1. doc.: IEEE 802.15-<doc#>
<month year>
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doc.: IEEE <doc#>
doc.: IEEE <doc#>
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Project: IEEE P Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: [EGTS Optimization]
Date Submitted: [20 Jan, 2009]
Source: [Betty Zhao, Yongjun Liu, Yong Xu, Liang Li, Pei Liu, Nu Ging, Jie Shen] Company [Huawei, Vinno, SIMIT]
Address [Beijing, , China]
Voice:[ ], FAX: [ ],
Re: [IEEE e group]
Abstract: []
Purpose: [This document is a response to item a) better support the industrial markets and b)increase the GTS flexibility such as peer to peer in IEEE P SG4e Call for Application on 14 November, 2007]
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
Slide 1
Betty Zhao, Yongjun Liu 1
Page 1
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EGTS Overview
EGTS Slots …
Channels
CH0
CH1
CH2
BO = 6, SO = 3, MO = 5
Superframe Structure
- Common channel : Beacon and CAP use a fixed single channel.
- Multi-channel for Enhanced GTS
- Multi-hop extension for EGTS
- Multi-superframe extension for EGTS
EGTS Allocation
- EGTS slot = tuple (time slot, channel)
- First, choose a time slot (or slots), which has at least one vacant channel.
- Then, choose a channel that is available in that time slot
- Three-way-handshake EGTS Allocation. Three command frames are transmitted during CAP period.
- EGTS request
- EGTS reply
- EGTS notify
I changed D-> C. 2
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3. Jan IEEE e
EGTS Optimization
If a node cannot use its allocated EGTS due to losing synchronization to coordinator, what should it do?
- EGTS Retrieve
If EGTS request is over the total EGTS slots, or important data is inquired to be sent in EGTS, what should coordinator do?
- EGTS Priority & FH-GTS
If along a multi-hop route, there is a node working in nonbeacon communication mode, what should be done to make the transmission smooth?
- EGTS Extension

4. doc.: IEEE 802.15-<doc#>
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EGTS Retrieve
Upon successful EGTS allocation, node may lose synchronization to its coordinator sometimes.
When that occurs, EGTS information request and reply are transmitted during CAP period to retrieve the allocated EGTS.
EGTS information request
Unicast from a source to a destination .
Request for synchronization and EGTS information.
EGTS information reply
Unicast from the destination.
Including timestamp and EGTS information.
Coordinator
EGTS
Node
EGTS information request
EGTS information reply 4
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5. Jan IEEE e
EGTS Priority & FH-GTS
Extend MLME-GTS.request and ‘EGTS request’ command with additional bits to indicate the priority of the data which be transmitted in EGTS.
Based on the priority information received, coordinator can optimize EGTS allocation in two ways.
- Slots re-allocation:
If ‘EGTS request’ command with higher priority is received when the EGTS slots have been used out, coordinator can reduce or cease the slots of EGTS being used by the nodes which sent the command with lower priority earlier.
- Channel choosing:
For the node indicating that its priority is high due to requirements of transmission reliability, coordinator allocates a sequence of hopping channels on purpose for its EGTS slots.
Slide 5

6. EGTS Extension for Nonbeacon Networks
Jan IEEE e
EGTS Extension for Nonbeacon Networks
EGTS exists in the superframe structure of beacon network.
Let some special nodes (connection device) which uses EGTS be able to send and receive data in nonbeacon network at the same time.
So, through the connection devices, regardless of beacon/nonbeacon mode,
- Any two nodes can interact;
- Any multi-hop routes can work smoothly;
- Network can be extended to be large and dense.
Promiscuous PAN:
Connection Device
Beacon-enabled PAN:
Coordinator
Device
Communicate
in beacon mode
Nonbeacon-enabled PAN:
in nonbeacon mode