<January 2002> doc.: IEEE 802.15-<02/139r0> March, 2008 Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [Reliable Performance Analysis of ] Date Submitted: [March 16, 2008] Source: [Kyungsup Kwak1,] Company: [Inha University1] Address: [ 6-141B, Inha University, 253 Yonghyun-dong, Nam-gu, Incheon, 402-751, Republic of Korea]1 Voice: [], FAX: [], E-Mail: [kskwak@inha.ac.kr (other contributors are listed in “Contributors” slides)] Re: [] Abstract: [????] Purpose: [To be considered in IEEE 802.15.3c standard] 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. Inha Univ. Chuck Brabenac, Intel Labs

Contributors Name E-mail Affiliation Kyungsup Kwak kskwak@inha.ac.kr March, 2008 Contributors Name E-mail Affiliation Kyungsup Kwak kskwak@inha.ac.kr Inha University Inha Univ.

Overview Backgrounds Objects(Goal) March, 2008 Overview Backgrounds Start at Question of last contribution Objects(Goal) Memory buffer size in receiver is very important. Superframe size is related to the buffer size. The application of uncompressed video transmission is delay sensitive and requires constant bandwidth allocation. Allocating Bandwidth below the required throughput causes service failure. So, PHY-SAP payload bit rate is key parameters Simulation and analytical results show that we can find superframe size and payload length according to the requirements (data rate, delay and memory usage). Propose a sizing procedure to find a proper superframe size according to the requirements of uncompressed video transmission. Inha Univ.

802.15.3c Performance Metrics Throughput End-to-End Delay March, 2008 802.15.3c Performance Metrics Throughput measured in terms of bits per second, is the amount of data delivered successfully by the peer MAC-SAP. End-to-End Delay measured in terms of second, is the amount of time taken for a MAC SDU to be transferred from the MAC-SAP of the transmitter to the peer MAC-SAP of the receiver. Memory usage (MAC) Memory usage represent the minimum buffer size required for continuous video representation Inha Univ.

Considering Superframe Structure March, 2008 Considering Superframe Structure Inha Univ.

Preamble and PLCP Header March, 2008 Parameters Assumed Use common mode beacon to 47.8 Mbps Assume error free PHY channel Set video traffic to CBR traffic mode One MAC SDU is composed of data bits transmitted in one horizontal line. Assume no buffer delay due to higher data rate Assume no propagation delay due to short distance ( < 10 meter) Consider transmission delay in terms of Overhead & Payload Size Simulate in the NS-2 Parameters Value Superframe Size 1 msec ~ 64 msec Beacon Interval ?? CAP Duration 0 / 200 usec Guard Time 0.02 usec SIFS 2.5 usec Preamble and PLCP Header 8.157 usec PHY-SAP Rate 1632, 2000 Mbps Payload Size 2 KB ~ 64 KB Sub-header Size 4 Bytes ACK Policy N/A Aggregation Method Applied MAC-SDU Size 5.5 KB Inha Univ.

March, 2008 MAC Throughput Superframe size = 16 ms, Preferred payload size = 5.5k, no aggregation Inha Univ.

Conclusions RT traffic (video streaming) NRT traffic (data transfer) March, 2008 Conclusions RT traffic (video streaming) Constant bandwidth Stringent timing requirement No ACK policy is preferred Near error-free channel Directly discard broken frames Retransmission is useless NRT traffic (data transfer) ACK and retransmission is needed to correct frame errors Imm-ACK has the lowest performance Dly-ACK can improve throughput Number of un-acked frames should not be small On the other hand, delay jitter may be larger. Inha Univ.

Procedure of Sizing the Superframe Size March, 2008 Procedure of Sizing the Superframe Size Inha Univ.

Consideration of Buffer and Its Utilization March, 2008 Consideration of Buffer and Its Utilization The buffer limit would be one of capability parameters of the device. It shows how many data can be temporarily stored in the device for the smoothly video representation. The occupation of this kind of buffer is related with data rate, and superframe size, etc. i.e. Minimal buffer required = data rate * superframe size Given a buffer limit, however, we would want to fully utilize it in order to achieve better performance. It is suggested that within the buffer limit of the device, select as large as possible superframe size in order to increase the CTAP efficiency additionally and reduce the delay. Inha Univ.

March, 2008 Conclusions With this comparison we can propose the minimum requirement on PHY-SAP rate to transfer uncompressed video traffic. To improve the transmission efficiency, the aggregation should be used, which results in larger payload length. However, the transmission delay is correspondingly increased. By considering the expense of beacon period and CAP, the channel time for each flow and relevant superframe size should be lengthened. However, there would be more buffered data and then more memory would be required. The superframe size should be set to relative bigger to achieve proper effective throughput, when the PHY-SAP rate is low. On the other hand, for the high PHY-SAP rate, the superframe size could be shortened to lower the memory requirement. In both cases, the delay should be considered in the selection of superframe size and payload length if the QoS is emphasized. Our proposal provide the baseline for finding superframe size in terms of delay requirement and memory usage. Inha Univ.

March, 2008 Appendix Inha Univ.

Delay and Throughput Definitions March, 2008 Delay and Throughput Definitions Maximum achievable throughput represents the maximum MAC capacity. In real world scenario, we can’t achieve the maximum achievable throughput because of several reasons like MSDU size, collision , etc. Minimum Delay bound is the minimum transmission time required by a MAC MSDU to reach destination MAC layer from Source MAC layer Inha Univ.

Parameters on Video Resolution March, 2008 Parameters on Video Resolution Formant V Freq HRES VRES DE_CNT DE_LIN Rate 24bit Rate 20bit Hsync (sec) Vsync (sec) 1080i 30 2200 562/ 563 1920 1080 5760 4800 3.77104E-06 0.000652/ 0.000681 1080p 1125 0.001333 60 1.88552E-06 0.000667 Inha Univ.