It was found that OFDM performs extremely well compared with CDMA, providing a very high tolerance to multipath delay spread, peak power clipping, and channel noise.
In addition to this it provides a high spectral efficiency.
This tolerance to clipping reduces the dynamic range overhead required in output stages of OFDM transmitters.
The noise performance of OFDM was found to depend solely on the modulation technique used for modulating each carrier of the signal.
The performance of the OFDM signal was found to be the same as for a single carrier system, using the same modulation technique.
The minimum signal to noise ratio (SNR) required for BPSK was ~7 d B, where as it was ~12 d B for QPSK and ~25 d B for 16PSK.
This thesis investigates the effectiveness of Orthogonal Frequency Division Multiplexing (OFDM) as a modulation technique for wireless radio applications.
The main aim was to assess the suitability of OFDM as a modulation technique for a fixed wireless phone system for rural areas of Australia.
In a typical system a delay spread of up to 100 msec could be tolerated, corresponding to multipath reflections of 30 km.
The only problem caused by multipath is frequency selective fading, which can result in carriers being heavily attenuated due to destructive interference at the receiver.