small sized bursty data
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Transport Formats / Configurations Transport Block (TB) Basic unit of data exchanged between L1 & MAC for L1 processing Transport Block Size: Number of bits in a TB. Transport Block Set (TBS) A set of TBs exchanged between L1 and MAC at the same time instant using the same transport channel Transport Block Set Size: Number of bits in a TBS Transmission Time Interval (TTI) Periodicity at which a TBS is transferred by the physical layer on to the radio interface - {10, 20, 40, 80 ms} MAC delivers one TBS to the physical layer every TTI
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Transport Formats / Configurations Transport Format (TF) Format offered by L1 to MAC (and vice versa) for the delivery of a TBS during a TTI on a given transport channel (TrCH) Dynamic part (TB size, TBS size) Semi-static part (TTI, type/rate of coding,size of CRC) TB size, TBS size, TTI define the TrCH bit rate before L1 processing e.g., TB size = 336 bits (320 bit payload + 16 bits RLC header) TBS size = 2 TBs per TTI, TTI = 10 ms DCH Bit rate (with RLC header) = 336*2/10 = 67.2 Kbps User Bit rate (without RLC header) = 320*2/10 = 64 Kbps Variable bit rate can be achieved by changing ( between TTIs ) either the TBS size only, or both the TB size and TBS Size Transport Format Set (TFS) a set of TFs associated with a TrCH semi-static part of all TFs in a TFS is the same
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Transport Formats / Configurations Transport Format Combination (TFC) Multiple TrCHs each having a TF Authorized combination of the currently valid TFs that can be submitted to L1 on a CCTrCH , containing one TF from each TrCH Transport Format Combination Set (TFCS) A set of TFCs on a CCTrCH. Produced by RNC TFCS is given to MAC by L3 for control MAC chooses between the different TFCs specified in the TFCS MAC has control over only the dynamic part of the TFs. Semi-static part relates to QoS (e.g., quality) and is controlled by RNC admission control Bit rate can be changed quickly by MAC with no need to L3 signaling Transport Format Indicator (TFI) A label for a specific TF within a TFS. Used between MAC and L1 Transport Format Combination Indicator (TFCI) Used to inform the receiving side of the currently valid TFC
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Transport Formats / Configurations TTI TTI TTI TTI TTI TTI TB DCH1 DCH2 TB TB TB TB TB TB Transport Block Set (TBS) TB TB Transport Format (TF) Transport Format Set (TFS) Transport Format Combination (TFC) Transport Format Combination Set (TFCS)
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore TFI and TFCI (Transmitter) Transport Chl 1 Transport Chl 2 Transport Block Transport Block Transport Block Transport Block TFI TFI TFCI Coding and Multiplexing Physical Layer Higher Layer DPCCH (Q-Chl) DPDCH (I-Chl) Physical Control Chl Physical Data Chl E.g: Two transport channels mapped to a single physical channel This dotted line represents the Iur interface in case of NW side
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore TFI and TFCI (Receiver) Transport Chl 1 Transport Chl 2 Transport Block & EI Transport Block & EI Transport Block & EI Transport Block & EI TFI TFI TFCI Decode Decoding and Demultiplexing Physical Layer Higher Layer DPCCH (Q-Chl) DPDCH (I-Chl) EI: Error Indication Physical Control Chl Physical Data Chl
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore TFI and TFCI Each transport channel is accompanied by a TFI at each time event at which data is expected to arrive from HL Physical layer combines the TFI info from different transport channels to the TFCI TFCI is sent on the DPCCH to inform the receiver about the instantaneous transport format combination of the transport channels mapped to the U/L DPDCH transmitted simultaneously
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Transport Format (e.g., Speech) Conversational Speech (12 Kbps) 12.2 Kbps max. TTI: 20 msec Transport Formats (TF) available: TF RAB1 RAB2 RAB3 TF0v 0 x 81 0 x 103 0 x 60 (e.g., silence) TF1v 1 x 81 1 x 103 1 x 60 (e.g, active voice) two other formats too (see Stds. Doc.) TFC: (TF0, TF0, TF0) e.g., during silence (TF1, TF1, TF1) e.g., during active voice periods
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Transport Format (e.g., Data) Interactive/Background Data (64 Kbps) 64 Kbps max. TTI: 20 msec Transport Block (TB) size = 336 bits Transport Formats (TF) available: TF0 - 0 x 336 TF1 - 1 x 336 TF2 - 2 x 336 TF3 - 3 x 336 TF4 - 4 x 336
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Transport Format (Speech + Data) Conversational speech (12 Kbps) + Interactive/Background Data (64 Kbps) Voice TrCH Data TrCH TFC1: (TF0v, TF0v, TF0v) TF0d TFC2: (TF0v, TF0v, TF0v) TF1d TFC3: (TF0v, TF0v, TF0v) TF2d TFC4: (TF0v, TF0v, TF0v) TF3d TFC5: (TF0v, TF0v, TF0v) TF4d TFC6: (TF1v, TF1v, TF1v) TF0d TFC7: (TF1v, TF1v, TF1v) TF1d TFC8: (TF1v, TF1v, TF1v) TF2d TFC9: (TF1v, TF1v, TF1v) TF3d TFC10: (TF1v, TF1v, TF1v) TF4d
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Multiplexing & Channel Coding Data arrives at the coding/mux unit in transport block sets, once every transmission time interval (TTI) TTI depends on the transport channel; {10, 20, 40, 80 ms}) Main steps Add CRC to each block transport block concatenation and block segmentation channel coding first interleaving (per TTI) radio frame segmentation (when TTI > 10 ms) rate matching (repetition or puncturing) multiplexing of transport channels (CCTrCH) insertion of DTX indication bits physical channel segmentation second interleaving (per radio frame, ie., among bits in 1 radio frame) mapping to physical channel
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Multiplexing & Channel Coding (U/L) CRC Attachment TrBk Concatenation/ Code Block Segmentation Channel Coding Radio Frame Equalization 1st Interleaving Radio Frame Segmentation Rate Matching CCTrCH CRC Attachment TrBk Concatenation/ Code Block Segmentation Channel Coding Radio Frame Equalization 1st Interleaving Radio Frame Segmentation Rate Matching TrCH-2 TrCH Multiplexing Physical Channel Segmentation 2nd interleaving TrCH-1 Physical Channel Mapping PhCH#2 PhCH#1
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Multiplexing & Channel Coding (..cntd) Applicable to DCH, RACH, CPCH, DSCH, BCH, FACH, PCH CRC add CRC to each transport block for error detection CRC calculated on entire transport block Size of CRC: 24, 16, 12, 8, 0 bits what CRC size is used for each TrCH is signaled from higher layers
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Multiplexing & Channel Coding (..cntd) TrBk Concatenation & Code Block Segmentation all transport blocks in a TTI are concatenated if no. of bits in a TTI after concatenation (X) is greater than the maximum size of the code block (in the channel coding block), then code block segmentation is done max. size of the code block (Z) depends on whether Convolutional code ( Z = 504 bits) or Turbo code ( Z = 5114 bits) is used for the TrCH Code blocks after segmentation are of the same size Filler bits (zeros) added to 1st coded block to to make integer number of code blocks, or if X < 40 bits when Turbo code is used
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Multiplexing & Channel Coding (..cntd) Channel Coding Coding Scheme Coding Rate Type of TrCH BCH PCH RACH DPCH, DCH, DSCH, FACH Convolutional Coding (constraint length = 9) Turbo Coding 1/3 1/3, 1/2 1/2 If number of coded blocks is greater than 1, they are serially concatenated
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Multiplexing & Channel Coding (..cntd) Radio Frame Equalization padding the input bit sequence in order to ensure that the output can be segmented into data segments of equal size I.e., number of bits per segment is same after radio frame equalization performed only on the U/L 1st Interleaving block interleaver among bits in a TTI
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Multiplexing & Channel Coding (..cntd) Radio Frame Segmentation when TTI > 10 msec, input bit sequence is segmented and mapped on to Fi consecutive radio frames Rate Matching means that bits on a transport channel are repeated or punctured to ensure that the total bit rate after TrCH multiplexing is identical to the total channel bit rate of the allocated dedicated physical channels higher layers assign a rate-matching (semi-static) attribute for each transport channel this attribute is used to calculate the number of bits to repeat or puncture, spreading factor, number of PhCHs needed, rate matching pattern
