Iterative frequency domain equalization for DQPSK signals

Abstract

Differentially encoded quadrature phase shift keying (DQPSK) modulation has worse bit error rate than coherent QPSK but on the other hand DQPSK is more robust to carrier frequency offset (CFO) offering a solution to the problem presented by the presence of CFO in wireless communication systems based on block transmission. Iterative block decision feedback equalization (IB-DFE) with CFO estimator proved to be a valid receiver structure for single carrier frequency domain equalization (SC-FDE) combined with QPSK modulations. In this paper we test the natural extension of the IB-DFE receiver for SC-FDE combined with DQPSK modulations in the presence of CFO.