Physical layer security transmission technology of relay broadcasting channel

This paper investigates the secrecy performance of half-duplex relay networks. First, we establish a relay broadcasting wiretap channel model using a half-duplex relay with multiple antennas and derive the instantaneous secrecy capacity of this system. With convex optimization, the upper bound on the capacity region is provided. Second, we give the expression for the ergodic secrecy rate and analyze some factors affecting the rate. Furthermore, the locations of nodes of the system are considered, which have an great impact on transmission security. Finally, some simulation results are presented to illustrate our theoretical derivations and we also find some methods to improve the security.