OFDM channel estimation using novel LMS adaptive algorithm

Abstract

Spectrally efficient orthogonal frequency division multiplexing (OFDM) offers an ideal solution to inter symbol interference (ISI), by maintaining the orthogonality among subcarriers. For a multi carrier (MC) communication system, the wireless channel impulse response (CIR) varies rapidly under severe channel fading conditions. Fixed step size (FSS) adaptive filtering (AF) provides a way out for channel estimation and equalization, in slow varying fading channels. In this work, an adaptive step size (ASS) least mean squares (LMS) AF is utilized for the purpose of OFDM channel equalization. The performance of the proposed ASS-LMS AF is compared with variable step size (VSS) LMS and normalized LMS (NLMS) algorithms. The superiority of the proposed ASS LMS algorithm is evaluated by the bit error rate (BER) and mean square error (MSE) parameters, which shows an improvement.