Patent ID: 8005173

Claim:
An apparatus for estimating a coarse frequency offset in Digital Multimedia Broadcasting (DMB) transmission frames, said apparatus comprising: a receiver that receives a phase reference symbol; a memory unit operatively connected to said receiver and comprising a programmable set of instructions; a display unit operatively connected to said memory unit; a buffer operatively connected to said memory unit, wherein said buffer comprises data fields for a peak of a correlator output, a frequency offset of said DMB frames, a counter, and a change flag; and a processor that processes said programmable set of instructions comprising: receiving said DMB transmission frames comprising a synchronization channel comprising a phase reference symbol; circularly shifting said phase reference symbol by applying a circular shift to said phase reference symbol; numerically correlating the circularly shifted phase reference symbol with a known correct phase reference symbol to obtain a highest peak and a side peaks of the numeric correlation; computing a phase reference symbol angle based on a multiplication of said peak and a carrier spacing of said DMB transmission frames; summing said phase reference symbol angle for all of sub carriers within said phase reference symbol; computing an average of said highest peak over said DMB transmission frames to reduce effects of said side peaks if a frequency offset exists in said buffer; updating said change flag; incrementing said counter; and determining a buffer entry if said buffer entry with said counter is greater than or equal to a predefined parameter.