1. 4 May 2019
Project: IEEE P Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: [Issues with Beacon-Mode SuperFrame Structure of IEEE ]
Date Submitted: [15 May, 2007]
Source: [Zafer Sahinoglu] Company [Mitsubishi Electric Research Labs]
Address [201 Broadway, Cambridge, MA 02139]
Voice:[(617) ], FAX: [ ],
Re: [N/A]
Abstract: [This documents highlights problems with the superframe structure in the IEEE specification]
Purpose: [This document is prepared to launch a Call for Interest]
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
Zafer Sahinoglu, Mitsubishi Electric

2. Issues with IEEE 802.15.4 MAC (Beacon Enabled Mode)
4 May 2019
Issues with IEEE MAC (Beacon Enabled Mode)
Dr. Zafer Sahinoglu,
Dr. Ghulam Bhatti,
Dr. Jinyun Zhang
MERL-MTL
July 15, 2007
Zafer Sahinoglu, Mitsubishi Electric

3. Outline Motivation Overview of IEEE 802.15.4 Superframe Structure
4 May 2019
Outline
Motivation
Overview of IEEE Superframe Structure
Issues
Summary and Conclusions
Zafer Sahinoglu, Mitsubishi Electric

4. 4 May 2019
Motivation
Wireless sensor networks are increasingly being deployed for residential and industrial applications
There are many applications with low latency and high reliability requirements
IEEE offers a beacon-mode to support low latency applications
IEEE is underutilizing communication resources (bandwidth, time, power etc)
IEEE MAC beacon-enabled mode needs major modification
Zafer Sahinoglu, Mitsubishi Electric

5. IEEE 802.15.4 Super Frame Structure (Overview)
4 May 2019
IEEE Super Frame Structure (Overview)
In the beacon enabled hybrid mode, the superframe consists of a beacon, CSMA period (CAP), TDMA period (CFP) and an inactive period
The idea was to allow messages that require low latency and high reliability use guaranteed time slots (GTS)
beacon
Superframe interval
beacon
Beacon interval
GTS
CAP
CFP
Inactive
CAP
GTS
GTS
GTS
Zafer Sahinoglu, Mitsubishi Electric

6. IEEE 802.15.4 Super Frame Structure (Overview)
4 May 2019
IEEE Super Frame Structure (Overview)
The CFP period consists of 7 GTSs
Allocation of GTSs is managed centrally by the PAN coordinator
beacon
Superframe interval
beacon
Beacon interval
GTS
CAP
CFP
Inactive
CAP
GTS
GTS
GTS
Zafer Sahinoglu, Mitsubishi Electric

7. Issues (1): Insufficient number of GTSs
4 May 2019
Issues (1): Insufficient number of GTSs
If 10 coordinators are connected to the PAN coordinator
Only 7 of them can use GTS in the same superframe
PAN coordinator
Coordinator
Zafer Sahinoglu, Mitsubishi Electric

8. Issues (2): Centralized GTS Management
4 May 2019
Issues (2): Centralized GTS Management
Device A can’t use GTS to communicate with its parent C or peer B B C A
Zafer Sahinoglu, Mitsubishi Electric

9. Issues (3): Problematic Retries for GTS
<month year>
doc.: IEEE <doc#>
4 May 2019
Issues (3): Problematic Retries for GTS
IEEE MAC is not well designed for low-latency and high reliability applications
GTS is defined for latency sensitive transmissions. However,
If the transmission fails, it is a very bad day for you – wait for the next superframe to retransmit
Even a successfully received frame shall wait for the next superframe for forwarding to a next hop
beacon
Superframe interval
beacon
Beacon interval
GTS
CAP
CFP
Inactive
CAP
GTS
GTS
GTS
DATA
ACK
This is only one hop latency
Can be in the order of seconds and even minutes
You can at the earliest transmit here,
if you can grab the channel
Zafer Sahinoglu, Mitsubishi Electric
<author>, <company>

10. Summary and Conclusions
4 May 2019
Summary and Conclusions
The beacon-enabled mode in the current spec is far from supporting low-latency and high reliability applications
A new study group should be formed to investigate MAC improvements
Zafer Sahinoglu, Mitsubishi Electric