  The main objective of this paper is to compare block transmission system
performance analytically for Code Divisional Multiple Access (CDMA) modulations
in Generalized Multicarrier environment against linear modulation techniques
for both single user and multiuser. The effectivity of GMC-CDMA for multiuser
will also be judged for different Direct Sequence CDMA (DS-CDMA) such as
MC-CDMA, MC-DS-CDMA, MC-SS-CDMA. The analytical comparison will be in terms of
computing probability of bit error for frequency selective and slow flat fading
channels for different modulation techniques. The Bit Error Rate should be a
good indication for of the performance. The tolerance characteristics of
DS-CDMA in frequency-selective channels and MC-CDMA in flat fading channels
will be shown analytically and improved capacity and Bit Error Rate performance
will be derived for Block Spread Multiuser Multicarrier by relying block symbol
spreading and Fast Fourier Transform (FFT) operations. GMC-CDMA should give
guaranteed symbol recovery regardless of channel limitations.
