A frequency and timing period acquisition technique for OFDM systems

Orthogonal frequency division multiplexing (OFDM) has been receiving a lot of attention in the field of broadcasting because of its robustness against the effects of multipath propagation which are main obstructions for mobile reception and realization of the single frequency network. This paper introduces a frequency and timing period acquisition technique for OFDM systems. The proposed technique estimates both the frequency and timing period offsets at the time by using only one pilot symbol with its suitable frequency assignment. Pseudo noise (PN) sequences are introduced to assign these frequencies of the pilot symbol so that the acquisition range can be widened. Numerical examples are given to show the estimate variances for both additive white Gaussian noise (AWGN) and multipath fading channels