Multiple access based on Gabor transform

An oversampled discrete-time Gabor (1946) transform (DTGT) has inherent redundancy for signal representation in the joint time-frequency domain. In the proposed multiple access communication system, this redundancy is used to separate different signals. The DTGTs of all users' signals are transmitted in the same time slots and frequency bands. The DTGTs of the signals can be separated if the analysis windows used in their computation satisfy a pseudo-orthogonality condition defined in this paper. A limit on the number of windows that can be pseudo-orthogonal (PO) to each other is derived. Two methods of designing PO windows using pseudo-noise sequences and wavelet filters are demonstrated.