Spread-spectrum signal acquisition: Methods and technology

A system and method of driect-sequence spread-spec trum TDMA (or TDD) digital communication, wherein acquisition and tracking occurs for a plurality of frames having a predetermined number of time slots. One of the predetermined number of time slots in each frame is assigned for acquisition purposes and carries acquisition and sync digital information. The remaining time slots in each frame have assigned header bytes for tracking purposes. The assigned acquisition time slot is spread with an acquisition direct-sequence spreading code. The remaining time slots are spread with a con munication direct-sequence spreading code. During acquisition, the signal strength in each successive time slot for each spread frame is measured for a given num ber of time frames. The peak is located within the given number of time frames through a major acquistion sweep and a refinement sweep. The major acquisition sweep and refinement acquisition sweep locate the frame and time slot boundaries of the transmitted signal. Once acquired, tracking occurs during the header bytes of each successive remaining time slot. Acquisition, tracking and demodulation of the digital data is per formed with the same circuitry.

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