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Multiplexing & Channel Coding (..cntd) TrCH Multiplexing every 10 msec, one radio frame from each TrCH is delivered to the TrCH multiplexing these radio frames are serially concatenated into a coded composite transport channel (CCTrCH) Physical Channel Segmentation when more than once PhCH is used, the physical channel segmentation divides the bits among different PhCHs 2nd Interleaving among bits within a radio frame
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Multiplexing & Channel Coding (..cntd) Insertion of Discontinuous Transmission (DTX) Indication Bits only on the D/L used to fill up the radio frame with bits insertion point depends on whether fixed positions (1st Insertion) or flexible positions (2nd Insertion) of the TrCHs in the radio frame are used During connection setup, NW decides if fixed or flexible position is used for each CCTrCH DTX Indication bits are not transmitted; they only tell when the Tx must be turned off
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Multiplexing & Channel Coding (..cntd) Transport Format Detection TFCI Based Detection Explicit Blind Detection using receive power ratio by use of channel decoding and CRC check Guided Detection Explicit blind detection used on Guiding TrCH Guiding TrCH has the same TTI as the TrCH under consideration
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Multiplexing & Channel Coding (..cntd) Blind Transport Format Detection Using Received Power Ratio (for the case of 2 TFs) Ratio of the power received on DPDCH (Pd) and DPCCH (Pc) Full Rate TF: if ratio Pd/Pc > threshold Zero rate TF: if ratio Pd/Pc < threshold Using CRC (for the case of multiple TFs) Receiver knows only the possible TFs or end bit (thru’ L3 signaling) Receiver performs FEC (Viterbi) decoding path metric selection among the surviving paths in the decoding
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore D/L Physical Channels Dedicated D/L Channels DPDCH DPCCH Common D/L Channels Common PIlot CHannel (CPICH) Primary CPICH Secondary CPICH Common Control Physical CHannel (CCPCH) Primary CCPCH, Secondary CCPCH Synchronization CHannel (SCH) Primary SCH, Secondary SCH
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Dedicated D/L Physical Channels Dedicated Physical CHannel (D/L DPCH) transmits dedicated data generated at L2 and above time-multiplexes with L1 control bits (Pilot, TPC, TFCI) D/L DPCH Time-multiplex of a D/L DPDCH and a D/L DPCCH
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore DL Frame Structure S0 10 msec frames divided into 15 slots No. of bits in different DPDCH field (Npilot, Ntpc, Ntfci, Ndata1, Ndata2) are given in tables Which slot format to use is configured (and reconfigured) by higher layers S1 S2 S3 S13 S14 1 Frame = 15 slots = 10 msec DATA 1 1 time slot = 2/3 msec DPDCH Pilot DPCCH TFCI TPC DATA 2 DPDCH DPCCH
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore D/L Transmission Multicode Transmission on D/L Multicode transmission can be employed on the D/L I.e., CCTrCH is mapped on to several parallel D/L DPCHs using the same spreading factor In this case, L1 control information is sent only on the first downlink DPCH Multiple CCTrCHs In case there are several CCTrCHs mapped to different DPCHs transmitted to the same UE, different spreading factors can be used on DPCHs multiple CCTrCHs feature for future release
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore WCDMA Transmission Rates (D/L) System Chip Rate : 3.84 Mcps Symbol Rates on Downlink Symb Rate Chl bit rate SF 7.5 Ks/s 15 Kb/s 512 15 Ks/s 30 Kb/s 256 30 Ks/s 60 Kb/s 128 60 Ks/s 120 Kb/s 64 120 Ks/s 240 Kb/s 32 240 Ks/s 480 Kb/s 16 480 Ks/s 960 Kb/s 8 960 Ks/s 1920 Kb/s 4
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Common D/L Physical Channels Common Pilot CHannel (CPICH) 30 Kbps fixed rate channel (SF = 256) Primary CPICH Always uses the same channelization code Scrambled by primary scrambling code There is one and only one P-CPICH per cell Broadcast over the entire cell Provides a phase reference for several D/L channels Secondary CPICH Uses an arbitrary channelization code of SF=256 Scrambled either by the primary or a secondary scrambling code A cell may contain 0,1, or several S-CPICH Broadcast over entire OR part of a cell A S-CPICH can be a phase reference to some D/L channels (which is communicated to the UE thru’ higher layer signaling)
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Common D/L Physical Channels Common Control Physical CHannel (CCPCH) Primary CCPCH (P-CCPCH) 30 Kbps fixed rate channel with SF=256 Carries BCH transport channel No TPC, TFCI, pilot bits are sent the transport channel mapped to P-CCPCH (I.e., BCH) can only have a fixed predefined TFC Secondary CCPCH (S-CCPCH) Carries FACH and PCH S-CCPCH can be with TFCI and without TFCI NW decides if TFCI has to be sent So UE should be (mandatory) capable of receiving with or without TFCI (i.e., blind) S-CCPCH can support multiple TFCs using TFCI Main difference between CCPCHs and Dedicated Physical Channels : a CCPCH is NOT inner loop Power Controlled
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Common D/L Physical Channels Synchronization CHannel (SCH) Downlink signal used for cell search Consists of Primary and Secondary subchannels Primary SCH Uses Primary Sychronization Code (PSC), TX once every slot PSC is the same for every cell in the system Secondary SCH Tx in parallel with Primary SCH SSC indicates which of the code groups (64 groups) the cell’s DL scrambling code belongs to
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore D/L Spreading DL Physical Channel data C d,SF,m Serial to Parallel Conv. I Q I+jQ S dl,n j Channelisation code: - Differentiate users in a cell - OVSF - UTRAN assigns channelisation codes to diff. phy. chls Scrambling Code: Differentiate cells
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Scrambling Codes # possible D/L scrambling codes = 2**18 -1 = 262143 Scrambling codes divided into 512 sets 1 primary scrambling code and 15 secondary scrambling codes So, there are 512 x 16 = 8192 codes Each cell is allocated one and only primary scrambling code The primary CCPCH (Common Control Physical CHannel) is Tx always using this primary scrambling code Other D/L physical channels can be Tx with either the PSC or SSC from the set associated with the PSC of the cell
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Multiplexing & Channel Coding (D/L) CRC Attachment TrBk Concatenation/ Code Block Segmentation Channel Coding Rate Matching 1st Insertion of DTX Indication 1st Interleaving Radio Frame Segmentation CCTrCH CRC Attachment TrBk Concatenation/ Code Block Segmentation Channel Coding Rate Matching 1st Insertion of DTX Indication 1st Interleaving Radio Frame Segmentation TrCH-2 TrCH Multiplexing Physical Channel Segmentation 2nd interleaving TrCH-1 Physical Channel Mapping PhCH#2 PhCH#1 2nd Insertion of DTX Indication
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Multiplexing & Channel Coding (..cntd) Physical Channel Mapping on U/L: PhCHs are either completely filled or not used at all on D/L: No bits in locations with DTX indication in compressed mode, no bits are mapped to certain slots in a PhCH. Reducing the SF by a factor of 2, 7.5 slots per frame is used in compressed mode
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Multiplexing & Channel Coding (..cntd) Insertion of Discontinuous Transmission (DTX) Indication Bits only on the D/L used to fill up the radio frame with bits insertion point depends on whether fixed positions (1st Insertion) or flexible positions (2nd Insertion) of the TrCHs in the radio frame are used During connection setup, NW decides if fixed or flexible position is used for each CCTrCH DTX Indication bits are not transmitted; they only tell when the Tx must be turned off
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore WCDMA Physical Channels P-CCPCH S-CCPCH DPDCH DPCCH PDSCH PCPCH PRACH BS UE AICH P-SCH S-SCH CSICH CPICH PICH CD/CA-ICH
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Channel Mapping on the U/L CCCH DTCH DCCH RACH DCH CPCH PRACH DPDCH DPCCH PCPCH Logical Channels Transport Channels Physical Channels
Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Channel Mapping on the D/L BCCH PCCH CTCH CCCH DCCH DTCH BCH PCH FACH DCH DSCH P-CCPCH S-CCPCH DPDCH DPCCH PDSCH Logical Channels Transport Channels Physical Channels

