An approximate analysis of asynchronous linear decorrelating detector for dynamic CDMA system

In this paper, the performance of asynchronous linear decorrelating detector (LDD) is analyzed for random signature waveforms. The performance of LDD is expressed in terms of the near-far resistance (NFR) defined as the reciprocal of a diagonal component of inverse cross-correlation matrix of signature vector set. For dynamic CDMA, wherein randomly time-varying signature waveforms are used, NFR is a random variable. Recently, many papers have dealt with the analysis of multiuser detectors for random signature sequences. In most cases, however, these analyses considered using some bounding techniques for asymptotic multiuser efficiency or near-far resistance. In this paper, we will directly derive an approximate PDF of the near-far resistance for an asynchronous LDD and the corresponding BER expression. For these parameters, a simple accurate expression is obtained. The approximate BER will also be verified via Monte-Carlo simulations