DPDToolkitOverview方案.PDFVIP

DPD Toolkit: Overview Background Digital Predistortion technology (DPD) enables power-efficient transmission in modern wireless communications systems. Prior to third generation (3G) cellular systems, wireless signals were relatively benign in that their envelope (i.e. how the instantaneous size of the signal varies as it is modulated with the digital data) was essentially constant. Subsequently (3G and beyond) the drive for enhanced data capacity has resulted in the wireless signal envelope becoming increasingly noise-like. This poses significant challenges for the transmitter and in-particular the power amplifier (PA). Efficient power amplifiers tend to be non-linear, which is fine when the signal envelope is benign, however the non-linear transmission of 3G/4G signals result in the generation of troublesome interference, which can exceed regulatory requirements. To fix this there are essentially two options, but only one practical choice:  Design a linear PA; such designs are expensive and highly inefficient (e.g. to transmit 20 Watts the PA would probably consume ~400 Watts or more). Or  Linearize the PA by a dynamic manipulation of the PA itself and/or its input signal. DPD is a linearization technology which enables interference-free transmission using an essentially non-linear (i.e. power efficient) PA. Since 2008, drawing on over thirty years of transmitter product design expertise, Systems4Silicon has supplied, supported and evolved its DPD technology to an international customer base. Development of algorithms for DPD is complex, costly and time consuming and the resulting solution may put significant demands upon the underlying signal processing resources. Systems4Silicon’s D