lte performance analysis on 800 and 1800 mhz bands
DESCRIPTION
LTE PERFORMANCE ANALYSIS ON 800 AND 1800 MHz BANDSLong Term Evolution (LTE) is a high speed wireless technology based on OFDM. Un-like its predecessors, its bandwidth can be scaled from 1.6 MHz to 20 MHz. Maximum theoretical throughputs from the LTE network in downlink can be estimated to range over 300 Mbps. The practical values are however limited by the channel overheads, path loss and cell loading. Its ability to deliver high throughput depends upon its radio access technology OFDM and the high bandwidth usage as well.TRANSCRIPT
LTE Performance
Anders Furuskär and Magnus LundevallWireless Access Networks
Ericsson Research
[anders.furuskar, magnus.lundevall]@ericsson.com
EAB-07:033455 Uen Rev A Ericsson Internal LTE Performance Checkpoint 2007-06-252
Outline
About Performance EvaluationsLTE Performance Checkpoint 2
– Delay and latency– Peak data rates– User throughput and spectrum efficiency– VoIP– MBSFN
1.7 bps/Hz/cell – good or bad?– Comparison to upper bound– Supported traffic volumes
Summary
EAB-07:033455 Uen Rev A Ericsson Internal LTE Performance Checkpoint 2007-06-253
Performance Evaluations
Scenario, models and assumptions
Pe
rfo
rma
nc
e Ide
ali
ty
Ideal receiver
Practical receiver
Practical deployment
Single-cell
EAB-07:033455 Uen Rev A Ericsson Internal LTE Performance Checkpoint 2007-06-254
Control Plane Latency
3GPP control plane latency target reached!
Targets:Idle Active in 100ms
Achievement:Idle Active in 47.5ms + 2xTs1cTarget:
<100ms
Achievement:47.5 + 2xTs1c
UE eNB MME
5. RRC Connection Request
3. TA + Scheduling Grant
2. RACH Preamble
8. Connection Request
10. Connection Setup
12. RRC Connection Setup
15. RRC Connection Complete
9. Processing delay in MME
1. Delay for RACH Scheduling period
4. Processing delay in UE
3. Processing delay in eNB
7. Processing delay in eNB
11. Processing delay in eNB
14. Processing delay in UE
13. H-ARQ Retransmission
16. H-ARQ Retransmission
6. H-ARQ Retransmission
5ms
1ms
1ms
1ms
5ms*
2.5ms
0.3x5ms
4ms
Ts1c (2-15ms)
Ts1c (2-15ms)1.5ms
0.3x5ms
0.3x5ms
4ms
5ms*
3ms
*) together
15ms
Note: FDD figures, similar results for TDD
EAB-07:033455 Uen Rev A Ericsson Internal LTE Performance Checkpoint 2007-06-255
User Plane Latency
3GPP user plane latency target reached!
Targets:1-way RAN delay <5ms
Achievement:3.5 + BLER x 5 ms
UE eNB
1 ms
1 ms
HARQ RTT 5 ms
1 ms
1 ms
TTI + framealignment
1.5 ms
1.5 ms
Note: FDD figures, similar results for TDD
EAB-07:033455 Uen Rev A Ericsson Internal LTE Performance Checkpoint 2007-06-256
Peak Data Rates
3GPP peak data rate targets reached!
19,6
39,2
81,6
163,2
244,8
326,4
3,5 8,619,9
41,5
63,1
84,7
0
50
100
150
200
250
300
350
1,25 2,5 5 10 15 20Bandwidth [MHz]
Peak
Dat
a R
ates
[Mbp
s]
Downlink 4x4Uplink (64QAM)
Targets:100Mbps DL (2x2)
50Mbps UL
Achievement:326Mbps DL (4x4)
173Mbps DL (2x2)
85Mbps UL (64QAM)
56Mbps UL (16QAM)
1.6Gbps in 100MHz IMT-A capable
DL target 100Mbps
UL target 50Mbps
EAB-07:033455 Uen Rev A Ericsson Internal LTE Performance Checkpoint 2007-06-257
Data Rates in LTE Test BedAssumptions:Over-the-air10MHz4x4 MIMO64QAMR ≅ 0.7TTI=0.67ms 16SCs/RB
Achievement102Mbps (non-optimized)
Source:Markus Ringström
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User throughput and Spectrum EfficiencyIntroduction
0 2 4 6 8 100
2
4
6
8
10
12
14
16
18
Sector Throughput [Mbps]
Mea
n U
ser T
hrou
ghpu
t [M
bps]
E-UTRABaselineTarget range (sim)
Downlink results in checkpoint 1 Relation to Checkpoint 1 (2006)
Revised evaluation frameworkSingle high-loaded operating point (10 UE/cell)
Increased realism (feedback delay, measurement errors, overhead)
EAB-07:033455 Uen Rev A Ericsson Internal LTE Performance Checkpoint 2007-06-259
User throughput and spectrum efficiencyDownlink
3GPP downlink targets reached!
Targets:Mean user tpt 3-4xCell-edge u tpt 2-3xSpectrum eff. 3-4xBaseline: Basic HSPA R6
Achieved spectrum eff.:LTE 2x2 1.7 bps/Hz/cellLTE 4x2 1.9 bps/Hz/cellLTE 4x4 2.7 bps/Hz/cell
UTRA Baseline E-UTRA 2x2 E-UTRA 4x2 E-UTRA 4x40
1
2
3
Spec
trum
eff.
