Offset Quadrature-Quadrature Phase Shift Keying with Half-Sine Pulse Shaping

In this paper, we present a new spectrally efficient modulation scheme named offset quadrature-quadrature phase shift keying with half-sine pulse shaping (OQ²PSK). This creates a four-dimensional signal space like quadrature-quadrature phase shift keying (Q²PSK) and achieves increased transmission rate over two-dimensional modulation schemes such as QPSK and MSK. The proposed scheme can be viewed as a quadrature multiplexing of two OQPSK streams with a raised-cosine pulse shaping which results in significantly lower sidelobes compared with Q²PSK. The cost of high transmission rate is destruction of the constant envelope property as in the case of Q²PSK. However, the peak to average power ratio (PAPR) of OQ²PSK is much lower than that of Q²PSK. The spectral efficiency and BER performance of OQ²PSK is investigated through computer simulation and mathematical analysis.