Detection Of The Pseudo Base Station Based On Location Updating Signaling

With the proliferation of pseudo base stations becomming a serious challenge to network security,controling the widespread pseudo base station is also becoming one of the key for the national network security.As an illegal fake base station,pseudo base station would lure mobile users to access,and then steal user information,send spam messages to the mobile users.It not only threaten the user's personal information and property security,but also is easy to cause the congestion to the network of the telecom operators for the increase of the location update signaling after the mobile user accessed to the pseudo base station.Since pseudo base station has formed a closed wireless communication system itself and is no need to contact with the current network,it has a certain privacy.Therefore,how to detect and locate the pseudo base station is an important issue for the academic community.In this paper,according to the main characteristics of the pseudo base sation,we studied the relationship between these characteristics and the appearance of the pseudo base sation.By the mathematic quantitative analysis,we find out the most significant correlation characteristic,as a theoretical basis for the pseudo base station detection algorithm study.Through the analysis and calculation,it is found that the location updating offset frequency is significantly correlated with the appearance of pseudo base station.And based on this,this paper has studied three kinds of pseudo base station detection algorithms from the simple to the complex.The first algorithm is the pseudo base station detection algorithm which based on the fixed LAC(Location Area Code)and mainly detected the early pseudo base station with the fixed location area code.This algorithm is based on the current user signaling data stream,and unnecessary to compare with the historical information,so it is very efficient and can identify pseudo base stations quickly.But it is completely ineffective to detect the pseudo base station whose location area LAC can be changed.Therefore,the second detection algorithm is coming:the pseudo base station detection algorithm based on the exclusion of normal location updating.However,there is a problem in this algorithm:maintaining the neighbour relation table by manual is time-consuming and error prone.In order to solve it,this paper introduced a self learning algorithm to maintain the neighbor relation table automatically.With the purpose of coping with the latest "intelligent" pseudo base station,this paper proposes the third pseudo base station detection algorithm:location updating record method.Due to this type of pseudo base station can detect and illegally use adjacent LAC,the first two detection algorithm are no long applicable.The basic thought of this algorithm is comparing and anlysising the location update history information with the abnormal historical location updating signaling data,so as to detect the pseudo base station in the network and to point out the cell location of pseudo base station.This is the main contribution of this paper.The last chapter of the thesis is the field verification and analysis according to the detection algorithm.And it uses mathematical method to analyze the reliability of the judgement of exist pseudo base station.The experimental results show that the proposed algorithm can effectively locate the existed pseudo base station area,and improve the detection successful rate of pseudo base station.