Continuous phase quadrature quadrature frequency/phase modulation (CP-QQFPM)

A new digital modulation scheme which is the continuous phase version of the recently proposed quadrature quadrature frequency/phase modulation (QQFPM) scheme and is referred to as continuous phase quadrature quadrature frequency/phase modulation (CP-QQFPM) is described. It is shown that the CP QQFPM format comprises a 4N-dimensional biorthogonal equal energy signal set of the size M=(2N) ⁴, where N is the number of frequencies employed. The power efficiency of CP QQFPM on the AWGN channel is the same as that of QQFPM and significantly higher than the power efficiency of an M-ary QAM scheme with a signal set of the same size. The bandwidth efficiency of CP QQFPM is inferior to that of QQFPM and QAM in terms of null-to-null bandwidth and a bandwidth that captures 90% of the total power, but is significantly better in terms of a 99%-power containment bandwidth. The proposed scheme has a self-synchronization capability