doc IEEE 802 15 03r 0 September 2003

doc. : IEEE 802. 15 -03/r 0 September 2003 Project: IEEE P 802. 15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: MAC enhancement considerations for multimedia streaming Date Submitted: September 17 th, 2003 Source: Wonyong Yoon, Yong Suk Kim, Kisoo Chang, Samsung Advanced Institute of Technology Address Suwon, Kyunggi-do, South Korea Voice: +82 -31 -280 -9529, FAX: +82 -31 -280 -9587, E-Mail: wy. yoon@samsung. com Re: [] Abstract: The document suggests some enhancement points for 15. 3 MAC to be used for multimedia streaming applications. Purpose: [Discussion on MAC enhancements for multimedia streaming] Notice: This document has been prepared to assist the IEEE P 802. 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 P 802. 15. Submission Yoon et al. , MAC enhancement considerations for multimedia streaming

doc. : IEEE 802. 15 -03/r 0 September 2003 MAC Enhancement Considerations for Multimedia Streaming September 17, 2003 Samsung (SAIT) Submission Yoon et al. , MAC enhancement considerations for multimedia streaming

doc. : IEEE 802. 15 -03/r 0 September 2003 Issues • • Qo. S Network utilization Network throughput Piconet formation Submission Yoon et al. , MAC enhancement considerations for multimedia streaming

doc. : IEEE 802. 15 -03/r 0 September 2003 Qo. S • IEEE 802. 15. 3 provides Qo. S by adopting TDMA architecture with channel time allocations (CTAs) – Isochronous streams – Asynchronous channel time • CTA in the current spec seems not perfectly adequate for real-time streaming applications – Q. Can we meet the requirement for transmission within the deadline in the case that channel status is not good? Submission Yoon et al. , MAC enhancement considerations for multimedia streaming

doc. : IEEE 802. 15 -03/r 0 September 2003 Qo. S (Cont’d) • Channel error – When channel status becomes bad, the source DEV of a isochronous stream cannot transmit its pending frames within the CTA of the current superframe Iso. stream Async. CTA scheduling point (before superframe) Allocated error Q. How do we know the exact amount of required channel time units a priori at the scheduling point? But in real, 3 more time units required for rtx That is, the allocation should have been … Submission Yoon et al. , MAC enhancement considerations for multimedia streaming

doc. : IEEE 802. 15 -03/r 0 September 2003 Utilization • Qo. S vs. network utilization of VBR streams – If we allocate channel time to the peak rate of a VBR stream, Qo. S is kept, but many of CTAs are not fully used, thereby resulting in lower utilization – If we allocate channel time to the average rate of the VBR stream, we cannot meet Qo. S requirements of all the VBR frames • Q. Can we transmit frames within the deadline while avoiding underutilization of channels in the case that the applications are VBR streams? (i) Peak rate allocation (ii) Average rate allocation Async. CTA Iso. stream I frame P frame Cannot send Not used B frame Submission Yoon et al. , MAC enhancement considerations for multimedia streaming

doc. : IEEE 802. 15 -03/r 0 September 2003 Throughput • A typical service scenario in the home can be characterized by the following streams occurring simultaneously (by Cable. Labs) – – 1 Hi-Def streams (max 19. 6~32 Mbps) 2 Std-Def streams (max 2*(4~14) Mbps) 2 -3 Audio Streams (max 3*384 Kbps (5. 1 channel)) 1 -2 PC Streams (max 2*(2~10) Mbps) • Excess bandwidth beyond the above is desirable – So that additional streams can be accommodated as future services are rolled out • Q. MAC overhead minimization (preamble, IFS, ACK, etc. ) is necessary as PHY data rates scale upward? Submission Yoon et al. , MAC enhancement considerations for multimedia streaming

doc. : IEEE 802. 15 -03/r 0 September 2003 Piconet Formation • Characteristics (goal) – Ability to form ad hoc connections – Ease of joining and leaving an existing network – Connection time less than 1 sec • Q. With the current spec, is it possible to limit connection time less than 1 sec? – Beacon detection – Association process • No guarantee in time bound contention in slotted aloha (in association MCTA) or CSMA/CA (in CAP) – Is secure membership establishment included in connection time? Submission Yoon et al. , MAC enhancement considerations for multimedia streaming