1. Advisor: Yeong-Sung, Lin, Ph.D. Presented by Yu-Ren, Hsieh
A Near-Optimal Distributed QoS Constrained Routing Algorithm for Multichannel Wireless Mesh Networks 多信道無線網狀網路下近似最佳化之分散式具服務品質限制路由演算法
Advisor: Yeong-Sung, Lin, Ph.D.
Presented by Yu-Ren, Hsieh

2. 2019/5/2
NTU IM OPLAB
Abstract
For each mesh client, it is desirable to choose the route with low interference and minimum delay to access the Internet; however, this is suboptimal for the whole system.
Channel assignment heuristic algorithm
Distributed QoS constrained routing algorithm
A routing metric which is composed of average cross-network packet delay and end-to-end delay and derived from a Lagrangean Relaxation based problem formulation.
OSPF based protocol for dynamic routing
K shortest paths and K fastest paths

3. Problem Description
2019/5/2
NTU IM OPLAB
The problem we addressed is to find out the arc weight form of each link while taking “system perspective” and “user perspective” into account
The environment we considered here is a multichannel WMN which is one case of this generic formulation for illustration purpose
In the multichannel WMN, the link capacity degrades due to the other links using the same channel in the interference range. Therefore, the link capacity is divided by the number of interference links in the following formulation (i.e., )

4. Problem Description Problem Assumptions:
2019/5/2
NTU IM OPLAB
Problem Assumptions:
The channel assignment for each mesh router is fixed for a long period.
Each mesh router is equipped with multiple a NICs, each of which operates on a particular and non-overlapping channel.
Each mesh router can simultaneously communicate with its neighbors in transmission range without interferences by using different channels for each link.
All mesh routers in the network use the same fixed transmission power and have fixed transmission range and interference range.
A virtual node is added as the destination node to only connect to the mesh access point via wired-line.
All flows are transmitted to this virtual node via the mesh access point.

5. Problem Description Given: Objective: Subject to: To determine:
2019/5/2
NTU IM OPLAB
Given:
The set of links.
The set of mesh routers.
The link capacity of each link.
The number of interference links of each link.
The traffic requirement for each O-D pair.
Objective:
To minimize the average cross-network packet delay of the WMN.
Subject to:
QoS constraints.
Path constraints.
Capacity constraints.
Flow constraints.
To determine:
The arc weight form of each link is composed of the link mean delay and the
derivative of queue length for each O-D pair.

6. Notation of Given Parameters
2019/5/2
NTU IM OPLAB

7. Notation of Decision Variables
2019/5/2
NTU IM OPLAB

8. Problem Formulation
2019/5/2
NTU IM OPLAB

9. Channel Assignment Heuristic
2019/5/2
NTU IM OPLAB
Channel Assignment Heuristic

10. Channel Assignment Heuristic
2019/5/2
NTU IM OPLAB

11. Channel Assignment Heuristic
2019/5/2
NTU IM OPLAB

12. Channel Assignment Heuristic
2019/5/2
NTU IM OPLAB

13. Channel Assignment Heuristic
2019/5/2
NTU IM OPLAB

14. Channel Assignment Heuristic
2019/5/2
NTU IM OPLAB

15. Channel Assignment Heuristic
2019/5/2
NTU IM OPLAB

16. Solution Approach for Multichannel WMN Formulation
2019/5/2
NTU IM OPLAB

17. Subproblem 1 (related to decision variable )
2019/5/2
NTU IM OPLAB

18. Subproblem 2 (related to decision variable and )
2019/5/2
NTU IM OPLAB

19. Subproblem 2 (related to decision variable and )
2019/5/2
NTU IM OPLAB

20. 2019/5/2
Routing Metric
NTU IM OPLAB

21. The Arc Weight of Each Link
2019/5/2
NTU IM OPLAB

22. Estimation of Routing Metric Parameters
2019/5/2
NTU IM OPLAB
Perturbation Analysis
ECHO packets
A monotonically increasing and convex function to approximate

23. Estimation of Routing Metric Parameters
2019/5/2
NTU IM OPLAB

24. Dynamic Routing Protocol
2019/5/2
NTU IM OPLAB

25. Dynamic Routing Protocol for Each Node
2019/5/2
NTU IM OPLAB

26. Routing Algorithm
2019/5/2
NTU IM OPLAB

27. The QoS Satisfaction Heuristic Algorithm
2019/5/2
NTU IM OPLAB

28. Thanks for your listening