Research On Optimal Bandwidth Allocation Strategy Of IEEE 802.11 Network

Over the past decade,IEEE 802.11 WLAN has been widely used in people's life and work because of its low cost,strong mobility and high compatibility,which is widely deployed in public places such as hospitals,factories,libraries and airports.But as the number of users in the WLAN is increasing,the limitations of WLAN are also exposed,and seriously affect the system throughput and fairness between users,network bandwidth cannot meet the needs of users in the network,so the limited network resources for efficient and reasonable optimization and distribution becomes particularly important.The main research results of this paper are as follows:First,in the multi-rate WLAN,because the probability of the network site access channel is equal,the time of the low rate site in the dense network environment is longer than that of the high-speed site,which affects the whole network to obtain higher system throughput,which causes the performance anomaly problem.While scholars at home and abroad solve the problem of abnormal performance,the method used is the time-fairness algorithm,but the disadvantage of the time-fairness algorithm is that it only applies to the condition of the network state saturation,so in order to ensure the normal implementation of the time-fairness algorithm,an adaptive access mechanism based on the network state detection is proposed in this paper.Through the communication between the site and AP,the average collision rate of the network is calculated,and the saturation or unsaturated state of the current network is determined,and then the access mechanism of the site is adaptively adjusted according to the status of the network to ensure that the time-fairness algorithm runs in saturation condition and adapts to the dynamic network environment.The simulation results show that the mechanism can detect the saturation of the network effectively,switch to the time-fairness algorithm,improve the throughput of the system,and avoid the delay of the low-speed site in the unsaturated environment.Then,in the study of the time-fairness algorithm to solve the problem of the performance of the multi-rate saturated network,it is found that the static time-fairness algorithm has a certain waste in channel utilization,and its fixed MAC layer parameters are not suitable for the dynamic network environment,resulting in the waste of resources.Therefore,this paper detects the average collision rate of the current network through the proposed network state detection mechanism and changes the parameters of Mac layer according to the average collision rate of the network to adapt to the dynamic network environment.The simulation results show that the algorithm improves the channel utilization and increases the total throughput of the system under the precondition of solving the performance anomaly problem.