BER Performance of OFDM Using Differentially Encoded 16-Star QAM in AWGN Rician Fading Channels

摘要

The multicarrier transmission technique known as Orthogonal Frequency Division Multiplexing (OFDM) is well established for voiceband data transmission. Today there are two principle OFDM applications, one is for the high speed digital subscriber loop and the other is for the broadcasting of digital audio and video signals. In this paper the use of OFDM for high-bit rate wireless applications is considered. In order to improve spectral efficiency, 16 star quadrature amplitude modulation (QAM) is deployed to modulate the parallel carriers in place of the usual quadrature phase shift keying (QPSK). This research investigates the bit error rate (BER) performance of OFDM utilising differentially encoded (DE) 16 star QAM and differentially coherent demodulation in frequency flat and two-path fading channels via Monte Carlo simulation. The BER performance of OFDM is also compared with equivalent single carrier systems.