A fast blind equalization algorithm for carrier recovery of underwater acoustic channel

Based on analysis of modified CMA (MCMA),a fast carrier recovery blind equalization algorithm suitable for QPSK (quaternary phase shift keying) signals is presented in this paper.A different error function from MCMA is constructed for faster convergence,which alone may be able to remove Inter-Symbol Interference (ISI) and correct the phase error and simultaneously improve the performance of convergence further.Different nonlinear transformations are implemented on the real and imaginary parts of the output signa's respectively in the proposed algorithm.Simulation tests are conducted using underwater acoustic channel data for numerical analysis and research of these algorithms.The result proves the proposed algorithm may not only correct phase rotation,but also outperform the MCMA in terms of convergence speed and residual mean squared error while both algorithms require an almost identical computational cost.