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Performance evaluation of frequency and symbol timing offset estimation methods for DAB/DAB+ receivers under multipath fading channels

In Orthogonal Frequency Division Multiplexing (OFDM) based systems, symbol timing errors and frequency offsets may lead to a significant performance degradation. For this reason, it is very important to achieve a high precision time and frequency synchronization. With the absence of pilot symbols, blind synchronization algorithms are necessary by either using different metric functions or statistics of the received signal. In this paper a new blind symbol timing and frequency offset estimation algorithm is proposed, based on the Maximum Likelihood (ML) principle. It only utilizes the redundant infor- mation contained in the guard interval and is suitable within the acquisition as well as the tracking phase of an OFDM receiver. To provide a fair comparison between the proposed and the most recent blind synchronization algorithms, all simulations are applied to the practical OFDM based Digital Audio Broadcasting (DAB/DAB+) system under different realistic multipath fading channel conditions to extract the best method for Software Defined Radio (SDR) based receivers.