Hlr Data Consistency And Realization

HLR (Home Location Register) is the central database in mobile communication system. In HLR, all the data information of subscribers is located, including location data, basic business data and supplementary business data. Along with the rapid development of mobile communication market and the increase for the demand of multi-media data business from users, HLR data volume is also in rapid expansion. In order to keep the correctness of HLR data, the problem of data coherence must be solved.HLR data coherence includes: logical coherence and temporal coherence, the former can be further divided into coherence between disk and memory and coherence between host and backup.The problem of coherence between disk and memory of HLR data: The access operation of HLR data demands high real-time performance. Therefore, memory database is widely adopted in HLR system. All the users' data is loaded in memory. When the data in memory is updated, there will be data incoherence between the memory and the disk. Compared with conventional solutions, this research adopts disk buffer technology in the solution to coherence between disk and memory. And NVRAM is used to renew the data queue. The reliability of HLR data is thus assured theoretically. At the same time, the bottleneck problem in I/O operation on disk is also eliminated. The problem of coherence between disk and memory is solved with the inter- collaboration among 3 software components: log, backup and restore.The problem of coherence between host and backup of HLR data: In most of existing solutions, dual HA structure is adopted and each system is taken as the host and backup of each other so as to ensure the high reliability of the system. After the primary data is updated, there will be the coherence problem of memory data between the host and the backup. Based on PCI address mapping, the research realized mutual access between any of the two SBCs on the compact PCI bus and the coherence between host and backup is thus realized.The temporal coherence of HLR data: When the properties of HLR subscribers are changed, the relevant data in HLR database must the updated effectively in time. And, when VLR and MSC ask for HLR data, there must be instant response. This character of HLR data is called temporal coherence, which is assured by the real-time performance in the access operation of data.For the real-time performance in operation, highly effective data indexing structure must be designed and HLR users' data must be reasonably organized and settled. These problems were studied in this research.Main contribution of the thesis: In the process to solve HLR data coherence, this researchimproved the conventional solution in following aspects:1) With disk cache disk technology, the bottleneck problem of disk I/O operation is solved. This research takes log disk space as high-speed buffer. The disk takes up frequent lower cases with continuous recording on the max. bandwidth so as the user could take large buffer space with the price of the disk space. The frequent I/O access performance is thus greatly raised and the reliability of data in cache disk is greater than that in RAM. Through the use of cache disk and with the updated buffer queue, this research transferred trivial disk operation into log operation. It not only realized the persistence of the data, but also eliminated the bottleneck of I/O operation on disk.2) Implementation of coherence between host and backup based on PCI address mapping system. With PCI address mapping mechanism, this research realized the inter-access between host and backup based on CPCI bus and the coherence between host and backup is thus realized. Compared with conventional scheme, this research shortens the incoherence time between host and backup to us class instead of the ms class that is widely adopted in conventional schemes. At the same time, the implementation of coherence between host and backup will not occupy the bandwidth of the networks, the capacity for HLR to receive and dispatch external message is also raised.By the end of the thesis, there is a conclusion in the thesis. And, problems to be solved are also pointed out to indicate the direction of the further exploration.