Research On Rate And Carrier Sense Threshold Adaptive Technology In 802.11 Wireless Local Area Network

Wireless Local Area Network(WLAN)has become the preferred way for users to access the network quickly.WLANs are deployed in densely populated areas such as large workplaces and apartments,and the number of WLAN-enabled smart devices has increased exponentially in recent years.In order to improve the efficiency of dense System capacity,need to deploy a large number of APs,it also caused serious OBSS interference.How to alleviate OBSS interference and improve system throughput has become one of the most urgent problems to be solved in the next generation of WLANs.At present,most of the existing algorithms manage the interference through channel allocation,rate control and power control.There are few studies on the adaptive carrier sense threshold that can improve the space utilization efficiency,and most of the existing adaptive carrier sense threshold algorithms are proposed based on the ideal analysis model,so the algorithms are not adaptable and some algorithms need to modify the protocol,the compatibility is not high.This paper firstly analyzes the channel access technology of IEEE 802.11,studies the reason of signal interference,and abstracts and models the channel transmission model.Then the relationship among rate,carrier sense threshold and SNR is analyzed respectively,and the effect of rate and carrier sense threshold on system throughput is summarized.This paper studies the IEEE 802.11 ax DSC algorithm,and some suggestions for improving the fairness of DSC algorithm are proposed.Considering that the relationship between the rate and the carrier sense threshold affects each other,a combined adjustment algorithm of rate and carrier sense threshold based on the Minstrel algorithm is proposed.The improved algorithm aims at improving the total system throughput in dense WLAN environment,and it is a heuristic and distributed algorithm.The improved algorithm enables nodes to select the appropriate rate and carrier sense threshold based on the channel interference.The improved algorithm based on the Minstrel algorithm is still an algorithm based on long-term probability statistics,which chooses the optimal rate and carrier sense threshold according to the expected throughput of the target function and the expected number of successes in the cycle,and uses a retry chain mechanism to adapt to sudden changes in channel quality.In this paper,NS3 is used as a simulation tool to compare the performance of the standard IEEE 802.11n,Minstrel algorithm and the improved algorithm.The simulation results show that the improved algorithm proposed in this paper improves the channel and space utilization efficiency in dense WLAN environment.The average throughput of nodes is higher than the standard IEEE 802.11n agreement increased 5.8%?10.3%.