Two Blind Adaptive Equalizers Connected in Series for Equalization Performance Improvement

Monika Pinchas^{*}

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A variable step-size parameter is usually used to accelerate the convergence speed of a blind adaptive equalizer with *N*_{1} + *N*_{2} －1 coefficients where *N*_{1} and *N*_{2} are odd values. In this paper we show that improved equalization performance is achieved when using two blind adaptive equalizers connected in series where the first and second blind adaptive equalizer have *N*_{1} and *N*_{2} coefficients respectively compared with the case where a single blind adaptive equalizer is applied with *N*_{1} + *N*_{2} －1 coefficients. It should be pointed out that the same algorithm (cost function) is used for updating the filter taps for the different equalizers and that a fixed step-size parameter is used. Simulation results show that for the low signal to noise ratio (SNR) environment and for the case where the convergence speed is slow due to the channel characteristics, the new method has a faster convergence speed with a factor of approximately two while leaving the system with approximately the same or lower residual intersymbol interference (ISI).

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