Dual-mode Multi-modulus Blind Equalization Algorithm for High-order QAM Signals
Yanping Zhang · 2008
In order to overcome the slow convergence rate and large state error of the CMA, based on the high utilization efficiency of QAM signal to the limited bandwidth channel and the feature of high-order QAM signals with different modulus, a Dual-Mode Multi-modulus blind equalization Algorithm (DMMA) for high-order QAM signals was proposed. This proposed algorithm used the CMA as the first mode whereas it employed the Multi-Modulus Algorithm (MMA) as the second mode, which could equalize for the higher order QAM signals with the different modulus. Furthermore, in the DMMA, the two modes operated concurrently, and in second mode, based on the decision of the equalizer’s output, the iteration process of the MMA alternated automatically among different modulus. The efficiency of the DMMA was proved by computer simulations in underwater acoustic channels.