Enhanced-accuracy phase-equalizer using conic-plus-nonlinear optimizations

Digital communication channel needs to have linear phase such that it does not distorts transmitted-signal waveform. Hence, a digital phase-equalizer (PE) is required for equalizing the nonlinear phase. This paper reveals that a PE resulting from the quadratic-cone programming (QConeP) can be further enhanced through adopting a further step by using nonlinear optimization. This is a two-process optimization technique. In this paper, we first formulate and review the QConeP-based PE design, which is an approximated QConeP formulation, and then show that the PE coefficients obtained from QConeP design can be regarded as a good starting point for the further nonlinear optimization. Therefore, this two-process optimization technique combines both QConeP optimization and nonlinear optimization. This two-process optimization method can yield a significantly enhanced PE as compared with the single QConeP design that does not apply further nonlinear optimization.