Research On Channel Allocation And User Access Algorithm Under Dense Deployment

With the rapid development of the mobile Internet and the arrival of the Internet of Things,intelligent terminal devices have emerged in large numbers.In order to better meet users' Internet access requirements,operators began to gradually expand the coverage of WLANs and are committed to improving their transmission rates.Then a large number of APs are deployed in public places by equipment provider.Since the WLAN mainly uses the ISM band,there are only 3 channels that do not overlap in this band.With the increasing density of AP deployments,the probability of overlap between APs and their neighboring APs is very high,therefore,serious co-channel interference is caused.So it is imperative to use wireless resource allocation technology to reduce interference in dense deployments and improve WLAN throughput.In this paper,aiming at the problem of co-channel interference under dense deployment,the channel allocation and user access algorithms in the wireless resource allocation technology are studied,and new channel allocation and user access algorithm are designed.The main content of the algorithm is as follows:(1)Interference-based Channel Assignment Algorithm: To solve the problem of overlapping between APs and their neighboring APs in dense deployments,this paper proposes a channel assignment algorithm based on interference packets by studying the channel grouping algorithm in the existing literature and the joint channel allocation algorithm.The algorithm adopts a centralized architecture and designs two parameters: I(interference of all users under the same AP by one AP)and SIR(ratio of signal power and interference power).Among them,the algorithm mainly identify the AP as the interference source that has the most interference to each AP through I,groups the AP that is interfered by the interference source AP,and adjusts the channel of the interference in the packet to reduce the interference to other APs.The algorithm passes multiple channel adjustment and compares the average SIR values of the Aps before and after adjustment so that the SIR value does not increase.The NS-2 simulation shows that the algorithm not only improves the average throughput of APs in dense deployments,but also reduces the interference of the same frequency.(2)Multi-factor Comprehensive User Access Algorithm: For the problem of user access in dense deployment,this paper studies the IEEE802.11 aa mechanism and the access control algorithm based on this mechanism,and the user access algorithm based on multi-factor synthesis is proposed.The algorithm designs two lists,List and Queen,where List is the list of APs that the new user can scan,and Queen is used to record the list of rejected users.When a new user requests access,the central control node will allow it to first access the AP with the strongest signal strength to understand the traffic demand of the user and obtain the List table.In addition,the algorithm proposes a new method for calculatng the availability of APs.That is,the signal strength,the load,the overlap rate with the channels used by neighboring APs,and the load of neighboring APs determine the APs to be allocated for new users jointly.For users who are rejected in Queen,the algorithm is based on a power level adjustment method that allows the rejected user access lighter APs.The simulation results of NS-2 show that the algorithm improves the average throughput and user access rate under dense deployment,and can effectively reduce co-channel interference.