Multi-Carrier CPFSK Systems

OFDM (Orthogonal Frequency Division Multiplex) techniques are touted as the most efficient method in digital communications. An excellent performance in error probability of fading channels and spectrum efficiency has sustained OFDM systems’ status for decades. However, due to its high PAPR (Peak –to- Average Power Ratio), amplifiers may work in the nonlinear region which results in performance degradation. On the other hand, CPM (Continuous Phase Modulation) signals have a superb advantage in PAPR. Moreover, some good spectral characteristic features are eminent as a consequence of its phase continuity. It is also known that any binary CPM-based signal can be decomposed into summation of several PAM (Pulse Amplitude Modulation) waves. By doing this, phase modulation is transformed into linear modulation, which simplifies its receiver design while not sacrificing its good properties. In this thesis, we will introduce a signaling model called multi-frequency CPFSK signaling which inherits most of the merits of multicarrier systems (such as OFDM systems) and CPM systems. We will discuss its receiver design and performance in detail later in this thesis.