Simple approach for joint blind equalization and order detection suitable for QAM signal

Abstract

A blind equalization and order detection algorithm suitable for QAM signal is proposed. By exploiting the inherent structural relationship between the 4-QAM signal's coordinates and other higher-order QAM signals' coordinates, a novel cost function including channel blind equalization and signal order detection is defined. In such method, by changing the coordinates of input signals, higher-order QAM signal can be equalized by the statistics of 4-QAM and its order can be detected accurately. Examples of five modulation types - 4-QAM, 8-QAM, 16-QAM, 32-QAM and 64-QAM - are given. Simulation results show that the proposed algorithm achieves satisfactory performance.