Spectrum-folding scalar-feedback architecture for wideband DPD with simple feedback circuit

A novel wideband digital predistortion (DPD) technique that enables a simpler feedback circuit is proposed. The proposed scalar feedback method in baseband can reduce the number of analog to digital converter (ADC) while keeping its bandwidth same as the conventional method. DPD parameter determination algorithm is modified to enable the scalar feedback. To compare the performance of the proposed and conventional techniques, computer simulations are conducted. The results show that they have the same performance in terms of adjacent channel leakage power ratio (ACLR) and error vector magnitude (EVM). Experiments using carrier-aggregated LTE signal with two component carriers are also conducted to validate the results. The proposed technique can provide high nonlinear compensation performance with lower circuit complexity.