More Related Content

PPT
3G overview final
Ahmed Emara
 
PPTX
5g-Air-Interface-pptx.pptx
Murali Munagapati
 
PDF
LTE Architecture and interfaces
Abdulrahman Fady
 
PDF
LTE (Long Term Evolution) Introduction
Guisun Han
 
PDF
5G technical_overview_training_sec_1
Sajal Kumar Das
 
PPT
Training document e ran2.2_lte tdd system multiple antenna techniques(mimo an...
ProcExpl
 
PDF
Lte principle
Hatim100
 
PDF
Hsdpa analysis
Mohammed Razuddin
 
3G overview final
Ahmed Emara
 
5g-Air-Interface-pptx.pptx
Murali Munagapati
 
LTE Architecture and interfaces
Abdulrahman Fady
 
LTE (Long Term Evolution) Introduction
Guisun Han
 
5G technical_overview_training_sec_1
Sajal Kumar Das
 
Training document e ran2.2_lte tdd system multiple antenna techniques(mimo an...
ProcExpl
 
Lte principle
Hatim100
 
Hsdpa analysis
Mohammed Razuddin
 

What's hot (20)

PDF
End-to-End QoS in LTE
Radisys Corporation
 
PDF
zte umts-cs-call-drop-analysis-guide-zte
3ggprs
 
PPTX
Gsm
Mustahid Ali
 
PPT
3 g rf_opt_process_ppt
Hatim100
 
PPTX
5G NR parameters
Sasi Reddy
 
PDF
Beginners: An Quick Introduction to 3GPP
3G4G
 
PPT
06a_LTE mobility management v1_0.ppt
ssuser022794
 
PPTX
5G_NR_Overview_Architecture_and_Operating_Modes
Aalekh Jain
 
PDF
Intermediate: Bandwidth Parts (BWP)
3G4G
 
PPTX
WCDMA Air Interface
Sujeet Kumar
 
PPT
Ip ran v1.1
Muhamad Yopan
 
PPTX
LTE Training Course
ChiehChun
 
PPSX
Paging in LTE
Surya Munda
 
PDF
5G Network Architecture, Design and Optimisation
3G4G
 
PDF
5G NR DSS - Explained Well
ssk
 
PPT
305090798 04-basic-parameter-planning-rules-v1-1
Nitin George Thomas
 
PDF
Gsm rf interview questions
radira03
 
PDF
5G massive mimo & planning.pdf
bagusmardani1
 
PPT
LTE - Long Term Evolution
Arief Gunawan
 
PDF
Lte protocol Stack
Shoeb Ahmed
 
End-to-End QoS in LTE
Radisys Corporation
 
zte umts-cs-call-drop-analysis-guide-zte
3ggprs
 
Gsm
Mustahid Ali
 
3 g rf_opt_process_ppt
Hatim100
 
5G NR parameters
Sasi Reddy
 
Beginners: An Quick Introduction to 3GPP
3G4G
 
06a_LTE mobility management v1_0.ppt
ssuser022794
 
5G_NR_Overview_Architecture_and_Operating_Modes
Aalekh Jain
 
Intermediate: Bandwidth Parts (BWP)
3G4G
 
WCDMA Air Interface
Sujeet Kumar
 
Ip ran v1.1
Muhamad Yopan
 
LTE Training Course
ChiehChun
 
Paging in LTE
Surya Munda
 
5G Network Architecture, Design and Optimisation
3G4G
 
5G NR DSS - Explained Well
ssk
 
305090798 04-basic-parameter-planning-rules-v1-1
Nitin George Thomas
 
Gsm rf interview questions
radira03
 
5G massive mimo & planning.pdf
bagusmardani1
 
LTE - Long Term Evolution
Arief Gunawan
 
Lte protocol Stack
Shoeb Ahmed
 
Ad

Viewers also liked (20)

