1 / 30

OFDMA performance in 11ax

OFDMA performance in 11ax. Date: 2016-07-25. Authors:. Introduction. From September 2015 meeting, we have addressed OFDMA performance using PHY/MAC integrated simulator [1]~[7] DL only, UL only DL and UL mixed Single BSS, OBSS(Residential) MU-RTS/CTS

gjude
Download Presentation

OFDMA performance in 11ax

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. OFDMA performance in 11ax Date: 2016-07-25 Authors: Suhwook Kim, LG Electronics

  2. Introduction • From September 2015 meeting, we have addressed OFDMA performance using PHY/MAC integrated simulator [1]~[7] • DL only, UL only • DL and UL mixed • Single BSS, OBSS(Residential) • MU-RTS/CTS • Full buffer traffic, low rate traffic Suhwook Kim, LG Electronics

  3. Simulator update • We had used only UDP (CBR) traffic in our simulator • UDP is very simple • Full buffer traffic model is widely used to evaluate communication system simulation • There are, however, so many TCP traffic in real world • Performance on TCP traffic may be different from UDP traffic because of its characteristics • So, we have implemented TCP model in our simulator • TCP traffic defined in our EMD[8] • TCP operation (TCP-Reno) Suhwook Kim, LG Electronics

  4. Traffic model • Traffic model in EMD • UDP • Wireless Display • TCP • Buffered Video Streaming (e.g., Youtube, Netflix) • Video Conferencing • Multicast Video Streaming • Gaming • Virtual Desktop Infrastructure • VoIP • FTP • HTTP Suhwook Kim, LG Electronics

  5. Topology • Topology description • Single BSS • Number of STA: 6 ~ 18 • Distance between STA: 10 meter … … … … TCP Case 1: Case 2: TCP UDP Suhwook Kim, LG Electronics

  6. Simulation cases • Case 1: TCP only • Number of STAs: 6, 9, 12, 15, 18 • Case 2: TCP and UDP mixed • Number of STAs: 12 • 6 STAs for TCP: left side of AP • 6 STAs for UDP: right side of AP • TCP traffic: Buffered Video Class 6 (15.6 Mbps) • Case 2-1 • fixed UDP DL: 15 Mbps • variable UDP UL: 1, 3, 5, 7, 9, 10, 13, 15, 17, 20, 30 Mbps • Case 2-2 • variable UDP DL: 10, 20, 30, 40 Mbps • fixed UDP UL: 1 Mbps Suhwook Kim, LG Electronics

  7. Buffered Video Streaming • Traffic class: BV1(2 Mbps) ~ BV6(15.6 Mbps) • DL: TCP Video data (MAX 1500 Byte) • UL: TCP ACK (40 Byte) • Reason why BV6 is selected in this simulation • Highest required data rate in TCP traffic: sensitive to network status • Video traffic: most favorite content in nowadays • DL oriented: more common traffic direction Suhwook Kim, LG Electronics

  8. Legacy vs. OFDMA on TCP OFDMA Legacy • TCP ACK will be sent by CSMA/CA manner • STA doesn’t have to wait for sending TCP ACK • TCP ACK will be sent by scheduled manner • STA has to wait for sending TCP ACK • If AP received TCP ACK, it increases congestion window (it means AP will send more data in next time) • If AP received TCP NACK, it decreases congestion window (it means AP will send less data in next time) Suhwook Kim, LG Electronics

  9. TCP timeout • TCP timeout has critical impact on performance • Condition • MAC Queuing delay + Data TX delay + ACK Access delay > Timeout • Operation • AP will retransmit only one TCP segment and wait for TCP ACK • set congestion window to minimum (data rate decreases dramatically) • increase congestion window after receiving TCP ACK Suhwook Kim, LG Electronics

  10. Simulation Setup: Parameters *drop-free TCP transmission: no TCP queue drop and achieving maximum data rate Suhwook Kim, LG Electronics

