Research On The Algorithm Of Generalized Signal Alignment On MIMO-Y Channel

With the rapid development of wireless communication, the contradiction between the increasing communication capacity and the limited spectrum resources is more and more prominent. In the case of no increase in system bandwidth and transmit power, MIMO technology can greatly improve the capacity of communication system. The problem that the signal strength decreased with the increasing transmission distance is due to the large-scale fading, and it can be overcome by radio relay technology. The MIMO radio relay technology has the advantages of MIMO and relay communication technology, which has a broad application prospect in mobile communication system.In the actual two-way relay channel, there are many users exchange information. The communication model has the MIMO-X channel model, the MIMO-Y channel model and so on. In these two channel models, combined with precoding and the physical layer network coding technology, the technology of interference alignment and signal space alignment is proposed, which can improve the multiplexing gain and improve the system efficiency.Based on the existing signal space alignment and MIMO-X channel generalized signal space alignment technology, this paper mainly studies the generalized signal space alignment technology in MIMO-Y channel.it is assumed that the number of antennas configured for the user node is M, and the number of antennas configured for relay nodes is N. To solve the problems that the needle of signal space alignment requirements on the number of users of the antennas is too high, and must meet the condition of N <2 M and generalized signal space alignment only studies 4 user algorithm realization process in MIMO-X channel, the generalized signal alignment algorithm when there are k users each sends single signal stream in the system is proposed, and thus increased the scope of the generalized signal alignment. On this basis, the situation that every user send single signal stream extended to send d independent information flow is discussed, and an algorithm is given.In this paper, the number of the users is extended from 4 to general situations, and the realization of the algorithm is proposed. On the basis of this, the independent signal flow is extended from single road to multi road. Through analysis and simulation, we prove that the generalized signal space alignment algorithm based on MIMO-Y channel presented in this paper, On the one hand, makes the number of user node's antennas increased by k,compared with high demand of it in the traditional signal space alignment technology, in which the growth of user node antennas is increased by 2k/ 4,the algorithm proposed in this paper greatly reduces the number of users antennas. On the other hand, it makes up for the defect of signal space alignment technology is unsuitable in the condition of N >2 M. In addition, the system normalized Do F and the speed of the system are improved.