Özet:

The popular multicarrier modulation technique, Orthogonal Frequency Division Multiplexing (OFDM), is used for high rate wireless communication systems, as well as for other inexplicit multipath channel applications, such as powerline and underwater communications. Final performance of an OFDM system depends highly on the channel because variations in the characteristics of the channel result with a degradation in the performance. In this study, a modular OFDM system which is modeled using Matlab/Simulink program is given. The proposed model is used for performance evaluation. The variations in the performance of the OFDM system are analyzed by investigating the Bit Error Rate (BER). A comparison is made for two modulation schemes, namely phase-shift keying (M-PSK) and quadrature amplitude modulation (M-QAM), under the additive white Gaussian noise assumption. It has been shown that for a safe communication on a heavy Rayleigh channel especially, channel estimation is a necessity.

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