Justifications of link adaptability of OFDM modulation scheme for different channel environment

Abstract

In this paper, performance analysis and the effectiveness of Orthogonal Frequency Division Multiplexing (OFDM) for different channels environment has been analyzed and investigated. In order to accomplish these tasks, an OFDM system model has been considered where a random bit sequence is generated and subsequently converted into decimal value depending on the word size of the system. In order to simulate the system, the power delay profile of different wireless channels, numbers of carriers, window type, and symbol duration have been chosen as simulation parameters. The whole system has been analyzed by modeling a transmission-reception OFDM wireless system using MATLAB code for four different channels i.e. urban, rural, terrain and rician channel. Factors that affect the performance of an OFDM system such as multipath delay spread, channel noise, distortion of the signal (clipping), and timing requirements have also been measured. Our study reveals that, for each channel the system must satisfied the conditions of flat fading. It has been realized that for total symbol duration of 80 microseconds to 148 microseconds, the whole system gives a satisfactory result for terrain channel. In these range of symbol duration, the performance seems to be at least 120 microseconds of length.