Comparison of direct-sequence spread-spectrum multiple-access systems with QPSK data modulation
Thomas G. Macdonald, M.B. Pursley · 2003
Two forms of quaternary direct sequence spread-spectrum multiple access, also known as code-division multiple access (CDMA), are described and evaluated. One form uses complex quaternary sequences as the spreading sequences, and the corresponding receiver employs a complex correlator and complex processing. The other form uses a pair of binary Gold sequences as the spreading sequences and the receiver employs in-phase and quadrature processing. The probability of symbol error is evaluated for each system.