Mobility management is very important in mobile cellular networks, since to connect incoming calls, the network must maintain the locations of the mobiles. This study considers the zone-based registration methods that most mobile cellular networks have adopted. We focus on two special zone-based registration methods, called two-zone registration (2Z), and two-zone registration with implicit registration by outgoing calls (2Zi). Although some mathematical models for their performances have been presented, they still cannot accurately estimate 2Zi performance. We provide a new and simple mathematical model based on Markov chain theory that can accurately analyze the performances of 2Z and 2Zi. We also explain the propositions underlying the explicit expressions adopted by our model. We finally present various numerical results, to compare the performance of 2Zi with those of 2Z and one-zone registration (1Z), and show that in every case, 2Zi is superior to 2Z, and in most practical cases, to 1Z.

In this study, 2-location distance-based registration (2DBR) is proposed to improve the performance of traditional distance-based registration. In distance-based registration, when a mobile station (MS) enters a new cell, the MS calculates the distance from the last registered cell and registers its location if the calculated distance reaches a prescribed distance threshold D. In 2DBR, an MS stores not only the last registered location area (LA) but also the second-to-last LA, and then no registration is performed when the MS crosses the two stored LAs. The 2DBR may increase paging cost but it may decrease registration cost. Simulation results show that our proposed 2DBR outperforms current distance-based registration in most cases.

In group location management, when a transportation system (TS) with mobile stations (MSs) changes location area (LA), only a single group location update by the TS is needed, instead of multiple individual location updates by MSs riding on the TS. Therefore, group location management significantly reduces location update signaling of the current individual location management. In this paper, we further improve the conventional group location management, by paging cells containing the route of public TS within an LA only, if an incoming call arrives at an MS riding on the TS, based on the observation that public TS, such as bus, subway, and train, follows a fixed route; its movement is not random. The performance of the proposed scheme is analyzed in terms of total signaling cost based on the modeling of public TS route. Numerical results reveal that the proposed scheme significantly outperforms the conventional scheme from the aspect of total signaling cost, at the expense of small network overhead due to the additional queries needed to acquire public TS route information.

Although a lot of works for location management in wireless networks have been reported in the literature, most of the works have been focused on designing per-user-based strategies. This means that they can achieve the performance enhancement only for a certain class of mobile users with a specific range of CMR (call-to-mobility ratio). However, these per-user-based strategies can actually degrade the performance if a user's CMR changes significantly. Therefore, an efficient uniform location management strategy, which can be commonly applied to all mobile users regardless of their CMR, is proposed and analyzed in this paper. The motivation behind the proposed strategy is to exploit the concepts of the two well-known existing strategies: the location caching strategy and the local anchor strategy. That is, the location caching strategy exploits locality in a user's calling pattern, whereas the local anchor strategy exploits locality in a user's mobility pattern. By exploiting these characteristics of both strategies together with the profile management at the HLR (home location register), the proposed strategy can reduce the frequent access to the HLR, and thus effectively results in significant reduction in terms of the total location management cost. The analytical results also demonstrate that the proposed strategy can be uniformly applied to all mobile users, while always maintaining the performance gain over the IS-41 standard regardless of a user's CMR and the network traffic conditions.

We propose Concatenated Location Management (CLM), utilizing tendency for mobile terminals (MTs) to move as a group. When many MTs are on the same train, for example, they move together and share the same mobility characteristics. Therefore, we propose to concatenate the MTs and link them to the train for more efficient location management. CLM can reduce the number of location management signals because the train sends only one location registration signal on behalf of all of the individual MTs when a location registration area boundary is crossed. We discuss the key functions for CLM including location registration, paging, and location register configuration.

Tracking mobile users in cellular wireless networks involves two basic functions: location update and paging. Location update refers to the process of tracking the location of mobile users that are not in conversation. Three basic algorithms have been proposed in the literature, namely the distance-based, time-based, and movement-based algorithms. The problem of minimizing the location update and paging costs has been solved in the literature by considering exponentially distributed Cell Residence Times (CRT) and Inter-Call Time (ICT), which is the time interval between two consecutive phone calls. In this paper we select the movement-based scheme since it is effective and easy to implement. Applying the theory of the delayed renewal process, we find the distribution of the number of cell crossings when the ICT is a mixture of exponentially distributed random variables and the CRT comes from any distribution with Laplace transform. In particular, we consider the case in which the first CRT may have a different distribution from the remaining CRT's, which includes the case of circular cells. We aim at the total cost minimization in this case.

The second generation of mobile communications is growing rapidly to the third generation due to various communication techniques and the increasing number of users. PCS, the communication method of the third generation, should be able to provide users with various services, independently of the current location. To PCS, the mobility management of users is essential. The mobility management method which has been used has a structural drawback: as the number of users increase, HLR becomes the bottleneck. Everyone is expected to have one terminal in the third generation mobile communications age. Therefore, an enhanced mobility management scheme to reduce the bottleneck of the HLR, should be used in the third generation mobile communications. In this paper, we propose a new mobility management method where the trace of terminals is left in the VLRs, so that a call can be connected by querying only to the VLRs rather than to the HLR when the terminal-terminated-call occurs. The proposed method distributes messages to VLRs and effectively reduce mobility management cost. To estimate overall mobility management cost, we simulated the new method of PCS network. The simulation model is based on the Jackson's network, and makes it possible to estimate mobility management cost of PCS networks. IS-41 and proposed scheme are compared based on the computer simulation. Considering the delay times both in HLR and VLR, and considering both location registration cost and call delivery cost, the proposed modeling method shows the improvement.

In this paper, we evaluated performance of mobile exchange control network. Queueing network model is used for modeling of mobile exchange control network. We developed a call control processing and location registration scenario that has a message exchange function between processors in mobile exchange control network. The network symbols are used the simulation models that are composed of the initialization module, message generation module, message routing module, message processing module, message generation module, HIPC network processing module, output analysis module. As a result of computer simulation, we obtain the processor utilization, the mean queue length, the mean waiting time of control network based on call processing and location registration capacity. The call processing and location registration capacity are referred by the number of call attempts in the mobile exchange and must be satisfied with the quality of service (delay time).

A location registration/paging procedure which is free from location registration area design is proposed. Each base station (BS) broadcasts a "responsibility area", composed of its own and neighboring cells' identification (ID). A mobile station (MS) makes a new location registration request when the current BS's responsibility area does not include the MS's registered location. Each BS is allowed to decide its own responsibility area autonomously based on route information, which is composed of neighboring cells' ID and reported from MSs. Therefore, the responsibility area can be adaptively changed based on MSs' moving characteristics. Moreover, this procedure solves the problems of registration traffic concentration and excess registration request on boundary BSs.