[bps
/Hz/
cell]
Case1 (ISD=500m)
Target
UTRA Baseline E-UTRA 2x2 E-UTRA 4x2 E-UTRA 4x40
0.1
0.2
0.3
0.4
Cell-
edge
use
r tp
[bps
/Hz]
Target
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User throughput and spectrum efficiencyUplink
3GPP uplink targets reached!
Targets:Mean user tpt 2-3xCell-edge u tpt 2-3xSpectrum eff. 2-3xBaseline: Basic HSPA R6
Achieved spectrum eff.:LTE 1x2 0.7 bps/Hz/cellLTE 1x4 1.1 bps/Hz/cell
UTRA Baseline E-UTRA 1x2 E-UTRA 1x40
0.5
1
1.5
Spec
trum
eff.
[bps
/Hz/
cell]
Case1 (ISD=500m)
Target
UTRA Baseline E-UTRA 1x2 E-UTRA 1x40
0.02
0.04
0.06
Cell-
edge
use
r tp
[bps
/Hz]
Target
EAB-07:033455 Uen Rev A Ericsson Internal LTE Performance Checkpoint 2007-06-2511
VoIP
123289Case3
-293Case2
241317Case1
ULDL
VoIP Capacity (users/sector/5MHz)Deployment
Scenario
Targets:Similar to UTRA CS (60-80 users/5MHz)Internal target200/5MHz
Achievement:240 users (case 1)
3GPP VoIP targets reached!
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MBSFNMulticast Broadcast Single Frequency Network
Targets:1bps/Hz
Achievement:3bps/Hz(1bps/Hz at 1700m ISD in case 1)
3GPP MBSFN targets reached!
500 1000 1500 2000 2500 3000 3500 40000
0.5
1
1.5
2
2.5
3
3.5
4
ISD [m]
MB
SFN
spe
ctru
m e
ffici
ency
[bps
/Hz]
Case1, 19 sites
Target 1bps/Hz
EAB-07:033455 Uen Rev A Ericsson Internal LTE Performance Checkpoint 2007-06-2513
0,0
0,5
1,0
1,5
2,0
2,5
3,0
3,5
4,0
4,5
Shannon(reuse 1,
RR)
Modulationand Coding
Cyclicprefix
Guardbands
CCHoverhead
Simulation(PF, ideal
CQI)
Simulation(PF, real
CQI)
Spec
trum
Effi
cien
cy [b
ps/H
z/se
ctor
]1.7 bps/Hz/sector – Good or Bad?’Theory’ and Simulation
-10 -5 0 5 10 15 200
20
40
60
80
100
Downlink Wideband C/(I+N) [dB]
C.D
.F. [
%]
LTE approaches theoretical limits!
R/W=2xlog2(1+SINR)
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1.7 bps/Hz/sector – Good or Bad?3GPP Case 1 (500m ISD) in a City Center Area (20,000km-2)
Sector Capacity1.7x20MHz =34Mbps
Sector Size6·(167·167·√3/2/2)= 0.0725km2
333mSubscriber DensityPop. dens. 20,000km-2
Penetration 90%Market share x30%Sub. dens: 5,400km-2
Subscribers per cell5400·0.0725 = 392
Capacity per subscriber34/392 = 87kbps(average over busy hour, << rate when active)
Assuming 30·10=300 busy hours per month:87·300·3600/8 =12GB/month
4,000 MP3s (3MB each)120,000 RAN1 Tdocs
EAB-07:033455 Uen Rev A Ericsson Internal LTE Performance Checkpoint 2007-06-2515
Summary
3GPP checkpoint passed– Peak data rates: DL 326Mbps, UL 86Mbps– Latency: CP ~50ms, UP 3.5ms, HO ~ 12ms– Throughput: DL >3 and UL >2 x UTRA baseline– VoIP: 240 users/5MHz– MBSFN: >3bps/Hz
LTE approaches theoretical limitsLTE can serve lots of traffic
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Handover Interruption Time
3GPP control plane latency target reached!
Targets:None
Achievement Contention-free:DL: 12msUL: 12msContention-based:DL: 25msUL: 18.5ms
UE SourceeNB
TargeteNB MME/UPE
HO command
HO complete
Ack
U-plane route update
(Path switch)
UL DL
(a) Interruption due to radio L1/L2 layers
(b) Interruption due to UL RRC signalling
(d) Interruption due to path switch(c) Interruption due to
DL RRC signalling
DL synchronisation+
Timing advance+
UL resource request/grant
U-plane active U-plane active
U-plane active U-plane activeForwardeddata only
Measurement report
HO request
HO request confirm
Data forwarding(background process)
......
Data forwarding may continue even after
path switch
UE SourceeNB
TargeteNB MME/UPE
HO command
HO complete
Ack
U-plane route update
(Path switch)
UL DL
(a) Interruption due to radio L1/L2 layers
(b) Interruption due to UL RRC signalling
(d) Interruption due to path switch(c) Interruption due to
DL RRC signalling
DL synchronisation+
Timing advance+
UL resource request/grant
U-plane active U-plane active
U-plane active U-plane activeForwardeddata only
Measurement report
HO request
HO request confirm
Data forwarding(background process)
......
Data forwarding may continue even after
path switch
12ms
6.5ms
6.5ms
(d) Forwarding delay at path switch exceeding (a)+(b) ~0ms
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