Power Allocation for Balancing the Effects of Channel Estimation Error and Pilot Overhead in Full-Duplex Decode-and-Forward Relaying

Abstract

This paper considers the transmit power balancing trade-off between the pilot and data signals in a two-hop full-duplex decode-and-forward relay link when the feedforward data channels are Rayleigh fading and the residual feedback self-interference channel follows Rician fading. The study concentrates on time-multiplexed orthogonal pilot sequences since simultaneously transmitted orthogonal pilots are disadvantageous for full-duplex relaying with self-interference. Average end-to-end achievable rate bounds are first formulated. Then the power allocation problem that can be solved only numerically in the general case is characterized. Finally, a simple suboptimal algorithm for power allocation is proposed. The numerical results illustrate that that the proposed simple algorithm provides near optimal performance over a wide range of scenarios. The benefit of optimizing the power allocation is apparent across the range of values considered and improves the achievable rate up to one bit per channel use compared to naive allocation schemes.