Switching point between full-duplex and half-duplex in cluster-based multicast relaying

This paper provides multicast outage probabilities in cluster-based mulitcast relaying networks with a full-duplex self-interference cancelation system and a half-duplex transmit beamforming system, respectively. In the full-duplex system, the source cluster head (CH) and the destination CH transmit the multicast signal in the same time slot, which causes the destination CH to suffer from self-interference. The self-interference is overcome by using an interference cancelation weight at the destination CH. In the half-duplex system, the source CH and the destination CH transmit the signal in different time slots. Each terminal in the destination cluster receives both of the signals from the source CH and the destination CH. Due to the tradeoff between the spectral efficiency and the interference caused by the full-duplex system, the outage probability of the full-duplex system finally becomes greater than that of the half-duplex system as the transmit SNR increases. We have provided a switching point of operation between the full- and half-duplex systems by an asymptotic analysis, which just has 3 dB error compared with an exact one obtained by a numerical method.