Research And Implementation Of Multi-Channel Aggregation Access Technology Based On IEEE802.11

With the development of wireless communication technology,the performance of Wi Fi,which is mainly oriented by transmission rate,has been breaking through,to meet the increasingly diverse application needs of users.From the first version of the IEEE802.11 standard in 1997 to the popular 802.11ax-Wi Fi6 standard,its peak transmission rate has increased thousands of times.However,with the convergence of heterogeneous networks and the continuous development of cognitive radio technology,problems such as shortage of wireless resources and complex wireless environment have become increasingly prominent.Multi-channel access technology has become a key research direction in many wireless communication fields including IEEE 802.11 and a technical specification that needs to be standardized.Therefore,this paper starts with IEEE802.11,and studies the multi-channel converged access technology and its realization.The main work accomplished in this paper is as follows:Firstly,this paper deeply studies the multi-channel technology in IEEE 802.11 series standards and related research.The key technologies and evolution of 802.11 supporting multi-channel access are investigated from the perspective of physical layer and data link layer respectively,including channel division,frame format and orthogonal frequency division multiple access technology in physical layer,single-channel basic intervention mechanism and multi-channel dynamic/static access mode in data link layer.It paves the way for the subsequent theoretical research and technical realization.Secondly,aiming at the practical problems in private networks and the related problems in the design of multi-channel wireless networks,a multi-channel design scheme with multi-node cooperation is proposed.Among them,a cooperative dual-threshold differential multi-channel detection method is proposed,which aims to eliminate the sharp changes and uncertainties of noise signals and co-channel interference caused by different geographical locations and time in complex wireless network environment,and ensure more accurate and objective channel detection of idle channels and busy channels.In addition,a channel allocation method for multi-node cooperation is studied.By introducing the concepts of cooperation success rate and cooperation conditions,the extra cost caused by cooperation is fully considered to maximize the channel utilization and minimize the conflict between nodes.In the experimental part,the simulation is carried out by the Monte Carlo method of Matlab.The results show that,compared with the traditional double-threshold channel detection method,the channel detection method in this paper has obvious performance improvement when the noise signal value and uncertainty are large.Finally,aiming at the technical realization of multi-channel converged transmission,this paper designs a dual-channel 40 MHz wireless transceiver system by Software Defined Radio instead of the traditional multi-interface and multi-antenna RF front end,and modularizes the above-mentioned channel detection method and cooperative method by GNU Radio.In the actual test of single-node and three-node transceiver,compared with the traditional single-channel 20 MHz transceiver system,the data transmission rate of dual-channel transceiver is increased by 75% and 60% respectively.At the same time,the channel switching and channel mode switching assisted by the channel detection module also have obvious effects,which proves the effectiveness of the system.