Efficient OFDM Symbol Estimation Algorithm over Time-Frequency-Selective Fading Channels

Abstract

In orthogonal frequency division multiplexing (OFDM) systems, time-frequency-selective, equivalently time-variant multipath fading destroys subcarrier orthogonality, resulting in intercarrier interference (ICI). OFDM systems with guard interval (GI) can prevent intersymbol interference (ISI) caused by frequency-selective fading, but do not combat ICI caused by time-selective fading. To mitigate the effects of ICI, several estimation methods have been proposed. These conventional algorithms are highly complex in general due to the large-sized matrix inversion. In this paper, we propose an efficient OFDM symbol estimation scheme, called iterative sequential neighbor search (ISNS) algorithm, which achieves an enhanced performance with a moderate complexity compared with the conventional methods. The validity of the proposed estimation scheme is demonstrated by computer simulations.