ESTIMATION OF THE EFFECT OF NONLINEAR HIGH POWER AMPLIFIER IN M-QAM RADIO RELAY SYSTEMS

Abstract

The estimation of the effect of both linear and nonlinear distortions in M-QAM radio systems requires either complicated analytical calculation or very long run of simulation. In this paper a new parameter of nonlinearity is produced and the relationship between this parameter and the signal to noise ratio degradation (S N RD) caused by the separated effect of nonlinear HPA (High Power Amplifier) is presented. In addition, the estimation of the simultaneous effect of linear and nonlinear distortions is discussed and a procedure to calculate the upper bound of BER (bit-error ratio) for this case is also presented.