Using a Novel Intelligent Location Management Strategy in Cellular Networks

This paper aims at improving the distance-based location management scheme for mobile communication networks. In location management, a mobile terminal (MT) is tracked based on its location-update area (LA). The improvement is brought about by joint optimization of LA center and LA size. For LA center optimization (LCO), we determine the optimal center position of the LA given the initial position of the MT upon each location update. The investigation of optimal LA center has eluded research to date. Based on the popular continuous-time random walk (CTRW) mobility model, we propose an analytical framework that uses a diffusion equation to determine the optimal LA center that minimizes the total cost of location management, consisting of the location update cost and terminal paging cost. This framework allows us to easily model the non-Markovian movement of the MT and evaluate the impact of various measurable physical parameters (such as length of road section, angle between road sections, and road section crossing time) and LA center. In particular, we show that proper LA center can significantly reduce the total cost. For example, for the circular LA and low Poisson call-arrival rate, optimizing the LA center alone has the potential of reducing the cost by up to 37 percent. Joint optimization of the LA center and terminal paging scheme can reduce the cost even further. Simulations results match the theoretical analysis to a gap within 3 percent, indicating that our theoretical model is very accurate.

In this paper, we develop an analytical model of the signaling costs due to location update and paging for the radio interface in mobile communications networks. This model accounts for the effects that the savings brought by different algorithms have on the total Location Management (LM) costs. It also takes into account the trade-off between the location update and paging costs, showing that those strategies that achieve savings in the location update costs deliver a larger overall improvement in the total LM costs than those algorithms focusing on the minimization of the paging costs. Moreover, leveraging the factors studied to obtain this model, we also analyze the overall LM costs including the fixed network part.

The paper proposes an integrated location management scheme, based on our previously proposed novel rule-based paging scheme (RBPS) for reducing the cost of terminal paging in a cellular wireless environment. We extend that scheme to propose a complete location management scheme. This requires application of RBPS together with a judicious movement based location update (LU) scheme. Numerical results show that the proposed integrated location management scheme, called RBPS*, not only attempts to resolve the issue of inherent tradeoff between the cost components, comprised of paging and LU cost, but also does reduce the total cost for location management compared to the other schemes. RBPS* significantly outperforms RBPS and the GSM-adopted blanket paging scheme along with movement based LU. When compared with the popular shortest distance first (SDF) scheme, results are again encouraging. The proposed scheme, RBPS*, is a generic one and can be deployed on-line. It has the potential for use in next generation wireless networks, irrespective of any standards.

Location management is the basis for ensuring service continuity in low earth orbit (LEO) satellite mobile communication systems. The dual mobility of LEO satellites and mobile users triggers frequent location update procedures, which will increase the network location management overhead and bring great challenges to network location management, especially in the mega satellite networks. In this paper, we propose a location management technology solution for mega satellite networks, including location management architecture, location area design, location update, and paging procedures. A medium earth orbit (MEO) satellite-assisted location management architecture is proposed to improve the efficiency of location management. It extends the location management control plane from the ground to space and adopts a distributed location management mechanism. A dual location area, including the satellite location area and user location area, is designed to balance the network location update and paging overhead. Based on the dual location area, we systematically design low-overhead location update and paging procedures. Simulation results have verified that the proposed location management technology solution can reduce the total location management overhead and delay by at least 45.8% and 20.8%, respectively.

Location management is a paramount issue in wireless mobile station communication systems to enable the terminals to continuously receive services when moving from one location to another. In this paper, we study the trends in the latest cellular wireless systems to page terminals, update location area and make handover decisions for a mobile station. Topics covered include static and dynamic location management, dynamic location areas and techniques, future location management developments, location tracking evolution and location management in 3G. It will be shown that location-area based location management methods designed around a profile or history-based direction information offer the best performance, in terms of location management cost, compared to all other alternative approaches while distance based schemes are to be the most efficient ones.

