LTE Dimensioning RCP and planning lte.ppt

EAB-08:079029 Uen Rev A Ericsson Internal 2009-02-11
1
Agenda
LTE Fundamentals
 Terminology
 Radio interface
 LTE Dimensioning
 LTE TDD UL-DL Config

2
EPS
EPC EPC - Evolved Packet Core
eUTRAN eUTRAN - Evolved UTRAN
EPS – Evolved Packet System
Terminology
SAE - System Architecture Evolution
LTE - Long Term Evolution

3
EPC
S1
S1 S1
X2 X2
eNodeB
eNodeB eNodeB
Terminology – Interfaces
Logical view

4
LTE/SAE Network Architecture
GGSN => Packet Gateway
SGSN => Mobility server
BSC
RNC
SGSN/ MME
GGSN/ P/S-GW
GSM, WCDMA
IP networks
LTE
SAE
MME = Mobility Management Entity
P/S-GW = PDN/Serving gateway

5
LTE introduction
 OFDM (Orthogonal Frequency Division Multiplex) radio access
technique is used in downlink
 SC-FDMA (Single Carrier Frequency Division Multiple Access) in
uplink.
 Orthogonal properties in uplink as well as in downlink
=> Own cell interference will be low.
 MIMO technology in downlink is introduced from start to allow high
peak rates, 64QAM is introduced from start in downlink
 Time Division Duplex (TDD) is supported

6
LTE Introduction – Downlink
 A user is scheduled every 1 ms => each user will get minimum 2 RBs at every
scheduling instance
 Bitrate/RB varies with channel model, SNR and antenna configuration
 In downlink the power per RB is fixed
time
frequency
User A
User B
User C
f = 15 kHz
180 kHz (12 x 15) over 0.5 ms = Resource block

7
f = 15 kHz
LTE DL Physical Resources
One slot
0.5 ms, 7 OFDM
symbols
One Resource Block
12 x 7 = 84 resource elements
12 sub-carriers
time
frequency
One subframe
1.0 ms, 14 OFDM
symbols
One Scheduling Block
180 kHz, 2 RB and 1 ms

8
LTE introduction - Uplink
 Bitrate requirement is expressed per RB
 RB in UL must be consecutive:
– The number of RB for each transmission is selected by the scheduler
– In dimensioning, it is set as a best guess
 In uplink there is power control
Time
Frequency
User 1 scheduled
180 kHz
1 ms
User 2 scheduled

9
Bandwidth – Resource Blocks
 The smallest bandwidth for
deployment is 6 Resource Blocks
– 1,08 MHz + guard band = 1,4
MHz
 The largest bandwidth for
deployment is 100 Resource Blocks
– 18 MHz + guard band = 20 MHz
Channel Bandwidth BWChannel [MHz] 1.4 3 5 10 15 20
Number of Resource Blocks (nRB) 6 15 25 50 75 100
Bandwidth [RB]
Transmission Bandwidth Configuration [RB]
Channel Bandwidth [MHz]
Resource
block
Channel
edge
Channel
edge
Active Resource Blocks

10
LTE DL peak rate
64 QAM and 20 MHz and 4x4 MIMO
 14 OFDM symbols per 1.0 ms sub frame
 64QAM - 6 bits per symbol
 6 x 14 = 84 bits per 1.0 ms sub frame
 84bits/1.0ms = 84kbps per sub carrier
 12 x 84kbps = 1.008Mbps per Resource Block
 100 resource blocks in 20MHz
 100 x 1.008Mbps = 100.8Mbps per antenna
 4 x 4 MIMO: 403.2Mbps !!
 BUT in reality approx. ~300Mbps
 In reality ~25% is overhead (ref signals, control signalling etc)

11
LTE Dimensioning
LTE radio dimensioning for coverage and capacity

12
Channel models
 Extended Pedestrian A, 5Hz Doppler (EPA5)
 Low speed pedestrian
 Extended Vehicular A, 70Hz Doppler (EVA70)
 Medium speed
 Extended Typical Urban, 300Hz Doppler (ETU300)
 Higher speed

