Research On Power Control Technologies In Wireless Mesh Networks

Wireless Mesh Networks (WMNs) are dynamically self-organized and self-configured. This feature brings many advantages to WMNs such as low up-front costs, easy network maintenance, roubustness, and reliable service coverge. Moreover, the gateway and bridge functionalities in mesh routers enable the integration of WMNs with various exiting wireless networks.Transmission Power Control (TPC) is a key technology to the performance of the WMN, since selecting the transmit power for each packet is of foremost importance to maximize network capacity. Although there have been many researches on power control aiming at improving the power efficiency in the environment of other type of networks, few works have been done to improve the performance in the context of WMNs .In this paper, a POwer COntrol and Scheduling scheme In Multi-rate wireless mesh network (POCOSIM) is proposed to meliorate the throughput and fairness of multi-rate WMN. It has considered the influence caused by data relaying of Mesh Router (MR), and the characteristic of the aggregated data flow.The system is modeled as a conflict graph and is formulated as multi-object programming problem. Differential evolution algorithm is used to solve the problem. Moreover, we induced POCOSIM to run in distributed mode. Firstly, a markov model of the network is induced and be used to analyse the network, and then used this model to calculate the minimal back-off windows in CSMA/CA mechanism. This solution makes POCOSIM more easy to be applied to real conditions. The main contributions of this thesis are as follows:(1) A conflict graph model is built to analyse the network. According to the transmission modes of the network, multi-object programming model including the fairness and throughput performances is established. Differential Evolution (DE) algorithm is used to solve the problem, and a cheme effective to the multi-rate WMN environment namedPOCOSIM, is proposed in this thesis.(2) The 2 dimension Markov model[44] propose by Bianchi, and used to analyse WMN.(3) The minimal back-off windows of the CSMA/CA schedule is calculated according to the time vector got from POCOSIM, so as to improve POCOSIM run in distributed way.Through simulation, the POCOSIM is proved to be more effective than other algorithms. The distributed solution of POCOSIM drops not too much in performance.