Patent ID: 8326238

Claim:
In a wireless transmission system adapted for use with a portable mobile device, a method for processing signals in preparation for wireless transmission, wherein the wireless transmission includes use of a power amplifier, the method comprising: maintaining a lookup table that contains pre-computed distortion contributions determined by monitoring the power amplifier following initialization of the power amplifier and prior to transmission, wherein determining distortion contributions includes: squaring an in-phase component of a signal representative of power amplifier output to produce a squared in-phase output value: squaring a quadrature component of the signal representative of power amplifier output to produce a squared quadrature output value; squaring an in-phase component of a signal representative of an input signal to produce a squared in-phase input value; squaring a quadrature component of the signal representative of the input signal to produce a squared quadrature input value; determining an in-phase difference between the squared in-phase input value and the squared in-phase output value; and determining a quadrature difference between the squared quadrature input value and the squared quadrature output value, the distortion contributions being based on the in-phase difference and the quadrature difference; accepting a value that reflects information to be communicated, the value hereinafter referred to as original value; generating a lookup-table key based on the original value, wherein the lookup-table key is digital; retrieving from the lookup table, using the lookup-table key, a pre-computed distortion contribution for the original value; distorting the original value based on the pre-computed distortion contribution to obtain a distorted value to pre-compensate for nonlinear characteristics of the power amplifier; and wirelessly transmitting based on the distorted value.