< April, 2012 > Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [Improvement of Data Transmission in Low Energy Mechanism] Date Submitted: [16 April, 2012] Source: [Yang Yang, Xiang Wang, Jie Shen] Company [Wuxi SensingNet Industrialization Research Institute] Address [No.767, Jinzhong Rd, Shanghai, China] Voice:[+86-021-52188899-635], FAX: [+86-021-52182002] E- Mail:[youcyyang@gmail.com] Re: [improvement of proposal (DCN: 15-11-0854-00, 15 November, 2011)] Abstract: [This document proposed improvement of data transmission in low energy mechanism for 4k.] Purpose: [Proposal for consideration of inclusion into 802.15.4k.] 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.

Improvement of Data Transmission in Low Energy Mechanism < April, 2012 > Improvement of Data Transmission in Low Energy Mechanism 16-April-2012

Outline Data Transmission Mode in Low Energy Proposal < April, 2012 > Outline Data Transmission Mode in Low Energy Proposal Problem Aroused by Implementation Improvement Suggestion Summary

Data Transmission Mode in Low Energy Proposal < April, 2012 > Data Transmission Mode in Low Energy Proposal DCN:854 More Low Energy Mechanism Details Normal transmission mode Coordinator main powered, keep listening for channel Endpoint device keep sleeping When endpoint device has data to transmit send data frame by using CSMA/CA, without receiving Ack, retransmit the data If coordinator has unicast frame to send, after receiving frame from the corresponding end point, send the frame as Ack for the frame If endpoint device receive frame from coordinator, will send back Ack If coordinator don’t receive Ack, will retransmit the frame

Problem Aroused by Implementation < April, 2012 > Problem Aroused by Implementation The former time of endpoint device waiting for Ack is set as macAckWaitDuration, If the coordinator is transmitting data frame to the endpoint device, but the endpoint device don’t receive it The endpoint device will retransmit its data frame after macAckWaitDuration Collision will happen Q: how long should endpoint device waiting for Ack or data frame from coordinator The transmission duration of frame from coordinator will be variable Slide 5

Improvement Suggestion < April, 2012 > Improvement Suggestion After sending data to coordinator, the endpoint device will waiting macAckWaitDuration for Ack from coordinator On receipt of data from endpoint device, coordinator will send back Ack If the coordinator has frame to send to the same endpoint device Indicate have pending frame in Ack, and waiting for data request from device If received Ack indicated pending frame from coordinator, the endpoint device will send data request After received data request, coordinator will send corresponding data frame

< November, 2011 > Summary Former data transmission mode of low energy will cause collision Add data request Keep waiting time of endpoint device to a certain duration Improve the successful rate of data transmission

< November, 2011 > Thank you!