Research On Interference Control Technologies Of Device-to-Device Communications Underlaying Full-duplex Cellular Networks

With the rapid growth of the number of wireless intelligent devices and the emergence of new Internet applications,the lack of spectrum resources has become a challenge for the new generation of wireless communication systems.The full duplex and Device-to-Device(D2D)can effectively improve the spectrum efficiency of cellular communication system,and the interference scenarios of the system become more complex.Therefore,to research on efficient interference control algorithm is useful to reduce system interference and improve the spectral efficiency.This thesis focuses on the interference scenario of the full duplex D2D communication underlaying cellular network,and carries out the research of interference control algorithm.The main work includes the following two aspects:Firstly,aiming at the one-to-one multiplexing communication system model of full duplex D2D link and cellular link,we propose interference control algorithms based on power allocation to maximize the D2D link rate under the constraint of ensuring cellular transmission.Because the objective function is a nonconvex problem,through the transformation of constraints,the objective function can be transformed into the structure of the difference of convex functions,and the difference part is linearized by the first-order Taylor expansion,the nonconvex objective function can be transformed into a convex function,and the iterative algorithm is used to solve the power problem.Another solution is to use an approximate algorithm of the high signal-to-noise ratio transmission characteristics of D2D communication,and solve the power problem of the corresponding objective function according to different power feasible regions.The results show that these two schemes can both improve the sum rate of D2D link.Secondly,for the full duplex relay assisted D2D underlaying cellular communication system,an interference control strategy considering power allocation and mode selection is proposed for four D2D working modes:full-duplex mode,half-duplex mode,Relay-assisted full-duplex mode,and Relay-assisted half-duplex mode.Under the requirement of guaranteeing the rate of cellular and D2D links,power optimization problems under different modes are constructed with the goal of maximizing the link and rate between D2D users,then the power and D2D link and rate of corresponding modes are solved by iterative and one-dimensional search algorithm respectively according to the type of objective function.To determine the optimal working mode and the corresponding equipment power.The results show that in different channel states,higher rate of D2D link can be obtained through mode selection.In conclusion,the proposed interference control algorithm for full duplex D2D communication underlaying cellular network can effectively improve the communication performance transmission rate of D2D link under the constraints of guaranteed cellular communication requirements.It provides technical support for the application of full duplex technology in cellular D2D system.