Effect of personal mobility management in mobile communication networks

Personal mobility (PM) is one of the key issues in realizing a personal communications service (PCS) in emerging third-generation mobile communication networks such as IMT-2000. It can be realized through the universal personal telecommunication (UPT) service. Two PM management schemes are proposed to manage PM information related to UPT users for incoming call (incall) registration/deregistration, incall registration reset by a mobile terminal (MT) owner, and incall delivery to UPT users in mobile communication networks based on the location information managed by the user's home network. The relative cost, i.e., the ratio of cost per unit time for supporting both terminal mobility (TM) and PM management to that of TM management, is derived, and the effect of PM management is analyzed from the aspects of update or query cost, signaling delivery cost, and processing cost. These results can be utilized in the implementation of PM management in IMT-2000.     

Developing technologies for personal communication networks

The author reviews the technologies needed to meet the demands of the personal communication network (PCN) service, and gives the reasons why the three successful PCN applicants stated their preference for Groupe Speciale Mobile, (GSM) as the basis for PCN. Then the author discusses how, based on GSM, the DCS1800 standard (digital communication system at 1800 MHz) was elaborated by ETSI to meet PCN requirements     

Satellite systems for personal communication networks

The paper addresses some issues related to Satellite Personal Communication Networks (S‐PCNs). The role of satellite communications in that scenario is discussed, and some characteristics of S‐PCNs are identified. In addition, the problem of the integration of S‐PCNs with the Universal Mobile Telecommunication System (UMTS) is considered. In this respect an original methodology for accomplishing such integration is proposed; such methodology aims at avoiding complex protocol conversions at the interfaces between the terrestrial and the satellite segment. The paper is partly based upon the work performed by the authors in the framework of the European Community INSURED Project “INtegrated Satellite UMTS Real Environment Demonstrator”. This revised version was published online in June 2006 with corrections to the Cover Date.     

Topology-based tracking strategies for personal communication networks

This paper explores tracking strategies for mobile users in personal communication networks which are based on thetopology of the cells. We introduce the notion oftopology-based strategies in a very general form. In particular, the known paging areas, overlapping paging areas, reporting centers, and distance-based strategies are covered by this notion. We then compare two topology-based strategies with the time-based strategy on the line and mesh cell topology.     

Restoration scheme of mobility databases by mobility learning andprediction in PCS networks

This paper proposes a restoration scheme based on mobility learning and prediction in the presence of the failure of mobility databases in personal communication systems (PCSs). In PCSs, mobility databases must maintain the current location information of users to provide a fast connection for them. However, the malfunction of mobility databases may cause some location information to be lost. As a result, without an explicit restoration procedure, incoming calls to users may be rejected. Therefore, an explicit restoration scheme against the malfunction of mobility databases is needed to guarantee continuous service availability to users. Introducing mobility learning and prediction into the restoration process allows systems to locate users after a failure of mobility databases. In failure-free operations, the movement patterns of users are learned by a neuro-fuzzy inference system (NFIS). After a failure, an inference process of the NFIS is initiated and the users' future location is predicted. This is used to locate lost users after a failure. This proposal differs from previous approaches using a checkpoint because it does not need a backup process nor additional storage space to store checkpoint information. In addition, simulations show that our proposal can reduce the cost needed to restore the location records of lost users after a failure when compared to the checkpointing scheme     

Empowering next-generation wireless personal communication networks

Next-generation wireless systems should provide to the user access to a broad range of services in a transparent way, independent of user location by making the technology invisible and embedded in the natural surroundings. Reaching this goal requires efficient cooperation between heterogeneous networking technologies and different protocols. Wireless personal networks are an integral part of such an emerging heterogeneous infrastructure. It is highly desirable, and in fact required due to economical constraints, to incorporate the present wireless systems in building the new paradigm. The key "protocol glue" between systems is the use of IP. Based on this scenario, we describe an architecture suited for the present and future personal mobile communications networks and services.     

Global mobility management by replicated databases in personalcommunication networks

This paper explores the use of replicated databases for management of customer data (e.g., mobility data, call routing logic) in global, intelligent, and wireless networks. We propose and analyze two, full and partial, data replication schemes-which are compatible with industry protocol standards-and compare them with the traditional, centralized database scheme. By identifying a set of key teletraffic and mobility parameters, we develop a modeling framework based on queueing models and apply it to assess the relative performance and merits of these schemes. The paper also addresses some implementation issues. Numerical results reveal that the full replication scheme outperforms the centralized one over a wide range of the parameters considered in this study. Furthermore, if some customer data-such as location data for highly mobile customers in wireless networks-change frequently, and if each call launches multiple queries into the databases, the partial replication scheme offers further performance improvement. In general, however, the choice of the database design would depend on the specific characteristics of the service and user behavior under consideration     

Locating strategies for personal communication networks, a noveltracking strategy

The partition of location areas is designed to minimize the total costs of finding users' location and tracking their movement in personal communication networks (PCNs). A new scheme to partition and track mobile users and its implementation based on cellular architecture are proposed. According to the tracking strategy, the mobile station (MS) transmits only update messages at specific reporting cells, while the search for a mobile user is done at the vicinity of the cell to which the user has just reported. We use the cost analysis model to demonstrate the feasibility of updating and searching costs to reduce the amount of resources when using wireless channels. Simulations are performed to compare the performance of three schemes: always update, always search, and our new scheme     

