Research On Reliable Transmission Control Technology In Wireless Networks

The wireless network has natural broadcast characteristics,and there is mutual interference between the receiving nodes.In addition,the wireless network is also affected by factors such as multipath and shadow fading.Therefore,the packet loss rate in the wireless network environment is higher than that of the wired network,but many applications now require high transmission reliability,so how to achieve reliable transmission in wireless networks has become an important issue.If the data packet is lost in the wireless network,it needs to be retransmitted by the sending end,and the bandwidth resources of the wireless network are very limited.A large number of direct retransmissions will waste the transmission bandwidth,so how to achieve reliable transmission of data in the wireless network and reduce the number of retransmissions times to reduce transmission overhead is of great significance.First,this paper designs a reliable transmission protocol based on the fixed-length sliding window cluster segmentation algorithm,and implements it on the Qt platform.Experimental test results show that the reliable transmission protocol designed in this paper can achieve highly reliable transmission.The comparison between the two indicators of transmission overhead and transmission load verifies the reliable transmission protocol based on the fixed-length sliding window cluster segmentation algorithm,the fixed-length sliding window algorithm and the direct retransmission algorithm.The results show that the protocol can effectively reduce the retransmission overhead during data recovery.However,the implementation results also show that there is a problem that the fixed-length window value cannot adapt to the dynamically changing channel error rate.Secondly,the minimum clique segmentation algorithm can divide the graph into cliques.But,the algorithm uses a method of randomly selecting an edge in the graph to calculate,this calculation method will cause two problems: First,conflicts will occur in the calculation of clique segmentation.Second,there is no guarantee that data packets will be sent in accordance with the timeliness of the data packets.In order to solve the above two problems,this paper proposes a low-latency cluster segmentation algorithm based on packet timeliness,and designs a new cluster segmentation calculation method,which can effectively avoid conflicts in the calculation process and can ensure that the data packets with short timeliness are preferentially encoded and sent,reducing the calculation and transmission delay.Finally,for the fixed-length sliding window cluster segmentation algorithm,there is a problem that the fixed-length window value cannot adapt to the dynamically changing channel environment.This paper proposes a reliable transmission algorithm for variablelength sliding window low-latency clique segmentation.This algorithm uses dynamically changing window values for transmission control.The channel bit error rate returned by the receiving end can be calculated by the sending end.The window value under the code rate is transmitted with a window value adapted to the current channel error rate during each transmission process,which can reduce packet loss caused by the transmission strategy.This algorithm combines the low-latency group segmentation algorithm and the XOR network coding,which can effectively reduce the number of retransmissions during the transmission process and reduce the packet transmission delay.It can also ensure that short-term data packets are sent preferentially to promote the sliding of the receiver window and improve the scalability of the algorithm.The simulation results show that the variable-length sliding window low-latency cluster segmentation algorithm can adapt to the dynamically changing channel environment.Compared with the original fixedlength sliding window cluster segmentation algorithm,it can effectively reduce packet loss and transmission overhead during transmission.