Reserch Of Concurrent Dual-Band Power Amplifier Digital Predistortion

Communication systems accommodating multi-band and multi-standard concurrently is a research hot spot now. As an important component of the RF Front end, Dual-band or multi-band power amplifiers operating in concurrent mode are is highly desirable. This paper proposed a New Form of Polynomial Model and a Nonlinear Filter Model to do the predistortion for Dual-band power amplifiers. Model frame, solution method are provided in this paper. And the models’ performance was test based on Digital predistortion hardware platform.On the basis of 2D-DPD Model, a new form of polynomial model was introduced, which avoided high order cross polynomials. The polynomials in 2D-DPD model has two dimensions, while proposed New Form of Polynomial Model just needs one dimensions. Therefore, it is easier to realize New Form of Polynomial Model. Nonlinear Filter Model uses one order nonlinear filter structure and avoids high order multiplication. Memory length is 2, nonlinear order of 2D-DPD Model and New Form of Polynomial Model is 8. K1=K2=10 and K3= K4=20 are set for Nonlinear Filter Model. The dual 20MHz bandwidth with 8dB PAPR spacing 140MHz were test based on Digital predistortion hardware platform. With the power changing from 27dBm to 31dBm, ACPR was improved 15dB. Proposed models show the same performance with 2D-DPD Model and simplified the operation sturtucre.Nonlinear Filter Model simplified 2D-DPD operation structure outstandingly. Model’s coefficient was stored in the LUT, which made the computational complexity just be related with memory length. When M=2, multipliers in the model just need be 18. Based on the the Digital predistortion hardware platform, Nonlinear Filter Model was implemented in FPGA. The calculation result of FPGA achieved -68dB NMSE with MATLAB. Test show the model realized on FPGA possesses the same proformace as 2D-DPD model.