Reduced-Rank Detection for Hybrid Direct-Sequence Time-Hopping UWB Systems in Nakagami-M Fading Channels

This paper investigates and compares the performance of hybrid Direct-Sequence Time-Hopping (DS-TH) Ultra-Wide Bandwidth (UWB) systems using full-rank and various reduced-rank detections when Minimum Mean-Square Error (MMSE) principles are applied, while communicating over Nakagami-m fading channels. In addition to the fullrank MMSE detection, three classes of reduced-rank MMSE techniques are investigated, which are derived based on the principles of Principal Components (PC), Cross-Spectral Metric (CSM) and Taylor Polynomial Approximation (TPA), respectively. The authors' study and simulation results show that the reduced-rank techniques constitute a family of promising detection techniques for UWB systems, which are capable of achieving similar Bit Error Rate (BER) performance as the full-rank detection, while with a detection complexity that is significantly lower than that of the full-rank detection.