Error rate of coherent modulation techniques for land mobile satellite channel

Abstract

This paper evaluates the error rate of four coherent modulation techniques namely quadrature phase shift keying (QPSK), quadrature partial response signaling (QPRS), 16-ary phase shift keying (16-ary PSK), and 16-ary quadrature amplitude modulation (16-QAM). The channel exhibits fading and shadowing as well as additive white Gaussian noise. Fading and shadowing cause both envelope and phase variations of the received signal. For QPSK, 16-ary PSK, and 16-QAM signaling schemes a raised-cosine pulse of 0.235 roll-off factor has been used. Regarding the envelop variations, the paper shows that QPRS and 16-QAM have approximately the same bit error rate performance. However, 16-QAM has a spectral efficiency twice that of QPRS. QPSK has the lowest bit error probability but it also has the lowest spectral efficiency. The 16-ary PSK has the highest bit error probability compared with the other modulation schemes. Regarding the phase variations, the performance of all techniques at high signal-to-noise ratio (SNR) becomes independent of SNR and the performance of 16-ary PSK becomes dominant.