MIMO Technology
doc.: IEEE 802.11-05/0716r0
System Performance Results for Scenario 1
Santosh Abraham, Arnaud Meylan, Sanjiv Nanda
Qualcomm, Inc.
[email protected]
Submission
Qualcomm, Inc.
July 12-16, 2004
MIMO Technology
doc.: IEEE 802.11-05/0716r0
Simulation Methodology
• The simulator is based on ns2
• Includes physical layer features
– TGn Channel Models
– PHY Abstraction determines frame loss events
• MAC features
–
–
–
–
–
–
EDCA
Adaptive Coordination Function (ACF): SCHED and SCAP
Frame Aggregation
ARQ with Block Ack
Closed Loop Rate Control (DRVF and DRV)
MIMO Modes (ES and SS)
• Transport
– File Transfer mapped to TCP
– QoS Flows mapped to UDP
Submission
Slide 2
Qualcomm, Inc.
July 12-16, 2004
MIMO Technology
doc.: IEEE 802.11-05/0716r0
Structure of the Simulator
Submission
Slide 3
Qualcomm, Inc.
MIMO Technology
July 12-16, 2004
doc.: IEEE 802.11-05/0716r0
Layered Structure for 802.11 Simulation
NODE A
TRANSPORT
TCP, UDP
NODE B
MIMO PROPAGATION
MODULE
TRANSPORT
TCP, UDP
COMPUTE RATES
COMPUTE PER
NETWORK
IP and Routing
NETWORK
IP and Routing
MAC 802.11N
MAC 802.11N
ARQ, Rate Control
ARQ, Rate Control
PHY LAYER
Submission
Slide 4
Qualcomm, Inc.
July 12-16, 2004
MIMO Technology
doc.: IEEE 802.11-05/0716r0
Statistics Obtained
• Throughput:
– As defined in CC 20. Throughput Metric 2.
– For each flow denote
• t l:
Time at which the last packet is transferred to the receiver LLC
• tf: Time at which the first packet arrives at the sender MAC SAP
• N: Number of packets delivered within the delay bound to the receiver
LLC by tl
• p: Packet size.
Np
Flow Throughput =
tl  t f
• Mean Delay:
– Mean of the time taken from packet arrival at the sender to packet arrival at
the receiver across all packets of the flow.
Submission
Slide 5
Qualcomm, Inc.
July 12-16, 2004
MIMO Technology
doc.: IEEE 802.11-05/0716r0
Statistics Obtained
• Packet Loss Rate:
– As defined in CC 19
– Number of MSDUs that are not delivered at the Rx MAC SAP
within the specified delay bound, divided by the total number of
MSDUs offered at the Tx MAC SAP
– Reasons for a packet being dropped are:
• Delay incurred by the packet exceeds the delay tolerance of the flow.
Delay is inclusive of scheduling and retransmission attempts.
• Packet has not been delivered after a maximum number of
transmission attempts.
Submission
Slide 6
Qualcomm, Inc.
July 12-16, 2004
MIMO Technology
doc.: IEEE 802.11-05/0716r0
Statistics Obtained
• Mean PHY Rate:
–
–
–
–
As defined in CC 27:
N: Number of packets transmitted.
ri: PHY Transmission rate of ith packet.
ti: Transmission time of the ith packet


N
Mean PHY Rate =
r
t
i
i 1 i
N
t
i 1 i
Submission
Slide 7
Qualcomm, Inc.
July 12-16, 2004
MIMO Technology
doc.: IEEE 802.11-05/0716r0
Simulation Scenarios
• Modified TGn Usage Models Scenario 1
– Channel Model B
– Scenario 1 HT (High Throughput)
• Increased Offered Non-QoS Load.
• Additional 25 Mbps Internet file transfer at 15.5 m for 2x2
• Additional 100 Mbps Internet file transfer at 15.5 m for 4x4
– Scenario 1 LD (Low Delay)
• Increased Offered Non-QoS Load.
• Reduce all multimedia application delays to 50 ms.
– Scenario 1 IR (Increased Range)
• Increased Offered Non-QoS Load.
• Reduce all multimedia application delays to 50 ms.
• HDTV receivers moved to 25 m (instead of 5 m)
Submission
Slide 8
Qualcomm, Inc.
