Joint Channel Estimation and Nonlinear Distortion Compensation in OFDM Receivers

TL;DR

This paper introduces a joint maximum-likelihood estimator for channel response and nonlinear PA distortion in OFDM systems, along with an adaptive compensation algorithm suitable for standard wireless LANs, improving signal quality.

Contribution

It proposes a novel joint estimator for channel and nonlinear distortion in OFDM, applicable to existing standards without transmitter modifications.

Findings

Estimator effectively models PA nonlinearity using Taylor series

Adaptive algorithm compensates nonlinear distortion at receiver

Simulation results show improved performance in wireless LAN scenarios

Abstract

Nonlinear distortion in power amplifiers (PA) can significantly degrade performance of orthogonal frequency division multiplexed (OFDM) communication systems. This paper presents a joint maximum-likelihood channel frequency response and nonlinear PA model estimator for OFDM signals. Derivation of the estimator is based on Taylor-series representation of power amplifier nonlinearity and is suitable for wide range of memoryless PA models. A sub-optimal decision-aided algorithm for adaptive compensation of nonlinear distortion effects at the receiver-side is also presented. It is shown that the proposed algorithms can be used in IEEE 802.11a/g/p/ac compliant wireless LAN receivers without any modifications at the transmitter side. The performance of the proposed algorithms is studied by means of computer simulation.