Research On Signal Transmission Algorithm In K-users MIMO-Y Two-way Relay Channel

In recent years, the technology of physical-layer network coding (PNC) and multiple in multiple out(MIMO) have been widely studied owing to their good performances. Physical-layer network coding is a kind of technology that apply the idea of network coding in cable network to wireless network.It makes the relays that simply forward packets in traditional wireless network be able to do some intelligent processing the received packets.such as combination and encoding.To some extent,it can solve the interference problem between the nodes in wireless network, increase the throughout of the network, save the radio frequency resouces and improve the security of iinformation. Multiple in multiple out technology combines the advantages of traditional diversity technology and multiplexing technology.It makes use of the space degree of freedom provided by multiple transmitting antennas and multiple receiving antennas and:can improve the spectrum efficiency and data transmitting rate of the communication system.k-users MIMO-Y channelsconsist of k users and one relay,in which all the users are equipped with Nt antennas and the relay is equipped with Nr antennas and every two users exchange information with each other via the relay.Each user receive messages from all other users while trasnsmit messages to all other users. It costs two timeslots, respectively called MAC phase and BC phase. Aim to exchange informations between every two users using physical-layer network coding in k-users MIMO-Y channels, We research the SSA-SSA scheme which make use of the signal space align(SSA) algorithm in both MAC phase and BC phase, and the GSA-GSA scheme which make use of the general signal align(SSA) algorithm in both MAC phase and BC phase.The former needs to satisfy the condition Nr<2Nt,while the latter needs to satisfy the condition Nr>(k-2)Nt.So in some extent, the two schemes can be regarded as a complement to each other.In this paper,the implementation algorithm of the SSA-SSA scheme and the GSA-GSA scheme is introduced in detail.The complexity and sum rate of the system also are theoretically analyzed.At last,a simulation of the GSA-GSA scheme and SSA-SSA scheme which reflects the system sum rate varies with SNR is made to compare with the SSA-INB scheme. The SNR has a scale of 0 to 50. It implies that under the same system DoF and SNR, the performance of the GSA-GSA scheme and the SSA-SSA scheme is better than the SSA-INB scheme,and the GSA-GSA scheme is better than the SSA-SSA scheme.