A multiprocessor approach for implementing a time-diversity spreadspectrum receiver

摘要

A modified RAKE-receiver resolving the multipath components of thechannel impulse response (time diversity) is introduced for amicrocellular indoor communications system with code-divisionmultiple-access (CDMA) using direct-sequence spread spectrum (DSSS).Data demodulation and pseudonoise (PN) code synchronization areperformed by a parallel processing architecture consisting of multipledigital signal processors (DSPs). Algorithms for code acquisition andtracking or scanning are presented which are based on real-timemeasurements of the channel impulse response. The parameters of thesealgorithms are adapted to the currently measured signal-to-noise ratioin the data band. It is concluded that the main advantage of theproposed receiver structure is the enormous flexibility which makes itpossible to implement and compare many different schemes of codesynchronization and data demodulation. Another advantage is that thesame hardware is used for synchronization and data demodulation