Ds-ss Signal Narrowband Interference Adaptive Suppression Algorithm And Hardware Implementation

The purpose of this thesis is to study the suppression of Narrow Band Interference for Direct-Sequence Spread Spectrum communication system. DS-SS communication system is well known for its inherent anti-jam character because of its processing gain. However, when the processing gain is not high enough to suppress the interference, system performance will degrade greatly . Instead of increasing the spreading factor arbitrarily, we can find some more economical and effective methods Adaptive interference suppression technique is an excellent solution. In this thesis, the system model of DS-SS system and the adaptive filter structure are first introduced . Then, the interference suppression(interferences including strong tone and NBI)using the LMS algorithm with adjudging and feedback is analyzed in detail. The algorithm performances in various conditions defined by parameters like reference signal or interference types are discussed and compared. Simulation is done to support our analysis. How to convert the RF analog signal to the base-band digital signal is one of the key problems of the new wireless communication systems. During the past several years, the software radio has emerged from demonstrations in military research to become a cornerstone of the 30 strategy for affordable, ubiquitous, global communications. Digital IF is the only viable alternative to analog IF in many cases at present. So, digital IF processing model is introduced in the third chapter of this thesis. Designing and testing of IF processing part are discussed. Also, the principles and applications of chips used in this system, as well as some key problems in hardware debug, are explained in the end of this thesis.