Rate-interference trade-off between duplex modes in decode-and-forward relaying

We study the fundamental rate-interference trade-off between full-duplex and half-duplex transmission modes in a two-hop infrastructure-based decode-and-forward relay link. First, we derive closed-form expressions for average end-to-end capacities. Then, we show that it may be better to tolerate some loop interference in the full-duplex mode than to halve the end-to-end symbol rate by allocating two orthogonal time slots in the half-duplex mode. Furthermore, we evaluate the loop interference power levels below which the full-duplex mode achieves better capacity than the half-duplex mode. Our results indicate that the full-duplex mode is preferable in terms of capacity for many practical signal-to-noise ratios, e.g., above 3-10dB depending on the setup. Finally, we show that full-duplex relays can further improve the end-to-end capacity by adjusting transmit power.