Concurrent dual-band digital predistortion for power amplifier based on orthogonal polynomials

This paper presents a 2D digital predistortion system to compensate for the nonlinearity of the power amplifier driven by a concurrent dual-band signal. In order to improve the numerical stability of the system, we introduce a new orthogonal polynomial basis. The numerical stability of the new representation is compared to the conventional polynomial. An experimental test bench employing an FPGA linked to two mixed signal system boards is also presented. Performances are evaluated with an experimental test setup using a 10W peak power amplifier and a dual-band signal (single-carrier WCDMA and 3-carrier WCDMA) center frequency spaced by 310MHz. Experimental results show numerical stability improvement with the new 2D orthogonal basis.