1. doc.: Submission Beelinker Technology Co.ltdSlide 1 Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [MAC Proposals for Low Energy Critical Infrastructure Networks] Date Submitted: [18 Jul, 2011] Source: [Hao Liu, Guolian Yao, Pingping Xu,] Company [Beelinker Technology Co., Ltd. Southeast University] Address [339 Linquan Road, Suzhou Industrial Park, Jiangsu 215123, China] [ 2 Si Pai ou,Nanjing,210096,China] Voice:[+86-13951080520 ， +86-25-83794525], E-Mail:[liuhao@beelinker.com, guoliang@ieee.org, xpp@seu.edu.cn ] Re: [Respond for CFP] Abstract:[An Adaptive MAC Proposals for Low Energy Critical Infrastructure Networks applications] Purpose:[Presented to the IEEE 802.15.4k LECIM task group for consideration] 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.

2. doc.: Submission Beelinker Technology Co.ltdSlide 2 Introduction Combination of inputs –Ideas shared in May 2011 meeting –Idea improvements –Test-bed based experiment results Reference documents: –P802.15-11-0478-00 –P802.15-11-0348-00 –Draft IEEE P802.15.4e/D5.0, June 2011 July 2011 Ben RolfeSlide 2

3. doc.: Submission Beelinker Technology Co.ltdSlide 3 Overview Introduction Channel Access Description Packet Structure Definition Discussion

4. doc.: Submission Beelinker Technology Co.ltdSlide 4 LECIM Application requirements –Low power consumption, end point need to periodically go to sleep to conserve energy –Large number of nodes, >1000 endpoints, good channel access efficiency is required. –Unreliability of the channel conditions, Propagation path loss of at least 120 dB

5. doc.: Submission Beelinker Technology Co.ltdSlide 5 IEEE P802.15.4e MAC-- Basic CSL Operation Challenges in 802.15.4K applications ： 1.Larger number of endpoints make high channel contention. Through 8 nodes testbed based experiments, we observe that even 0.5 packet/s traffic with 50 bytes packet length (0.5kbps/s), buffer accumulation takes place in receiver nodes. 2.It cost a long period for node to seize the channel again in duty-cycling operation, so the buffered packets need to be drained drain ASAP. 3.imperfect channel condition led to packet lost during transmission, packets buffer schemes and retransmission is necessary

6. doc.: Submission Beelinker Technology Co.ltdSlide 6 Our Schemes with MSP430 microcontroller has 10k bytes ram Current typical off-the-shelf nodes ( equipped with 802.15.4 radio part ) Traditional program cost 1,500 bytes ram footprint, which used for variable allocation and operation system running. 8,500 bytes spare ram is available for buffer design Buffer design Consideration Maximal frame length of MPDU in IEEE 802.15.4 2006 standard is 128 bytes Total buffer capacity available in Telosb node: 8500/128=66, which is sufficient for buffer based MAC scheme design Telosb

7. doc.: Submission Beelinker Technology Co.ltdSlide 7 Our Schemes listen ack Batch transmission ( based onIEEE P802.15.4e -- Basic CSL Operation ) (1)If sender detect N packets in buffer, it launch batch transmission to alleviate congestion. (2)After receive the first ACK, sender transmit a bulk of packets, then wait the ACK that acknowledge the series. (3)If packets lost caused by imperfect channel, sender retransmit the packets. ack Node A Node C wakeup Early ack to end preamble and begin to transmission. Also contains free buffer size information on receiver dataN data1 data2data3 …… Group Ack to comfirm the batch series. The packet which not received are reply to sender for retransmission Packet accumulated in buffer Batch packets number is embedded in the preamble data0

8. doc.: Submission Beelinker Technology Co.ltdSlide 8 MAC Protocol Description Reliability Transmission Consideration  The first data packet has the information about how many packet need to send in current burst transmission.  The first ACK includes the information about spare buffer space on receiver, which can be used for batch transmission control.  The second ACK is used for acknowledge which packet are received successfully, which is store in the bitmap field.

9. doc.: Submission Beelinker Technology Co.ltdSlide 9 Our Schemes Contribution 3 –batch transmission Important packet parameters Nmax-- the maximum packets allowed in a batch transmission Ncur-- calculated packets number in a burst transmission Nbst-- current actual packets number in a burst transmission Qmax--maximum capacity of node Tmax—maximum time allowed by fairness requirement. 1.Nbst1 < Qmax- η2 2.Let 3.So 4.if Ncur >Nmax, Nbst=Nmax; else if Ncur≤ Nmax, Nbst=Ncur; K: Transmission speed, Lack: length of ACK packet Ldata: length of data packet, tsifs: interval of two consetive data packets sender receiver η2η2 η1η1 Qmax Nbst1

10. doc.: Submission Beelinker Technology Co.ltdSlide 10 Experiment results Experiments senarios Senario1: 8 nodes small scale network in a living room Todo, 实验结果图 吞吐率和延迟。

11. doc.: Submission Beelinker Technology Co.ltdSlide 11 Experiment results channel access without priority priority based channel access scheme Node 0Node 1Node 2 Node 0 Node 1 Node 2

12. doc.: Submission Beelinker Technology Co.ltdSlide 12 Packet Structure modification Data0 packet Structure ACK0 packet Structure Extend the Frame of 802.15.4 2006 to support burst transmission and reliability transmission ACK1 packet Structure

13. doc.: Submission Beelinker Technology Co.ltdSlide 13 Thank you for your attention Any Questions ?