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: [Energy Saving protocol for Mesh networks] Date Submitted: [Sept 2007] Source: [Tae Rim Park*, Myung Lee*, Jaehong Ryu**] Company [*CUNY, **ETRI] Address [Electrical Engineering, Steinman Hall, 140th St & Convent Ave, New York, NY 10031, USA] Voice:[+1-212-650-7260], FAX: [+1-212-650-8249], E-Mail:[taerim@ee.ccny.cuny.edu] Re: [] Abstract: [This proposal discusses power saving issue arising inIEEE 802.15.5 WPAN Mesh] Purpose: [This proposal is provided for the discussion for IEEE 802.15.5 WPAN Mesh] 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. Tae Rim Park

2. Energy Saving Protocol for Mesh Networks Tae Rim Park, Myung J. Lee, Jaehong Ryu CUNY, ETRI Tae Rim Park

3. Objectives • To propose a power saving solution for the current IEEE 802.15.5 draft. Tae Rim Park

4. Proposal Outline • Design consideration • Energy saving protocol for mesh networks • Concept • Detailed protocol • Evaluation • Summary Tae Rim Park

5. Long Battery Life • Two AA batteries • 2000 mA-hr • Energy consumption of cc2420 (from datasheet) • Tx; 17.4 mA • Rx, Idle listening; 19.7 mA • Idle; 0.4 mA • Power down; 0.02mA • Trun on/Wakeup/active; Tx, Rx, Idle listening, • Trun off/Sleep/inactive; Idle • When a device turns on the transceiver w/o any other component (ex. 4Mhz Atmega128L:5.5mA, MSP430:2mA) • 3~5 days  Minimizing active time is the key! Tae Rim Park

6. Design Consideration • Mesh layer solution based on IEEE 802.15.4-2006 • Supporting long battery life • Two AA batteries, 1year • Flexible active time • End-to-end latency constraint • Synchronous usually has longer latency • Considering receiver energy consumption • Tree relation • Easy implementation Tae Rim Park

7. Mesh Layer Solution • Control methods • Standard primitive • MCPS-DATA/PURGE • MLME-SET/GET • Can not use information inside MAC • Can not add MAC control frames • Timing problem • Can not guarantee response time • Ex. The time from calling MCPS-DATA.request to starting backoff Tae Rim Park

8. ESM Overview • Energy Saving protocol for Mesh networks • Requirement • Timer of 1ms resolution • Prompt cooperation of MAC • Features • Asynchronous wakeup • Receiver oriented • Communication are allowed within receiver’s active duration • Flexible active duration • Extensible • Schedule optimization • Local synchronization Tae Rim Park

9. ESM Unicast Tae Rim Park

10. ESM Broadcast • Same as LPE and LPEA (known as XMAC) Tae Rim Park

11. ESM Details • Three state machines for normal operation • 3 control frames • Two data transmission methods • Receiver oriented unicast • Transmitter oriented broadcast • Variable & constant • Higher layer decision Tae Rim Park

12. Three Normal State Machines Periodic events Reception events Transmission events Tae Rim Park

13. Variables and Constants • MeshESMOn • meshBaseActiveDuration; 5ms • meshWakeupOrder (WO); 0~14 • meshActiveOrder (AO); 0~14 • meshDestActiveOrder • meshWRWaitTime • meshDataTimeout Tae Rim Park

14. Command Frames • Wakeup Notification (0x0D) • macMinBE; 1, macMaxCsmaBackoffs; 0, macMaxFrameRetries; 0, • 1 byte command payload • b7~b4; WO, b4~b0; AO • Extension REQuest (0x0B) • macMaxCsmaBackoffs; 0, macMaxFrameRetries; 0 • Extension REPonse (0x0C) • macMaxCsmaBackoffs; 0, macMaxFrameRetries; 0 Tae Rim Park

15. Frame Transmission • Data frame • ESM unicast; Retry control within receiver’s active time • ESM broadcast • ESM command frame • MAC broadcast • No retry if channel is busy • WN; backoff exponent (1) • 15.5 command frame • ESM unicast or broadcast • ESM command frame • Beacon; no control • Beacon request; ESM broadcast • Association req, disassociate notification, orphan notification, coord realignment; ESM unicast • Data request, Association response; 15.4 unicast Tae Rim Park

16. Association • Active scan • Beacon request with ESM broadcast • One scan request for one channel • Association request • ESM unicast Tae Rim Park

17. Tae Rim Park

18. ESM Evaluation • Active ratio • Turn on time/time spent • Star topology (emulating sink tree) • Three transmitters and one receiver • Traffic • Unicast and broadcast • Data frame: 50 byte, EREQ/EREP: 27 bytes, WN: 28 bytes • Arrival rate: 0.01 to 0.00125fr/s (100s to 13.3 min) • Exp • Micaz, Chipcon engine base • 600~800s experiment time Tae Rim Park

19. Analysis TminAD; minimum active duration tWI: wakeup interval r ; arrival rate TT; Time duration for transmission rb=0 rb=0.00125 Tae Rim Park

20. Experiment • Margin; 1~2 ms • Active durations of LPE: LPEA: ESM = 6:10:8 rb=0.00125 rb=0 Tae Rim Park

21. Summary • To get long battery life • Minimizing active time • Accepting trade off relation • Mesh layer solution • With only standard primitives • Asynchronous algorithms is better to implement • ESM • Asyn and flexible frame work for sensor networks • 15.5 addition & modification • Can be a good solution Tae Rim Park

22. Asynchronous Protocols • LPE (BMAC) • LPEA (XMAC) Tae Rim Park