Carrier-to-Interference Ratio Estimation of Arbitrary Signals Distorted by Nonlinear Devices

This paper presents a new method for estimating the total carrier-to-interference ratio (CIR) of an arbitrary signal distorted by a nonlinear device. Using a kernel function derived from swept power two-tone intermodulation distortion (IMD) measurements, the CIR versus input power of a nonlinear device may be determined for any arbitrary input signal. Only a knowledge of the input signal peak-to-average power ratio (PAPR) distribution is required. Simulation results are compared to measured results of output signal CIR of a nonlinear amplifier fed by a CDMA signal over a range of power levels. Better than 1 dB agreement was achieved over a 14 dB range of input power.