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: [Cooperative Communication in Mesh Networking] Date Submitted: [11 March, 2005] Source: [Klaus Fosmark] Company [University of Texas at Dallas] Address [Eng. Dept. MS EC 33, 2601 North Floyd, Richardson, TX 75080] Voice:[214-674-9607], FAX: [425-969-2125], E-Mail:[klaus.fosmark@utdallas.edu] Re: [Response to call for proposal for 802.15.5 Mesh protocol.] Abstract: [Partial proposal describing how “Cooperative Communication” can be an easy addition to a 802.15.5 Mesh protocol with resulting improved performance.] Purpose: [For discussion in the IEEE 802.15.5 Study Group] 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. Klaus Fosmark, University of Texas at Dallas

2. What is Cooperative Communication? • Normally, in ARQ protocols, when a packet is not received at the Destination (or received with error), the following happens: • The packet is lost (discarded) • An ACK is NOT generated from the Destination • The Source will retransmit the packet later • With Cooperative Communication, when a packet is not received at the Destination (or received with error), the following happens: • The packet is lost (discarded) • An ACK is NOT generated by the Destination • A relay node that successfully overheard the packet may relay this to the Destination • The Source will retransmit if there no successful relay Klaus Fosmark, University of Texas at Dallas

3. Example ? Destination Source Relay Klaus Fosmark, University of Texas at Dallas

4. Performance Benefit Simulations • Academic and non-802.15 related protocol simulation: • Slotted, non-contention protocol • Flat Rayleigh fading, constant over frame and independent of other frames • ACKs are error free • 3 nodes: Source and Destination and a Relay node • One-way traffic only • Poisson traffic arrival • Relay node always attempts to retransmit (if there is an error) regardless of location Klaus Fosmark, University of Texas at Dallas

5. Simulation Results • Fixed best case location of nodes: Source Relay Destination Klaus Fosmark, University of Texas at Dallas

6. Source: Destination: Relay: Latency improvement depending on location of relay node: Klaus Fosmark, University of Texas at Dallas

7. Why is this Mesh relevant? • Predetermined protocol as part of Mesh: • Whatever mechanism used to define the Mesh Paths could also identify possible Relay nodes for each pair of nodes along path • Whenever a packet is lost, the predetermined Relay node will retransmit • Dynamic Protocol • Relay nodes are determined dynamically. • Independent of Mesh configuration. Klaus Fosmark, University of Texas at Dallas

8. Further work / Issues / Conclusion • Determine relevance for Mesh and 802.15.5 • MAC change! • Work into Mesh Protocol • Performance analysis of protocol • Academic references also incorporate forward error correction which improves the benefit of cooperation since the strength of the error correction can increase with a relay retransmission. Klaus Fosmark, University of Texas at Dallas

9. References • A. Nosratinia, T. Hunter, and A. Hedayat, “Cooperative Communication in Wireless Networks,” IEEE Communications Magazine, vol. 42, no. 10, pp. 74–80, October 2004, http://www.utdallas.edu/~thunter/CommMag03.pdf. • E. Zimmermann, P. Herhold and G. Fettweis, “The Impact of Cooperation on Diversity-Exploiting Protocols,” 59th IEEE Vehicular Technology Conference (VTC Spring 2004), Milan, Italy, May 2004, http://www.ifn.et.tu-dresden.de/~zimmere/papers/impact_of_cooperation_on_diversity_exploiting_protocols_VTC_Spring_2004.pdf. • P. Gupta, I. Cerutti, A. Fumagalli, “Three Transmission Scheduling Policies for a Cooperative ARQ Protocol in Radio Networks”, Proc. WNCG conference, Austin, October 2004. • M. Tacca, P. Monti, A. Fumagalli, “Cooperative and Non-Cooperative ARQ Protocols for Microwave Recharged Sensor Nodes”, to be published in Proc. 2nd European Workshop on Wireless Sensor Networks (EWSN), Istanbul, Turkey, January-February 2005. Klaus Fosmark, University of Texas at Dallas