Realization Of Interference Cancellation System Based On FPGA

With the development of wireless communication, the quality of signal transmission is more and more important. To the theoretical basis of Shannon’s theorem, it is obvious that interference will influence the signal transmission quality. Therefore it is important way to improve the signal transmission quality by interference filter.Interference cancellation system, referred to as ICS (Interference Cancellation System), mainly uses adaptive interference cancellation technology to achieve the purpose of eliminating interference. It is good for eliminating the interference signal through digital processing technology. Moreover, when the feedback interference signal larger than the base station signal, ICS still able to maintain coverage signal quality and eliminate some problems caused by feedback interference from the re-issued antenna to the donor antenna.This paper researches the use of the CDMA Repeater Interference Cancellation system included digital IF and baseband processing in the FPGA implementation. In addition, this paper introduces design principle as the key technology at first. The design is based on software-defined radio as the main method to design the relevant hardware platform. The basic idea of software radio is used to establish a common hardware platform, broadband A/D converter as close to radio antennas that will receive as early as possible to transform the analog signals into digital signals so that the maximum extent through DSP Software. Therefore, it has great flexibility and compatibility advantages.This design also uses adaptive filtering and digital conversion technology. Adaptive filtering is the core of interference cancellation algorithms, the digital frequency signal is converted to the baseband processor of the key technologies. Moreover, this paper gives the overall design analysis in the characteristics of repeater, points out design advantages compared to conventional repeater, and introduces the interference cancellation system as a whole design principles, architecture and key algorithms.This article focuses on the digital conversion and digital baseband in the FPGA implementation. According to the design requirement, it is important to select the appropriate device based on the characteristics of the chips and give a reasonable framework for software design. In the FPGA implementation processing, it is not only achieving design features, but also give full consideration to the utilization of resources and stability issues. Furthermore, according to the software characteristics, digital conversion use simple FIR core interface configuration methods and the complex coefficient filter algorithm structure, so that resources have been fully utilized and the system is more stable timing.Use of the software radio system can take into account the compatibility of the system, therefore, in the 3G development process; it is good for improving development efficiency. In short, interference cancellation system has a very important significance to solve the strong echo interference in the process of the wireless signal coverage.