Exploiting Multiple Rates to Maximize the Throughput of Wireless Mesh Networks
Date Issued
2009
Date
2009
Author(s)
Lin, Ching-Ju
Abstract
Multi-radio Multi-channel wireless mesh networks (WMNs) aim to perform ubiquitous wireless broadband network access. In WMNs, much attention has been paid to the problem of resource allocation, i.e. how to efficiently utilizeultiple orthogonal channels and multiple communication radios to enhance the aggregate throughput. In multi-channel wireless mesh networks (WMNs), the routing and channel assignment can interdependently determine network capacity. Some literatures show that a multi-channel, multi-radio WMN can achieve higher aggregate throughput if it can solve the routing and channel assignment problems jointly. However, current works on the joint routing and channel assignment (JRC) problem in wireless mesh networks (WMNs) assume that all links operate at the base rate. In other words, they do not consider the presence of multiple bit-rates. However, in multi-rate WMNs, the achievable throughput of a link operating at higher rates could be much less than its bit-rate when it has to contend with low-rate links. This is also known as the multi-rate sharing problem. To address the problem, we first present a numerical formulation for estimating the dynamic link capacity, which can indicate the degree of the multi-rate sharing problem. Next, we propose an optimization model called Multi-Rate JRC, which solves the JRC problem by considering the dynamic link capacity in order to maximize the throughput in multi-rate, multi-radio, multi-channel WMNs. We then reformulate the primal problem as a Lagrangian dual problem, and apply the subgradient method to approach the dual. Finally, since each subproblem in the dual problem is also a non-linear problem, we design a polynomial-time algorithm to solve it. Our experiment results demonstrate that the proposed capacity formulation can approximate the actual link throughput. We compare the multi-rate JRC model with the base-rate JRC model via simulations. The results show that the multi-rate JRC model achieves throughput gains of 3-4 times and recover from network failure efficiently.
Subjects
Wireless Mesh Networks
Routing and Channel Assignment
Multiple Bit-Rates
Multi-Radio Multi-Channel
Type
thesis
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