  11. Simulation Result – Case 1 • TCP only Suhwook Kim, LG Electronics

  12. Simulation Result – Case 1 • TCP only *drop-free TCP transmission: no TCP queue drop and achieving maximum data rate Suhwook Kim, LG Electronics

  13. Discussion • Result • OFDMA shows better performance over legacy • Data rate of each TCP transmission • Number of drop-free TCP transmission • OFDMA gain over legacy significantly increases with the number of STAs transmitting TCP data • Analysis • TCP ACK transmission can be more failed by collision and hidden terminal when there are many TCP traffic in legacy system • Even though RTS/CTS is used, STA fails to transmit TCP ACK within TCP timeout bound sometimes Suhwook Kim, LG Electronics

  14. Simulation Result – Case 2 - 1 • TCP and UDP mixed, variable UDP UL Suhwook Kim, LG Electronics

  15. Simulation Result – Case 2 - 1 • TCP and UDP mixed, variable UDP UL *drop-free TCP transmission: no TCP queue drop and achieving maximum data rate Suhwook Kim, LG Electronics

  16. Simulation Result – Case 2 - 1 • TCP and UDP mixed, variable UDP UL Suhwook Kim, LG Electronics

  17. Simulation Result – Case 2 - 1 • TCP and UDP mixed, variable UDP UL Suhwook Kim, LG Electronics

  18. Discussion • Result • OFDMA shows better TCP performance in TCP/UDP mixed traffic • Even though there are a little throughput drop in UDP traffic in OFDMA, total throughput of TCP + UDP is enhanced • Analysis • TCP traffic is very sensitive about surroundings channel load • TCP ACK transmission can be more challenging job for STA in TCP and UDP mixed traffic because of long ACK access delay • When the number of UDP STA is increased, TCP STA couldn’t get TXOP to send TCP ACK easily Suhwook Kim, LG Electronics

  19. Simulation Result – Case 2 - 2 • TCP and UDP mixed, variable UDP DL Suhwook Kim, LG Electronics

  20. Discussion • Result • OFDMA shows better TCP performance in TCP/UDP mixed traffic even though UDP UL rate is very low • Analysis • In high rate UDP case, AP spent most time to send data for UDP station • TCP ACK transmission can be more challenging job in TCP and UDP mixed traffic because of MAC queuing delay Suhwook Kim, LG Electronics

  21. Conclusion • We observed that OFDMA shows a better TCP performance by well protecting TCP ACK from congestion • OFDMA gain will be increased by exploiting flexible RU (here we only used 242 RU) and a better scheduler (here we used random scheduler) • Will be done in next step Suhwook Kim, LG Electronics

  22. Reference • [1] ~ [7] 11-15/1095r0 ~ r6 • [8] 11-14/0571r12 11ax Evaluation Methodology • [9] 11-14/620r0 link adaptation for PHY SLS calibration Suhwook Kim, LG Electronics

  23. Appendix Suhwook Kim, LG Electronics

  24. Simulation Result – Case 2 - 1 • TCP and UDP mixed, variable UDP UL Suhwook Kim, LG Electronics

  25. Simulation Result – Case 2 - 1 • TCP and UDP mixed, variable UDP UL Suhwook Kim, LG Electronics

  26. Simulation Result – Case 2 - 2 • TCP and UDP mixed, variable UDP DL *drop-free TCP transmission: no TCP queue drop and achieving maximum data rate Suhwook Kim, LG Electronics

  27. Simulation Result – Case 2 - 2 • TCP and UDP mixed, variable UDP DL Suhwook Kim, LG Electronics

  28. Simulation Result – Case 2 - 2 • TCP and UDP mixed, variable UDP DL Suhwook Kim, LG Electronics

  29. Simulation Result – Case 2 - 2 • TCP and UDP mixed, variable UDP DL Suhwook Kim, LG Electronics

  30. Simulation Result – Case 2 - 2 • TCP and UDP mixed, variable UDP DL Suhwook Kim, LG Electronics

More Related