Wireless Relay Transmission Performance Based On Hybird Network Coding

In the wireless transmission network,the data needs a certain relay node to transmit,since the physical distance between the sending node and the receiving node is too far away or the channel fading is particularly serious,thereby the relay node could expand the scope of data transmission.Until now,the academic community has been exploring relay forwarding methods that maximize relay channel interaction information,and network coding has also been born.The emergence of network coding has brought revolutionary influence to the development of modern communication technologies.The most significant contribution is to improve the throughput of data transmission in wired communication networks.The proposal of the physical layer network coding in the field of wireless communication further reduces the time for data transmission,and it has further improved the throughput compared to the traditional network coding scheme.This paper takes the fusion between traditional network coding and physical-layer network coding as research points,constructing a coding model of hybrid network coding based on Y-type relay network,moreover expanding the Y-type relay network for communication scenarios.A hybrid network-encoded relay transmission mechanism is designed based on the extended Y-type relay network model.In the extended Y-relay network scenario,when the source node sends data packets to the destination node,While the destination node does not have data packets to the source node at this time,the physical layer network coding will be attenuated into the traditional relay storage-forwarding situation.In order to solve this problem,a hybrid network coding method is introduced.When the physical layer network coding fails,the relay node can use conventional network coding for data transmission.By using the method of Markov State Transition Probability Analysis,the storage-and-forward scheme,the traditional network coding scheme,the physical layer network coding scheme and the throughput expression in the hybrid network coding scheme under the extended Y-type relay network scenario are deduced.,and the necessary and sufficient conditions to make sure the relay nodes not saturated in each scheme have been given.Through the simulation results and analysis,it is proved that in the extended Y-type relay scenario,the maximum gain of the hybrid network coding scheme can reach 123.3%,163.7% and 188.6% respectively compared with the PNC scheme,the HNC scheme and the NNC scheme.In addition,we also found that in the hybrid network coding scheme,when the probability of physical layer network coding is relatively small,the relay node transmission probability should not be too large,which affects the probability of high-level network coding.The maximum network throughput performance also decreases as the number of client nodes per group increases.