Research On Resource Assignment And Scheduling In Wireless Mesh Networks

Wireless mesh networks with multi-channel multi-radio availability are attracting more and more attention from the research community because of its performance improvement and relative low complexity.Firstly, in this paper, we address the channel assignment problem for multi-channel multi-radio wireless mesh networks. We focus on heterogeneous static wireless mesh networks where multiple non-overlapping channels are available for each wireless radio. Our objective is to find the optimal channel assignment which maximizes the number of bidirectional links that can be activated simultaneously, subject to the interference constraints. We present an applied integer linear programming model for solving the fixed channel assignment problem with multiple radios. We then use this model to study the impact of channel and radio constrains.Then, we investigate the effect of heterogeneous interface for the capacity of distributed channel-assignment mesh network, present a new ILP model of joint radio and channel assignment, which consider radio-links as the object of channel-assignment, and propose a new distributed greedy algorithm. It is an adaptive and provable convergent distributed algorithm, which can get the maximal sum of radio-links throughput with the weight of queue length, based on 2-hop interference model and the load of the network. We find this algorithm has the same time-complex order as Dist. Greedy algorithm of the current non-heterogeneous interface. The simulation result shows that this algorithm can improve the performance of the network efficiently.Finally, we present a new hybrid scheduling algorithm based on time division multiple access (TDMA) and maximal scheduling for multi-hop wireless mesh networks. It solves the problem that the capacity of wireless mesh network obviously drops when the active transmitters increase since the probability of collisions increases. In this algorithm, each link is assigned with one sub-timeslot with the same colors. According to the color of links, each link can be scheduled directly on the sub-timeslot of same color as link with TDMA algorithm, and links can be scheduled with maximal scheduling on the sub-timeslots of different colors from links, when these sub-timeslots are not occupied. The analysis of algorithm shows that our proposed hybrid algorithm can achieve a provable fraction of the maximum system capacity. The simulation results show significant improvement in network throughput when compared with 802.11-based mesh networks using maximal scheduling algorithm.