DSP implementation and blind equalization algorithms based on coordinate transformation

According to large misjudgment for making equalization to higher order Quadrature Amplitude (16QAM) signals by Constant Modulus Algorithm (CMA), the paper analyzes the character of 16 QAM signals constellation, proposes blind equalization algorithms based on coordinate transformation. In the proposed algorithm, output signal of equalizer is made coordinate transformation, the error function of Constant Modulus Algorithm (CMA) is improved, which will become exactly zero when the channel is perfectly equalized. Simulation results with an underwater acoustic channel model illustrate the effectiveness of proposed algorithm, and parameters of algorithm are obtained. On the basis of fast operation speed and high data processing ability of digital signal processor chip TMS320VC5502, algorithm code is compiled with C language and obtained parameters in integrated development environment (CCS). The algorithm is realized by debugging in DSP. Besides, a good result is achieved. It has certain reference value in designing equalizer of 16QAM communication system.