Demodulation of a direct sequence spread-spectrum signal using an optimal time-dependent receiver

The OTDR (optimal time-dependent receiver) is shown to be capable of adaptively despreading, downconverting, and rejecting interference. Only the spreading sequence length and a training sequence consisting of symbols are required for the OTDR to despread the signal. The OTDR does not require prior knowledge of the actual spreading sequence or the carrier frequency. The OTDR is also capable of exploiting the processing gain to enhance the detectability of the spread-spectrum signal. The only prior knowledge required is the spreading sequence length. Computer simulations are presented to demonstrate the principle of the OTDR for despreading and enhancing the detectability of a direct-sequence spread-spectrum signal corrupted by noise and interference