Abstract:
field of telecommunications has made tremendous progress of the past decade, especially in the area of wireless communications. Nowadays everything is going wireless. Mobile phones, wireless internet, wireless LANS, WANS are just a few examples of the advent of the wireless technology.
With the world becoming a global village due the advancement in the field of wireless communications, the requirement for standardization and uniformity becomes an essential issue. To resolve this problem the International Telecommunications Union (ITU) is working to develop a family of standards for the next generation wireless devices and a global network known a Universal Mobile Telecommunication System (UMTS).
Our aim is to study and implement one of these standards i-e IMT-2000 for 3rd generation mobile systems, using Wideband Code Division Multiple Access (WCDMA).
The computational requirements for UMTS wideband CDMA (WCDMA) are substantially higher than that of the second-generation GSM and CDMA systems.
For the first-generation of UMTS handsets, RAKE receiver will be used as the receiver of choice. In a RAKE receiver, one RAKE finger is assigned to each multipath, thus maximizing the amount of received signal energy. Each of these different paths are combined to form a composite signal that is expected to have substantially better characteristics for the purpose of demodulation than just the a single path. In order to combine the different paths meaningfully, the RAKE receiver needs the knowledge of channel parameters such as, number of paths, their location (in the delay domain) and (complex-valued) attenuation. These perimeters are determined with the help of Channel Estimation.
