Robust Multiuser Automatic Modulation Classifier for Multipath Fading Channels

Automatic Modulation Classifier (AMC) is an important component of a Cognitive Radio (CR) architecture that helps in better utilization of the spectrum. AMC in literature is mostly developed for classifying the signal transmitted by a single user. Multiuser AMC, as the name suggests, simultaneously classifies signals transmitted by multiple users. In this paper we propose a fourth order cumulant based multiuser AMC that can perform well even in a multipath fading environment. A recursive blind multiuser channel estimation algorithm, which forms an integral part of the multiuser AMC, is also proposed. Simulation results are provided to illustrate the promising results yielded by the proposed algorithm.