COMMUNICATIONS SYSTEM EMPLOYING DIFFERENTIAL ORTHOGONAL MODULATION

摘要

A system and method for orthogonal modulation (150) of signals in communication systems. In the transmitter (150), differentially coded symbols (106, 110, 122) are used to select time-shifted code sequences (124, 130, 134, 138). The timing, or code position, of a code sequence is determined at the receiver by comparison to the previous code from the same channel, thus eliminating the need for dual-channel transmission and eliminating error due to differences in path propagation time. A fixed preamble code is also used to synchronize the receiver.