Application of AI techniques for locating mobile terminals in mobile wireless cellular networks: A novel paging scheme

Location management schemes are essentially based on users' mobility and incoming call rate characteristics. The network mobility process has to face strong antagonism between its two basic procedures: location update (or registration) and paging. The location update procedure allows the system to keep location knowledge more or less accurately in order to find the user in case of an incoming call, for example. Location registration also is used to bring the user's service profile near its location and allows the network to rapidly provide the user with services. The paging process achieved by the system consists of sending paging messages in all cells where the mobile terminal could be located. A detailed description of the means and techniques for user location management in present cellular networks is addressed.A network must retain information about the locations of endpoints in the network in order to route traffic to the correct destinations. Location tracking (also referred to as mobility tracking or mobility management) is the set of mechanisms by which location information is updated in response to endpoint mobility. In location tracking, it is important to differentiate between the identifier of an endpoint (i.e., what the endpoint is called) and its address (i.e., where the endpoint is located). Mechanisms for location tracking provide a time-varying mapping between the identifier and the address of each endpoint. Most location tracking mechanisms may be perceived as updating and querying a distributed database (the location database) of endpoint identifier-to-address mappings. In this context, location tracking has two components: (1) determining when and how a change in a location database entry should be initiated; and (2) organizing and maintaining the location database. In cellular networks, endpoint mobility within a cell is transparent to the network, and hence location tracking is only required when an endpoint moves from one cell to another. Location tracking typically consists of two operations: (1) updating (or registration), the process by which a mobile endpoint initiates a change in the location database according to its new location; and (2) finding (or paging), the process by which the network initiates a query for an endpoint's location (which also may result in an update to the location database). Most location tracking techniques use a combination of updating and finding in an effort to select the best trade-off between update overhead and delay incurred in finding. Specifically, updates are not usually sent every time an endpoint enters a new cell, but rather are sent according to a predefined strategy so that the finding operation can be restricted to a specific area. There is also a trade-off, analyzed formally between the update and paging costs.Location management methods are most adapted and widely used in current cellular networks, e.g., GSM, IS-54. IS-95, etc. The location management methods are broadly classified into two groups. The first group includes all methods based on algorithms and network architecture, mainly on the processing capabilities of the system. The second group contains the methods based on learning processes, which require the collection of statistics on subscribers' mobility behavior, for instance.

Location management which keeps track of the mobile terminals moving from place to place in a wireless networks is a key issue in resource management particularly in 3G cellular networks. Two basic operations are involved in location management: location update and paging. It is necessary to provide a good trade off between location update and paging to reduce the total cost. This goal however needs good algorithms for both registration and paging. We propose a dynamic movement-base location management scheme for 3G networks where Home Location Registers (HLR's), Gateway Location Registers (GLR's), and Visitor Location Registers (VLR's) are formed into three level hierarchical mobility data base structure. A simulator based on MATLAB which can study location update and paging performance was developed. It is expected that the average number of location updates could be reduced using the movement-base scheme.

A practical information theoretic framework is developed for studying the optimal tradeoff between location update and paging costs in cellular networks. The framework envisions the quantization of location information into a registration area (RA) level granularity, followed by the use of an entropy-coding technique to decrease the location update rate. The rate distortion theory of the lossy quantization is identified as an appropriate measure for capturing the optimal tradeoff between a mobile's update rate and its location uncertainty. Based on LZ-78 compression, two different RA-level location update algorithms (RA-LeZi and LeZi-RA) have been developed, both of which asymptotically approach this rate-distortion bound. By allowing for quantization loss in the mobile node's movement pattern, this framework can reduce the overall update cost below the entropy bound associated with the original loss-less LeZi-update mobility management algorithm. Simulation results demonstrate a sharp decrease (/spl sim/ 50%) in the update cost, at the expense of a minor (/spl sim/ 25%) increase in the overall location management costs. The key essence of this framework lies in its practical applicability, because today's wireless networks already track the mobile user at an RA-level granularity.

