1. , Slide 1 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. doc.: IEEE 802. 15-08-0689-00-0006

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

3. 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. Introduction Slide 3, doc.: IEEE 802. 15-08-0689-00-0006

4. 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. Assumptions Slide 4, doc.: IEEE 802. 15-08-0689-00-0006

5. RTSCTSDATAACK A very urgent packet needs to be transmitted But still needs to wait for this long time Low Priority Flow Low Priority Source Data is Long Slide 5, doc.: IEEE 802. 15-08-0689-00-0006

6. RTSCTS DATAACK Low Priority Flow High Priority Flow RTS CTSDATA ACK To limit max Data Length Carrier Sense/Backoff High Priority Flow gets the channel faster than previous slide A very urgent packet needs to be transmitted Low Priority Source Data is Short Slide 6, doc.: IEEE 802. 15-08-0689-00-0006

7. 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 Simple Comparison Slide 7, doc.: IEEE 802. 15-08-0689-00-0006

8. Latency for Hi-Priority Source Slide 8, doc.: IEEE 802. 15-08-0689-00-0006

9. Throughput for Lo-Priority Source Slide 9, doc.: IEEE 802. 15-08-0689-00-0006

10. 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. Summary Slide 10, doc.: IEEE 802. 15-08-0689-00-0006

11. This work has been supported by HNRC of IITA. Slide 11, doc.: IEEE 802. 15-08-0689-00-0006

12. Thank You! Slide 12, doc.: IEEE 802. 15-08-0689-00-0006