Examination of wavelet packet signal sets for over-saturated multiple access communications

This paper addresses the problem of signature set design for uncoded multiple access (MA) communication in which user signature waveforms are linearly dependent. In general, the linearly dependent or "over-saturated" scenario requires an exponentially complex detector. The introduction of an optimal tree-structured joint detector of extremely low complexity has sparked our interest in signature set choice for over-saturated MA communications. The tree detector requires the set of linearly dependent user signatures to have tree-structured cross-correlations. This design guideline is a natural by-product of redundant wavelet packet signals. In this paper we explore, via simulations, the performance of wavelet packet signature sets and find them to do very well in general and to offer promising behavior with the introduction of arbitrary carrier phase.