Research On Key Technologies Of QoS Optimization For Multi-user TCP Service In WiFi Home Environment

With the development of the IEEE 802.11 standard,the scenario where multiple users are connected to use a Wi Fi network at the same time is everywhere.The TCP protocol for wired networks has poor performance in the Wi Fi multi-user environment.How to improve the TCP service quality in the Wi Fi multi-user scenario has very important research significance.First of all,this thesis analyzes the problem of Qo S optimization of the Wi Fi multi-user TCP service.The analysis shows that the MAC ACK of edge users in the Wi Fi environment easy losses results in unnecessary retransmission of downlink data,wasting a lot of air interface channel resources,and the Qo S of TCP services for edge users will be reduced accordingly.This thesis uses the IEEE 802.11 standard MAC layer block confirmation mechanism and the TCP protocol reliable transmission mechanism,the information redundancy of the two,proposes a TCP ACK and BA joint processing downstream TCP optimization scheme,aimed at further determining whether it is necessary to retransmit MAC layer data frames containing TCP data segments of edge users,so as to improve the overall air interface resource utilization rate of multiple users.This thesis designs an algorithm to detect the presence of edge users on the wireless router side,and proposes an effective strategy to judge whether the downlink data of the TCP service sent to the edge user is really lost in the air interface channel,and proposes an effective strategy to eliminate the packet loss interference of TCP service on the server-side wired network.At the same time,the TCP ACK and BA frame uplink joint transmission mechanism is further proposed.Through the custom MAC layer data frame carrying block confirmation information and TCP ACK information at the same time,the amount of data sent by edge users is compressed,reducing the burden of edge users’ uplink transmission and releasing more air interface resources to other users.Then,based on the Linux development environment,the TCP ACK and BA joint processing downstream TCP optimization scheme was implemented.This thesis builds a test scenario to verify the function of the solution,and the performance test shows that the solution has an optimized effect on edge users’ TCP traffic and delay.Finally,this thesis combines the UL-OFDMA process introduced by the next-generation IEEE 802.11 ax standard,and proposes a multi-user resource allocation scheme based on TCP model under Wi Fi6.The scheme proactively allocate uplink resources for TCP service users through the prediction results of uplink TCP services.Theoretical analysis shows that after limiting the number of TCP service users participating in active distribution,the scheme can effectively reduce the uplink collision rate and additional delay overhead caused by wireless access.