Synchronization and Channel Estimation in Wireless CDMA Systems

Wireless CDMA (code division multiple access) systems need proper synchronization and channel estimation to provide a desirable transmission quality. Here, the authors will discuss techniques which are suitable for the application in the UMTS (Universal Mobile Telecom-munications System) FDD (Frequency Domain Duplex) mode WCDMA (Wideband Code Division Multiple Access). In particular, the manuscript will focus on the implementation of sliding correlation based novel fast iterative tap amplitude and delay estimation for RAKE receivers required for the downlink. This algorithm shall be abbreviated by CITADE. Texas Instruments' TMS320C6416 DSP (Digital Signal Processor), operating at 720 MHz clock rate, will be taken as the target hardware for the implementation of CITADE, exploiting both the hierarchical structure of the primary synchronization channel (PSC) code and the tailored instructions of the TMS32OC6416 DSP. The demand on computational power of the discussed CITADE algorithm is smaller by a factor of approx. 3.6 than the minimum requirements of the algorithm presented in [1], which was implemented on StarCoreTM SC140 DSP. Furthermore, this communication will give a detailed discussion about the authors' view on software defined and cognitive radio applicable to WCDMA. The authors will first consider important aspects of software radio and then present a novel approach on cognitive radio. As proof of concept a demonstrator termed "FALCON" which has been realized by the authors, will be illustrated.