Multi parameter trade-off of full duplex SWIPT bidirectional DF relay system for D2D Communications

The full duplex simultaneous wireless information and power transfer bidirectional DF relay communication system in device-to-device (D2D) scenario is developed on the basis of bidirectional DF relay communication system. Relay nodes transmit information and transmit energy at the same time. Considering the self-interference of full duplex and transmission threshold, this paper constructs a product trade-off function which can flexibly conFigure the proportion of information transmission and energy transmission. Through a series of simplification and calculation, the equivalent optimization problem of the above product trade-off function optimization problem is obtained, and the one variable multiple equation of the power distribution variable is obtained through the KKT condition simultaneous equations. So the product trade-off function optimization problem can be solved by Newton method, dichotomy method and other one-dimensional search methods. The experimental results show that the optimal value of z-max of product trade-off function optimization problem can be obtained through one-dimensional search in both symmetric and asymmetric channels. In symmetric channel, the solution of the equation $P_{R}$=0.28 is brought into the expression of product trade-off function to obtain the maximum value of 0.2463, which is the same as the simulation result. Similarly, the same maximum value can be obtained in asymmetric channel.