PDF
For spreading factor & channels
Shivendra Verma
 
PPT
Wcdma Overview Presentation
Amir Malik
 
PPTX
WCDMA
Harshal Tiwari
 
PPT
UMTS system architecture, protocols & processes
Muxi ESL
 
PPT
01 principles of the wcdma system
khurrambilal01
 
PDF
3G basic good
Jit Pal Dhanjal
 
PPTX
Gsm cell analysis
Muxi ESL
 
DOC
Cs irat degradation due to physical channel failure
fateh-med
 
PPT
Wcdmaphysicallayer 111120031701-phpapp02
Terra Sacrifice
 
PDF
2009 Security Mega Trends & Emerging Threats
Lumension
 
PPTX
Event management
sabinraj khanal
 
PPSX
Mega Events- מכון היצוא
Israel Export Institute_מכון היצוא
 
PPTX
Security MEGA PRojects
Wasef Al-Hakim
 
PPT
Physical Layer Optical Network Security Thesis Presentation To The CNY ISSA C...
Joshua S. White, PhD josh@securemind.org
 
ODP
Jupiter physical security ppt 2016 1
Maxpromotion
 
PDF
Umts call-flows
sivakumar D
 
PDF
מצגת ערים חכמות
Israel Export Institute_מכון היצוא
 
PPT
T20 World Cup 2012 Android Apps
Enuke Software Pvt Ltd
 
PPTX
Mega event managemnt
Dr. Ravindra Pastor
 
PPTX
Tourism Finance Corporation of India(TFCI)
ashna arora
 
For spreading factor & channels
Shivendra Verma
 
Wcdma Overview Presentation
Amir Malik
 
WCDMA
Harshal Tiwari
 
UMTS system architecture, protocols & processes
Muxi ESL
 
01 principles of the wcdma system
khurrambilal01
 
3G basic good
Jit Pal Dhanjal
 
Gsm cell analysis
Muxi ESL
 
Cs irat degradation due to physical channel failure
fateh-med
 
Wcdmaphysicallayer 111120031701-phpapp02
Terra Sacrifice
 
2009 Security Mega Trends & Emerging Threats
Lumension
 
Event management
sabinraj khanal
 
Mega Events- מכון היצוא
Israel Export Institute_מכון היצוא
 
Security MEGA PRojects
Wasef Al-Hakim
 
Physical Layer Optical Network Security Thesis Presentation To The CNY ISSA C...
Joshua S. White, PhD josh@securemind.org
 
Jupiter physical security ppt 2016 1
Maxpromotion
 
Umts call-flows
sivakumar D
 
מצגת ערים חכמות
Israel Export Institute_מכון היצוא
 
T20 World Cup 2012 Android Apps
Enuke Software Pvt Ltd
 
Mega event managemnt
Dr. Ravindra Pastor
 
Tourism Finance Corporation of India(TFCI)
ashna arora
 
Ad

Similar to Wcdma physical layer (20)

PPT
UMTS Channel Overview - Transport/logical
somimunni
 
PPT
Wcdma channels
Terra Sacrifice
 
PDF
List channel in wcdma
Tan Chap
 
PDF
14 wcdma
Rakesh Tripathi
 
PPT
Wcdma channels
Manish Srivastava
 
PDF
Lte phy fundamentals
derejew
 
PDF
Lte phy fundamentals
Prashant Sengar
 
PDF
39540950 gsm-ion-course-130814024028-phpapp01
Ahlem DRIRA
 
PDF
Wcdma
Dlip Nyk
 
PDF
Wcdma
บอย วีระ
 
PPT
03 umts radio path and transmissionnew
sivakumar D
 
PDF
HSPA Essentials
Luca Matteo Ruberto
 
PPTX
Wcdma presentation4
Mohammad Kaleem
 
PPT
Wcdma p&amp;o-c-en-channel structure-3-40
Jose Asuncion Silva Vasquez
 
PPT
Gsm air interface
Rizwan Pasha M
 
PPT
Sdcch 12704657711474-phpapp02
Tapiwa Munetsi
 
PPT
Sdcch
Deepak Sharma
 
PPTX
It802 d mobilecommunicationspart4
Debasis Das
 
PPT
Nachiket mehta
purnima205
 
PPT
3g wireless technology
Kumar Gaurav
 
UMTS Channel Overview - Transport/logical
somimunni
 
Wcdma channels
Terra Sacrifice
 
List channel in wcdma
Tan Chap
 
14 wcdma
Rakesh Tripathi
 
Wcdma channels
Manish Srivastava
 
Lte phy fundamentals
derejew
 
Lte phy fundamentals
Prashant Sengar
 
39540950 gsm-ion-course-130814024028-phpapp01
Ahlem DRIRA
 
Wcdma
Dlip Nyk
 
Wcdma
บอย วีระ
 
03 umts radio path and transmissionnew
sivakumar D
 
HSPA Essentials
Luca Matteo Ruberto
 
Wcdma presentation4
Mohammad Kaleem
 
Wcdma p&amp;o-c-en-channel structure-3-40
Jose Asuncion Silva Vasquez
 
Gsm air interface
Rizwan Pasha M
 
Sdcch 12704657711474-phpapp02
Tapiwa Munetsi
 
Sdcch
Deepak Sharma
 
It802 d mobilecommunicationspart4
Debasis Das
 
Nachiket mehta
purnima205
 
3g wireless technology
Kumar Gaurav
 

Recently uploaded (20)

PDF
advance database management system book.pdf
hinamannan364
 
PPTX
Orientation - ARALprogram of Deped to the Parents.pptx
JeromeTamayoSantiago1
 
PDF
Chinmaya Tiranga quiz Grand Finale.pdf
Nitin Suresh
 
PPTX
Tissue processing ( HISTOPATHOLOGICAL TECHNIQUE
mathiasmelwyn7
 
PDF
Trump Administration's workforce development strategy
Mebane Rash
 
PDF
LDMMIA Reiki Yoga Finals Review Spring Summer
LDMMia Reiki Lectures
 
PDF
A GUIDE TO GENETICS FOR UNDERGRADUATE MEDICAL STUDENTS
DrBincy A. S
 
PDF
Weekly quiz Compilation Jan -July 25.pdf
Nitin Suresh
 
PPTX
CHAPTER IV. MAN AND BIOSPHERE AND ITS TOTALITY.pptx
greciamaycalambro
 
PPTX
Introduction to Building Materials
Mrunali Vasava
 
PDF
What if we spent less time fighting change, and more time building what’s rig...
Derek Wenmoth
 
PDF
Empowerment Technology for Senior High School Guide
solthereseamericandr
 
PDF
Black Hat USA 2025 - Micro ICS Summit - ICS/OT Threat Landscape
Chris Sistrunk
 
PDF
RTP_AR_KS1_Tutor's Guide_English [FOR REPRODUCTION].pdf
RobertMentino1
 
PDF
Computing-Curriculum for Schools in Ghana
abigailanane203
 
PDF
1_English_Language_Set_2.pdf probationary
emailjagmeetsingh9
 
PDF
SOIL: Factor, Horizon, Process, Classification, Degradation, Conservation
Sipra Biswas
 
