1. May 2006
doc.: IEEE
May 2006
Project: IEEE P Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: [Mesh networking for low-rate systems]
Date Submitted: [May, 2006]
Source: [Arnaud Tonnerre, Serge Héthuin, Isabelle Bucaille] Company [THALES Communications]
Address [THALES Communications, 146 boulevard de Valmy, Colombes, France]
E−Mail:
Re: [ ]
Abstract: [Mesh networking for low-rate systems]
Purpose: [To promote discussion in ]
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
Arnaud Tonnerre, Serge Héthuin, Isabelle Bucaille
Arnaud Tonnerre, Serge Héthuin, Isabelle Bucaille

2. Mesh networking for low-rate systems
May 2006
doc.: IEEE
May 2006
Mesh networking for low-rate systems
Arnaud Tonnerre, Serge Héthuin, Isabelle Bucaille
THALES Communications France
Arnaud Tonnerre, Serge Héthuin, Isabelle Bucaille
Arnaud Tonnerre, Serge Héthuin, Isabelle Bucaille

3. May 2006
doc.: IEEE
May 2006
Objectives
To present a Mesh design for low-rate systems based on
To make recommendations on Centralized Mesh networking
To provide simulation results related to Mesh architectures
The work has been partly supported by the European Commission R&D Integrated Project PULSERS, IST-FP and IST-FP
Arnaud Tonnerre, Serge Héthuin, Isabelle Bucaille
Arnaud Tonnerre, Serge Héthuin, Isabelle Bucaille

4. Contents Centralized Mesh networking Routing protocol: 2-LMR
May 2006
Contents
Centralized Mesh networking
Routing protocol: 2-LMR
Multi-piconet architecture
Simulation results
Arnaud Tonnerre, Serge Héthuin, Isabelle Bucaille

5. Centralized Mesh networking
May 2006
Centralized Mesh networking
Arnaud Tonnerre, Serge Héthuin, Isabelle Bucaille

6. Centralized Mesh networking
May 2006
Centralized Mesh networking
The coordinator handles synchronization and scheduling
2-step formation:
Scheduling Tree construction
Used for control frame transmissions
Meshing the topology based on the Scheduling Tree
Scheduling Tree
Mesh network
Arnaud Tonnerre, Serge Héthuin, Isabelle Bucaille

7. Mesh superframe structure
May 2006
doc.: IEEE
May 2006
Mesh superframe structure
Superframe structure based on
Beacon
period
Request
Topo mgmt
Control portion
Data portion
CAP
CFP
Inactive
Control portion
Data portion
CAP
CFP
Inactive
Beacon slot
Control portion length is increased
Beacon period
Request period
Topology Management period
Arnaud Tonnerre, Serge Héthuin, Isabelle Bucaille
Arnaud Tonnerre, Serge Héthuin, Isabelle Bucaille

8. Mesh superframe structure
May 2006
Mesh superframe structure
Fine structure
Superframe is divided equally into slots
Use of Minislots in the Control portion
Provides flexibility: adaptation to different frame durations
Guaranteed Time MiniSlot (GTMS) can be introduced in CFP
Particularly interesting for short data frames such as ranging signaling
Ranging is a major function of a
Arnaud Tonnerre, Serge Héthuin, Isabelle Bucaille

9. Mesh superframe structure
May 2006
Mesh superframe structure
Beacon period
The beacons are relayed along the Scheduling Tree
The beacon-frame length shall be minimized
Dropping overheads introduced by beacon relaying
Reducing address size to 8 bits (mesh addresses)
Beacon alignment procedure
To avoid interference between close neighbors
Algorithm based on the tree level (number of hops to reach the coordinator)
Minislot
Beacon period
Slot
Tree Level 0
Tree Level 1 B
Arnaud Tonnerre, Serge Héthuin, Isabelle Bucaille

10. Mesh superframe structure
May 2006
Mesh superframe structure
Request period
Request period is a set of GTS dedicated to allocation demands
Transmission from the leaves to the coordinator
Tree Level 3
Tree Level 2
Tree Level 1
Tree Level 0
Coordinator A B C D E F G H I J K
GTS request frames
GTS requests require guaranteed access in the superframe
Arnaud Tonnerre, Serge Héthuin, Isabelle Bucaille

11. Mesh superframe structure
May 2006
Mesh superframe structure
Request period
Peak of delay due to request/grant allocation
Behavior of the MAC in overloaded networks
Simulations: 2 types of request transmission
In CAP of data portion
In guaranteed time slot of the control portion
GTS request sent in a GTS
Max delay = 35 ms
GTS request sent in CAP
Max delay = 7 s
Arnaud Tonnerre, Serge Héthuin, Isabelle Bucaille

12. Mesh superframe structure
May 2006
Mesh superframe structure
Topology Management period
Two types of message are sent in this period
Link State procedure
Allows the coordinator to build the Scheduling Tree
Periodic transmission of Hello frames from every associated device
Hello frames transport the 2-hop neighborhood of the originator
Scheduling Tree update
Keep informed the devices of the Tree structure
Hello frames (Link State procedure)
Scheduling Tree Update (STU) frames
Arnaud Tonnerre, Serge Héthuin, Isabelle Bucaille

