Research on Physical Layer Security of MIMO Two-way Relay System

MIMO system makes full use of the space dimension, in the era of increasingly tense spectrum resources, which greatly improves the spectrum efficiency and is one of the future communication support technologies. At the same time, considering the high cost of direct communication between the two parties in a long distance, the relay communication mode has been paid more and more attention. In relay communication network, each node connected by relay has different security levels. In order to forward the information of all nodes, the relay node has the lowest security permission level. Therefore, it is meaningful to study the physical layer security problem in MIMO two-way relay system with relay as the eavesdropper. In view of the above situation, this paper proposes the physical layer security model of MIMO two-way relay cooperative communication network, designs a communication matching grouping algorithm with low complexity and a two-step carrier allocation optimization algorithm, which improves the total security capacity of the system. At the same time, theoretical analysis and simulation verify the effectiveness of the proposed algorithm.