Call/mobility processing capacity of the personal communication exchange

We analyze the call processing capacity of a personal communication exchange (PCX) for various call types (local, outgoing, incoming and transit calls). We also analyze the mobility processing capacity of the PCX for mobility functions (handover and location registration). The call/mobility processing capacities are calculated by simulation on a queueing network model. The delay times in the processing of call and mobility functions are also calculated by simulation and queueing network analyzer (QNA) for comparison between the two methods. We focus our analysis on the PCX system with distributed call/mobility processing structure, which has been under development in Korea. The numerical computations show that the results from the simulation and QNA are in closer agreement when the utilization rate (the faction of time a processor is busy) of processor handling the mobility functions becomes lower. It is estimated that the call processing capacity of the PCX is 421,280 busy hour complete call (BHC) which is equivalent to 150,700 subscribers of 1.6 BHC. The handover and location registration processing capacities are calculated to be 26,000 transactions/hour and 406,000 transactions/hour, respectively. This revised version was published online in August 2006 with corrections to the Cover Date.     

Transition management for sustainable personal mobility

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Design and analysis of dynamic mobility tracking in wirelesspersonal communication networks

In personal communication networks (PCN), mobility tracking provides the function of locating a mobile user within the service area. We propose an intersection-oriented dynamic location update (LU) strategy, which is designed to minimize the cost of mobility tracking by optimally partitioning the service area into location registration (LR) areas on a per-user basis. A realistic mobility model is proposed in which we consider not only the mobility behavior of the individual subscriber, but also the street layout. Based on this model, a transient Markov process is developed to analyze the tracking cost. To reduce the implementation cost and to make the proposed strategy feasible, the concept of mobile subscriber (MS) grouping, and equivalent quadrangular LR area are also adopted     

Performance evaluation of a CDMA protocol for voice and dataintegration in personal communication networks

Future wireless personal communication networks (PCN's) will require voice and data service integration on the radio link. The multiaccess capability of the code-division multiple-access (CDMA) technique has been widely investigated in the recent literature. The aim of this paper is to propose a CDMA-based protocol for joint voice and data transmissions in PCN's. The performance of such a protocol has been derived by means of an analytical approach both in terms of voice packet dropping probability and mean data packet delay. Voice traffic has been modeled as having alternated talkspurts and silences, with generation of voice packets at constant rate during talkspurts and no packet generation during silence gaps. A general arrival process is assumed for the data traffic. However, numerical results are derived in the case of a Poisson process. Simulation results are given to validate our analytical predictions. The main result derived here is that the proposed CDMA-based protocol efficiently handles both voice and data traffic. In particular, it is shown that the performance of the voice subsystem is independent of the data traffic     

Active tracking: Locating mobile users in personal communication service networks

The problem of tracking mobile users in Personal Communication Service (PCS) networks is discussed. We propose a novel approach for reducing the wireless cost of tracking users. The basic idea is to use nonutilized system resources for initiating queries about the location of mobile users, in addition to the process of user registration. Queries are applied at each cell, independently of the other cells, whenever the load on the local control channel drops below a predefined threshold. Our study focuses on two issues: (1) proposing the initiated queries approach and an algorithm for its application, and (2) studying and quantifying the value of location information and evaluating the parameters affecting it. Our analysis shows that the expected benefit due to location knowledge in a Markovian motion model depends, among other things, on the determinant of the transition matrix and on the variability of the location distribution function. The active tracking approach, as opposed to other dynamic strategies, does not require any modification of user equipment. The importance of this property is in its practicality: An implementation of a new registration strategy in current systems would require a modification of the users equipment. Moreover, the proposed method can be easily implemented in addition to any known tracking strategy, to reduce further the tracking cost. The performance of the active tracking method is evaluated under two registration strategies: The geographicbased strategy, currently used in cellular networks, and the profilebased strategy, suggested elsewhere. Under both strategies, it significantly reduces the tracking cost.     

Energy-efficient resource allocation model for device-to-device communication in 5G wireless personal area networks

In general, there are several many devices that can overload the network and reduce performance. Devices can minimize interference and optimize bandwidth usage by using directional antennas and by avoiding overlapping communication ranges. In addition, devices need to carefully manage their use of resources, such as bandwidth and energy. Bandwidth is limited in wireless personal area networks (WPANs), so devices need to carefully select which data to send and receive. In this paper, an intelligent performance analysis of energy-efficient resource optimization model has been proposed for device-to-device (D2D) communication in fifth-generation (5G) WPAN. The proposed energy-efficient resource allocation in D2D communication is important because it helps reduce energy consumption and extend the lifespan of devices that are communicating with each other. By allocating resources in an efficient manner, communication between two devices can be optimized for maximum efficiency. This helps reduce the amount of energy needed to power the communication, as well as the amount of energy needed to power the device that is communicating with another device. Additionally, efficient resource allocation helps reduce the overall cost of communication, as the use of fewer resources results in a lower overall cost. The proposed efficient resource allocation helps reduce the environmental impact of communication, as less energy is used for communication. The proposed energy-efficient resource allocation model (EERAM) has reached 92.97% of energy allocation, 88.72% of power allocation, 87.79% of bandwidth allocation, 87.93% of spectrum allocation, 88.43% of channel allocation, 25.47% of end-to-end delay, 94.33% of network data speed, and 90.99% of network throughput.     

