1. , Slide 1 Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [Reliable Broadcast for WBAN] Date Submitted: [September, 2008] Source: [Sungrae Cho, Wonsuk Choi, Xiangbo Zhang, Laihyuk Park and Dong Dong] [School of Computer Science and Engineering, Chung-Ang University ] Address [221 Heukseok, Dongjak, Seoul 156-756, Republic of Korea] Voice:[+82-2-820-5766], FAX: [+82-2-820-5766], E-Mail:[srcho@cau.ac.kr] Re: [Contribution to IEEE 802.15.6 Meeting, September 2008] Abstract:[This document is a summary of the proposed Timer-based Reliable Broadcast (TRB) for WBAN networks.] Purpose:[Contribution] 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. doc.: IEEE 802. 15-08-0688-00-0006

2. Reliable Broadcast for WBAN Slide 2, UC UC LAB Chung-Ang University Sungrae Cho, Wonsuk Choi, Xiangbo Zhang, Laihyuk Park, and Dong Dong doc.: IEEE 802. 15-08-0688-00-0006

3. Why reliable broadcast is needed? –Sometimes medical emergency event occurs in WBAN and needs to be broadcast to entire network reliably. –Some control information needs to be delivered to entire network reliably. –S/W update needs to be done reliably Introduction Slide 3, doc.: IEEE 802. 15-08-0688-00-0006

4. Simple Flooding: it starts with a source node broadcasting a frame to all neighbors. Each of neighbors in turn forwards the frame to all its neighbors exactly one time and this continues until all reachable network nodes have received the frame. NAK-based: receivers respond with only negative acknowledgments. ACK-based: more reliable scheme where the transmitter waits for all ACKs from the receivers until it transmits the next frame Different Reliable Broadcast Schemes Slide 4, doc.: IEEE 802. 15-08-0688-00-0006

5. Suppose that every receiver node acknowledges for broadcast data, e.g., The broadcast node will be overwhelmed by acknowledge messages (a.k.a. implosion problem). This acknowledgments are generated almost simultaneously if no control enforced. MOTIVATION (1/2 MOTIVATION (1/2) Slide 5, doc.: IEEE 802. 15-08-0688-00-0006

6. This implosion problem also causes the problems of –Unnecessary Collision –Unnecessary Power Consumption Solution: randomize the transmission of the ACKs How?: –Use timers –Implicit ACK (reduce the # of acks) MOTIVATION (2/2 MOTIVATION (2/2) Slide 6, doc.: IEEE 802. 15-08-0688-00-0006

7. Transmitter Behavior –Transmitter broadcasts data and waits for. –Transmitter maintains a Bit Map indicating whether it received an ACK from a particular one-hop neighbor. –If the Bit Maps are all set (Tx received all ACKs) before expires, the transmitter broadcasts the next data. –If any of the Bit Maps are not set after expires, the transmitter rebroadcasts the data. TRB (Timer based Reliable Broadcast) Slide 7, doc.: IEEE 802. 15-08-0688-00-0006

8. Receiver Behavior (after receiving broadcast data) –On successful receipt of broadcast data, each receiver acts as a transmitter by broadcasting the data using random timer D R. –This timer randomizes transmission of the received broadcast data. –One of the transmissions is considered to be an implicit ACK to the original broadcaster. TRB (Timer based Reliable Broadcast) Slide 8, doc.: IEEE 802. 15-08-0688-00-0006

9. 8 1 broadcast coordinator 2 3 4 5 6 7 Slide 9, TRB (Timer based Reliable Broadcast) doc.: IEEE 802. 15-08-0688-00-0006

10. coordinator broadcast 1 2 3 4 5 6 7 Implicitly considered as anACK 8 Slide 10, TRB (Timer based Reliable Broadcast) doc.: IEEE 802. 15-08-0688-00-0006

11. coordinator 1 2 3 4 5 6 7 8 ACK Slide 11, TRB (Timer based Reliable Broadcast) doc.: IEEE 802. 15-08-0688-00-0006

12. Collision Coordinator 1 2 3 4 5 6 7 8 ACK Slide 12, TRB (Timer based Reliable Broadcast) doc.: IEEE 802. 15-08-0688-00-0006

13. coordinator broadcast 1 2 3 4 5 6 7 8 Random timer Slide 13, TRB (Timer based Reliable Broadcast) doc.: IEEE 802. 15-08-0688-00-0006

14. Simulations Setup Results -- 10 nodes -- 20 nodes -- 30 nodes -- 40 nodes -- 50 nodes Performance Evaluation (1) Slide 14, doc.: IEEE 802. 15-08-0688-00-0006

15. Simulation platform: NS2 + LR-WPAN # of nodes: Variable Neighbor distance: 7 m ~ 11m Tx range: 12 m PAN Coordinator (PC): bottom node (or designated node) Network startup: –PC starts at: 0.0 –Any other node starts at: random time between 1.0 and 3.0 Frame error rate : 10% Experimental setup Performance Evaluation (2) Slide 15, doc.: IEEE 802. 15-08-0688-00-0006

16. Successfully received nodes (%):Successfully received nodes (%): we collected # of nodes that received the frame successfully per each frame. Then, the percent of successfully received nodes is calculated as the ratio of # of successfully received nodes to entire # of nodes. Energy consumption:Energy consumption: average # of transmissions of a frame as an energy budget. Measured Performance Evaluation (3) Slide 16, doc.: IEEE 802. 15-08-0688-00-0006

17. 10 nodes : Reliable Broadcasting PAN Coordinator Node having asso ciated and being coordinator Node having associ ated and being leaf node 25 [18] Parent ID Node ID Performance Evaluation (4) Slide 17, doc.: IEEE 802. 15-08-0688-00-0006

18. 20 nodes : Reliable Broadcasting PAN Coordinator Node having asso ciated and being coordinator Node having associ ated and being leaf node 25 [18] Parent ID Node ID Performance Evaluation (5) Slide 18, doc.: IEEE 802. 15-08-0688-00-0006

19. 30 nodes : Reliable Broadcasting PAN Coordinator Node having associated and being coordinator Node having associated and being leaf node 25 [18] Parent ID Node ID Performance Evaluation (6) Slide 19, doc.: IEEE 802. 15-08-0688-00-0006

20. 40 nodes : Reliable Broadcasting PAN Coordinator Node having associated and being coordinator Node having associated and being leaf node 25 [18] Parent ID Node ID Performance Evaluation (7) Slide 20, doc.: IEEE 802. 15-08-0688-00-0006

21. 50 nodes : Reliable Broadcasting PAN Coordinator Node having associated and being coordinator Node having associated and being leaf node 25 [18] Parent ID Node ID Performance Evaluation (8) Slide 21, doc.: IEEE 802. 15-08-0688-00-0006

22. Successfully received nodes (%) Slide 22, doc.: IEEE 802. 15-08-0688-00-0006

23. Energy Consumption Slide 23, doc.: IEEE 802. 15-08-0688-00-0006

24. This work has been supported by HNRC of IITA. Slide 24, doc.: IEEE 802. 15-08-0688-00-0006

25. Thank You! Slide 25, doc.: IEEE 802. 15-08-0688-00-0006