Multicast Transmissions With Full-Duplex Amplify-and-Forward User Cooperation

In order to improve the multicast transmissions, a full-duplex (FD) user cooperation scheme is proposed. In this paper, the transmitter sends the common messages to two FD users, and each user forwards its received signals to its counterpart by amplify-and-forward (AF) scheme. Considering the imperfect self-interference (SI) cancellation at the users and the AF scheme, the residual self-interference and the additive noise (RIAN) is shown to be accumulated over time. This paper first analyzes the equivalent channel model of the considered system, as well as the asymptotic statistics of the accumulated RIAN. Then, with the forward and backward decoding schemes, the corresponding achievable rates are derived, and the optimal power allocation is obtained via solving a max-min problem. In particular, one-side cooperation scheme (i.e., only one user forwards its received signal to its counterpart) is shown to be optimal to achieve the best system performance.