OPTIMIZATION OF DATABASE PLACEMENT USING DYNAMIC PROGRAMMING IN MOBILE COMMUNICATION NETWORK

OPTIMIZATION OF DATABASE PLACEMENT USING DYNAMIC PROGRAMMING IN MOBILE COMMUNICATION NETWORK

ABSTRACT

User mobility causes two main problems with call set-up and routing that are not encountered in a network containing only stationary users. Firstly, call set-up requires at least one database access to find the current location of the user being called. Secondly, if the network maintains an up-to-date list of the location of each mobile user, then each location change requires one or more database updates. One possible solution to these problems is to use a single database which stores the location of the entire user in the network. This database must then be updated (accessed) every time a user changes location (make a call). This solution becomes infeasible if a single database cannot handle the number of updates and access generated in this manner.
To maintain track with mobile user and assign databases as per up-date list of location of each mobile user, requires lot of computation work. This can be calculated with dynamic programming. We propose a hierarchical arrangement of databases of mobility tracking which reduces the access and update load on each database, relative to the centralized scheme just described. This scheme was motivated by recent studies which estimate the amount, updates, queries, and signaling traffic. its assumed in GSM , that each user is identified with a particular node in the signaling network, called a Home Location Register (HLR), which contains the user current location. Each location change (call set-up) then requires that the HLR be updated (accessed). This system becomes inefficient if a user travels far from his HLR, or if there is a relatively large amount of traffic between the two HLRs far apart in the network. In each case, update and query traffic must travel long distances over the signaling network. The hierarchical scheme presented here has the capability of greatly reducing the distances over which signaling traffic must travel in the situation.