< Sungrae Cho >, <Chung-Ang UNIV> <September 2008> doc.: IEEE 802. 15-08-0689-00-0006 Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [Impact of Frame Length on Latency and Throughput] Date Submitted: [September, 2008] Source: [Sungrae Cho, Wonsuk Choi, Xiangbo Zhang, Laihyuk Park and Dong Dong] [School of Computer Science and Engineering, Chung-Ang University ] Address [221 Heukseok, Dongjak, Seoul 156-756, Republic of Korea] Voice:[+82-2-820-5766], FAX: [+82-2-820-5766], E-Mail:[srcho@cau.ac.kr] Re: [Contribution to IEEE 802.15.6 Meeting, September 2008] Abstract: [This document describes an impact of frame length on latency and throughput for WBAN networks.] Purpose: [Contribution] Notice: This document has been prepared to assist the IEEE P802.15. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor acknowledges and accepts that this contribution becomes the property of IEEE and may be made publicly available by P802.15. <September, 2008> < Sungrae Cho >, <Chung-Ang UNIV>

Impact of Frame Length on Latency and Throughput <September 2008> doc.: IEEE 802. 15-08-0689-00-0006 Impact of Frame Length on Latency and Throughput Sungrae Cho, Wonsuk Choi, Xiangbo Zhang, Laihyuk Park, and Dong Dong UC LAB Chung-Ang University <September, 2008> < Sungrae Cho >, <Chung-Ang UNIV> Slide 2

< Sungrae Cho >, <Chung-Ang UNIV> <September 2008> doc.: IEEE 802. 15-08-0689-00-0006 Introduction The QoS management and reliability should be provided for high priority alarm message and real time vital information Differentiation (or Prioritization) is necessary based on Timeliness (Urgency) Reliability Etc. <September, 2008> < Sungrae Cho >, <Chung-Ang UNIV> Slide 3

< Sungrae Cho >, <Chung-Ang UNIV> <September 2008> doc.: IEEE 802. 15-08-0689-00-0006 Assumptions Considers CSMA/CA. Single channel. Two types of priority groups: Hi and Lo Different priority sources use different access mechanisms. High priority sources randomly choose backoff interval in range of [0, α-1], and low priority sources choose in range of [α, β-1] where β > α+1. Different priority sources use different exponential increase factors. <September, 2008> < Sungrae Cho >, <Chung-Ang UNIV> Slide 4

Low Priority Source Data is Long doc.: IEEE 802. 15-08-0689-00-0006 Low Priority Source Data is Long Low Priority Flow RTS CTS DATA ACK But still needs to wait for this long time A very urgent packet needs to be transmitted <September, 2008> < Sungrae Cho >, <Chung-Ang UNIV> Slide 5

Low Priority Source Data is Short doc.: IEEE 802. 15-08-0689-00-0006 Low Priority Source Data is Short To limit max Data Length Low Priority Flow RTS CTS DATA ACK High Priority Flow Carrier Sense/Backoff RTS CTS DATA ACK High Priority Flow gets the channel faster than previous slide A very urgent packet needs to be transmitted <September, 2008> < Sungrae Cho >, <Chung-Ang UNIV> Slide 6

< Sungrae Cho >, <Chung-Ang UNIV> <September 2008> doc.: IEEE 802. 15-08-0689-00-0006 Simple Comparison C++ event-driven simulation 2Mb/s link without noise or inference Poisson packet arrivals Frame header 50B Cwmin = 16 (Hi CW: 0~7, Lo CW: 8~15) Exponential Backoff Measured Latency: average waiting time for hi-priority source to gain the channel Throughput: average throughput for lo-priority source <September, 2008> < Sungrae Cho >, <Chung-Ang UNIV> Slide 7

Latency for Hi-Priority Source doc.: IEEE 802. 15-08-0689-00-0006 Latency for Hi-Priority Source <September, 2008> < Sungrae Cho >, <Chung-Ang UNIV> Slide 8

Throughput for Lo-Priority Source doc.: IEEE 802. 15-08-0689-00-0006 Throughput for Lo-Priority Source <September, 2008> < Sungrae Cho >, <Chung-Ang UNIV> Slide 9

< Sungrae Cho >, <Chung-Ang UNIV> <September 2008> doc.: IEEE 802. 15-08-0689-00-0006 Summary Prioritization is necessary with respect to Timeliness (Urgency) and Reliability, etc. Using shorter frame allows hi-priority source to access the channel earlier at the expenses of decreased throughput of lo-priority source. Is a restriction of lo-priority data frame necessary for hi-priority sources? Or is there any way to stop long data frame of lower priority source in order to send higher priority source’s urgent data. <September, 2008> < Sungrae Cho >, <Chung-Ang UNIV> Slide 10

This work has been supported by HNRC of IITA. <September 2008> doc.: IEEE 802. 15-08-0689-00-0006 This work has been supported by HNRC of IITA. <September, 2008> < Sungrae Cho >, <Chung-Ang UNIV> Slide 11

< Sungrae Cho >, <Chung-Ang UNIV> <September 2008> doc.: IEEE 802. 15-08-0689-00-0006 Thank You! <September, 2008> < Sungrae Cho >, <Chung-Ang UNIV> Slide 12