18 / 2016-07-14 12:25:57

Performance evaluation of various Channel Equalization Techniques in terms of BER for OFDM System

intersymbol interference,equalizer,bit error rate,signal to noise ratio,matlab,mutipath,constant modulus algorithm

Orthogonal frequency division multiplexing is a type of multi-carrier transmission where all the subcarriers are orthogonal to each other. There is always a need for higher data rate and for this OFDM technique is used. At high data rates, the channel distortion to the data is very important and it is impossible to recover the transmitted data with a simple receiver. So, a complex receiver structure is needed which uses computationally expensive equalization and channel estimation algorithms to estimate the channel. These estimations can be used within the received data to recover the originally transmitted data. OFDM can simplify the equalization problem by changing the frequency-selective channel into a flat channel. The intersymbol interference (ISI) can occur in received signal due to multipath fading. In order to remove the ISI many kind of equalizers can be used. Equalizer is intend to work in such a way that Bit Error Rate (BER) should be low and Signal-to-Noise Ratio (SNR) should be high. An equalizer within a receiver compensates for the average range of expected channel amplitude and delay characteristics. This paper deals with the various equalization techniques (LMS, RLS and CMA) used for OFDM system. A comparative analysis of Bit error rate (BER) using different equalization technique along with different digital modulation is done using MATLAB Simulink. Simulation results shows that constant modulus algorithm (CMA) results in minimum value of BER which can be further used to enhance the performance of OFDM.