Distributed Maximum Likelihood Classification of Linear Modulations Over Nonidentical Flat Block-Fading Gaussian Channels

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DÜLEK B. , Özdemir O., Varshney P. K. , Su W.

IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS, cilt.14, sa.2, ss.724-737, 2015 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 14 Konu: 2
  • Basım Tarihi: 2015
  • Doi Numarası: 10.1109/twc.2014.2359019
  • Sayfa Sayıları: ss.724-737


In this paper, we consider distributed maximum likelihood (ML) classification of digital amplitude-phase modulated signals using multiple sensors that observe the same sequence of unknown symbol transmissions over nonidentical flat block-fading Gaussian noise channels. A variant of the expectation-maximization (EM) algorithm is employed to obtain the ML estimates of the unknown channel parameters and compute the global log-likelihood of the observations received by all the sensors in a distributed manner by means of an average consensus filter. This procedure is repeated for all candidate modulation formats in the reference library, and a classification decision, which is available at any of the sensors in the network, is declared in favor of the modulation with the highest log-likelihood score. The proposed scheme improves the classification accuracy by exploiting the signal-to-noise ratio (SNR) diversity in the network while restricting the communication to a small neighborhood of each sensor. Numerical examples show that the proposed distributed EM-based classifier can achieve the same classification performance as that of a centralized classifier, which has all the sensor measurements, for a wide range of SNR values.