Robust synchronization for asynchronous multi-user chaos-based DS-CDMA

In this paper we propose two systems for achieving synchronization in asynchronous multi-user chaos-based DS-CDMA. For the first system, synchronization process is realized thanks to a binary code used as an additive pilot sequence to the spreaded signal. Gold sequences are used as pilot signals for the different users to accomplish the synchronization. For the second synchronization system, the synchronization is made through a binary code used as a multiplicative pilot signal for the spreaded data sequence. These synchronization processes are evaluated under the assumption of an additive white Gaussian noise channel together with multi-user interferences. In this paper we will focus on the initial synchronization phase (code acquisition) and we assume that the system can achieve correctly the code tracking after this first synchronization phase. The code acquisition for the two systems is evaluated in terms of the probability of detection and probability of false alarm.