In the mobile telecommunication systems the microcellular systems are needed to accommodate the increasing subscribers, especially in PCS environment. In that case the paging signaling cost minimization problems are arised. Recent researches introduce the location registration methods and cluster paging methods to minimize the paging signals. Cluster paging methods used the appropriate sized paging zones considering the existing probability of the subscriber of each cell. However this method can reduce the paging signal, the time delay of call setup becomes large. If we decide the small paging zone to reduce the paging signals, the call setup delay is larger than that of large paging zone. Thus, we cannot improve the call quality. In order to improve the call quality considering the minimization of the paging signals, we use the location registration methods. In this method, we divide the total area into small subareas and all subscribers are registered in that subarea. If a subscriber moves into another subarea, the location updating is occurred.
In this research we analyze the paging and location updating signal functions to improve the paging and location registration method. The appropriate location area size is determined by the ratio of user velocity to call arrival rate and the ratio of location updating cost to paging cost. If we can construct the appropriate sized location areas to each subscriber according to the subscribers characteristics, we can minimize the location updating and paging signals. This method is called individual location registration scheme. However we cannot construct the own area to each subscriber, we use the multi-layered location area scheme. In this scheme we construct some layered location areas according to the pre-determined subscriber characteristics of the group and each subscriber belong to appropriate sized layer.
We decide the pre-determined subscriber characteristics of the group and subscriber grouping according to the pre-determined characteristics. In order to group the subscriber, we define subscriber grouping problem. Propositions are examined to solve the grouping problem. The performance of the proposed subscriber grouping algorithm is tested with some examples. Simulation results indicate that the subscriber grouping procedure is effective for determining the number of layers and group characteristics of each layer.
Next, multi-layered location area scheme is considered to minimize the boundary cell overload in the microcellular systems. The formulation for the appropriate location registration area is obtained by the considering the regional information, traffic rates and call arrival rates of each cell. And we solve the formulation by the modified graph partitioning algorithm and feasible LR area procedure. Some simulations are performed to investigate the performance of the multi-layered scheme. The results of the simulation indicate that the multi-layered scheme produces less paging and location updating signal cost than that of the one-layer scheme.
Finally, A 0-1 integer programming model is considered to determine the most appropriate dynamic location registration area of each subscriber in microcellular systems. The minimization model of the LR area updating and paging signal costs is examined. The model is based on the subscriber characterisitcs such as the call arrival rate and the velocity as well as the regional information. The control channel blocking probabilities are considered as constraints to meet the service level of subscribers. A dynamic scheme which adaptively updates the size and shape of the location areais developed by solving the minimization problem. Paging and location updating procedures are presented based on the dynamic procedure.
The dynamic location registration method and multi -layered location area scheme can be used to minimize the paging and location updating signals in the micorcellular telecommunication systems and personal communication services. And these schemes can be used in the interation of total communication systems and next generation telecommunication systems.
