1. November 2006
Project: IEEE P Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: [Distributed Channel Time Allocation for WPAN Mesh Networks]
Date Submitted: [November 04, 2006]
Source: [Young Ae Jeon, Sang Sung Choi, Seung Hyong Rhee, Byungjoo Lee, Wangjong Lee]
Company [Electronics & Telecommunications Research Institute / Kwangwoon University]
Address [161 Gajeong, Yuseong, Daejeon, , Korea]
Voice:[ ], FAX: [ ],
Re: [Call for additional contributions: IEEE P /0333r5]
Abstract: [This document suggests to adopt a distributed and self-managed mechanism that achieves a fair channel time allocation and admission control in WPAN mesh networks. It also provides a distributed means for providing QoS differentiation.]
Purpose: [Providing technical contributions to IEEE TG5]
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
Jeon, Choi, Rhee, Lee and Lee <ETRI/KWU>

2. Distributed Channel Time Allocation for WPAN Mesh Networks
November 2006
Distributed Channel Time Allocation for WPAN Mesh Networks
November 2006
ETRI/KWU
Jeon, Choi, Rhee, Lee and Lee <ETRI/KWU>

3. Authors Name Company Address Phone E-mail Young Ae Jeon ETRI Korea
November 2006
Authors
Name
Company
Address
Phone
Young Ae Jeon
ETRI
Korea
Sang Sung Choi
Seung Hyong Rhee
KWU
Byungjoo Lee
Wangjong Lee
ETRI – Electronics and Telecommunications Research Institute, Daejeon, Korea
KWU – Kwangwoon University, Seoul, Korea
Jeon, Choi, Rhee, Lee and Lee <ETRI/KWU>

4. Hierarchy between DEVs and PNC [Shao06a]
November 2006
Hierarchy between DEVs and PNC [Shao06a]
Jeon, Choi, Rhee, Lee and Lee <ETRI/KWU>

5. Hierarchical Mesh Architecture [Shao06a]
November 2006
Hierarchical Mesh Architecture [Shao06a]
Jeon, Choi, Rhee, Lee and Lee <ETRI/KWU>

6. Example: Mesh MAC [Hiertz05]
November 2006
Example: Mesh MAC [Hiertz05]
Superframe equally slotted
Medium Access Slots (MAS)
Mesh WPAN devices serve devices as PNC
Reserved MAS for piconet traffic
Jeon, Choi, Rhee, Lee and Lee <ETRI/KWU>

7. 15.5 Scope: Mesh Architecture
November 2006
15.5 Scope: Mesh Architecture
Agreements
Every mesh-capable device has to beacon
Distributed channel time sharing between mesh devices
Mutual coordination of neighbor’s channel time allocation
Jeon, Choi, Rhee, Lee and Lee <ETRI/KWU>

8. Motivation No central controller for the mesh devices
November 2006
Motivation
No central controller for the mesh devices
Among the mesh devices, we still need
Fair channel time allocation
Decentralized admission control
Service differentiation
How can the channel time management be done in a distributed and fair manner?
Jeon, Choi, Rhee, Lee and Lee <ETRI/KWU>

9. Problems Could be Hard…
November 2006
Problems Could be Hard…
Mesh devices will be on the move
They may join and leave the network frequently
It makes the resource allocation and admission control harder
Multimedia traffic transmissions
They usually have minimum bandwidth requirements
Sometimes exist maximum requirements
Jeon, Choi, Rhee, Lee and Lee <ETRI/KWU>

10. Notation: Reservations among Mesh Devices
November 2006
Notation: Reservations among Mesh Devices
Mesh DEV i reserves duration Ti of MAS
Their min/max requirements (mi / Mi) are given
Reservation vector T = (T1 ,…,TK ) is feasible if C
beacon
period
reserved for DTP
(data transmit period)
CAP
(inactive period) T1 T2
Jeon, Choi, Rhee, Lee and Lee <ETRI/KWU>

11. Algorithm 1: Computing the Share
November 2006
Algorithm 1: Computing the Share
Mesh DEVs take turns to make reservations
DEV i , at its turn,
Computes T1
Computes T2
Computes Tn
▪ ▪ ▪ ▪ T1 T2 Tn
DEV1 beacon
DEV2 beacon
DEVn beacon
beacon period
Jeon, Choi, Rhee, Lee and Lee <ETRI/KWU>

