PERFORMANCE STUDY OF FOUR EQUALIZATION TECHNIQUES OVER A WIRELESS COMMUNICATION CHANNEL

Abstract

Abstract. Equalization techniques are commonly used in low to moderate data transmission over time varying wireless mobile channels. Their use is mainly to alleviate the detrimental effect of intersymbol interference brought about by the multipath phenomena of such channels. The wireless multipath channel is time varying which makes the use of adaptive equalization a necessity to cope with channel variations and consequently to overcome resulting intersymbol interference effects, restore the transmitted symbols, and extract the information being sent. The first part of this paper presents a comparison study of the performances of four representative methods of adaptive equalization. Linear and nonlinear structures each with both LMS and RLS adaptation algorithms are used in the investigation. In the second part of the paper, a computer simulation is carried out to investigate the relationship between the number of propagation paths of the wireless mobile channel and the number of taps in the incorporated adaptive equalizer. Four equalizer structures are used in this investigation which is based on Simulink software package to simulate a communication system incorporating these equalizers. The bit error rate (BER) performance is used as a measure for establishing this dependency.

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Keywords

• intersymbol interference(ISI); LMS and RLS algorithms; linear equalizers,decision feedback equalizers

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