Novel Pilot Design and Signal Detection for SC-FDE Systems With Frequency-Domain Pilot Multiplexing Technique

The performance of single-carrier frequency-domain equalization systems with the frequency-domain pilot multiplexing technique is affected by the level of signal distortion, which highly depends on the pilot position selection (PPS) scheme at the transmitter and the signal detection (SD) scheme at the receiver. In this letter, by exploring the relationship between distorted symbols and decision boundaries, we propose a novel PPS scheme to confine the distorted symbols within their designated decision regions, which dispenses with a priori knowledge of the channel. Based on the maximum-likelihood criterion, we also propose a novel SD scheme to avoid error propagation, which operates on a symbol-by-symbol basis. Simulation results on bit error rate show that our proposed PPS scheme achieves almost the same performance as the optimal one and our proposed SD scheme outperforms the existing one in additive white Gaussian noise channels; in addition, both proposed schemes outperform their existing counterparts in frequency-selective Rayleigh fading channels.