Mobility management is an important aspect in LEO systems. In terrestrial wireless networks, the movement of the user triggers location updating and determines the paging scheme, while in LEO satellite systems, location updating and paging is mainly based on the movement of satellites. Terrestrial location management techniques must be altered to fit LEO systems. The paper introduces a modified movement-based location update and paging scheme in LEO networks. We propose the meta-cell concept, which includes two spot-beams of one satellite. First, we present a location management scheme based on the architecture with a meta-cell location area. Then, an analytical model is applied to formulate the cost of location updating and location paging for the movement and meta-cell based dynamic location update scheme. The comparison of performance between the meta-cell architecture method and the conventional signal-spot-cell architecture method is provided to demonstrate the cost-effectiveness and robustness of the proposed scheme under various parameters. To reduce the impact of meta-cell architecture on location paging cost, we present a forced location update strategy which is used in the case that the meta-cell includes two spot-beams from different satellites.

The scarce radio resources available to any cellular radio network have to be shared between its revenue-generating voice- and data-carrying services, and non-revenue-generating management services. One of these management services is location management, crucial for the network to keep track of the location of its subscribers and to connect their incoming calls. Location management consists of the two activities, paging and location updating, both of which are structured around a subdivision of the network service area called the location area (LA). The ways in which the service area is partitioned therefore has a direct impact on the amount of radio bandwidth that has to be spent on location management. However, paging and location updating share an antagonistic relationship, and finding the optimal LA partitioning that strikes a balance between the two is a challenging design problem. In this paper, the problem of finding the optimal LA partitioning of a cellular radio network service area in order to minimise the total location management signalling cost is addressed. The choice of the decision variables used in the mathematical programming model results in an objective function that is conceptually easy to understand and a solution method that is simple and straightforward.

Location management deals with how to track mobile users within the cellular network. It consists of two basic operations: location update and paging. The total location management cost is the sum of the location update cost and the paging cost. Location areas and reporting centers are two popular location management schemes. The motivation for the study is the observation that the location update cost difference between the reporting centers scheme and the location areas scheme is small whereas the paging cost in the reporting centers scheme is larger than that in the location areas scheme. The paper compares the performance of the location areas scheme and the reporting centers scheme under aggregate movement behavior mobility models by simulations. Simulation results show that the location areas scheme performs about the same as the reporting centers scheme in two extreme cases, that is, when a few cells or almost all cells are selected as the reporting cells. However, the location areas scheme outperforms the reporting centers scheme at the 100% confidence level with all call-to-mobility ratios when the reporting cells divide the whole service area into several regions.

LOCATION MANAGEMENT AND COST PLANNING FOR PERSONAL COMMUNICATION SYSTEMS

As PCS networks aim to provide 'anytime-anywhere' cellular services, mobile terminals' (MTs) locations should be managed continuously. Location management (LM) includes two processes; registration and paging. Registration concerned with reporting MTs current locations, while, paging locates the callee MT. Both processes incur signalling cost across the wireless channel, which need to be reduced due to the scarcity of PCS wireless bandwidth. In spite of its minimal latency, blanket paging, used in current networks, wastes the network bandwidth. This paper aims to reduce the paging signalling cost under delay bounds. The paper contributions can be summarised as: 1) establishing a family of paging strategies under two proposed probability based LM strategies (PBLM and MPBLM); 2) introducing a novel topology for PCS registration area called the 'hot spot topology' (HST); 3) based on HST, another new LM strategy called 'flower based location management' (FBLM) is introduced. The proposed paging strategies substantially lower the signalling cost compared with the blanket one. Also, experimental results have shown that FBS dramatically reduce the signalling load (up to 80%) with a minimal increase in paging delay.

This paper proposes a location management scheme—combining dynamic location update scheme with static one for the next-generation mobile cellular networks. In the proposed strategy, instead of adopting dynamic location management for all mobile users, classifying them into DLMU(Dynamic Location Management User) and SLMU(Static Location Management User) by a CMR(Call-to- Mobility-Ratio) threshold. Compared with the conventional location update scheme, this strategy can make good use of the dynamic, movement-based location update scheme employed in this paper. Moreover, this paper analyzes how to choose the CMR threshold by simulation. As for the next-generation mobile cellular networks, this proposed scheme can be implemented to reduce the signaling cost evidently, for its facility and feasibility compared with the conventional dynamic location management.