Research On QoS Guarantee Technology For Next Generation WLAN

With the widespread use of wireless local area networks(WLANs),increasing of link speed is no longer the only focus of the evolution of wireless local area network(WLAN)protocols.The diversification and emerging real-time mobile Internet applications raised the request of the user experience of WLANs.How to guarantee the quality of service(Qo S)of real-time services has become an important key to the technology of WLAN.The standard of next-generation WLAN 802.11 ax protocol is aimed at improving the efficiency of wireless spectrum,enhancing the actual performance of high-density deployment of the network and improving users' experience.It is an important research direction for 5G.The existing WLAN Qo S guarantee technology has many limitations in the high-density scenario: the back-off based distributed access method cannot solve the problem of serious internal conflicts of real-time service users;as for the central control method based on access point(AP)polling,although real-time service transmission can be guaranteed,there is a problem of excessive polling overhead in a dense scenario.How to guarantee the service quality of a large number of real-time data flow in intensive scenarios has become an important challenge for the Qo S assurance technology of the next-generation wireless local area network.From the perspective of studying the Qo S guaranteed multiple access scheme for the next-generation WLAN,the thesis conducts the following research work:First,combining the next-generation wireless local area network scenarios and requirements,and analyzes the problems of existing Qo S guarantee technologies for wireless LANs that exposed in the current real-time traffic-intensive and real-time service-intensive user environments.At the same time,combining the characteristics of orthogonal frequency division multiple direct access technology(OFDMA)to support multi-user parallel transmission,from the perspective of Qo S guarantee,a MAC protocol framework based on AP periodic scheduling and uplink 2D time frequency block random access is designed.It is easy to obtain the Qo S requirements of users and the optimal configuration of link resources.Second,based on the multiple access scheme based on AP periodic scheduling,this thesis starts from the perspective of ensuring the access of real-time users,and uses G-S networkanalysis to derive the access delay for different service priority users,the mathematical formula of throughput,and gives simulation verification.Based on the theoretical formula,an adaptive access scheme based on priority Qo S guarantee is proposed.Then through simulation analysis,the throughput and delay of different priority users under different access modes are compared to prove that the adaptive access scheme is able to guarantee Qo S of real time data transmission for users,and can dynamically adapt to changes in the load of the network.Finally,this thesis designs an implementation platform of adaptive access scheme based on priority Qo S guarantee,which mainly includes the design of signaling interactive process of access scheme,the design of related important interfaces,and the fast processing and caching mechanism of high-speed real-time data flow.At the same time,the above solution is implemented on an embedded development platform based on dual CPUs,and a test platform for the prototype of the project is built.The feasibility of the adaptive access scheme based on priority Qo S guarantee is verified by testing the transmission performance of the real-time video flow.