Research Of Broadcast Retransmission Algorithm Based On Network Coding In Wireless Networks

Over the past years,the society is gradually transforming from the traditional Internet era to the mobile Internet era.The explosion of mobile data traffic has brought greater challenges to mobile wireless communications technology.In order to ensure the reliability of data transmission in wireless networks,it is an effective way to retransmit the lost data packets.At the same time,retransmissions also caused additional resource consumption.The proposed network coding provides new ideas for retransmission studies in wireless networks.This paper studies the network coding based retransmission algorithm in wireless networks.The main work of the paper is as follows:1.This paper introduces and analyzes the existing two typical network encoding broadcast retransmission algorithms.In order to reduce the overall number of retransmissions in the case of scarce channel resources,a Hash searching based non-block retransmission(HSNBR)scheme is proposed.First,we used the Hash value to construct the Hash table.Then we used the hash table for the hash neighborhood searching to find the packet combination which meets certain conditions quickly.And we also used the buffer update mechanism to increase the opportunity for packet combination.In this way we can reduce the number of retransmissions.Simulation results show that this HSNBR can effectively reduce the number of retransmissions,and outperforms existing solutions in terms of retransmission efficiency.2.In order to reduce the number of timeout packets,we proposed a Low Latency-Hash Searching based Non-Block Retransmission(LL-HSNBR)for the real-time application which is sensitive to network delay.In this scheme,the sending node sorts packets according to their values of lifecycle(LC)and uses the Hash values of packets to construct the Hash table.Based on the packet with the minimum LC,we used the Hash neighborhood searching to find packet combination.The simulation results show that the LL-HSNBR scheme can effectively reduce the packet timeout rate and has higher retransmission efficiency,and is more suitable for wireless network real-time applications which are sensitive to delay.