Iterative blind estimation of nonlinear channels

Abstract

Nonlinear distortions in analog frontends are becoming a growing problem which is not limited to power amplifiers. Modern modulation methods such as OFDM and next generation standards have high linearity requirements on all components in the signal path. A radio system that can tolerate a certain degree of nonlinear distortion without substantial loss of performance could enable high cost savings in development and production. In this paper we present a novel iterative blind estimator for nonlinear distortions. It complements existing mitigation algorithms by providing them with accurate estimates of the nonlinearity characteristic. It is shown that there is a negligible performance gap between perfect and estimated knowledge. The method is designed to be computationally inexpensive and can be readily implemented on today's digital signal processing systems.