PDF
Complications of Minimal Access Surgery at WLH
mohitsuren827
 
PPTX
1st Inaugural Professorial Lecture held on 19th February 2020 (Governance and...
kawisojames10
 
PDF
IGGE1 Understanding the Self1234567891011
rhea22labucay
 
advance database management system book.pdf
hinamannan364
 
Orientation - ARALprogram of Deped to the Parents.pptx
JeromeTamayoSantiago1
 
Chinmaya Tiranga quiz Grand Finale.pdf
Nitin Suresh
 
Tissue processing ( HISTOPATHOLOGICAL TECHNIQUE
mathiasmelwyn7
 
Trump Administration's workforce development strategy
Mebane Rash
 
LDMMIA Reiki Yoga Finals Review Spring Summer
LDMMia Reiki Lectures
 
A GUIDE TO GENETICS FOR UNDERGRADUATE MEDICAL STUDENTS
DrBincy A. S
 
Weekly quiz Compilation Jan -July 25.pdf
Nitin Suresh
 
CHAPTER IV. MAN AND BIOSPHERE AND ITS TOTALITY.pptx
greciamaycalambro
 
Introduction to Building Materials
Mrunali Vasava
 
What if we spent less time fighting change, and more time building what’s rig...
Derek Wenmoth
 
Empowerment Technology for Senior High School Guide
solthereseamericandr
 
Black Hat USA 2025 - Micro ICS Summit - ICS/OT Threat Landscape
Chris Sistrunk
 
RTP_AR_KS1_Tutor's Guide_English [FOR REPRODUCTION].pdf
RobertMentino1
 
Computing-Curriculum for Schools in Ghana
abigailanane203
 
1_English_Language_Set_2.pdf probationary
emailjagmeetsingh9
 
SOIL: Factor, Horizon, Process, Classification, Degradation, Conservation
Sipra Biswas
 
Complications of Minimal Access Surgery at WLH
mohitsuren827
 
1st Inaugural Professorial Lecture held on 19th February 2020 (Governance and...
kawisojames10
 