July 12-16, 2004
MIMO Technology
doc.: IEEE 802.11-05/0716r0
Simulation Conditions
• Simulation Parameters Alternate values considered in italics
–
–
–
–
–
–
ACF and EDCA
Frame Aggregation
Block ACK (Delayed ACK)
Highest MCS: 7 bits/symbol. Also considered 5 bits/symbol
All links: 2x2. Also considered 4x4.
5.25 GHz
• EDCA Parameters
AC
0
1
2
3
4
Submission
CW min
127
31
63
63
127
CW max
1023
1023
1023
1023
1023
AIFS
2
2
4
8
10
Slide 9
Usage
Block Ack
VoIP
Video
Other RT applications
Best effort
Qualcomm, Inc.
July 12-16, 2004
MIMO Technology
doc.: IEEE 802.11-05/0716r0
Performance Metrics
• Per flow
–
–
–
–
Throughput
Packet loss rate (PLR)
Mean delay
Time-averaged PHY data rate
• Per scenario
–
–
–
–
Submission
Total throughput,
Latency of QoS flows,
Throughput for non-QoS flows
MAC Efficiency
Slide 10
Qualcomm, Inc.
July 12-16, 2004
MAC Mode
MIMO Technology
MAC
Efficiency
doc.: IEEE 802.11-05/0716r0
Total
Throughput
QoS Flows Latency and
Packet Loss Rate (PLR)
Non-QoS
Throughput
Scenario 1 HT (High Throughput)
ACF
0.77
107.27
HDTV/SDTV mean delay < 18 ms
Gaming PLR ~ 10^-3
55.42
EDCA with
Frame Aggr
0.46
59.42
HDTV/SDTV mean delay < 10 ms
Gaming PLR > 10%
MP3 PLR ~ 10^-3
7.40
HDTV/SDTV mean delay < 10 ms
Gaming PLR ~ 10^-3
51.64
Scenario 1 LD (Low delay)
ACF
0.76
103.53
EDCA with
Frame Aggr
0.48
60.40
HDTV/SDTV PLR ~ 10^-3
Gaming PLR > 10%
MP3 PLR ~ 10%
8.46
Scenario 1 IR (Increased Range)
ACF
0.76
93.57
HDTV/SDTV mean delay < 10 ms
41.69
SDTV PLR ~ 10^-3
Gaming & VOD Ctrl PLR ~ 10^-3
EDCA with
Frame Aggr
Submission
0.56
59.15
HDTV/SDTV PLR ~ 10^-3
Gaming PLR > 10%
MP3 PLR > 10%
Slide 11
7.24
Qualcomm, Inc.
MIMO Technology
July 12-16, 2004
doc.: IEEE 802.11-05/0716r0
Scenario 1 IR Using ACF: Per Flow Results
Application
HDTV_PCM
HDTV
SDTV
Internet_file
VoIP
VoIP
VoIP
Streming_video
MP3_audio
VoD_Ctl_channel
VoD_Ctl_channel
File_Transfer
Video_Phone
Video_Phone
VoIP
VoIP
VoIP
Console_to_Inet
Ctrler_to_cons
File_Transfer
Distance [m]
Offered Load
[Mbps]
Delay
Tolerance
[ms]
Mean Delay
[ms]
PLR (CC19)
CC20 Metric 1
[Mbps]
Mean PHY rate
[Mbps]
25.0
25.0
9.9
9.9
20.0
20.0
20.0
14.1
14.1
25.0
25.0
24.0
21.2
21.2
20.0
20.0
20.0
14.1
11.2
15.6
19.2
24
4
1
0.096
0.096
0.096
2
0.128
0.06
0.06
30
0.5
0.5
0.096
0.096
0.096
1
0.5
25
0.05
0.05
0.05
-1
0.03
0.03
0.03
0.05
0.05
0.05
0.05
-1
0.05
0.05
0.03
0.03
0.03
0.05
0.016
-1
4.7
3.9
9.9
12.1
8.1
8.0
8.0
5.7
5.2
10.8
7.8
101.3
12.3
11.4
8.1
8.1
8.2
15.3
4.3
73.6
0.00E+00
0.00E+00
1.39E-03
0.00E+00
0.00E+00
3.33E-04
6.66E-04
0.00E+00
0.00E+00
6.78E-03
1.42E-03
0.00E+00
3.80E-03
2.45E-03
2.46E-02
2.82E-02
2.99E-02
7.05E-03
3.00E-03
0.00E+00
18.960
23.699
3.948
1.001
0.095
0.095
0.095
2.002
0.126
0.060
0.059
16.771
0.496
0.495
0.092
0.092
0.092
0.994
0.495
23.237
104.19
112.73
131.79
135.46
100.98
102.43
104.00
126.31
123.88
138.38
139.02
119.55
116.81
122.41
147.25
148.79
148.79
161.83
166.39
158.56
92.905
123.91
108.524
Submission
Slide 12
Qualcomm, Inc.
