Transmission Scheme Based On Sparse Network Coding In Multi-Relay Cooperative Wireless Network

Network coding is allowed to encode the original packets received at the intermediate node,and then forward the encoding packet.Compared with the traditional transmission mode,more effective information for the next node can be achieved by the single transmission,the network transmission throughput is improved effectively.Especially,the random linear network has been proved to be the best throughput mechanism.But the effective coding packets can be generated with high probability only when the finite field is large enough,that leads to the high computational complexity.On the other hand,the relay cooperation technology can utilize the diversity gain among the multiple nodes to extend the network transmission range,and the wireless network transmission reliability is improved simultaneously.The wireless network transmission media has the broadcast characteristics,the combination of relay cooperation communication and network coding can complement each other to improve the transmission effectiveness.Aiming at the problem that the computational complexity of random linear network coding in wireless multicast networks is high and the network transmission performance is susceptible to feedback information,a priority scheduling scheme based on adaptive random linear network coding(PSARLNC)is proposed.A sparse adaptive network coding scheme suitable for multicast is adopted in PSARLNC,the computational complexity of traditional random linear network coding is reduced,and comprehensively considers the remaining transmission slots of the data packet simultaneously.Each relay node constructs its own decoding probability value according to the reception condition,and determine the scheduling priority and complete the forwarding.Simulation results show that the feedback dependence is reduced effectively,and simultaneously the better performance can be guaranteed with the computational complexity and the feedback dependence reduced.Aiming at the problem that the sparseness adjustment of sparse network coding in the multi-relay cooperative network lacks the dynamic adaptability to the network state,the linear density adjustment scheme based on spare network coding(LDAS-SNC)and the phase density adjustment scheme based on spare network coding(PDAS-SNC)are proposed.LDAS-SNC and PDAS-SNC all use the adjustable sparse network coding,and dynamically adjust the coding sparsity according to the receiving situation of the node in the multi-relay network transmission procedure,simultaneously the node decoding efficiency is guaranteed by increasing the sparsity gradually.The simulation shows PDAS-SNC reduces the computational complexity of random linear network coding,but the number of system transmissions is increased,which has an impact on system throughput in some degree.LDAS-SNC can maintain better system throughput with the computational complexity reduced,that improve the network transmission efficiency.