12. Algorithm 2: Admission Control
November 2006
Algorithm 2: Admission Control
Mesh DEV i makes a self-decision for joining the mesh network
At the end of BP,
read m1
read m2
read mn
decision
▪ ▪ ▪ ▪ m1 m2 mn
DEV1 beacon
DEV2 beacon
DEVn beacon
beacon period
Jeon, Choi, Rhee, Lee and Lee <ETRI/KWU>

13. Example: Fairness & Convergence (1)
November 2006
Example: Fairness & Convergence (1)
DTP length: 100 MAS
α1 = α2 = α3 = 0.5
Jeon, Choi, Rhee, Lee and Lee <ETRI/KWU>

14. Example: Fairness & Convergence (2)
November 2006
Example: Fairness & Convergence (2)
DTP length: 100 MAS
α1 = α2 = α3 = 0.25
DTP length: 100 MAS
α1 = α2 = α3 = 0.75
Jeon, Choi, Rhee, Lee and Lee <ETRI/KWU>

15. Example: Service Differentiation
November 2006
Example: Service Differentiation
α1 = 0.5
α2 = 0.66
α1 = 0.5
α2 = 0.75
Jeon, Choi, Rhee, Lee and Lee <ETRI/KWU>

16. Example: Minimum Requirements
November 2006
Example: Minimum Requirements
Min requirement of DEV1: 30 MAS
α1 = α2 = α3 = 0.5
Jeon, Choi, Rhee, Lee and Lee <ETRI/KWU>

17. Example: Join/Leave of DEVs
November 2006
Example: Join/Leave of DEVs
Jeon, Choi, Rhee, Lee and Lee <ETRI/KWU>

18. Analytical Modeling [Rhee06]
November 2006
Analytical Modeling [Rhee06]
Our resource allocation mechanism can be modeled as follows:
where Ui is a strictly concave real function such that
Given C and T = (T1 ,…,TK ), this is a distributed optimization problem among the devices
Jeon, Choi, Rhee, Lee and Lee <ETRI/KWU>

19. Gauss-Seidel Type Iteration
November 2006
Gauss-Seidel Type Iteration
We adopt the Gauss-Seidel type iteration
Only one component of T is updated at a time
The most recent information is available to the devices
Let T(t) = (T1(t), …, TK(t)), our iterative equation is
T(t+1) = F(T(t)), t = 0,1,…
In our implementation,
T(t) and T(t+1) are different only in their ith element
DEV obtains info on T(t) from previous beacons
DEVs are asynchronous: no pre-specified order among them
Jeon, Choi, Rhee, Lee and Lee <ETRI/KWU>

20. November 2006
Our Proof Shows that
All devices converge to a unique equilibrium point T*, regardless of
Number of devices
The values of αi and min/max requirements [mi , Mi]
Their reservations converge to T*
Always within a finite time
The amount of allocation at the equilibrium is
Jeon, Choi, Rhee, Lee and Lee <ETRI/KWU>

21. Conclusion Distributed channel-time allocation for mesh WPANs
November 2006
Conclusion
Distributed channel-time allocation for mesh WPANs
Fair allocation without a controller
Decentralized admission control
Service differentiation
Analytical modeling proves
Self-stabilizing property of our algorithm
Fair and differentiated allocation
Correctness of the simulation results
Jeon, Choi, Rhee, Lee and Lee <ETRI/KWU>

22. November 2006
References
[Shao06a] Shao et al, “IEEE P Draft candidate,” IEEE P /0237r2, July 2006
[Shao06b] H. Shao, “Call for additional contribution for Mesh Networking,” IEEE P /0333r5, July 2006
[Hiertz05] Hiertz et al, “Mesh PAN Alliance (MPA) and integration,” IEEE P /0670, Nov. 2005
[Rhee06] Rhee et al, “Self-managed multiple access control for the distributed wireless PANs,” submitted to a journal
Jeon, Choi, Rhee, Lee and Lee <ETRI/KWU>