An Efficient Multicast Scheme Based On Network Coding In Wireless Networks

In wireless networks, a node transmits its data to multiple nodes by means of multicast. Due to the characteristic of wireless link, when receivers with better link reliability have received that packet successfully, while the others with worse link state do not, since reliability is time varying. In order to ensure all the receivers can get that packet, traditionally, the sender has to retransmit that packet until all receivers receive it. Obviously, when the reliability of wireless links between nodes varies greatly, nodes with better link reliability will receive duplicated packets due to sender's retransmission, which will waste the node's bandwidth and energy and cause radio interference, etc. Thus, it is significant to design an efficient and reliable multicast scheme to improve the efficiency of transmission and the wireless link bandwidth utilization and to reduce node's energy consumption.This paper presents a reliable multicast relay scheme based on random linear network coding in wireless networks. Through the relay node's selection algorithm, the source elects relay nodes and then forms the network topology. The basic idea of that scheme is to allow parts of the sinks with better link reliability to forward the packets sent by the source with random linear network coding in the form of relay to fulfill the transmission of those sinks with higher link failure in order to improve the efficiency of packet transmission. While the previous research based on network coding either lets the source send that packet or use some of the intermediate nodes relaying to the sinks until all receivers receive it successfully, it does not consider the sink as a part of the relay. Through mathematical derivation and simulation analysis, this paper compares the performance of traditional multicast with the proposed scheme under different parameters of the number of sink, the number of packets encoded, the receiving radius of sink and the fading factor of wireless link. Simulation results show that the proposed scheme can improve the transmission efficiency of wireless networks under certain conditions.