Comparison of Bit Error Rate Performance of Multi Tone Channel Utilising De-OQPSK and De-Off Set 16 QAM with Guard Interval

Abstract

Digital communications systems use Multi tone Channel (MC) transmission techniques with differentially encoded and differentially coherent demodulation. Today there are two principle MC application, one is for the high speed digital subscriber loop and the other is for the broadcasting of digital audio and video signals. In this study the comparison of multi carriers with OQPSK and Offset 16 QAM for high-bit rate wireless applications are considered. The comparison of Bit Error Rate (BER) performance of Multi tone Channel (MC) with offset quadrature amplitude modulation (Offset 16 QAM) and offset quadrature phase shift keying modulation (OQPSK) with guard interval in a fading environment is considered via the use of Monte Carlo simulation methods. BER results are presented for Offset 16 QAM using guard interval to immune the multi path delay for frequency Rayleigh fading channels and for two-path fading channels in the presence of Additive White Gaussian Noise (AWGN). The BER results are presented for Multi tone Channel (MC) with differentially Encoded offset 16 Quadrature Amplitude Modulation (offset 16 QAM) and MC with differentially Encoded offset quadrature phase shift keying modulation (OQPSK) using guard interval for frequency flat Rician channel in the presence of Additive White Gaussian Noise (AWGN). The performance of multitone systems is also compared with equivalent differentially Encoded offset quadrature amplitude modulation (Offset 16 QAM) and differentially Encoded offset quadrature phase shift keying modulation (OQPSK)with and without guard interval in the same fading environment.