IGGE1 Understanding the Self1234567891011
rhea22labucay
 

Wcdma physical layer

  • 1. WCDMA Physical Layer Design A. Chockalingam Assistant Professor Indian Institute of Science, Bangalore-12 [email_address] http://ece.iisc.ernet.in/~achockal
  • 2. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Outline WCDMA Network Architecture WCDMA Physical Layer Physical / Transport / Logical Channels Uplink Spreading - Channelisation / Scrambling Transport Formats and Configuration Multiplexing and Channel Coding Downlink Spreading / Scrambling / Channelisation Multiplexing and Channel Coding
  • 3. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore 2G to 3G Evolution IS-95A IS-95B cdma2000 IMT2000 IMT2000: ITU’s Standardization Effort towards 3G (IMT-2000 previously termed as FPLMTS) UMTS: European Effort (Specified by 3G Partnership Project 3GPP) GSM GPRS WCDMA EDGE D A T A I S 9 9
  • 4. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore UMTS NW Model USIM Mobile Equipment Access Network Serving Network PS/CS Transit Network Cu Uu Iu Yu User Equipment Access Network Core Network Infrastructure Home Network Access Stratum (Protocols between UE and Access NW) Non-access Stratum (Protocols between UE and Core NW) Zu Stratum: Refers to a way of grouping protocols handling activities
  • 5. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore UMTS NW Architecture Node B UE UE UE Node B Node B Node B RNC RNC UTRAN RNS RNS CN CN (CS Domain) CN (PS Domain) SGSN GGSN Registers HLR/AuC/EIR (Home Network) 3G MSC / VLR 3G GMSC Uu Iu Iur Iub
  • 6. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore WCDMA System Features UTRA FDD mode and TDD mode UTRA FDD features Multiple Access: CDMA Channel Spacing: 5 MHz Chip Rate: 3.84 Mcps Frame Length: 10 msec Time Slots: 15 slots per 10 msec frame Spreading Factor: 4 to 512 Multi-rate: Through Multi-code or Orthogonal Variable Spreading
  • 7. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore UTRA FDD Features FEC Codes: Rate 1/2, 1/3 convolutional code with constraint length K = 9 Rate 1/3, 8-state Turbo coding Interleaving: Intra- or Inter-frame interleaving (10, 20 40, 80 msec) Modulation: QPSK Detection: Coherent based on pilot symbols Micro diversity: RAKE in BS and UE Power Control: Fast closed-loop at 1500 Hz rate Intra-frequency HO: Soft / Softer Handover Inter-frequency HO: Hard Handover Interference Cancellation: Support for multiuser detection
  • 8. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Radio Interface Protocol Model PHY MAC RLC Transport Channels Logical Channels User Plane Radio Bearers Signalling Radio Bearers PDCP BMC RRC USER PLANE CONTROL PLANE Control L1 (Radio Physical Layer) L2 (Radio Link Layer) L3 (Radio Network Layer) U-Plane Radio Bearers
  • 9. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore WCDMA Radio Channels Physical Channels Transmission media. Two types of physical channels defined in L1; FDD and TDD. FDD is characterized by frequency, code, I/Q phase Follow a layered structure of “radio frames” and “time slots” Transport Channels describes the way information is transferred over the radio interface Logical Channels the type of information transferred characterizes a logical channel UE BS RNC Logical Channels Transport Channels Physical Channels
  • 10. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Physical Channels Corresponds to a specific carrier frequency, code, relative phase in I and Q branches Dedicated and Common Physical Channels Layered structure of radio frames and time slots A radio frame = 10 msec = 15 slots/frame 1 frame = 38400 chips, 1 slot = 2560 chips Slot configuration varies depending on the channel bit rate of the physical channel # bits/slot different for different physical channels may vary with time (on a frame by frame basis)
  • 11. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore U/L Physical Channels Dedicated U/L Channels DPDCH DPCCH Common U/L Channels PRACH Preamble part Message part PCPCH Preamble part Message part
  • 12. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Dedicated U/L Physical Channels Two types Dedicated Physical Data CHannel (DPDCH) Dedicated Physical Control CHannel (DPCCH) Both are I/Q code multiplexed within each radio frame U/L DPDCH carries the DCH transport channel U/L DPCCH carries L1 control bits such as Pilot bits (to enable channel estimation for coherent detection at BS) Transmit power control (TPC) commands Feedback Information (FBI) used for CL transmit diversity and Site Selection Diversity Transmission (SDTC) Transport Format Combination Indicator (TFCI) for several simultaneous services. Informs the rx of the transport format combination of the transport channels mapped to DPDCH
  • 13. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore U/L Frame Structure There is only one U/L DPCCH on each radio link There can be 0, 1, or several DPDCHs on each radio link 10 msec frames divided into 15 slots S0 S1 S2 S3 S13 S14 1 Frame = 15 slots = 10 msec DATA 1 time slot = 2/3 msec DPDCH (on I-Chl) Pilot DPCCH (on Q-Chl) TFCI FBI TPC 10 bits = 2560 chips => SF = 256 (N data bits)
  • 14. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore I, Q Spreading for DPDCH, DPCCH DPDCH-1 DPDCH-3 C d,1 C d,3 B d B d I DPDCH-2 DPCCH-2 C d,2 C c B c B d Q I+jQ S dpch,n C c, C d,n: Channelization codes Sdpch,n: Scrambling code B d, B c: Gain factors Up to 6 DPDCHs in parallel j
  • 15. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore WCDMA Transmission Rates (U/L) System Chip Rate : 3.84 Mcps Symbol Rates on Uplink Chl Symb Rate Chl Bit Rate SF Bits/frame N data 15 Ks/s 15 Kb/s 256 150 10 30 Ks/s 30 Kb/s 128 300 20 60 Ks/s 60 Kb/s 64 600 40 120 Ks/s 120 Kb/s 32 1200 80 240 Ks/s 240 Kb/s 16 2400 160 480 Ks/s 480 Kb/s 8 4800 320 960 Ks/s 960 Kb/s 4 9600 640
  • 16. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore WCDMA Channelisation Codes Orthogonal codes Used for channel separation both in U/L and D/L directions Can have different spreading factor values (thus support different symbol rates) C ch,SF,k : SF - Spreading Factor, k is the code number 0<=k<= SF-1 Spreading factor value indicates how many bits of those codes are used in a connection
  • 17. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore U/L Channelization Codes Orthogonal Variable Spreading Factor (OVSF) channelization codes Separates data / control channels from same UE Preserves orthogonality between these channels (1) (1,1) (1,-1) (1,1,1,1) (1,1,-1,-1) (1,-1,1,-1) (1,-1,-1,1) SF=1 SF=2 SF=4 C(SF,k) SF: Spreading Factor k: code number 0<k<=SF-1
  • 18. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore U/L Scrambling Codes Use complex valued scrambling code Long scrambling sequences (2^24) Gold sequences (linear combination of two m-sequences) Short scrambling sequences (2^24) from a family sequence of periodically extended S(2) codes Long or short sequences for DPCCH / DPDCH Only long sequences for message parts of PRACH and PCPCH
  • 19. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore WCDMA Code Types Scrambling Codes, Channelisation Codes Uplink Downlink Scrambling codes User separation Cell separation Channelisation Data and Control Users within a codes channels from the cell same terminal Spreading code = Scrambling code x Channelisation code
  • 20. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Common U/L Physical Channels Two Types Physical Random Access CHannel (PRACH) Physical Common Packet CHannel (PCPCH) Physical Random Access CHannel (PRACH) carries RACH Uses S-ALOHA technique with fast Acquisition Indication Access slots (15 access slots per 2 frames) RA transmission consists of several 4096 chip preambles (uses 256 repetitions of 16 chips signature sequence) and 1or 2 frame message Preamble Message Part (1 or 2 frames) 4096 Chips Preamble
  • 21. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Random Access UE BS PRACH: Preamble sent (initial access) No detection on AICH PRACH: Preamble sent (initial access) AICH: Preamble sent detected PRACH: Random Access Info sent
  • 22. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Common U/L Physical Channels Physical Common Packet CHannel (PCPCH) Carries CPCH CPCH is based on DSMA-CD technique with fast Acquisition Indication Access slot timing and structure are identical to those defined for RACH Transmission consists of Access preamble(s) - one or several each 4096 chips Collision Detection preamble DPCCH Power Control Preamble (0 or 8 slots) Message of variable length (Nx10 msec) PCPCH good for carrying small sized bursty data
