Patent ID: 7319658

Claim:
A multirate communication system comprising: a set of orthogonal spreading modulation vectors, each vector being 2 v chips in length, where v is any positive integer, each modulation vector supporting the transfer of information at a first information rate; a first subset of the set of modulation vectors defining biorthogonal codewords for biorthogonal coding of information; a second subset of the set of modulation vectors supporting the transfer of information at an information rate 2 n times the first information rate, where n is any positive integer, with the exclusion of (2 n −1) vectors in said set of modulation vectors not orthogonal to the first 2 (v−n) chips of said set of modulation vectors; a transmitter for modulating and transmitting information over said set of modulation vectors; and a receiver for receiving and demodulating information over said set of modulation vectors.