Relay Power Control for In-Band Full-Duplex Decode-and-Forward Relay Networks Over Static and Time-Varying Channels

This article considers a one-way full-duplex decode-and-forward relay network consisting of a source, a relay, and a destination. Due to the self-interference (SI) channel estimation error at the relay, SI cannot be completely canceled. In the presence of the residual SI, there is a tradeoff between the achievable rate of the relay-destination link in a given time slot and that of the source-relay link in the next time slot depending on the relay transmit power in that time slot. As the relay transmit power increases, the achievable rate from the relay to destination increases, whereas the achievable rate from the source to the relay in the next time slot decreases. Motivated by this observation, relay power control schemes for maximizing achievable rates over static and time-varying channels are proposed in this article. Next, a closed-form expression for the relay transmit power in each time slot is derived. Numerical results show that the proposed relay power control schemes outperform the conventional maximum power transmission scheme in terms of achievable rates.