Performance analysis of balanced QPSK DS-CDMA system using Hilbert transformed PN code

It is necessary to apply the bandwidth efficient SSB (single side-band) modulation scheme to DS-CDMA in order to increase the capacity of mobile communication systems with limited bandwidth resources. The balanced QPSK DS-CDMA signal with SSB is generated using inphase PN code and its Hilbert transformed quadrature PN code. The phase estimation structure, using orthogonality between inphase PN code and its Hilbert transformed quadrature PN code, makes it possible for coherent demodulation without pilot aid. Multiple access interference of balanced-QPSK DS/CDMA with SSB are analyzed to be equal to balanced-QPSK DS/CDMA with DSB and bit error rate, phase error variance and PDF of relative amplitude of MAI, are shown to be nearly equal to the DSB balanced-QPSK DS-CDMA system through computer simulation.