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A Dual-mode Blind Equalization Algorithm for Improving the Channel Equalized Performance

Jing Zhang, Zhihui Ye, and Qi Feng
School of Electronic Science and Engineering, Nanjing University, Nanjing 210023, China
Abstract—In this paper, we propose a new dual-mode blind equalization algorithm to improve the channel equalization performance. First, a kind of new error function is proposed and a nonlinear function between the step-size factor and the new error function is built to realize the variable step-size constant modulus algorithm (CMA). Then, in order to optimize the channel equalization performance, the variable step-size CMA is combined with decision directed least mean square (DDLMS) algorithm to form the new dual-mode algorithm. The new dual-mode algorithm uses either switching-dual mode or weighted dual-mode to update the coefficient of blind decision feedback equalizer. The simulation results show that in the situation of Gaussian white noise with 30dB signal-to-noise ratio, the proposed algorithm reduces the steady-state error to -12dB and drops inter symbol interference to -31dB in the condition of satellite channel. The new dual-mode algorithm not only increases the rate of convergence but also reduces the steady-state error. The proposed algorithm can be widely used in different communication channels such as the satellite channel.

Index Terms—Blind equalization; constant modulus algorithm; variable step-size; decision directed least mean square.

Cite: Jing Zhang, Zhihui Ye, and Qi Feng, "A Dual-mode Blind Equalization Algorithm for Improving the Channel Equalized Performance," Journal of Communications, vol. 9, no. 5, pp. 433-440, 2014. Doi: 10.12720/jcm.9.5.433-440
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