1. Simulation for EDCF Enhancement Comparison
November 2002
doc.: IEEE /xxxr0
January 2003
Simulation for EDCF Enhancement Comparison
Isaac Lim Wei Lih
Matsushita Electric Ind.
Isaac Lim, Matsushita Electric Ind.
Menzo Wentink, Intersil Corp.

2. EDCF Enhancement Simple Queue Control for EDCF
January 2003
EDCF Enhancement
Simple Queue Control for EDCF
Station contend for an EDCF TXOP when the MAC transmission queue size is greater than a specified limit
Use EDCF TXOP more effectively
Reduce the numbers of collisions
Queue size limit depends on traffic requirement
Isaac Lim, Matsushita Electric Ind.

3. Case 1: Simulation Scenario
January 2003
Case 1: Simulation Scenario
Four 6Mbps streams transmitted using Block Ack mechanism at 36Mbps OFDM PHY with 10% PER
TXOP Limit = 3msec
MSDU Size = 1402 Bytes
Block Ack Request control frame is generated after 8 data frames being transmitted.
Case 1a – Normal EDCF:
AIFS = DFIS, CWmin = 15, CWmax = 1023
Case 1b – Simple Queue Control
Queue Size Limit = 8 MSDUs
AIFS = DIFS, CWmin = 15, CWmax = 1023
Isaac Lim, Matsushita Electric Ind.

4. Bandwidth Utilization
January 2003
Bandwidth Utilization
Normal EDCF
EDCF with Simple Queue Control
Isaac Lim, Matsushita Electric Ind.

5. End-to-End Delay January 2003 Case 1a Case 1b
Isaac Lim, Matsushita Electric Ind.

6. Detail Results November 2002 doc.: IEEE 802.11-02/xxxr0 January 2003
Parameter Settings
Data Rate
= 6Mbps
No of source STA
= 4
Type of ACK
= Block ACK (8)
Nominal MSDU size
= 1402 bytes
Delay Bound
= 64TU
PER
= 10%
Case
Limit
Mean ETE Delay (sec)
S.D. ETE Delay (sec)
MSDU Dropped
MSDU Transmitted
STA1
STA2
STA3
STA4
1a – No Control -
19, 76
8, 18
5, 21
19, 111
315675
1b – Queue Control
8 data frames
3, 20
3, 18
3, 21
7, 41
SER refers to Slot Error Rate.
PER refers to Packet Error Rate.
PI refers to Polling Interval.
MSDU received with end-to-end delay > delay bound
MSDU dropped by transmitter due to exceed delay bound
Isaac Lim, Matsushita Electric Ind.
Menzo Wentink, Intersil Corp.

7. Case 2: Simulation Scenario
January 2003
Case 2: Simulation Scenario
Same setting as in Case 1 with 1Mbps background traffic being added to each scenario.
10 background traffic generator with each is having data 100Kbps to be transmitted using legacy setting
Isaac Lim, Matsushita Electric Ind.

8. End-to-End Delay January 2003 Case 2a Case 2b
Isaac Lim, Matsushita Electric Ind.

9. Throughput for Background Traffic
January 2003
Throughput for Background Traffic
Case 2a
Average Throughput = bps
Case 2b:
Average Throughput = bps
Isaac Lim, Matsushita Electric Ind.

10. Results with background traffic
November 2002
doc.: IEEE /xxxr0
January 2003
Results with background traffic
Parameter Settings
Data Rate
= 6Mbps
No of source STA
= 4
Type of ACK
= Block ACK (8)
Nominal MSDU size
= 1402 bytes
Delay Bound
= 64TU
PER
= 10%
Case
Limit
Mean ETE Delay (sec)
S.D. ETE Delay (sec)
MSDU Dropped
MSDU Transmitted
STA1
STA2
STA3
STA4
2a – No Control -
3207, 19693
3014, 17657
3076, 18176
2584, 15425
315675
2b – Queue Control
8 data frames
280, 1246
313, 1568
241, 1033
271, 1160
SER refers to Slot Error Rate.
PER refers to Packet Error Rate.
PI refers to Polling Interval.
MSDU received with end-to-end delay > delay bound
MSDU dropped by transmitter due to exceed delay bound
Isaac Lim, Matsushita Electric Ind.
Menzo Wentink, Intersil Corp.

11. Conclusion Simple Queue Control Simple to Implement
January 2003
Conclusion
Simple Queue Control
Simple to Implement
Can be implementation Specific
Bandwidth usage reduction is caused by the reduction in collisions.
Distributed in nature
Each stream can determine it’s own queue size limit base on it’s own traffic requirement in order to yield better results
Fail to operate when network is overloaded
Need a Bandwidth Resource Controller to prevent network to be overloaded
Isaac Lim, Matsushita Electric Ind.