Crest factors of complementary-sequence-based multicode MC-CDMA signals

The crest factor properties of binary phase-shift keying modulated two- and four-code assisted multicarrier code-division multiple-access (MC-CDMA) employing complementary-sequence-based spreading sequences are characterized. More specifically, a complementary-sequence pair, a complementary-sequence-based subcomplementary code pair, and a Sivaswamy complementary code set are studied. It was found that the corresponding crest factors are bounded by 3 dB, which corresponds to the crest factor of a single sine wave. This low crest factor resulted in a lower power loss and a lower out-of-band power spectrum due to clipping when the time-domain signal was subjected to a typical nonlinear power amplifier, in comparison to those of Walsh code and orthogonal Gold code-spread MC-CDMA signals.