Obtaining polynomial coefficients from intercept points of RF power amplifiers

The RF power amplifier is a critical component in 4G wireless communication systems. One of the main concerns of RF power amplifier design is its nonlinearity, which is more severe in OFDM modulation widely used in LTE and WiMAX systems. Nonlinearity is typically described in terms of the intercept points. It is very useful for the design to obtain coefficients of the memoryless polynomial of the power amplifier model from those intercept points. Previously, the expression of the fifth-order coefficient from the fifth intercept point IP₅ was derived. This expression is low generalised to arbitrarily high order. A downlink LTE advanced signal is used for experimental verification. This result could be used for the design of power amplifiers or predistorters.