Analysis on QPSK Modulation Technique for Wideband Code Division Multiple Access

This paper is the study of the QPSK (Quadrature Phase shift keying) modulation technique using AWGN (Additive white Gaussian noise) and Multipath Rayleigh fading channel. In QPSK scheme we can transmit one of the 4 possible signals during each interval of signalling. WCDMA systems are based on higher modulations which provide transmission at higher data rates. In this we studied the scatter plot, eye diagram and signal trajectory of QPSK system over different communication channels. All modulation techniques have different performance charact eristics over various signals which are affected by noise and interference.