Patent ID: 7224716

Claim:
A method of spread-spectrum communication wherein a sequence of N multiplied by M chips is generated, where N and M are integer numbers, comprising the steps of: generating a series of direct sequence codewords of length N in which each chip in said sequence of N multiplied by M chips is modulated by a phase value selected from the group consisting of 0 degrees, 90 degrees, 180 degrees, and 270 degrees; modulating each said direct sequence codeword with an additional phase, constant for the duration of each said direct sequence codeword, wherein said additional phase is the phases of a chirp-derived Doppler Tolerant Polyphase Code (DTPC) of length M, thus forming a modulated direct sequence codeword; concatenating each said modulated direct sequence codeword to form a transmitted signal; and transmitting and transmitted signal for reception by a receiver.