Matched Filter Detectors for Next Generation Mobile Radio Channels

Matched filter is a linear filter which is designed to provide the maximum signal to noise power ratio at its output for a given transmitted symbol waveform. When the ISI is not present in the received signal, the detection based on the matched filter is an optimum detection process in the sense that it minimizes the probability of error at the front end of the receiver. This paper deals with the high speed data transmission techniques for new wireless and mobile systems. In particular, it looks at some of the signal processing techniques that are to be carried out in the receiver of such systems, because the mobile radio channels are characterized by frequency selective fast fading. Thus, the signal transmission performance is severely degraded because of such factors. Specifically, this paper deals with the detection using a matched filter followed by near maximum likelihood detector (NMLD) for the application of mobile radio environments. NMLD and its complexity depend on length and the numbers of stored vector. So, it is important to choose optimum NMLD, here we choose in this research four stored vectors while the length of the stored vector is of eight symbols length which is sometimes called as delay in detection. The performance of the detector is plotted in terms of bit error rate (BER) versus signal to noise ratio (SNR). Various cases of the matched filter based detector are studied in this paper. All the results obtained by this work are based on the channel with four independent fading paths. The channels used in this paper are generated and tested successfully before using them for the study of the detector. Channel used for this study is generated for the outdoor vehicular environment with the Doppler spread 100 Hz and with the delay spread nearly 14 microseconds.