Research On Adaptive Transmission Scheme Based On Sparse Network Coding In Wireless Network

In sparse network coding,a large number of zero coding coefficients are selected to encode in the original packet set,a sparse decoding matrix can be generated at the sink node.In order to reduce the decoding complexity and transmission delay,partial decoding can be implemented in sparse network coding,and the original data can be decoded by collecting partial coded packets on the premise of decoding the whole generation of original packets.Sparse network coding can effectively improve transmission efficiency in relay cooperative wireless networks.By adjusting the transmission mode of relay nodes,the ratio of innovative packets can be maximized and decoding probability can be improved under the condition of the limited transmission cost.To the traditional transmission scheme based on sparse network coding,the sink node decoding probability is strongly dependence on linearly coded packets,which makes the decline of innovative packets probability and the lower decoding probability.An adaptive decoding transmission scheme based on sparse network coding which applies to wireless networks is proposed(ADTS-SNC).In this scheme,the linear dependence function is obtained by analyzing the receiving probability of linear packets in the decoding matrix,and the decoding critical function is proposed by combining the maximum value range of the linear dependence expected number of the sparse random matrix,and the function value is taken as the partial decoding condition of relay nodes to improve the efficiency in the end of transmission.The simulation results show that the matrix maintains a high decoding probability and tends to be stable with the increase of the number of rounds in the later transmission period,which effectively reduces the dependence of linearly dependent packets and maximizes the decoding gain of sink nodes.The current research of sparse network coding density almost relies on a single density distribution function,the decoding complexity can be reduced by the high sparsity encoding method,but a large transmission overhead occurs.In order to solve the problem of density dynamic adjustment in wireless network,a dense adjustment scheme based on sparse network coding(DAS-SNC)is proposed.In this scheme,the expected total transmission overhead is obtained by analyzing the probability of receiving innovative packets,and then the optimal density is adjusted by comparing the transmission overhead density adjustment function under the condition of limited transmission overhead.Simulation results show that the decoding probability decreases slightly in the begining transmission,but remains high decoding probability results as a whole.The cost is decreased at the later stage of transmission,leading decoding probability to a lower result.But the ratio of the number of innovative packets is high,which improves the effective utilization of the transmission cost value.