A quasi-constant envelope quadrature overlapped modulation and its performance over non-linear band limited satellite channels

Abstract

A new quadrature-overlapped modulation (QOTRC modulation) with a quasi-constant envelope is proposed in this paper. The new modulation possesses fast-decayed spectral side lobes. Bandwidth efficiency and detection efficiency of the new modulation under coherent detection over a band-limited non-linear satellite channel are studied and compared with those of MSK (a constant-envelope modulation) and SQORC (staggered quadrature-overlapped raised-cosine) modulations. The results obtained in this paper show that the new modulation can offer a satisfactory bit error rate (BER), which is comparable to or even better than that of MSK and much better than that of SQORC (a previously reported quadrature-overlapped modulation), depending on the signal-to-noise ratios (SNRs) and system bandwidth.