Performance Investigation of Angle Differential-QAM Scheme in High Mobility Environments

Abstract

Angle differential quadrature amplitude modulation (ADQAM) is a high spectral efficiency modulation scheme which can be non-coherently demodulated without any channel state information. In this paper, we investigated the performance of ADQAM in high mobility environments where the channel varied rapidly. A comparison has been made among ADQAM, QAM and differential amplitude and phase shift keying (DAPSK) scheme in terms of bit error ratio through numerical simulations. The results showed that ADQAM outperformed DAPSK and QAM significantly in the time rapidly varying channel at high signal noise ratio, while QAM with channel estimation only had 1dB advantage over ADQAM in the time invariant channel. ADQAM was more robust to Doppler shift than DAPSK and QAM. We suggested that ADQAM scheme was more suitable for communication systems in high mobility environments.