Research On High-efficient Transmission Scheme Of Ultra Dense Network Based On Relay Coordination

With the continuous development of communication technologies,people are increasingly demanding data traffic.The 5G network will have a 1000-fold increase in traffic.The ultra-dense network has become one of the key technologies for improving data traffic.In order to improve the transmission performance of ultra-dense networks,this dissertation conducts in-depth research on the topic of "Research on Ultra-Dense and High-Efficiency Transmission Schemes Based on Relay Coordination".The research content concerns the efficient transmission protocol design of D2 D communication in ultra-dense networks,based on layered Super-dense network throughput enhancement method for skipping physical layer network coding and cooperative transmission scheme and performance analysis for ultra-dense network.The specific research content and main work are as follows:Focused on the requirement of Gigabit level throughput of 5G networks,two typical backhaul solutions in ultra-dense networks architectures are studied.On the basis of the distributed network architecture,a transmission protocol design for device-to-device communication in ultra-dense networks is proposed,and interdevices can communicate directly through multi-hop relay without macro base stations to forward.According to the millimeter wave coverage characteristics of adaptive bandwidth of D2 D communication,adaptive bandwidth and millimeter-wave dynamic bandwidth improvement mechanism are proposed.Simulation and analysis results show that compared with the traditional communication scheme,the proposed scheme reduces the bit error rate of the network,promotes the system throughput and improves the energy efficiency of communication channel effectivelyAiming at the problem of inter-cell interference caused by intensive deployment and the problem of signal fading caused by shrinkage of base station coverage area in ultra-dense networks,in order to meet the "capacity" and "coverage" requirements of dense networks at the same time,a throughput enhancement method based on hierarchical multi-hop physical layer network coding is proposed.By using the heterogeneous hierarchical feature of multi-node and combining with the high spectral efficiency characteristics of multi-hop physical layer network coding,the throughput in ultra-dense network can be enhanced effectively,the time slot from source node to the terminal node can be saved and interference of the system can be reduce without the need for the direct link from source node to terminal node in the case.The validity and correctness of the proposed scheme were verified,and the system performance effectively was improved compared with the traditional scheme.In view of the scenario of cooperative transmission where the terminal has no interference and the terminal has aggregated interference in ultra-dense network,the performance of the user's end when the physical location of the base station obeys the Poisson point distribution is analyzed.The maximum ratio combining transmission scheme using multiple cooperative relays orthogonal transmission is used to analyze the outage probability of the combined signal at the receiving end in the absence of interference of the terminal and the average bit error rate of the network coding transmission scheme without the cooperative relay selection.Considering that the terminal is subject to aggregation interference,the probability density function of the signal to interference and noise ratio of the terminal under aggregation interference is derived,and the closed expression of the terminal capacity under co-channel interference is obtained.The correctness of the theoretical result is verified through simulation.