Abstract: Traditional dual-mode blind equalization algorithm is based on constant modulus channel equalization, its convergence is slow, and it has a low efficiency of bandwidth. For overcoming its shortcoming, two blind equalization algorithms suitable for high-order QAM signals were proposed. These are double mode multi-module equalization algorithm (DMMA) and semi-blind equalization algorithm (SBEA). DMMA used multi-module equalization algorithm as first mode and multi-module assistant equalization algorithm as second mode, both modes simultaneously equalized the signal. For achieving a fastest convergence and lowest error rate, DMMA's result was regard as the pilot data for least mean square algorithm (LMS), which is called SBEA. Simulation results show that the two algorithms have a superior performance by increasing the convergence rate and decreasing the steady mean square error.

Key words: multi-module algorithm, adaptive algorithm, double mode multi-module algorithm, semi-blind equalization algorithm