September 2003 Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: MAC enhancement considerations for multimedia streaming Date Submitted: September 17th, 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 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. Yoon et al., MAC enhancement considerations for multimedia streaming

MAC Enhancement Considerations for Multimedia Streaming September 2003 MAC Enhancement Considerations for Multimedia Streaming September 17, 2003 Samsung (SAIT) Yoon et al., MAC enhancement considerations for multimedia streaming

Issues QoS Network utilization Network throughput Piconet formation September 2003 Issues QoS Network utilization Network throughput Piconet formation Yoon et al., MAC enhancement considerations for multimedia streaming

September 2003 QoS IEEE 802.15.3 provides QoS 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? Yoon et al., MAC enhancement considerations for multimedia streaming

QoS (Cont’d) Channel error September 2003 QoS (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 … Yoon et al., MAC enhancement considerations for multimedia streaming

Utilization QoS vs. network utilization of VBR streams September 2003 Utilization QoS vs. network utilization of VBR streams If we allocate channel time to the peak rate of a VBR stream, QoS 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 QoS 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 Iso. stream Async. CTA Iso. stream Async. CTA I frame Cannot send P frame Not used Not used B frame Yoon et al., MAC enhancement considerations for multimedia streaming

September 2003 Throughput A typical service scenario in the home can be characterized by the following streams occurring simultaneously (by CableLabs) 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 (5.1channel)) 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? Yoon et al., MAC enhancement considerations for multimedia streaming

Piconet Formation Characteristics (goal) 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? Yoon et al., MAC enhancement considerations for multimedia streaming