Research On The Wireless Relay Transmission Mechanism Based On Network Coding

As an effective method to resist the wireless channel fading,Currently,wireless two-way relay network has become a hot spot due to its low complexity,spatial diversity and the ability of expanding the coverage of the networks.However,its network capacity and spectrum efficiency still need to be further improved.Then network coding technology can effectively improve the network throughput,balanced network load and enhance the robustness of the network.Therefore,the combination of network coding and two-way relay network can get better system performance,because it not only can save the resource cost of the system,but also can further improve the system capacity and spectrum efficiency.Moreover,it has been one of the hotspots of the current wireless communication network.In order to improve the throughput of the system and to ensure the performance requirements of the users,this paper summarizes the research status of wireless bi-directional relay network and network coding,and deeply studies the two-way relay networks based on network coding.In this paper,the existing relay selection mechanism is analyzed and compared,and the existing relay selection mechanism is improved and innovated.Some innovation and improvement has been done on the existing relay selection schemes.The main innovations points are listed as follows:(1)A wireless cooperative relay selection mechanism based on analog network coding(ANC)is proposed for wireless bi-directional relay system.The mechanism jointly considers the channel state,the relay node buffer occupancy and the residual energy of the relay node.By designing the buffer indicators and the energy indicator to indicate the buffer usage status and energy surplus of the relay node.And introducing them into the traditional rate formula.Then an appropriate relay node is selected according to the set of rate formulas which introduce the buffer indicator and the energy indicator,the throughput of the network can be improved through reasonable scheduling.The algorithm performance and experimental simulation show that the mechanism can effectively improve the network throughput.(2)A wireless cooperative relay selection mechanism based on link weight is be proposed.This mechanism can make full use of the nature of network coding can effectively reduce the transmission time slots.Meanwhile taking into account the residual energy of all nodes in the network,the buffer occupancy of relay nodes,and the channel state of the links.By defining a virtual token bucket for each relay's buffer space,making token number indicates the buffer occupancy and the residual energy of the relay node.According to the channel state,the relay buffer occupancy and the residual energy of each node,the weight of each link is calculated.The appropriate relay node is selected based on the obtained weight set,and the file transfer time is effectively reduced by reasonable scheduling.Theoretical analysis and simulation results show that the algorithm significantly reduces the time complexity and file transfer time.