Research On Digital Baseband Technology Based On FDD-TDD

There are many communication manufacturer developed almost one hundred kinds of terminal that can support both FDD and TDD mode with the wide application of LTE standard all around the world. In view of this, the FDD-TDD communication system will get more extensive application in the future.The main content of this project is to design a high-speed communication system can support both FDD and TDD mode. The modulation mode is high order QAM based on FDD, while that of TDD is QPSK. This thesis focuses on the FDD digital baseband system. The difficulty is the design and implementation of digital signal processing algorithms. Additionally, the communication between FPGA and ADC/DAC or DSP is also needed to be realized. It is the implementation and optimization method that descripted in detail based on the introduction of the function and principle of each algorithms module. Besides of this, a thorough and extensive research on blind equalization algorithm for high order QAM system is also completed. It’s improved to CADAMA considering the QAM system’s charactristics that signal’s modulus is not constant. In order to eliminate the phase rotation, it’s improved to MCADAMA. A new equalizer is designed that assisted by T/4 FSE and prediction decision feedback structure to achive faster convergence and lower steady state error. A series of performance index of the blind equalizer is carried out after a lot of simulation based on Simulink. The validity of the system is proved by the test and analysis displayed in the end.