Design And Implementation Of VLR Database Based On The Shared Memory

VLR(Vistor Location Register) is a very important functional unit in mobile communication network system. The database used for VLR is required high capacity and high real-time quality. Commercial database is usually used in the actual product design. As the cost of commercial database is very expensive, it is necessary to develop a database decicated to VLR with simple function, high efficiency and low cost.The design of my project originates the VLR database project of Shanghai Bell Alcatel-Lucent Enterprise, which bases on Linux operating system and uses shared memory technology. It is applied to the switch5060WCS of Shanghai Alcatel-Lucent Enterprise.In this special database, shared memory is used to store data and one special data structure according to the characteristic of shared memory is adopted. Relative address is needed for processes to access data which is stored in the shared memory. This design uses hash index to improve the speed of data query and chooses list to deal with the conflict and to reduce the average time of searching. Data synchronization between the primary and secondary databases is through messaging mechanism, which is. supplied by the Base Platform of5060WCS. And it aims at several typical erroneous to setup recover data mechanism. At the last part of the paper, the efficiency and the availability of this database is proved through tests.