Design of ODMA digital waveforms using non-convex optimization methods

This paper presents a new approach for the design of a set of orthogonal digital filters which can be used as message-carrying waveforms in orthogonality division multiple access (ODMA) communication systems. The filter set design problem is formulated as a constrained L2 space optimization problem. For bandwidth efficiency, all the digital filters in the set are constrained to have approximately the same desired spectral shapes in a prescribed passband. To minimize intersymbol interference and co-channel interference, all the digital filters in the set are constrained to have low values of auto-correlation at nonzero translates of multiple symbol interval and low values of cross-correlation at all translates of multiple symbol interval. Methods for solcing the proposed non-convex optimization problem are outlined. Numerical results are presented to illustrate the usefulness of the proposed method.