Low-complexity estimation of symbol timing offset for OFDM-based DRM+

Abstract

Orthogonal frequency division multiplexing (OFDM) is an effective modulation technique for high-rate and high-speed transmission over frequency selective fading channels. However, OFDM systems can be extremely sensitive and vulnerable to synchronization errors. One of the main limitations of orthogonal frequency division multiplexing (OFDM) is its sensitivity to symbol timing offset (STO) because it is difficult to obtain an accurate interpolation between the pilot subcarriers in the presence of a residual STO. And general requirements of OFDM receiver are the ratio of the number of overhead bits for synchronization to the number of message bits must be kept to minimum and low-complexity algorithms. Based on these criteria for OFDM based communication system, we propose a novel symbol timing offset estimation algorithm. This dissertation focuses the low-complexity point of view and proposes a low complexity STO estimation scheme in OFDM based digital radio mondiale plus (DRM+) system. To this end, the pilot symbols used for STO estimation in the DRM+ system are partitioned into a number of pilot subsets, and pilots in each subset are phase-rotated to have a unique phase so that the estimator is made computationally efficient. Via computer simulation, such a design achieves not only a low computational load but also comparable performance, when compared to the conventional STO estimation scheme.