Logarithmic cost-based improved constant modulus type blind channel equalisation algorithm for M-QAM/M-PSK signal

Abstract

In this paper, authors have proposed the blind channel equalisation algorithm based on logarithmic cost function for QAM/PSK signal which is widely used in the digital communication system. Constant modulus algorithm (CMA) and modified constant modulus algorithm (MCMA), the two widely referenced algorithms for blind equalisation of a QAM/PSK signal, exhibit very slow convergence rates and large steady-state mean square error. The proposed algorithm attains faster convergence speed and low steady state mean square error by incorporating the improved logarithmic cost-based error function in the resilient back propagation-based framework. This makes the weight adaption of equaliser simple. Simulation results show that the proposed algorithm has better convergence rate and lower steady state error in comparison to CMA and MCMA algorithms.