1st International ICST Conference on Communication System Software and MiddleWare

Research Article

Blind Adaptive Recognition of Different QPSK Modulated Signals for Software Defined Radio Applications

  • @INPROCEEDINGS{10.1109/COMSWA.2006.1665163,
        author={M. Vastram  Naik and  R.  Bhattacharjee and A. Mahanta and B.  Nemade},
        title={Blind Adaptive Recognition of Different QPSK Modulated Signals for Software Defined Radio Applications},
        proceedings={1st International ICST Conference on Communication System Software and MiddleWare},
        publisher={IEEE},
        proceedings_a={COMSWARE},
        year={2006},
        month={8},
        keywords={},
        doi={10.1109/COMSWA.2006.1665163}
    }
    
  • M. Vastram Naik
    R. Bhattacharjee
    A. Mahanta
    B. Nemade
    Year: 2006
    Blind Adaptive Recognition of Different QPSK Modulated Signals for Software Defined Radio Applications
    COMSWARE
    IEEE
    DOI: 10.1109/COMSWA.2006.1665163
M. Vastram Naik1,2,*, R. Bhattacharjee1,2,*, A. Mahanta1,2,*, B. Nemade1,2,*
  • 1: Department of Electronics and Communication Engineering,
  • 2: Indian Institute of Technology Guwahati, Guwahati, India
*Contact email: vastram@iitg.ernet.in, ratnajit@iitg.ernet.in, anilm@iitg.ernet.in, harshal@iitg.ernet.in

Abstract

This paper addresses the issue of recognizing and distinguishing among QPSK modulated signal variants such as QPSK, OQPSK and pi/4-DQPSK, from the samples of received noisy and faded PSK signal. The proposed algorithm is based on computation of relative Euclidean distance and relative phase difference among the received symbols in a frame. Constant modulus (CM) equalization is performed prior to recognition. Simulation results show that proposed method can perform recognition task with high accuracy even at low signal to noise ratio (SNR) values and employing reasonably small number of data samples. To the best of our knowledge any method for distinguishing among QPSK variants has not been reported in literature