Td Base Station Power Amplifier Linearization And Its Fpga Implementation

The demands of the wireless communication service in modern society request higher quality and capacity of the transmission of the communication system since the wireless communication technology has been developing rapidly from 1980s. To meet this requirement, modern communication system tends to adopt the linear modulation technique, e.g., the QAM, QPSK and so on. In the traditional constant envelope modulations(GMSK,FM), the harmonic interference can be eliminated through the filter. But when the signal passes through the radio, the envelope fluctuation in the linear modulations will cause cross-modulation distortion of the devices which operating near the saturation area. This kind of distortion can be shown in its spectrum when diffusing to the adjacent channel, and it will disturb the other users. However, in the practical applications, it allows little distortion to the users in the adjacent frequency range in the most wireless communication systems.So, while the linear modulation can use the bandwidth more effectively than the non-linear modulation, it remains foibles, such as the sensitivity to the non-linear distortion of the system, especially when the radio operating in saturation state for the maximum power of output. In this kind of condition, the non-linear distortion can be worse along with the increment of the output power. To solve this problem, the power amplifier must be linearized. So, the technique of the power amplifier linearization plays a more and more important role in the wireless communication system.The thesis makes an analysis of the non-linearization of the power amplifier, a compare between the techniques of the linearization of the PA, and the theory of the adaptive digital predistortion. Then it introduces the design of the digital medium frequency hardware platform bases on the thought of the software defined radio. And finally it gives a detailed account of the realization of FPGA in the digital predistortion hardware platform based on the systematic design tool in System Generator, and also the results of the emulation and the test. The results show that the design which this thesis adopted achieved a perfect effect for the linearization of the radio.