MIMO Technology
July 12-16, 2004
MAC Mode
MAC
Efficiency
doc.: IEEE 802.11-05/0716r0
Total
Throughput
QoS Flows Latency and
Packet Loss Rate (PLR)
Non-QoS
Throughput
Scenario 1 IR 2x2
ACF
0.76
93.57
HDTV/SDTV mean delay < 10 ms
41.69
SDTV PLR ~ 10^-3
Gaming & VOD Ctrl PLR ~ 10^-3
EDCA with
Frame Aggr
0.56
59.15
ACF
0.74
190.17
EDCA with
Frame Aggr
0.35
70.44
HDTV/SDTV PLR ~ 10^-3
Gaming PLR > 10%
MP3 PLR > 10%
7.24
Scenario 1 IR 4x4
Submission
HDTV/SDTV mean delay < 10 ms
Gaming PLR ~ 10^-3
HDTV/SDTV PLR ~ 10^-3
Gaming PLR > 10%
MP3 PLR ~ 5%
Slide 13
138.27
18.46
Qualcomm, Inc.
July 12-16, 2004
MAC Mode
MIMO Technology
MAC
Efficiency
doc.: IEEE 802.11-05/0716r0
Total
Throughput
QoS Flows Latency and
Packet Loss Rate (PLR)
Non-QoS
Throughput
Scenario 1 HT Maximum 5 bits/symbol
ACF
0.78
90.62
HDTV/SDTV mean delay < 20 ms
38.75
EDCA with
Frame Aggr
0.52
59.93
HDTV/SDTV mean delay < 10 ms
Gaming PLR> 10%
Video CTRL ~ 10^-2
7.97
HDTV/SDTV mean delay <10 ms
34.85
Scenario 1 LD Maximum 5 bits/symbol
ACF
0.75
86.74
SDTV PLR ~10^-4
EDCA with
Frame Aggr
0.53
HDTV/SDTV PLR ~ 10^-3
VoIP PLR ~ 10%
Gaming and MP3 PLR > 10%
60.98
9.00
Scenario 1 IR Maximum 5 bits/symbol
ACF
0.76
79.48
HDTV/SDTV mean delay < 10 ms
27.61
SDTV & Gaming PLR ~ 10^-3
EDCA with
Frame Aggr
Submission
0.59
58.51
HDTV/SDTV PLR ~ 10^-2
Gaming and MP3 PLR > 10%
VoIP PLR < 10%
Slide 14
6.65
Qualcomm, Inc.
July 12-16, 2004
MIMO Technology
doc.: IEEE 802.11-05/0716r0
Conclusions from Scenario 1 Study
• TGn Usage Models Scenario 1 requirements can be met and exceeded
with 2x2.
• Using Scheduled operation:
– MAC Efficiency is in the range 74%-78%.
– Scenario 1 HT: Throughput can be increased to above 100 Mbps
– Scenario 1 LD: Video stream latency can be reduced below 50 ms (from
200 ms). Total throughput: 103 Mbps
– Scenario 1 IR: Range of HDTV flows can be increased from 5 m to 25 m.
Total throughput: 92 Mbps
• MAC Efficiency of EDCA with Frame Aggregation is around 56% for
2x2 and falls to 35% for 4x4.
• Throughput with 256 QAM
– ~15% throughput improvement with 256 QAM
– By setting Maximum MCS=5 bits/symbol obtain 80-92 Mbps for IR, LD,
HT.
Submission
Slide 15
Qualcomm, Inc.