Research On TCP Performance Optimization For Next Generation WiFi Network

With the rapid development of WLAN and the rapid increase of TCP-based wireless traffic in the network,how to enhance the TCP transmission performance of the WiFi network has significan practical significance and research value for promoting the development of the WiFi protocol.The paper analyzes the problems and influencing factors of the TCP performance in WiFi,and then proposes a new mechanism of TCP performance optimization for WiFi network from the perspective of improving the impact of air interface packet loss on TCP performance and reducing double-acknowledgement resource overhead.The paper mainly completes fore aspects of work.First,in order to solve the problem of redundancy overhead caused by duplicate ACK,a cross-layer collaboration acknowledgment mechanism is proposed and an adaptive handover algorithm based on wireless link quality is designed,and a radio link quality assessment model is built.On this basis,self-adaptive handover of the confirmation mode is completed.While ensuring reliability,the goal of reducing redundant acknowledgement transmission in the network and reducing bandwidth resource overhead is achieved.Second,for the problem of seriously aggravating TCP performance caused by dropped packets on the air,AP cache retransmission and timeout avoidance optimization strategies is proposed.Compared with the existing mechanism,three improvements are made: Firstly,fast retransmission is performed by the AP to improve retransmission efficiency.Secondly,by filtering the duplicate TCP acknowledgments transmitting to the sender to prevent the sender from initiating congestion control,maintain throughput stability,and save resource overhead.Thirdly,prevent the sender from TCP timing out by sending TCP acknowledgments to the sender before the TCP timeout.Thirdly,in order to improve the uplink transmission performance of 802.11 ax,an optimization method for active channel allocation is proposed,and a acknowledgment aggregation scheme suitable for 802.11 ax is designed,and a specific frame format for confirming convergence is given.The AP actively allocates uplink channel resources in advance for users having uplink transmission requirements,which can improve the uplink data and acknowledgment information transmission efficiency,reduce the transmission delay in the uplink direction,and achieve the goal of increasing the uplink throughput.Finally,based on NS-3,the optimization mechanism simulation platform is built,and the TCP transmission performance of the WiFi network under the optimization mechanism and the existing mechanism are simulated.Simulation results shows that the optimization mechanism has higher performance in terms of throughput and resource overhead than the existing mechanism.