Channel Estimators for Full-Duplex Communication Using Orthogonal Pilot Sequences

Abstract

Full-duplex communication is desirable to maximize the spectral efficiency, despite the challenges it puts forth. The key challenge inhibiting the operation of radios in full-duplex mode is self-interference. In this paper, we propose a pilot-based channel estimation to estimate both self-interference and communication channels simultaneously at both ends of a full-duplex link using orthogonal sequences. The Cramer-Rao Lower Bound for estimators of both the channels was determined and compared with the half-duplex channel estimator. We performed simulations varying sequence length and channel taps and studied the performance of the estimators. We also studied the effect of synchronization between the sequences on the performance of the estimators. Thus, providing a solution to balance the trade-off between the accuracy of the channel estimation and the overhead added to the transmissions for full-duplex communication.

Keywords

• Channel estimation
• orthogonal m-sequences
• full-duplex (FDX)
• half-duplex (HDX)
• self-interference (SI)
• Cramer-Rao lower bound (CRLB)