Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)

1. Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: LMP Command Discussion Date Submitted: November 13, 2001 Source:Adrian P Stephens, Mobilian Corporation Company: Mobilian Corporation Address: NW Evergreen Pkwy. Hillsboro, OR. USA. Email: adrian.stephens@mobilian.com Abstract: This document contains a framework for discussion of the LMP commands necessary to manage AFH. Purpose: To stimulate discussion. 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. Adrian P Stephens, Mobilian Corporation

2. LMP Command Discussion • Agenda • Nature of channel metrics reporting • LMP Commands Adrian P Stephens, Mobilian Corporation

3. Open Issues (Raised in meeting) • Channel measurement • Overhead of polling doesn’t seem too great • Master can respond to change in its own environment in polling rate • No objections to polled mechanism • Use 1 bit of slave reporting per channel, no benefit currently demonstrated for >1bit • Re-examination of bad channels? How? How Often? • Capabilities • Is channel measurement technology reported? • Is baseband ACK usable to imply slave has received AFH update? • Support for Partition Mapping is not included Adrian P Stephens, Mobilian Corporation

4. Channel Metrics reporting • Optional behaviour at both Master and Slave • Slave reports capability to master when asked by the Master • Slave continuously measures channel metrics • Slave reports channel metrics when polled by Master based on current state • Master polls according to its own schedule to meet applicable regulations • Slave characterises channels as good-or-unknown vs bad (i.e. reports only definitely bad channels) Adrian P Stephens, Mobilian Corporation

5. Capability Exchange • Additional fields in the existing features structure (2 or 3 bits needed) • Existing LMP_features req/res commands suffice • AFH supported when operating in a slave role capability • Channel metrics measurement & reporting supported capability (?? and classification technology) • Partition-mapping capability iff it becomes optional • + reserved bits for future use (5 bits) Adrian P Stephens, Mobilian Corporation

6. Directed Signaling • All LMP commands regarding AFH are directed • Reliability & simplicity • Reduced overhead over broadcast in typical small piconets & interference levels • Master updates slaves in a sequence of its own choosing and at a time of its own choosing. There is a transition period when the different slaves’ views of the adaptation are slightly different. • LMP_accepted LM ACK or baseband ACK of LMP packet indicates slave is operating the adapted hopset. (?? why did HOLD LMP command need a timer to be added to its ACK) • Require a certain amount of overlap between successive adaptations Adrian P Stephens, Mobilian Corporation

7. LMP_set_AFH command • Master -> Slave • Specifies a mask of used/unused channels • Implicitly enables AFH operation by the slave • TBD: Will also need to specify partition-mapping enabled/disabled state if this is optional and may need additional parameters. We should avoid the need for two LMP packets per update. Adrian P Stephens, Mobilian Corporation

8. LMP_disable_AFH command • Guess what this does Adrian P Stephens, Mobilian Corporation

9. LMP_channel_metrics • LMP_channel_metrics_req • Master->Slave poll • LMP_channel_metrics_res • Slave->Master • Channel map: bad vs not-known-to-be-bad • Over < last 10 s measurements Adrian P Stephens, Mobilian Corporation

10. Behaviour • Legacy & non-AFH • AFH-disabled (initial state of a link) • AFH-enabled Adrian P Stephens, Mobilian Corporation

11. Behaviour • SNIFF & HOLD • AFH-enabled state unaffected • Master can consider the slave to be AFH-disabled if its adaptation and the current adaptation have no channels in common. • PARK • Slave is implicitly AFH-disabled on park Adrian P Stephens, Mobilian Corporation

12. Broadcast • A: Beaconing & access windows (park mode slaves) – unadapted hopset • B: Broadcast to active slaves – restricted slots (unadapted good channels) • Broadcast to all: Both A and B must be used Adrian P Stephens, Mobilian Corporation