PCMA: parametric constant modulus algorithm for demodulating co-channel FM signals

Abstract

We propose a new approach called parametric constant modulus algorithm (PCMA) for demodulating two co-channel signals, each of which are frequency modulated. The algorithm is of interest in cellular communications and military/intelligence applications. Our method is based on minimizing a constant-modulus error (CME) criterion. It as different from the well-known constant modulus algorithm (CMA). Firstly, the CMA is traditionally employed for channel equalization problems. Secondly, the CMA minimizes the CME over the parameters of a transversal filter. On the other hand, our procedure extends the CMA concept to the co-channel signal separation problem: it uses a parametric model for the underlying signals and minimizes the CME over the parameters of the signal model, hence the name parametric CMA (PCMA).