13
LTE Dimensioning
Process overview
1. Identify quality requirements
at cell edge
 Throughput requirements
on cell edge and average
2. Calculate coverage
 Pathloss
 Cell range
 Site-site distance
3. Calculate Capacity
 Cell capacity
Quality at cell
edge
- Path loss
- Cell range
- Site-to-site
distance
- Cell
capacity
- MIMO
- Tx diversity
- RBS power
- UE power
- UE Rx diversity
If input
requirements
are not met
Capacity
Coverage
Done

14
Workflow for calculating a Linkbudget
1. Bitrate requirement
2. SNR requirement
3. Receiver sensitivity, eNodeB
4. Uplink noiserise (interference
margin)
5. UE power per resource block
6. Uplink linkbudget
7. Path loss from uplink
8. Bitrate requirement
9. Power per RB
10. Downlink noiserise (interference
margin)
11. Downlink linkbudget
12. Receiver Sensitivity, UE
13. Bitrate at cell edge
14. Concluding the linkbudget
Uplink Coverage
Downlink Coverage

15
LTE Dimensioning
Coverage - SNR requirement, uplink
Values are for Ped A channel model, RLC rate per RB, bitrate
include all common channel overhead,
J
a
BPL
CPL
BL
LNF
IUL
eNodeB
RB
pmax L
G
L
L
L
B
B
S
P
L 








 Nt Thermal noise: -174 dBm/Hz
 Nf Noise factor in node B [dB]
 BW Bandwidth per resource block: 180
kHz
  SINR [dB] required for
dimensioning
service on cell border




 )
log(
10 W
f
t
eNodeB B
N
N
S UL SNR vs throughput per RB
0
100
200
300
400
500
600
700
800
900
-10 -5 0 5 10 15 20 25 30 35 40
SINR (dB)
Throughput
(kbps)

16
Indata for Linkbudget example, UL
 UL cell edge throughput 500 kbps
 UL cell throughput 3 Mbps
 UE Pout = 24dBm
 DL cell edge throughput 10 Mbps
 DL cell throughput 15 Mbps
 eNodeB Pout = 40 W, 2x2 MIMO, RRU
 20MHz Bandwidth
 Frequency band 2600MHz

17
Bitrate per RB = 100 kbps
LTE Dimensioning
Coverage – uplink example
32% system load => requested cell average throughput of 3Mbps
UL LTE
UE Output power 24
Number of RB 5
UE Output power/RB
17
Thermal noise -119,2
Noise factor RBS 2,2
User bitrate 500kbps
SINR 0,06
RBS Sensistivity -119,1
Antenna gain 18,5
Feeder loss 0
Jumper loss 0
ASC insertion loss 0
Body loss 1
Penetration loss 18
Fading margin 4,9
Max pathloss
unloaded
130,8
System Load UL 32%
Interference margin 0,82
Max pathloss 129,93
Range [km] 627m
24dBm divided by 5RBs
UL SNR vs throughput per RB
0
100
200
300
400
500
600
700
800
900
-10 -5 0 5 10 15 20 25 30 35 40
SINR (dB)
Throughput
(kbps)

18
J
a
BPL
CPL
BL
LNF
IDL
UE
ref
TX
pmax L
G
L
L
L
B
B
S
P
L 







 ,
 Lpmax maximum path loss due to propagation in the air [dB]
 PTX,ref transmitter power at the system reference point per RB
[dBm]
 SUE UE sensitivity [dBm]
 BIDL noise rise or the downlink interference margin [dB]
 BLNF log-normal fading margin [dB]
 LBL, LCPL, LBPL body loss, car penetration loss, building penetration loss [dB]
 Ga sum of RBS antenna gain and UE antenna gain [dBi]
 LJ jumper loss [dB]
LTE Dimensioning
Coverage – Downlink link budget
PTX,ref
SUE
Lpmax
BIDL
Maximum cell size
 All calculations for dimensioning are made per Resource Block (RB)

