Code acquisition in DS-SSMA systems in the presence of multiple access interference and data modulation

Direct-Sequence Spread Spectrum Multiple Access (DS-SSMA) techniques are being proposed for modern personal and mobile radio communication networks. Fast and accurate acquisition of synchronism between the received code sequence and the locally generated sequence plays a fundamental role in the successful utilization of any code division multiple access technique. In this paper, the performance of the code acquisition sub-system is analysed in the presence of multiple access interference, data modulation and noise. The effect of interference from other codes is analysed without resorting to a Gaussian approximation; this approach allows the evaluation of the properties of different families of codes. Results of the analysis are presented for Maximal Length Shift Register (MLSR), Gold and Kasami sequences, with and without verification mode, with absorbing and non absorbing false alarm state.