Değişen eşitleştirici parametrelerinin çoklu radyo yanma kanalı üzerindeki etkilerinin performans çalışması

The basic form of a digital communication system consists of three major components; a transmitter, channel, and receiver connected somehow together in cascade. The transmitter maps a message signal generated by a digital source into an electrical waveform suitable for transmission over the channel, the channel, which might be either a physical structure or space, suffers from two major kinds of impairments; intersymbol interference and noise. The combined effects of these two impairments are the introduction of noise and distortions to the transmitted signal at the channel output. In order to reduce the effects of these distortions an equalizer is used at the receiver end. The main role of the equalizer is to reconstruct the transmitted symbols by observing the received noisy signal. The adaptive equalizers using a least mean square (LMS) and the recursive least-squares (RLS) algorithms are investigated in this work for wireless communication systems. Both linear transversal equalizer and non-linear decision feedback equalizer (DFE) with LMS and RLS algorithms are implemented in a simplified communication system model operating over a multipath fading channel model. The impact of some influential parameters, such as the number of taps of the adaptive equalizers and the number of significant paths in a multipath fading channel were investigated using Simulink software package. The Simulink simulation program was used to implement LMS and RLS Algorithms in the simplified simulated communication system which calculates the bit error rates versus SNR. Quantitative Results obtained were presented in graphs. These graphs clearly illustrate the absence of a definite relationship between the number of multipath in the channel and the length of the equalizer being implemented. This finding is clearly reflected by the performance of the communication system in terms of bit error rate.