Non-coherent direct sequence spread spectrum receiver for detecting bit/symbol chip sequences using threshold comparisons of chip sequence correlations

摘要

A method and apparatus for transmitting and receiving a direct sequence spread spectrum signal encoded using two or more chip sequences to encode an information signal. The encoded information signal is received using a bank of matched filters (501a-501l), a bank of threshold comparators (505a-505l), a non-frequency locked bit clock circuit (509, 509') and a bit detector (510). Frequency locking is avoided by performing correlation on both the I- and Q- baseband signals and by logically combining the correlation results to recover the bit clock. In one embodiment, the method and apparatus uses binary phase shift keying to modulate the direct sequence spread spectrum signal with a carrier. In another embodiment, quadrature phase shift keying is used.