Polynomial approximations in predistortion workfunctions

Alternative approaches for approximating the ideal predistortion workfunction with a polynomial are compared. It is found that the inclusion of even order linearizing terms leads to small performance improvements but puts more stringent requirements on workfunction circuitry, increases coefficient sensitivity, and slightly degrades the adaptation speed. Hence, the choice of whether or not to include even order linearizing terms depends on whether the objective is to achieve high linearity or low implementation complexity.