Sept 2010 Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: Proposed MAC Comment Resolutions Date Submitted: September 6, 2010 Source: David M. Davenport, Company: GE Global Research Address: 1 Research Circle, Niskayuna, NY USA, Voice: +1 518-387-5041, E-Mail:davenport@ge.com Re: Proposed Resolution of D0 MAC Comment S6-522 Abstract: Proposed resolution for comments: S6-522. Purpose: This document is for the MAC comment resolution discussion for TG6 draft D01. 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. D.Davenport, GE Global Research

Proposed Resolution of D0 MAC Comment S6-522 Sept 2010 Proposed Resolution of D0 MAC Comment S6-522 David M. Davenport GE Global Research D.Davenport, GE Global Research

doc.: IEEE 802.15-<doc#> <month year> doc.: IEEE 802.15-<doc#> Sept 2010 D0 Comment S6-522 Comment: Requirements needing Uplink Access Mode can be satisfied with the BiLink Access Mode. In BiLink Mode, after a Poll, the Uplink Data Frame may be sent by the Node. If a T-Poll is used, the Node may skip listening to the Beacon, and only wake-up during its scheduled allocation. This saves power for the node. The only advantage of having Uplink Mode is in the case where a large number of Nodes have constant rate uplink data frames to transfer, where many Polls can be saved, thus slightly improving the bandwidth utilization of the BAN. However, this mode requires that the Node does not use N-ACK, because an ACK is needed in case the Hub needs to communicate with the Node. This complicates that Hub's strategy for sending management frames to the Nodes, since it now must use another mechanism other than Bilink or CSMA response. There seems to be minimal advantage to having Uplink Access when BiLink is available and the Hub requires a means to send management frames to all nodes. (page 59, subclause 6.7.2, line 4) Proposed Change: Either: 1) Show that BiLink cannot adequately satisfy the needs for transacting Scheduled Uplink Frames, and that it is worth the additional complexity Or: 2) Remove Uplink Access Mode, Uplink Request IE, and Uplink Assignment IE. D.Davenport, GE Global Research <author>, <company>

D0 Comment S6-522 should be rejected <month year> doc.: IEEE 802.15-<doc#> Sept 2010 D0 Comment S6-522 should be rejected BILINK cannot satisfy the requirements of continuous medical monitoring The requirements for continuous medical monitoring applications are satisfied by UPLINK allocation where nodes can immediately wake and transmit over a fixed duration which recurs at a known temporal interval which is based on the medical application requirements of that node Provides for bounded medical monitoring data latency and data loss Provides for low power operation from battery Refer to DCN 15-08-0108-01-0006, presented March 2008 to TG6 Refer to 5-08-0407-06-0006-tg6-applications-summary.doc BILINK is essentially a polled allocation Initially proposed to accommodate MICS/MedRadio applications where a regular beacon is undesirable D0 page 5 defines Bilink allocation as “an allocation with allocation interval(s) in which a hub or a node initiates one or more frame transactions to transmit management and data traffic to a node or a hub, respectively, and the recipient returns acknowledgement if required, with the provision that the node initiates frame transaction(s) only after receiving a poll from the hub. D.Davenport, GE Global Research <author>, <company>

D0 Comment S6-522 should be rejected (continued) <month year> doc.: IEEE 802.15-<doc#> Sept 2010 D0 Comment S6-522 should be rejected (continued) UPLINK allows continuous medical monitoring nodes to immediately wake and transmit Avoids unnecessary receive period for node to await an initial poll which wastes power After a poll, node would then transition from receive to transmit mode, wasting further time/bandwidth Initial poll message may be lost due to link conditions, leading to Longer unnecessary receive mode power consumption, Further spectrum inefficiency Non-deterministic latency for transmission of the medical data Medical node has already been granted exclusive access to the UPLINK allocation interval. Nodes can conserve power by sleeping on a regular, scheduled basis and awaken to efficiently transmit their data messages in their allocated intervals Interval is based on amount of data to be transferred with given QoS and will be utilized by the node Fundamental performance benefits of Selective Repeat ARQ or even Go-Back-N ARQ with sliding receive and transmit windows versus the Stop-and-Go ARQ approach (gated uplink messages via Bilink polling) which is being proposed by comment S6-522. D.Davenport, GE Global Research <author>, <company>

doc.: IEEE 802.15-<doc#> <month year> doc.: IEEE 802.15-<doc#> Sept 2010 Proposed Resolution D0 Comment S6-522 should be rejected Scheduled UPLINK allocation is a key enabler of continuous medical monitoring application requirements D.Davenport, GE Global Research <author>, <company>