1. doc.: IEEE 802.15-<doc#>
<month year>
doc.: IEEE <doc#>
July 2004
Project: IEEE P Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: [Some Modification for CSMA/CA and Superframes of the MAC Protocol]
Date Submitted: [July 2004]
Source: [Liang Li, Xin Wang, Chenyang Yang, Zhijian Hu ] Company: [WXZJ Inc./Helicomm Inc.]
Address: [Building D, No.2, Shangdi XinXi Lu, Beijing, China ]
Voice:[],
Re: [ IEEE ]
Abstract: [This contribution proposes an enhanced MAC for TG4.]
Purpose: [Response to the call for proposal of IEEE b, Doc Number: b]
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
Liang Li, WXZJ Inc./Helicomm
<author>, <company>

2. Proposal Enhance the IEEE802.15.4 CSMA/CA algorithm
July 2004
Proposal
Enhance the IEEE CSMA/CA algorithm
New super-frame format and BEACON frame format in star networks
Liang Li, WXZJ Inc./Helicomm

3. Problems In the Current CSMA/CA
July 2004
Problems In the Current CSMA/CA
It is possible to be dead-lock as two nodes send the data to each other simultaneous.
The transmission procedure is not atomic.
Liang Li, WXZJ Inc./Helicomm

4. Suggestion to the CSMA/CA Procedure
July 2004
Suggestion to the CSMA/CA Procedure
The MAC layer should read the CCA status during the backoff period. When the result is BUSY, it should pause the backoff and resume when the result is IDLE.
When MAC receive the data during the backoff period, it should process this frame and send ACK (or wait for an ACK period) if necessary.
Liang Li, WXZJ Inc./Helicomm

5. Proposal about PLME-CCA Primitives
July 2004
Proposal about PLME-CCA Primitives
The CCA value should be valid when the Rx has been on for at least 8 symbols.
Add the CCA status to PHY PIB.
The PLME-CCA primitives may be not necessary.
Liang Li, WXZJ Inc./Helicomm

6. New Superframe Format Supporting QoS-1
July 2004
New Superframe Format Supporting QoS-1
Group Polling Protocols:
Divide the nodes into groups.
According to the demand, the MAC of coordinator can change the length and the period of the superframe freely.
Each superframe belongs to one or some specifically groups. Only the nodes in these groups have the priority to access the medium.
Liang Li, WXZJ Inc./Helicomm

7. New Superframe Format Supporting QoS-2
July 2004
New Superframe Format Supporting QoS-2
The BEACON frame should announce which groups the following superframe belongs to.
If one group has only one node. This node can start the transmission directly after the BEACON (set BE to zero). The protocol becomes a polling protocol.
Liang Li, WXZJ Inc./Helicomm

8. New Superframe Format Supporting QoS-3
July 2004
New Superframe Format Supporting QoS-3
A Sample of the division of the nodes
Liang Li, WXZJ Inc./Helicomm

9. New Superframe Format Supporting QoS-4
July 2004
New Superframe Format Supporting QoS-4
The support of the broadcast:
Add the broadcast superframes.
The coordinator broadcast the start time of the broadcast superframe in BEACON frame.
The nodes will set their Rx on if they would like to receive the broadcast frames.
Liang Li, WXZJ Inc./Helicomm