08-16-2017, 09:45 PM
Orthogonal Frequency Division Multiplexing (OFDM)
ABSTRACT
Orthogonal Frequency Division Multiplexing (OFDM) has recently gained a lot of attention and is a promising candidate for future wireless multimedia communications due to it is resistive to frequency-selective fading and its flexibility for handling multiple data rates for Fourth Generation (4G) wireless systems also it promises data rates up to 10Mbps. A variation of OFDM is Multi-Carrier CDMA (MC-CDMA), in which an OFDM technique and CDMA technique are combined, where the individual data symbols are spread using a spreading code in the frequency domain. MC-CDMA provides multiple access technique as well as interference suppression and also good spectral efficiency. In MC-CDMA spreading of the information is not in the time domain as in the Direct Sequence CDMA technique but in the frequency domain. Performance of MC-CDMA is limited by self-interference (SI) and multi user interference (MUI).
In this thesis OFDM and MC-CDMA model is developed and based on that, BER performance is simulated for various channels like AWGN and Rayleigh, for different number of user , sub carriers and SNR in MATLAB . The goal of the simulations was to allow for different MC-CDMA configurations to be tested in order to obtain the best system parameters. GUI and Simulink model is also developed in MATLAB.