1. < April, 2012 >
Project: IEEE P 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:[ ], FAX: [ ] E-
Re: [improvement of proposal (DCN: , 15 November, 2011)]
Abstract: [This document proposed improvement of data transmission in low energy mechanism for 4k.]
Purpose: [Proposal for consideration of inclusion into k.]
Notice: This document has been prepared to assist the IEEE P 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 P

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

3. 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

4. Data Transmission Mode in Low Energy Proposal
< April, 2012 >
Data Transmission Mode in Low Energy Proposal
DCN: 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

5. 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

6. 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

7. < 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

8. < November, 2011 >
Thank you!