Performance Analysis of QAM and QPSK in AWGN and Multipath Fading Channel

To deliver multimedia content application over the cellular networks, high data rate modulation scheme is one of the important criteria besides good error coding. However, the implementation of high data rate modulation techniques that have good bandwidth efficiency in W-CDMA cellular communication requires perfect modulators, demodulators, filter and transmission path that are difficult to achieve in practical radio environment. Modulation schemes which are capable of delivering more bits per symbol are more immune to errors caused by noise and interference in the channel. Moreover, errors can be easily produced as the number of users is increased and the mobile terminal is subjected to mobility.QAM and QPSK are considered as one of the most commonly used modulation schemes for wireless communication now a days. The performance analysis of these modulation schemes are carried out in terms of Bit Error Rate (BER) versus Signal to Noise Ratio (SNR) in AWGN and Multipath Rayleigh Fading channel .The transmission of signal from base station to mobile station using Quadrature Phase Shift Keying (QPSK) and M-ary Quadrature Amplitude modulation (QAM) modulation scheme are consider in WCDMA system. In this paper it will be proved that for increased value of M the data rate will be increased but with a increasing value of BER but QPSK will perform better than M-ary QAM.