  • 23. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Transport Formats / Configurations Transport Block (TB) Basic unit of data exchanged between L1 & MAC for L1 processing Transport Block Size: Number of bits in a TB. Transport Block Set (TBS) A set of TBs exchanged between L1 and MAC at the same time instant using the same transport channel Transport Block Set Size: Number of bits in a TBS Transmission Time Interval (TTI) Periodicity at which a TBS is transferred by the physical layer on to the radio interface - {10, 20, 40, 80 ms} MAC delivers one TBS to the physical layer every TTI
  • 24. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Transport Formats / Configurations Transport Format (TF) Format offered by L1 to MAC (and vice versa) for the delivery of a TBS during a TTI on a given transport channel (TrCH) Dynamic part (TB size, TBS size) Semi-static part (TTI, type/rate of coding,size of CRC) TB size, TBS size, TTI define the TrCH bit rate before L1 processing e.g., TB size = 336 bits (320 bit payload + 16 bits RLC header) TBS size = 2 TBs per TTI, TTI = 10 ms DCH Bit rate (with RLC header) = 336*2/10 = 67.2 Kbps User Bit rate (without RLC header) = 320*2/10 = 64 Kbps Variable bit rate can be achieved by changing ( between TTIs ) either the TBS size only, or both the TB size and TBS Size Transport Format Set (TFS) a set of TFs associated with a TrCH semi-static part of all TFs in a TFS is the same
  • 25. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Transport Formats / Configurations Transport Format Combination (TFC) Multiple TrCHs each having a TF Authorized combination of the currently valid TFs that can be submitted to L1 on a CCTrCH , containing one TF from each TrCH Transport Format Combination Set (TFCS) A set of TFCs on a CCTrCH. Produced by RNC TFCS is given to MAC by L3 for control MAC chooses between the different TFCs specified in the TFCS MAC has control over only the dynamic part of the TFs. Semi-static part relates to QoS (e.g., quality) and is controlled by RNC admission control Bit rate can be changed quickly by MAC with no need to L3 signaling Transport Format Indicator (TFI) A label for a specific TF within a TFS. Used between MAC and L1 Transport Format Combination Indicator (TFCI) Used to inform the receiving side of the currently valid TFC
  • 26. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Transport Formats / Configurations TTI TTI TTI TTI TTI TTI TB DCH1 DCH2 TB TB TB TB TB TB Transport Block Set (TBS) TB TB Transport Format (TF) Transport Format Set (TFS) Transport Format Combination (TFC) Transport Format Combination Set (TFCS)
  • 27. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore TFI and TFCI (Transmitter) Transport Chl 1 Transport Chl 2 Transport Block Transport Block Transport Block Transport Block TFI TFI TFCI Coding and Multiplexing Physical Layer Higher Layer DPCCH (Q-Chl) DPDCH (I-Chl) Physical Control Chl Physical Data Chl E.g: Two transport channels mapped to a single physical channel This dotted line represents the Iur interface in case of NW side
  • 28. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore TFI and TFCI (Receiver) Transport Chl 1 Transport Chl 2 Transport Block & EI Transport Block & EI Transport Block & EI Transport Block & EI TFI TFI TFCI Decode Decoding and Demultiplexing Physical Layer Higher Layer DPCCH (Q-Chl) DPDCH (I-Chl) EI: Error Indication Physical Control Chl Physical Data Chl
  • 29. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore TFI and TFCI Each transport channel is accompanied by a TFI at each time event at which data is expected to arrive from HL Physical layer combines the TFI info from different transport channels to the TFCI TFCI is sent on the DPCCH to inform the receiver about the instantaneous transport format combination of the transport channels mapped to the U/L DPDCH transmitted simultaneously
  • 30. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Transport Format (e.g., Speech) Conversational Speech (12 Kbps) 12.2 Kbps max. TTI: 20 msec Transport Formats (TF) available: TF RAB1 RAB2 RAB3 TF0v 0 x 81 0 x 103 0 x 60 (e.g., silence) TF1v 1 x 81 1 x 103 1 x 60 (e.g, active voice) two other formats too (see Stds. Doc.) TFC: (TF0, TF0, TF0) e.g., during silence (TF1, TF1, TF1) e.g., during active voice periods
  • 31. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Transport Format (e.g., Data) Interactive/Background Data (64 Kbps) 64 Kbps max. TTI: 20 msec Transport Block (TB) size = 336 bits Transport Formats (TF) available: TF0 - 0 x 336 TF1 - 1 x 336 TF2 - 2 x 336 TF3 - 3 x 336 TF4 - 4 x 336
  • 32. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Transport Format (Speech + Data) Conversational speech (12 Kbps) + Interactive/Background Data (64 Kbps) Voice TrCH Data TrCH TFC1: (TF0v, TF0v, TF0v) TF0d TFC2: (TF0v, TF0v, TF0v) TF1d TFC3: (TF0v, TF0v, TF0v) TF2d TFC4: (TF0v, TF0v, TF0v) TF3d TFC5: (TF0v, TF0v, TF0v) TF4d TFC6: (TF1v, TF1v, TF1v) TF0d TFC7: (TF1v, TF1v, TF1v) TF1d TFC8: (TF1v, TF1v, TF1v) TF2d TFC9: (TF1v, TF1v, TF1v) TF3d TFC10: (TF1v, TF1v, TF1v) TF4d
  • 33. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Multiplexing & Channel Coding Data arrives at the coding/mux unit in transport block sets, once every transmission time interval (TTI) TTI depends on the transport channel; {10, 20, 40, 80 ms}) Main steps Add CRC to each block transport block concatenation and block segmentation channel coding first interleaving (per TTI) radio frame segmentation (when TTI > 10 ms) rate matching (repetition or puncturing) multiplexing of transport channels (CCTrCH) insertion of DTX indication bits physical channel segmentation second interleaving (per radio frame, ie., among bits in 1 radio frame) mapping to physical channel
  • 34. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Multiplexing & Channel Coding (U/L) CRC Attachment TrBk Concatenation/ Code Block Segmentation Channel Coding Radio Frame Equalization 1st Interleaving Radio Frame Segmentation Rate Matching CCTrCH CRC Attachment TrBk Concatenation/ Code Block Segmentation Channel Coding Radio Frame Equalization 1st Interleaving Radio Frame Segmentation Rate Matching TrCH-2 TrCH Multiplexing Physical Channel Segmentation 2nd interleaving TrCH-1 Physical Channel Mapping PhCH#2 PhCH#1
  • 35. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Multiplexing & Channel Coding (..cntd) Applicable to DCH, RACH, CPCH, DSCH, BCH, FACH, PCH CRC add CRC to each transport block for error detection CRC calculated on entire transport block Size of CRC: 24, 16, 12, 8, 0 bits what CRC size is used for each TrCH is signaled from higher layers
  • 36. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Multiplexing & Channel Coding (..cntd) TrBk Concatenation & Code Block Segmentation all transport blocks in a TTI are concatenated if no. of bits in a TTI after concatenation (X) is greater than the maximum size of the code block (in the channel coding block), then code block segmentation is done max. size of the code block (Z) depends on whether Convolutional code ( Z = 504 bits) or Turbo code ( Z = 5114 bits) is used for the TrCH Code blocks after segmentation are of the same size Filler bits (zeros) added to 1st coded block to to make integer number of code blocks, or if X < 40 bits when Turbo code is used
  • 37. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Multiplexing & Channel Coding (..cntd) Channel Coding Coding Scheme Coding Rate Type of TrCH BCH PCH RACH DPCH, DCH, DSCH, FACH Convolutional Coding (constraint length = 9) Turbo Coding 1/3 1/3, 1/2 1/2 If number of coded blocks is greater than 1, they are serially concatenated
  • 38. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Multiplexing & Channel Coding (..cntd) Radio Frame Equalization padding the input bit sequence in order to ensure that the output can be segmented into data segments of equal size I.e., number of bits per segment is same after radio frame equalization performed only on the U/L 1st Interleaving block interleaver among bits in a TTI
  • 39. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Multiplexing & Channel Coding (..cntd) Radio Frame Segmentation when TTI > 10 msec, input bit sequence is segmented and mapped on to Fi consecutive radio frames Rate Matching means that bits on a transport channel are repeated or punctured to ensure that the total bit rate after TrCH multiplexing is identical to the total channel bit rate of the allocated dedicated physical channels higher layers assign a rate-matching (semi-static) attribute for each transport channel this attribute is used to calculate the number of bits to repeat or puncture, spreading factor, number of PhCHs needed, rate matching pattern
