Spectrum efficiency of a mobile cellular radio system using direct sequence spread spectrum

Direct Sequence Spread Spectrum Multiple Access (DS/SSMA) is proposed for mobile cellular systems with coherent phase shift keying (CPSK) modulation. Spectrum efficiency and bit error probability are evaluated taking co-channel interference into account for uncorrelated (fast) Rayleigh fading and (slow) log-normal shadowed signals, The analysis is significant for a mobile radio system using Direct Sequence Spread Spectrum because in such a system co-channel interference is always present.