19
Values are for Ped A channel model, RLC rate per RB, values given with
2x2 MIMO and TX diversity
LTE Dimensioning
Coverage – downlink SNR requirements
J
a
BPL
CPL
BL
LNF
IDL
UE
ref
TX
pmax L
G
L
L
L
B
B
S
P
L 







 ,
 Nt Thermal noise: -174 dBm/Hz
 Nf Noise factor [dB]
 BW Bandwidth per resource block: 180
kHz
  SINR available on cell border [dB]




 )
log(
10 W
f
t
UE B
N
N
S
DL SNR vs throughput per RB
0
200
400
600
800
1000
1200
1400
1600
-10 -5 0 5 10 15 20 25 30 35 40
SNR
Throughput
(kbps)
TX diversity MIMO

20
Indata for Linkbudget example, DL
 UL cell edge throughput 500 kbps
 UL cell throughput 3 Mbps
 UE Pout = 24dBm
 DL cell edge throughput 10 Mbps
 DL cell throughput 15 Mbps
 eNodeB Pout = 40 W, 2x2 MIMO, RRU
 20 MHz Bandwidth
 Frequency band 2600 MHz

21
LTE Dimensioning
Coverage – DL example
20 MHz BW  100 RB
Power per RB=40/100= 0,4W
0
50
100
150
200
250
300
-5 -4 -3 -2 -1 0 1 2 3 4 5
SNR
Throughput
(kbps)
TX diversity MIMO
SINR=1,5=>167kbps/RB
100RB=>17Mbps
System loading can be selected within a wide range to satisfy the requirements
DL LTE
Output Power 40W
Number of RB 100
Power per RB 0,4W
Thermal noise -113,4
Noise factor UE 8
User bitrate 17Mbps
SINR 1,5
UE Sensistivity -116,3
Antenna gain 18,5
Feeder loss 0
Jumper loss 0
ASC insertion loss 0
Body loss 1
Penetration loss 18
Fading margin 4,9
Load DL 60%
Interference margin 7
Max Pathloss 129,9
Range [km] 627m

22
 Average interference depends on:
– Cell range (Lsa,max)
– Bandwidth (power per RB)
– Average load (by way of noiserise)
 Average SINR gives average throughput per RB
 Maximum user throughput (average) by
considering entire deployed bandwidth
 Total throughput by considering uplink loading
Uplink Capacity
sa,max
IUL
RB
RB
UE
ave
UL
HL
B
N
n
P


,

 
PUCCH
RB
UL
RB
UL
max n
n
T
T 
 ,
,
UL
max
UL
UL
cell T
Q
T ,
, 
γUL,ave
TRB,UL
UL SNR vs throughput per RB
0
100
200
300
400
500
600
700
800
900
-10 -5 0 5 10 15 20 25 30 35 40
SINR (dB)
Throughput
(kbps)

23
 Average interference depends on
– Cell range (Lsa,max)
– Bandwidth (power per RB)
– Average load (can be expressed as average
noiserise)
 Average SINR gives average throughput per RB
 Maximum user throughput (average) by
considering entire deployed bandwidth
 Total throughput by considering downlink loading
Downlink Capacity
sa,max
RB
noiserise
DL
RB
tx
ave
DL
HL
N
B
P


,
,

sa,max
RB
DL
RB
tx
noiserise
DL
L
N
F
Q
P
B
,
1


RB
DL
RB
n
T
T DL
max ,
, 
DL
max
DL
DL
cell T
Q
T ,
, 
γDL,ave
TRB,DL
0
50
100
150
200
250
300
-5 -4 -3 -2 -1 0 1 2 3 4 5
SNR
Throughput
(kbps)
TX diversity MIMO

24
TDD UL-DL configurations
6UL-2DL-2S
4UL-4DL-2S
2UL-6DL-2S
3UL-6DL-1S
2UL-7DL-1S
1UL-8DL-1S
5UL-3DL-2S
Suported configurations

25
Subframe configurations
Suported

26
Q&A

27

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