17 / 2016-07-08 14:14:53

Experimental Analysis and Investigation of WCDMA Link Using Vector Signal Transceiver (VST) 5644

10836,249,10837

In WCDMA systems, the physical radio channel is viewed as a combination of a spreading code, bandwidth, time slot and transmitted power. The assigned bandwidth and the time slot duration are assumed invariable but the spreading code and transmission power are variable and depend on various parameters like the required bit rate, the QoS and the instantaneous interference. In uplink direction, in Wideband CDMA (WCDMA) systems, orthogonal codes are used to differentiate the physical channels of transmitter & Pseudo Noise (PN) sequences are used. WCDMA make use of Direct Sequence spreading, where spreading process is performed by combining the baseband information signal to high chip rate binary code. The proposed WCDMA work is based experimentally on VST 5644R.The modulation scheme used for the investigating WCDMA link on VST platform is QPSK. Here the results are measured in terms of EVM (Error Vector Magnitude). The results have shown that WCDMA Link based on QPSK scheme with ‘long’ scrambling code and scrambling factor of 128 performs much better as compare to that using ‘short’ scrambling code.