A new digital approach to design 3-D CAP waveforms

Abstract

A minimax optimization approach has been previously contributed to extend the conventional two-dimensional (2-D) carrierless amplitude/phase modulation (CAP) scheme to three-dimensional (3-D). In this paper, we show that there is no guarantee of spectral efficiency by this approach. This is a potentially fatal design flaw which results in the 3-D CAP system being exceptionally susceptible to noise, even if it is of very small magnitude, for example, quantization noise. A new minimax approach is, thus, contributed to design bandwidth-efficient 3-D CAP waveforms which are more robust and useful for very high-speed digital subscriber loop applications and high-speed LAN systems. Some design examples are provided.