The Research Of Adaptive Wide-Bandwidth Digital Predistortion’s Technology And FPGA’s Implementation

With the development of communication technology, the source of spectrum that can be used in space is become more and more scarcity. Higher order modulation technology is extensive used to pursuit higher data transfer rates and spectral efficiency in the limited spectrum resources. However, this makes the power amplifier’s non-linear characteristics become much more apparently. And it could causes the degradation of system’s reliability, the waste of source and the growth of operation costs more likely. So it has been become the main subject in development of communication region at present that how to overcome the non-linear distortion. The technology of digital pre-distortion has received the most attention and research and become the one of the major solutions to realize the power amplifier’s linearization at present by its advantages such as the easier to implement, the lower cost, the higher degree of flexibility and the much more effective of linearization effect between many RF power amplifier’s linearization technologies.This thesis focuses on the research of adaptive wide-bandwidth digital predistortion’s technology and FPGA’s implementation. It used Xilinx Virtex-6FPGA’s logic hardware resources to build various functional modules include the pre-distorer. And it embedded Microblaze CPU to responsible for coefficient’s estimation. Then completing the construction of the whole system and making associated performance verification. Following four aspects are main contents and originally innovatfve discoveries:1. From two aspects of easy implementation and performance good, This paper select MP to achieve pre-distortion technology. And updated the original system architecture by increasing IQ calibration, PC communicate interface and others. Then making greatly improved of the performance and human computer interaction.2. Because of the original algorithm’s issues such as occupying much more system’s memory and low efficiency in the process of carrying out coefficient estimates in MicroBlaze CPU, the paper proposed a new way to construce the matrix and factorize it making the memory space occupied has a significant reduced and code efficiency greatly improved.3. Point to transceiver system’s disadvantage of IQ imbalance, the paper qualitatively and quantitatively analyzes its firstly, and then build on the compensation model. Finally, with no additional hardware circuit, it brings out a new IQ compensation algorithm and realized it on FPGA. Tests show that the algorithm could cause great upgrade of the system linearity.4. Making overall test to the whole pre-distortion platform. The results show that the effect of pre-distortion produced by this design could achieved the expected goals.