Milad Daneshvar - Department of Telecommunication Engineering, Shiraz Branch, Islamic Azad University, Shiraz, Iran
Nasser Parhizgar - Department of Telecommunication Engineering, Shiraz Branch, Islamic Azad University, Shiraz, Iran

This paper is focused on the optimization of the physical layer of digital communication systems and it provides innovations for both multi and single-carrier systems. For single carrier systems we have proposed a method to optimize constellation design in presence of a strong distortion, such as the non linear distortion provided by satellites’ on board high power amplifier, then we developed a method to calculate the bit/symbol error rate related to a given constellation, achieving an improved accuracy with respect to the traditional Union Bound with no additional complexity. A low complexity Signal-to-Noise Ratio (SNR) estimator saves one-half of multiplication with respect to the Maximum Likelihood (ML) estimator, and it has similar estimation accuracy.

SNR Estimator, ML Estimator, Gaussian distribution, Cramer-Rao Bound, Mean Square Error