Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)

1. Project: IEEE P802.15 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, 305-700, Korea] Voice:[+82-42-860-6497], FAX: [+82-42-860-6645], E-Mail:[yajeon@etri.re.kr] Re: [Call for additional contributions: IEEE P802.15-06/0333r5] 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 802.15 TG5] Notice: This document has been prepared to assist the IEEE P802.15. 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 P802.15. Jeon, Choi, Rhee, Lee and Lee <ETRI/KWU>

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

3. Authors 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] Jeon, Choi, Rhee, Lee and Lee <ETRI/KWU>

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

6. Example: Mesh MAC[Hiertz05] • Superframe equally slotted • Medium Access Slots (MAS) • Mesh WPAN devices serve .15.3 devices as PNC • Reserved MAS for piconet traffic Jeon, Choi, Rhee, Lee and Lee <ETRI/KWU>

7. 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 • Among the mesh devices, we still need • Fair channel time allocation • Decentralized admission control • Service differentiation • How can the channel time management be done ina distributed and fair manner? Jeon, Choi, Rhee, Lee and Lee <ETRI/KWU>

9. 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. Our Algorithm in the 3-way Negotiation Transmitter Receiver Reservation request How much? Reservation reply Reservation IE Finally, how much? reserved Jeon, Choi, Rhee, Lee and Lee <ETRI/KWU>

11. Notation: Reservations among Mesh Devices • Mesh DEVi 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>

12. 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>

13. 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>

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

15. 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>

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

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

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

19. 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>

20. 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>

21. Our Proof Shows that • All devices converge to a unique equilibrium point T*, regardless of • Number of devices • The values of αiand 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>

22. Multi-Hop Mesh DEVs Jeon, Choi, Rhee, Lee and Lee <ETRI/KWU>

23. Example: Multi-Hop Mesh DEVs • MDEV 1, 2 &3 • MDEV 3 & 4 Jeon, Choi, Rhee, Lee and Lee <ETRI/KWU>

24. 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>

25. References [Shao06a] Shao et al, “IEEE P802.15.5 Draft candidate,” IEEE P802.15-06/0237r2, July 2006 [Shao06b] H. Shao, “Call for additional contribution for 802.15.5 Mesh Networking,” IEEE P802.15-06/0333r5, July 2006 [Hiertz05] Hiertz et al, “Mesh PAN Alliance (MPA) and .15.3 integration,” IEEE P802.15-05/0670, 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>