1. January 2007
Project: IEEE P Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: [Distributed Channel Time Allocation for WPAN Mesh Networks]
Date Submitted: [January 15, 2007]
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
January 2007
Distributed Channel Time Allocation for WPAN Mesh Networks
January 2007
Sangsung Choi
ETRI/KWU
Jeon, Choi, Rhee, Lee and Lee <ETRI/KWU>

3. Authors Name Company Address Phone E-mail Young Ae Jeon ETRI Korea
January 2007
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]
January 2007
Hierarchy between DEVs and PNC [Shao06a]
Jeon, Choi, Rhee, Lee and Lee <ETRI/KWU>

5. Hierarchical Mesh Architecture [Shao06a]
January 2007
Hierarchical Mesh Architecture [Shao06a]
MPNC
Jeon, Choi, Rhee, Lee and Lee <ETRI/KWU>

6. Example: Mesh MAC [Hiertz05]
January 2007
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
January 2007
15.5 Scope: Mesh Architecture
Agreements
Every mesh-capable PNC 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 PNCs
January 2007
Motivation
No central controller for the Mesh PNCs
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…
January 2007
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 PNCs
January 2007
Notation: Reservations among Mesh PNCs
Mesh PNC i reserves duration Ti of MAS
Their min/max requirements (mi / Mi) are given
Reservation vector T = (T1 ,…,TK ) is feasible if
Jeon, Choi, Rhee, Lee and Lee <ETRI/KWU>

11. Algorithm 1: Computing the Share
January 2007
Algorithm 1: Computing the Share
Mesh PNCs take turns to make reservations
MPNC i , at its turn,
Computes T1
Computes T2
Computes Tn
▪ ▪ ▪ ▪ T1 T2 Tn
MPNC-1 beacon
MPNC-2 beacon
MPNC-n beacon
C = (reference) MPNC superframe
Jeon, Choi, Rhee, Lee and Lee <ETRI/KWU>

12. Algorithm 2: Admission Control
January 2007
Algorithm 2: Admission Control
Mesh PNC i makes a self-decision for joining the mesh network
During one Mesh Superframe,
read m1
read m2
read mn
decision
▪ ▪ ▪ ▪ m1 m2 mn
MPNC-1 beacon
MPNC-2 beacon
MPNC-n beacon
C = (reference) MPNC superframe
Jeon, Choi, Rhee, Lee and Lee <ETRI/KWU>

13. Example: Fairness & Convergence (1)
January 2007
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)
January 2007
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
January 2007
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
January 2007
Example: Minimum Requirements
Min requirement of MPNC1: 30 MAS
α1 = α2 = α3 = 0.5
Jeon, Choi, Rhee, Lee and Lee <ETRI/KWU>

17. Example: Join/Leave of MPNCs
January 2007
Example: Join/Leave of MPNCs
Jeon, Choi, Rhee, Lee and Lee <ETRI/KWU>

18. Analytical Modeling [Rhee06]
January 2007
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
January 2007
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
MPNC obtains info on T(t) from previous beacons
MPNCs are asynchronous: no pre-specified order among them
Jeon, Choi, Rhee, Lee and Lee <ETRI/KWU>

20. January 2007
Our Proof Shows that
All MPNCs converge to a unique equilibrium point T*, regardless of
Number of MPNCs
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. Multi-Hop Mesh PNCs January 2007
Jeon, Choi, Rhee, Lee and Lee <ETRI/KWU>

22. Example: Multi-Hop Mesh PNCs
January 2007
Example: Multi-Hop Mesh PNCs
MPNC 1, 2 &3
MPNC 3 & 4
Jeon, Choi, Rhee, Lee and Lee <ETRI/KWU>

23. Conclusion Distributed channel-time allocation for mesh WPANs
January 2007
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>

24. January 2007
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>