Evaluation of a novel Constant Envelope Spread-Spectrum Modulation technique

Constant envelope, spread spectrum modulation is highly desirable for low-power, battery-operated systems - but only if the cost of any increase in receiver complexity or reduction in bit error rate performance is offset by a realizable reduction in either the transmit power or DC power requirements for the system. This paper defines and analyzes a novel approach to a constant envelope spread spectrum modulation type and provides an analysis of the complexity and performance of the modulation scheme. The hybrid continuous phase modulation (CPM) waveform is a constant-envelope modulation that provides an inherent phase and frequency diversity which has similar properties to the standard spread-spectrum m-PSK DSSS modulation. The performance in AWGN, multipath, and a severe interference environment is provided and compared to a simple example of random PN spread-spectrum BPSK modulation and a gold-code spread MSK modulation - both modulation schemes with a similar receiver complexity as the hybrid CPM modulation scheme.