May 2003 doc IEEE 802 11 03567 r

May 2003 doc. : IEEE 802. 11 -03/567 r 0 Throughput Enhancement via Frame Aggregation – A Sequel Youngsoo Kim*+, Sunghyun Choi*, Hyosun Hwang+, and Kyunghun Jang+ +Samsung Advance Institute of Technology (SAIT) and *Seoul Submission National University (SNU) 1 Youngsoo Kim, Samsung/SNU and S. Choi, SNU

May 2003 doc. : IEEE 802. 11 -03/567 r 0 Contents • Introduction • Frame aggregation • New Results – Numerical throughput analysis with channel error – Performance measurement using TCP and UDP traffic • Conclusion Submission 2 Youngsoo Kim, Samsung/SNU and S. Choi, SNU

May 2003 doc. : IEEE 802. 11 -03/567 r 0 Introduction • Objective – To achieve high throughput/efficient schemes to improve the current 802. 11 MAC • Background – 802. 11 MAC/PHY has fixed overheads irrespective of packet size – The small-size packet can cause more throughput degradation – To reduce the overheads is the one of main concerns to enhance current 802. 11 WLAN Submission 3 Youngsoo Kim, Samsung/SNU and S. Choi, SNU

May 2003 doc. : IEEE 802. 11 -03/567 r 0 Throughput Performance Analysis • Assumptions – There is a single transmitter and a single receiver – The 802. 11 DCF is used – All the datagrams have a fixed size – The transmitter has infinite number of datagrams – Channel error is not considered – Throughput is determined at the LLC SAP between LLC and IP Submission 4 Youngsoo Kim, Samsung/SNU and S. Choi, SNU

May 2003 doc. : IEEE 802. 11 -03/567 r 0 Theoretical Throughput for 54 Mbps Preferred Operation Range Submission 5 Youngsoo Kim, Samsung/SNU and S. Choi, SNU

May 2003 doc. : IEEE 802. 11 -03/567 r 0 Frame Aggregation • Aggregation of multiple frames in order to reduce the fixed overheads relatively! • Aggregation was once part of 802. 11 e in 802. 11 e/D 1. 0 – It defined a new management frame for this aggregation mechanism – Multiple MSDUs are aggregated into a single management frame • Frame aggregation was presented at the May 2003 meeting (11 -03376 r 0 -HTSG-Throughput_Enhancement_via_Frame_Aggregation. ppt) Submission 6 Youngsoo Kim, Samsung/SNU and S. Choi, SNU

May 2003 Original doc. : IEEE 802. 11 -03/567 r 0 Frame Formats (Example) With aggregation Submission 7 Youngsoo Kim, Samsung/SNU and S. Choi, SNU

May 2003 doc. : IEEE 802. 11 -03/567 r 0 Numerical Analysis with Channel Error • Compare throughput performance by distance of two scenarios – Without aggregation • One 1000 bytes frame (IP datagram size) – With aggregation • Two 1000 bytes frames are aggregated • Assumption – Ideal rate-adaptation (maximizing throughput) • Path loss exponent = 4 & Tx_power = 200 m. W – Based on error performance analysis assuming • Binary convolutional coding • Hard-decision Viterbi decoding with AWGN at the input Submission 8 Youngsoo Kim, Samsung/SNU and S. Choi, SNU

May 2003 doc. : IEEE 802. 11 -03/567 r 0 Numerical Analysis Result Submission 9 Youngsoo Kim, Samsung/SNU and S. Choi, SNU

May 2003 doc. : IEEE 802. 11 -03/567 r 0 Some Lessons from Error Performance Throughput gain Short distance (high Tx rate) High Error Low performance loss Long distance (low Tx rate) Low High • Frame aggregation seems a good solution to improve throughput when the distance between sender and receiver is relatively short ! Submission 10 Youngsoo Kim, Samsung/SNU and S. Choi, SNU

May 2003 doc. : IEEE 802. 11 -03/567 r 0 Performance Measurement • Implement frame aggregation in real platform • Linux & Intersil-based platform (11 b) • Measure throughput performance of UDP and TCP traffic • Note: Frame aggregation is only applied when there are multiple frames in the queue Traffic generator Submission AP 11 STA Youngsoo Kim, Samsung/SNU and S. Choi, SNU

May 2003 doc. : IEEE 802. 11 -03/567 r 0 New Measurement Results - UDP • Throughput performance of packet aggregation with fixed rate UDP Submission 12 Youngsoo Kim, Samsung/SNU and S. Choi, SNU

May 2003 doc. : IEEE 802. 11 -03/567 r 0 New Measurement Results - TCP • Throughput performance of packet aggregation with TCP Submission 13 Youngsoo Kim, Samsung/SNU and S. Choi, SNU

May 2003 doc. : IEEE 802. 11 -03/567 r 0 Conclusion • Shown via analysis that frame aggregation is a good way to improve 802. 11 MAC efficiency • Measurements from real implementation also show the performance enhancement • Frame aggregation can be done above the MAC SAP very easily • Frame aggregation can be considered an enhanced mechanism Submission 14 Youngsoo Kim, Samsung/SNU and S. Choi, SNU

May 2003 doc. : IEEE 802. 11 -03/567 r 0 Future Work • Measurement/simulations with more realistic traffic scenarios – Considering usage scenarios developed in this group • Incorporating the PHY channel error performance – Based on a more realistic simulation, not an analysis (given here) Submission 15 Youngsoo Kim, Samsung/SNU and S. Choi, SNU

May 2003 doc. : IEEE 802. 11 -03/567 r 0 Any Comments or Questions ? Submission 16 Youngsoo Kim, Samsung/SNU and S. Choi, SNU