Reasearch Of Channel Allocation Algorithms In Next-Generation WLANs

IEEE 802.11 has evolved from 802.11a/b/g/n to 802.11ac to meet rapidly increasing data requirements in WLANs.One important technique adopted in 802.11ac is the channel bonding(CB)that combines multiple 20MHz channels for a single transmission in 5GHz band.In order to effectively access channel after a series of operations,802.11ac specifies two different CB operations:Dynamic Channel Bonding(DCB)and Static Channel Bonding(SCB).This thesis investigates the channel allocation problem in 802.11ac DCB networks.First,based on our performance analysis on "all-inclusive" DCB networks and "not-all-inclusive" DCB networks under different channel allocation schemes,we respectively construct channel allocation optimization models.Furthermore,a channel allocation algorithm is designed based on the Branch-and-Bound Method(BBM)for "all-inclusive" DCB networks and a heuristic channel allocation,algorithm is proposed for"non-all-inclusive" DCB networks.Finally,simulations validate the correctness and effectiveness of the proposed algorithms.Specifically,the main contribution of this thesis are as follows:(1)For an "all-inclusive" DCB network,a channel allocation optimization model with the target of maximizing aggregate throughput is constructed,and a channel allocation algorithm based on BBM to find the optimal channel allocation scheme is proposed.Specifically,this thesis analyzes the aggregate throughput performances under different channel allocation schemes,based on which an integer non-linear programing(INLP)model is established.We then propose an optimal channel allocation algorithm based on the BBM to achieve the maximal aggregate link throughputs.Finally,simulations show that the proposed channel allocation algorithm can achieve the maximum aggregate throughput under various network settings and is always better than other channel allocation algorithms.(2)For a "non-all-inclusive" DCB network,a channel allocation optimization model with the target of maximizing the average system utility is constructed and a heuristic channel allocation algorithm is proposed.Specifically,we propose a throughput computation method based on the Continuous-Time Markov Chain(CTMC)model,based on which we analyze the aggregate throughput and average system utility under different channel allocation schemes.Furthermore,we construct a channel allocation optimization model with the target of maximizing the average system utility.To solve the complex optimization model,a heuristic channel allocation algorithm to achieve near-optimal channel system performance is proposed.Simulations show that the performance of the proposed heuristic channel allocation algorithm can achieve good system performance in terms of average system utility and aggregate throughput.Moreover,the performance of the proposed scheme is always better than that of the other channel allocation algorithms.