1. Project: IEEE 802.15 Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: [Beacon scheduling MAC hooks]
Date Submitted: [15 Sept 2004]
Source: [Monique Bourgeois Brown] Company [Motorola, Inc.]
Address [1150 Kifer Road, Sunnyvale, CA 95131, USA]
Voice:[ ],
Re: [ b]
Abstract: [How to use the existing 15.4 MAC to enable beacon scheduling]
Purpose: [To illustrate design of 15.4 MAC to support beacon scheduling mechanism in the next higher layer.]
Notice: This document has been prepared to assist the IEEE 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
September 2004
September 2004
Monique Brown, Motorola, Inc.

2. Beacon Scheduling Support in IEEE 802.15.4 Monique Bourgeois Brown
September 2004
September 2004
Beacon Scheduling Support in IEEE
Monique Bourgeois Brown
Motorola Labs
Monique Brown, Motorola, Inc.

3. Beacon Scheduling Support in 15.4
September 2004
September 2004
Beacon Scheduling Support in 15.4
The MAC was designed to include hooks for implementing beacon scheduling at the next higher layer.
Proposal: Let’s use what we have!
Existing hooks:
During a scan, a coordinator learns when each neighbor transmits its beacon
MLME-BEACON-NOTIFY.indication contains a timestamp telling the next higher layer when neighbor’s beacon was received
MLME-START.request used by the next higher layer of coordinator to begin its own beacon transmissions
Coordinator knows when it transmits its own beacon
contained in macBeaconTxTime
Monique Brown, Motorola, Inc.

4. What’s needed in 15.4b This approach has no issues with Scalability
September 2004
What’s needed in 15.4b
One change is necessary: MLME-START.request requires a StartTime parameter to instruct the MAC on when to begin beacon transmissions.
StartTime parameter should be same format as RxOnTime parameter in MLME-RX-ENABLE.request.
This approach has no issues with
Scalability
Backwards compatibility
It addresses the needs of low duty cycle (15.4) applications.
Monique Brown, Motorola, Inc.

5. Coordinator Superframe Structure
September 2004
Coordinator Superframe Structure
Every beaconing coordinator has its own superframe structure consisting of the beacon, CAP and, optionally, an inactive period.
SO=0; 6 BO yields duty cycle between <2% - ~ 0.1%
Coordinator A (parent)
Inactive portion
Inactive portion
Coordinator B (child of A)
Parent beacon tracking
(optional at higher layer)
Coordinator C (child of A)
StartTime of C may be chosen using knowledge of A, B gained through scanning.
Monique Brown, Motorola, Inc.