A multiprocessor approach for implementing a time-diversity spread spectrum receiver

A modified RAKE-receiver resolving the multipath components of the channel impulse response (time diversity) is introduced for a microcellular indoor communications system with code-division multiple-access (CDMA) using direct-sequence spread spectrum (DSSS). Data demodulation and pseudonoise (PN) code synchronization are performed by a parallel processing architecture consisting of multiple digital signal processors (DSPs). Algorithms for code acquisition and tracking or scanning are presented which are based on real-time measurements of the channel impulse response. The parameters of these algorithms are adapted to the currently measured signal-to-noise ratio in the data band. It is concluded that the main advantage of the proposed receiver structure is the enormous flexibility which makes it possible to implement and compare many different schemes of code synchronization and data demodulation. Another advantage is that the same hardware is used for synchronization and data demodulation