Nonlinearity Amplifier Effects on QPSK Technique

In this paper, signal compression due to the nonlinearity of RF Amplifier in Quadratuer-Phase Shift Keying (QPSK) is examined for a specific power amplifier (PA) nonlinearity model, by using simulation. One of the most important aspects in the future radio communication services is the use of spectrally efficient modulation schemes to increase the system capacity. Modulation schemes such as QPSK with an appropriate pulse shaping is spectrally efficient, but this type of modulation presents variations in amplitude and phase due to filtering. A matched Root Raised Cosine (RRC) filtering and an ideal Additive White Gaussian Noise (AWGN) channel are used in baseband equivalent simulation model, in order to isolate the effects in Solid Stat power Amplifier.