  A new Efficient-bandwidth code-division-multiple-access (CDMA) for
band-limited channels is introduced which is based on finite field transforms.
A multilevel code division multiplex exploits orthogonality properties of
nonbinary sequences defined over a complex finite field. Galois-Fourier
transforms contain some redundancy and just cyclotomic coefficients are needed
to be transmitted yielding compact spectrum requirements. The primary advantage
of such schemes regarding classical multiplex is their better spectral
efficiency. This paper estimates the \textit{bandwidth compactness factor}
relatively to Time Division Multiple Access TDMA showing that it strongly
depends on the alphabet extension. These multiplex schemes termed Galois
Division Multiplex (GDM) are based on transforms for which there exists fast
algorithms. They are also convenient from the implementation viewpoint since
they can be implemented by a Digital Signal Processor.