Per-user checkpointing for mobility database failure restoration

This paper studies the failure restoration of mobility database for Universal Mobile Telecommunications System (UMTS). We consider a per-user checkpointing approach for the home location register (HLR) database. In this approach, individual HLR records are saved into a backup database from time to time. When a failure occurs, the backup record is restored back to the mobility database. We first describe a commonly used basic checkpoint algorithm. Then, we propose a new checkpoint algorithm. An analytic model is developed to compare these two algorithms in terms of the checkpoint cost and the probability that an HLR backup record is obsolete. This analytic model is validated against simulation experiments. Numerical examples indicate that our new algorithm may significantly outperform the basic algorithm in terms of both performance measures.     

Paging area optimization based on interval estimation in wireless personal communication networks

We consider an optimum personal paging area configuration problem to improve the paging efficiency in PCS/cellular mobile networks. The approach is to set up the boundaries of a one-step paging area that contain the locations of a mobile user with a high probability and to adjust the boundaries to gain a coverage that is matched to the mobile user's time-varying mobility pattern. We formulate the problem as an interval estimation problem. The objective is to reduce the paging signaling cost by minimizing the size of the paging area constrained to certain confidence measure (probability of locating the user), based on a finite number of available location observations of the mobile user. Modeling user mobility as a Brownian motion with the drift stochastic process and by estimating the parameters of the location probability distribution of the mobility process, the effects of the mobility characteristics and the system design parameters on the optimum paging area are investigated. Results show: (1) the optimum paging area expands with the time elapsed after the last known location of the user; (2) it also increases with the length of a prediction interval and the location probability; (3) the relative change in the paging area size decreases with the increase in the number of location observations. This revised version was published online in June 2006 with corrections to the Cover Date.     

Paging area optimization based on interval estimation in wireless personal communication networks

We consider an optimum personal paging area configuration problem to improve the paging efficiency in PCS/cellular mobile networks. The approach is to set up the boundaries of a one-step paging area that contain the locations of a mobile user with a high probability and to adjust the boundaries to gain a coverage that is matched to the mobile user's time-varying mobility pattern. We formulate the problem as an interval estimation problem. The objective is to reduce the paging signaling cost by minimizing the size of the paging area constrained to certain confidence measure (probability of locating the user), based on a finite number of available location observations of the mobile user. Modeling user mobility as a Brownian motion with the drift stochastic process and by estimating the parameters of the location probability distribution of the mobility process, the effects of the mobility characteristics and the system design parameters on the optimum paging area are investigated. Results show: (1) the optimum paging area expands with the time elapsed after the last known location of the user; (2) it also increases with the length of a prediction interval and the location probability; (3) the relative change in the paging area size decreases with the increase in the number of location observations. This revised version was published online in June 2006 with corrections to the Cover Date.     

The simulation modelling and performance analysis of low earth orbit satellite communication networks for personal communications

This paper extends previous research efforts related to the simulation performance modelling and analysis of satellite communication networks. Specifically, the use of low earth orbit (LEO) satellite networks for personal communications is examined. Six different satellite constellation configurations are investigated in a packet‐switched operating environment. Performance metrics examined are the end‐to‐end packet delay and the utilization of satellite channels in the dynamic environment. Realistic and accurate models of the physical satellite network and its terrestrial transmitters require that numerous operating characteristics and assumptions be specified. These are based on proposed design requirements of commercial systems, such as Iridium. Via the use of simulation, we show the relative delay and utilization performance of differing satellite network architectures. From these simulation models, mathematical metamodels are derived for the system delays. These innovative models are used to predict the delay performance of different network architectures not previously simulated. Comparison of these metamodels with simulation results show that metamodels provide an accurate means for performance prediction. Copyright © 1999 John Wiley & Sons, Ltd.     

光网络分布式恢复机制的恢复时间分析

针对光网络分布式恢复中动态恢复和预计算路由恢复两大类机制,就恢复时间这一至关重要的恢复参数进行了性能分析.通过比较,指出预计算路由恢复机制在快速恢复方面具有更优的性能.     

Control architecture for next-generation communication networksbased on distributed databases

Intelligent routing control is defined as the process in which the network interrogates the databases containing the relationships between logical numbers, such as personal or information identifiers, and physical addresses in the transport network to find the terminal having the information required to process a user request. The routing control system presented uses distributed databases, each of which manages a switching system and all of which are connected through high-speed signalling networks separate from the transport network. If the requested physical address cannot be found in one database, search requests are distributed at the same time to all other databases. For up to 100 million subscribers, the routing control system can find a physical address within 1 s when each database uses ten memories accessed at 200 ns with an interdatabase linkage speed of 14 Mb/s