Complex Baseband Myriad Filtering and Maximum Likelihood MSK Demodulation under Symmetric Alpha-Stable Noise

Abstract

Symmetric α-stable (SαS) distribution noise is widely used to model co-channel and network interference in wireless communication systems. As robust and adaptive techniques, myriad filtering (MyF) and spherically symmetric vector MyF have been applied to suppress univariate and spherically symmetric multivariate SαS distribution noise, respectively. At a communication receiver, the received band-pass noisy signals are usually down-converted to complex baseband, and the resulted complex baseband SαS noise has been demonstrated not to be circularly symmetric. In this paper, we proposed a complex baseband MyF (CBMyF) to suppress the non- circularly symmetric complex baseband SαS noise. Besides, there are few researches with respect to the demodulation of memory modulation signals, e.g., minimum shift keying (MSK) signal, under SαS noise. Thus, based on CBMyF, we proposed coherent and non-coherent MSK demodulation algorithms under SαS noise in this paper. Furthermore, maximum likelihood (ML) MSK demodulation under SαS noise also been proposed. Simulation results show that the bit error rate (BER) performance of the proposed CBMyF based MSK demodulation can closely approach that of ML demodulation. Meanwhile, the proposed CBMyF is compared with the common used clipper, and the results validate its advantage of robustness and adaptivity.