13. 2-Level Mesh Routing protocol (2-LMR)
May 2006
2-Level Mesh Routing protocol (2-LMR)
Arnaud Tonnerre, Serge Héthuin, Isabelle Bucaille

14. 2-LMR protocol 2-LMR protocol provides routing based on Link States
May 2006
2-LMR protocol
2-LMR protocol provides routing based on Link States
Reuse of link state procedure dedicated to tree construction
No additional messages is required
Efficient pro-active routing protocol
Packets can be routed using 2 types of path:
Tree route based on the scheduling tree
Local route defined by the local link states
Arnaud Tonnerre, Serge Héthuin, Isabelle Bucaille

15. 2-LMR protocol Local Route repair
May 2006
2-LMR protocol
Local Route repair
Starts when a non-tree link is broken
Detected thanks to the Link State procedure
A new route is built based on updated link states
Repaired route is inserted in the local routing tables
Coordinator A
Source B H
Destination C F I
Hello frame D E G J K
Initial route
Repaired route
Arnaud Tonnerre, Serge Héthuin, Isabelle Bucaille

16. 2-LMR protocol Tree Route repair Starts when a tree link is broken
May 2006
2-LMR protocol
Tree Route repair
Starts when a tree link is broken
Information transferred to the coordinator (Link State procedure)
The coordinator builds a new Scheduling Tree
The structure is broadcast using Scheduling Tree Update (STU) frames
Coordinator A
Source B H
Destination C F I
STU frame D E G J K
Initial route
Repaired route
Arnaud Tonnerre, Serge Héthuin, Isabelle Bucaille

17. May 2006
Multi-piconet
Arnaud Tonnerre, Serge Héthuin, Isabelle Bucaille

18. Multi-piconet Simultaneous operating piconet (SOP) Lower complexity
May 2006
Multi-piconet
Simultaneous operating piconet (SOP)
Mandatory use of CDMA
Optional use of FDMA if several frequency bands are available
Use of Inactive period is possible in some cases
Duty cycle should be very low
The inactive periods should be large enough
Lower complexity
Requires coordination between SOP
Involves a significant loss of bandwidth
Arnaud Tonnerre, Serge Héthuin, Isabelle Bucaille

19. Multi-piconet Communication between piconets
May 2006
Multi-piconet
Communication between piconets
Clusters (or piconets) are structured hierarchically
Primary piconet is the parent cluster of every cluster in the network
Parent / Child structure
Border nodes are coordinators of child clusters (Cluster Heads)
Management of the border nodes is touchy
Arnaud Tonnerre, Serge Héthuin, Isabelle Bucaille

20. May 2006
Simulations
Arnaud Tonnerre, Serge Héthuin, Isabelle Bucaille

21. Simulations Centralized Mesh architecture
May 2006
Simulations
Centralized Mesh architecture
Scheduling Tree centralized on the coordinator
Mesh network based on the Tree
Arnaud Tonnerre, Serge Héthuin, Isabelle Bucaille

22. Simulations Centralized Mesh architecture
May 2006
Simulations
Centralized Mesh architecture
End-to-end delay is a significant “figure of merit”
Traffic behavior depends on the selected access protocol
Grasp the impact of relaying
Average end-to-end delay as a function of the number of relays in CFP
Average end-to-end delay as a function of the number of relays in CAP
Arnaud Tonnerre, Serge Héthuin, Isabelle Bucaille

23. Simulations Clusterized Mesh architecture
May 2006
Simulations
Clusterized Mesh architecture
Dedicated to high density environment
Structure:
A Backbone, based on a Centralized Mesh topology
Clusters in single-hop topology
Backbone
Cluster
Arnaud Tonnerre, Serge Héthuin, Isabelle Bucaille

24. Average end-to-end delay as a function of the number of relays
May 2006
Simulations
Clusterized Mesh architecture
Simulation results
Average end-to-end delay as a function of the number of relays
Arnaud Tonnerre, Serge Héthuin, Isabelle Bucaille

25. Simulations Cluster Tree architecture
May 2006
Simulations
Cluster Tree architecture
Extend range in a low density environment
Structure:
Set of clusters representing a tree
Each cluster is a Centralized Mesh topology
Arnaud Tonnerre, Serge Héthuin, Isabelle Bucaille

26. Average end-to-end delay as a function of the number of relays
May 2006
Simulations
Cluster Tree architecture
Simulation results
Average end-to-end delay as a function of the number of relays
Arnaud Tonnerre, Serge Héthuin, Isabelle Bucaille

27. Conclusion Division of Slots into Minislots for flexibility
May 2006
Conclusion
Division of Slots into Minislots for flexibility
In Control portions
In the CFP of Data portions
GTS request requires guaranteed access in the superframe
2-LMR routing protocol
Efficient pro-active protocol
Without additional control overload
Use of CDMA for multi-piconet access
Arnaud Tonnerre, Serge Héthuin, Isabelle Bucaille

28. May 2006
References
PULSERS D3a2, “Candidate architecture for HDR and LDR-LT operational modes”, December 2004.
PULSERS D51b, “Definition of new concepts/architectures for UWB MAC and networking [HDR and LDR-LT]”, March 2005.
PULSERS D3a3, “Selection of architecture for HDR and LDR-LT operational modes including simulation results”, June 2005.
Arnaud Tonnerre, Serge Héthuin, Isabelle Bucaille