CC/RR Performance Evaluation - Revisited Month 1998 doc.: IEEE 802.11-98/xxx March 2002 CC/RR Performance Evaluation - Revisited Javier del Prado and Sunghyun Choi Philips Research USA Briarcliff Manor, New York sunghyun.choi@philips.com J. del Prado and S. Choi, Philips

March 2002 Simulation Goal In 01/571r0 the results showed a better performance with CC/RR compared to straight PCF Straight PCF does poll all the stations These results were not enough to validate the CC/RR mechanism HCF should not implement a straight polling, so it is not a good comparison We show new scenarios with more simulation results for further discussion J. del Prado and S. Choi, Philips

Simulation Model Used the simulation model provided by AT&T March 2002 Simulation Model Used the simulation model provided by AT&T The results in 01/571 were obtained with the same simulation model Modified to support new scenarios It supports: DCF PCF (or HCF without TXOP, working in CFP only) CC/RR Direct STA-to-STA transmission J. del Prado and S. Choi, Philips

March 2002 Simulation Scenarios 1 AP, 6 voice STAs and 23 FTP heavy and HTTP heavy STAs The application parameters are taken from 01/571r1. All the application start after 100 sec from the simulation start. The WLAN parameters are the same as in 01/571r1. Beacon interval of 20 ms with CFP of 18 ms J. del Prado and S. Choi, Philips

March 2002 Simulation Scenarios J. del Prado and S. Choi, Philips

March 2002 Simulation Scenarios J. del Prado and S. Choi, Philips

Simulation Scenarios 4 different simulation scenarios: March 2002 Simulation Scenarios 4 different simulation scenarios: Standing Poll (legacy PCF) All STA & AP set for Standing Poll All STA are polled using “Round Robin” One STA is polled continuously while it has more data The CFP ends when all STA have been polled CC/RR All STA & AP set for CC/RR CC Parameters chosen from 01/571r0 Polling list updated using RR information The STAs are polled while enough time in the CFP Simulated in 01/571r0 J. del Prado and S. Choi, Philips

Simulation Scenarios New simulation scenarios: March 2002 Simulation Scenarios New simulation scenarios: 3) Polling only voice stations and downlink traffic to voice stations during CFP Data downlink traffic transmitted during CP After polling all voice stations, CFP ends “Round Robin” polling A voice STA is polled while it has more data to send 4) Polling voice stations and all downlink traffic during CFP Uplink data traffic is transmitted during CP J. del Prado and S. Choi, Philips

Throughput (moving average of 240) March 2002 Throughput (moving average of 240) J. del Prado and S. Choi, Philips

Load (moving average of 240) March 2002 Load (moving average of 240) J. del Prado and S. Choi, Philips

March 2002 Data Dropped AP J. del Prado and S. Choi, Philips

March 2002 Delay (global) J. del Prado and S. Choi, Philips

Delay (II) (without Standing Poll) March 2002 Delay (II) (without Standing Poll) J. del Prado and S. Choi, Philips

Control Traffic Received at AP March 2002 Control Traffic Received at AP J. del Prado and S. Choi, Philips

Control Traffic sent by AP March 2002 Control Traffic sent by AP J. del Prado and S. Choi, Philips

Media Access Delay at Voice STA 1 March 2002 Media Access Delay at Voice STA 1 J. del Prado and S. Choi, Philips

Media Access Delay at Voice STA #19 March 2002 Media Access Delay at Voice STA #19 J. del Prado and S. Choi, Philips

Voice Throughput per STA March 2002 Voice Throughput per STA J. del Prado and S. Choi, Philips

FTP Traffic served (moving average of 240) March 2002 FTP Traffic served (moving average of 240) J. del Prado and S. Choi, Philips

HTTP Traffic served (moving average of 240) March 2002 HTTP Traffic served (moving average of 240) J. del Prado and S. Choi, Philips

FTP download time (moving average of 10) March 2002 FTP download time (moving average of 10) J. del Prado and S. Choi, Philips

HTTP Page Response Time (moving average of 10) March 2002 HTTP Page Response Time (moving average of 10) J. del Prado and S. Choi, Philips

HTTP Object Response Time (moving average of 10) March 2002 HTTP Object Response Time (moving average of 10) J. del Prado and S. Choi, Philips

March 2002 Conclusions (I) The scenario was designed to demonstrate the utility of CC/RR. However, comparable performance was achieved without CC/RR. CC/RR mechanism may even degrade the overall performance in some cases due to the unnecessary overhead. Parameterized QoS streaming will not need the CC/RR mechanism. Resource request can be done via QoS Null or another management frame. J. del Prado and S. Choi, Philips

March 2002 Conclusions (II) We believe that the performance w/o CC/RR can be better via more intelligent scheduling Note that … HC can poll voice STAs during the CP (not implemented in the current simulation model) HC can get information in the QoS control field of data frames (not implemented in the current simulation model) CC/RR complexity is not justified! J. del Prado and S. Choi, Philips