Sub-optimal initialization for blind equalization with fast convergence in OFDM/OQAM modulation

Abstract

This paper deals with blind equalization in orthogonal frequency division multiplexing/offset quadrature amplitude modulation (OFDM/OQAM) systems. Blind equalization is an interesting solution with regard to the spectral efficiency since no pilot is used for the signal recovering, but blind iterative algorithms suffer from a large convergence speed toward the steady-state. An initialization strategy using features of the OFDM/OQAM modulation scheme is proposed in order to improve the convergence speed of the blind equalizer. It is shown that no optimal solution can be found in the complex field, but a sub-optimal initialization value can be derived in the real subset. Simulations results show that a gain of thousands of iterations is achieved by the proposed initialization method compared with the technique that consists of setting the same initialized value for all subcarriers.