  • 40. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Multiplexing & Channel Coding (..cntd) TrCH Multiplexing every 10 msec, one radio frame from each TrCH is delivered to the TrCH multiplexing these radio frames are serially concatenated into a coded composite transport channel (CCTrCH) Physical Channel Segmentation when more than once PhCH is used, the physical channel segmentation divides the bits among different PhCHs 2nd Interleaving among bits within a radio frame
  • 41. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Multiplexing & Channel Coding (..cntd) Insertion of Discontinuous Transmission (DTX) Indication Bits only on the D/L used to fill up the radio frame with bits insertion point depends on whether fixed positions (1st Insertion) or flexible positions (2nd Insertion) of the TrCHs in the radio frame are used During connection setup, NW decides if fixed or flexible position is used for each CCTrCH DTX Indication bits are not transmitted; they only tell when the Tx must be turned off
  • 42. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Multiplexing & Channel Coding (..cntd) Transport Format Detection TFCI Based Detection Explicit Blind Detection using receive power ratio by use of channel decoding and CRC check Guided Detection Explicit blind detection used on Guiding TrCH Guiding TrCH has the same TTI as the TrCH under consideration
  • 43. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Multiplexing & Channel Coding (..cntd) Blind Transport Format Detection Using Received Power Ratio (for the case of 2 TFs) Ratio of the power received on DPDCH (Pd) and DPCCH (Pc) Full Rate TF: if ratio Pd/Pc > threshold Zero rate TF: if ratio Pd/Pc < threshold Using CRC (for the case of multiple TFs) Receiver knows only the possible TFs or end bit (thru’ L3 signaling) Receiver performs FEC (Viterbi) decoding path metric selection among the surviving paths in the decoding
  • 44. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore D/L Physical Channels Dedicated D/L Channels DPDCH DPCCH Common D/L Channels Common PIlot CHannel (CPICH) Primary CPICH Secondary CPICH Common Control Physical CHannel (CCPCH) Primary CCPCH, Secondary CCPCH Synchronization CHannel (SCH) Primary SCH, Secondary SCH
  • 45. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Dedicated D/L Physical Channels Dedicated Physical CHannel (D/L DPCH) transmits dedicated data generated at L2 and above time-multiplexes with L1 control bits (Pilot, TPC, TFCI) D/L DPCH Time-multiplex of a D/L DPDCH and a D/L DPCCH
  • 46. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore DL Frame Structure S0 10 msec frames divided into 15 slots No. of bits in different DPDCH field (Npilot, Ntpc, Ntfci, Ndata1, Ndata2) are given in tables Which slot format to use is configured (and reconfigured) by higher layers S1 S2 S3 S13 S14 1 Frame = 15 slots = 10 msec DATA 1 1 time slot = 2/3 msec DPDCH Pilot DPCCH TFCI TPC DATA 2 DPDCH DPCCH
  • 47. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore D/L Transmission Multicode Transmission on D/L Multicode transmission can be employed on the D/L I.e., CCTrCH is mapped on to several parallel D/L DPCHs using the same spreading factor In this case, L1 control information is sent only on the first downlink DPCH Multiple CCTrCHs In case there are several CCTrCHs mapped to different DPCHs transmitted to the same UE, different spreading factors can be used on DPCHs multiple CCTrCHs feature for future release
  • 48. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore WCDMA Transmission Rates (D/L) System Chip Rate : 3.84 Mcps Symbol Rates on Downlink Symb Rate Chl bit rate SF 7.5 Ks/s 15 Kb/s 512 15 Ks/s 30 Kb/s 256 30 Ks/s 60 Kb/s 128 60 Ks/s 120 Kb/s 64 120 Ks/s 240 Kb/s 32 240 Ks/s 480 Kb/s 16 480 Ks/s 960 Kb/s 8 960 Ks/s 1920 Kb/s 4
  • 49. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Common D/L Physical Channels Common Pilot CHannel (CPICH) 30 Kbps fixed rate channel (SF = 256) Primary CPICH Always uses the same channelization code Scrambled by primary scrambling code There is one and only one P-CPICH per cell Broadcast over the entire cell Provides a phase reference for several D/L channels Secondary CPICH Uses an arbitrary channelization code of SF=256 Scrambled either by the primary or a secondary scrambling code A cell may contain 0,1, or several S-CPICH Broadcast over entire OR part of a cell A S-CPICH can be a phase reference to some D/L channels (which is communicated to the UE thru’ higher layer signaling)
  • 50. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Common D/L Physical Channels Common Control Physical CHannel (CCPCH) Primary CCPCH (P-CCPCH) 30 Kbps fixed rate channel with SF=256 Carries BCH transport channel No TPC, TFCI, pilot bits are sent the transport channel mapped to P-CCPCH (I.e., BCH) can only have a fixed predefined TFC Secondary CCPCH (S-CCPCH) Carries FACH and PCH S-CCPCH can be with TFCI and without TFCI NW decides if TFCI has to be sent So UE should be (mandatory) capable of receiving with or without TFCI (i.e., blind) S-CCPCH can support multiple TFCs using TFCI Main difference between CCPCHs and Dedicated Physical Channels : a CCPCH is NOT inner loop Power Controlled
  • 51. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Common D/L Physical Channels Synchronization CHannel (SCH) Downlink signal used for cell search Consists of Primary and Secondary subchannels Primary SCH Uses Primary Sychronization Code (PSC), TX once every slot PSC is the same for every cell in the system Secondary SCH Tx in parallel with Primary SCH SSC indicates which of the code groups (64 groups) the cell’s DL scrambling code belongs to
  • 52. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore D/L Spreading DL Physical Channel data C d,SF,m Serial to Parallel Conv. I Q I+jQ S dl,n j Channelisation code: - Differentiate users in a cell - OVSF - UTRAN assigns channelisation codes to diff. phy. chls Scrambling Code: Differentiate cells
  • 53. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Scrambling Codes # possible D/L scrambling codes = 2**18 -1 = 262143 Scrambling codes divided into 512 sets 1 primary scrambling code and 15 secondary scrambling codes So, there are 512 x 16 = 8192 codes Each cell is allocated one and only primary scrambling code The primary CCPCH (Common Control Physical CHannel) is Tx always using this primary scrambling code Other D/L physical channels can be Tx with either the PSC or SSC from the set associated with the PSC of the cell
  • 54. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Multiplexing & Channel Coding (D/L) CRC Attachment TrBk Concatenation/ Code Block Segmentation Channel Coding Rate Matching 1st Insertion of DTX Indication 1st Interleaving Radio Frame Segmentation CCTrCH CRC Attachment TrBk Concatenation/ Code Block Segmentation Channel Coding Rate Matching 1st Insertion of DTX Indication 1st Interleaving Radio Frame Segmentation TrCH-2 TrCH Multiplexing Physical Channel Segmentation 2nd interleaving TrCH-1 Physical Channel Mapping PhCH#2 PhCH#1 2nd Insertion of DTX Indication
  • 55. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Multiplexing & Channel Coding (..cntd) Physical Channel Mapping on U/L: PhCHs are either completely filled or not used at all on D/L: No bits in locations with DTX indication in compressed mode, no bits are mapped to certain slots in a PhCH. Reducing the SF by a factor of 2, 7.5 slots per frame is used in compressed mode
  • 56. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Multiplexing & Channel Coding (..cntd) Insertion of Discontinuous Transmission (DTX) Indication Bits only on the D/L used to fill up the radio frame with bits insertion point depends on whether fixed positions (1st Insertion) or flexible positions (2nd Insertion) of the TrCHs in the radio frame are used During connection setup, NW decides if fixed or flexible position is used for each CCTrCH DTX Indication bits are not transmitted; they only tell when the Tx must be turned off
  • 57. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore WCDMA Physical Channels P-CCPCH S-CCPCH DPDCH DPCCH PDSCH PCPCH PRACH BS UE AICH P-SCH S-SCH CSICH CPICH PICH CD/CA-ICH
  • 58. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Channel Mapping on the U/L CCCH DTCH DCCH RACH DCH CPCH PRACH DPDCH DPCCH PCPCH Logical Channels Transport Channels Physical Channels
  • 59. Dr. A. Chockalingam Dept of ECE, IISc, Bangalore Channel Mapping on the D/L BCCH PCCH CTCH CCCH DCCH DTCH BCH PCH FACH DCH DSCH P-CCPCH S-CCPCH DPDCH DPCCH PDSCH Logical Channels Transport Channels Physical Channels