Key Generation Rate in the Full Duplex Relay Wireless Communication Network

Secret key agreement from reciprocal wireless channels has been the hot spot of research which focus on the security at physical layer. In future 5G systems, full-duplex (FD) communication will be one of the key technologies, whose one ability should be security. However, most key agreement models are the half duplex (HD). Due to the FD wireless transmission merit, transmitting simultaneously receives the signal from the other. Therefore, in this paper, we investigate the key generation problem in the FD relay channel, in which there is no direct channel between the key generation terminals. We propose an effective key generation scheme that achieves a substantially larger key rate than that of HD situation. It turns out that, for the application of key agreement, the FD approach enables advantages over the conventional HD setups with less self-interference (SI), but enable advantages under a certain SNR regime while lost the advantages in the high SNR regime and has an upper bound due to the non-negligible SI. Meanwhile, key rate in FD relay network lost its advantage when SI is higher.