On the performance of a CDMA system with user signatures based on packet wavelets in multipath channels
Mariana IONESCU, Mark A. Wickert · 2002
A class of optimum full response signaling envelopes for a single user system are identified; such signaling waveforms can isolate the multiple paths and facilitate the estimation of path parameters with a matched filter scheme. The effect of both pure multipath and combined multipath/multiuser interference (asynchronous) on the estimation of parameters for an isolated path is described; upper margins for the signal to noise ratio degradation are derived in two settings, namely for packet wavelet and PN/Gold code signatures, respectively. Numerical results are shown for the upper margins. The performance with shift orthogonal envelopes shows an overwhelming improvement over Gold codes, especially when the signature regularity increases. Bandwidth wise, it turns out that packet wavelet signatures are twice as compact as PN codes for a given delay resolution. The major disadvantage of shift-orthogonal waveforms is a nonconstant envelope.