Reducing location update and paging costs in a PCS network

Mobility tracking operations in a personal communication service (PCS) system are signaling consuming. Several strategies have been proposed in the literature to reduce both the location update (LU) and the paging (PG) costs. In this paper, we propose a location-tracking algorithm called three-location area (TrLA), combined with selective paging. In TrLA, the mobile terminal (MT) allocates the identification of three neighboring location areas (LAs) in its local memory. We call this set of three LAs, a big-location area (BLA). Each time the MT exits the BLA, it triggers an LU message to the system databases via a base station, in order to maintain the databases up to date. The MT also updates its cache memory. A two-step selective PG is also considered and compared with the single-step (or nonselective PG). An analytical model based on a semi-Markov process has been used to evaluate our proposal. This scheme is compared with the classical Global System for Mobile Communications (GSM) standard and the two-location algorithm proposal. As a result, this new scheme outperforms the cited strategies, and in our opinion, it can easily be implemented in existing standard cellular and personal communication systems     

室内定位系统中位置指纹库滤波算法研究

WiFi指纹定位是目前最受欢迎的室内定位技术之一,离线阶段创建的位置指纹库的精确与否对定位的精准度有很大的影响。传统的指纹库构建一般对采集的数据进行均值滤波,误差较大,并且在范围较大的场合进行定位时,由于位置指纹数据过多,使得定位时效性不好,结果不理想。为了提高指纹库的可靠性,通过给采集的源指纹数据赋予权值并根据权值的大小划分有效数据进行滤波处理,建立高精度指纹库,并利用基于临近域加权最近邻算法进行验证。实验结果表明,与传统的构建指纹库和定位算法相比,该方法显著提高了定位精度,缩短了定位时间。     

Dynamic periodic location area update in mobile networks

In mobile communications networks, periodic location area update (PLAU) is utilized to detect the presence of a mobile station (MS). In the 3GPP Technical Specifications 23.012 and 24.008, a fixed PLAU scheme was proposed for the Universal Mobile Telecommunications System (UMTS), where the interval between two PLAUs is of fixed length. We observe that MS presence can also be detected through call activities and normal location area update (NLAU). Therefore, we propose a dynamic PLAU scheme where the PLAU interval is dynamically adjusted based on the call traffic and NLAU rate. An analytic model is developed to investigate the performance of dynamic and fixed PLAU schemes. This paper provides guidelines to select parameters for dynamic PLAU.     

Reducing location update cost in a PCS network

Location tracking operations in a personal communications services (PCSs) network are expensive. Several strategies have been proposed to reduce the location update cost. This paper studies a special case of a location tracking algorithm called the alternative location algorithm. This special case is referred to as the two location algorithm (TLA). An analytical model is proposed to compare the performance of the TLA and the IS-41 protocol. Our study indicates that the performance of the TLA is significantly affected by the user moving patterns and the call traffic. If the user mobility is higher than the call frequency or the user tends to move back to the previously visited registration areas, then the TLA may significantly outperform IS-41. We also observe that the variance of the portable residence times in registration areas has an impact on the performance of the TLA (i.e., better performance is expected for larger variance)     

基于多跳蜂窝网的组位置管理策略

提出了一种成组进行位置管理的策略,分析了彼此临近的移动台组成一个自组织网的基本网络模型,提出了向中继点注册,由中继点进行信令压缩,组成组控制信令,成批向网络报告位置的位置更新的策略;采用M/M/n/n模型具体比较了批处理方案与传统方案的性能,说明作者的方案不仅减少了移动台的发射功率,还大量节省了频率资源,增加了系统的吞吐能力。     

Dynamic provisioning of availability-constrained optical circuits in the presence of optical node failures

This paper investigates what impact optical node failures may have on wavelength-division-multiplexed networks, in which reliable end-to-end optical circuits are provisioned dynamically. At the node level, the optical cross-connect (OXC) equipment availability measure is estimated using proven component level availability models. At the network level, end-to-end optical circuits are provisioned only when the level of connection availability required by the application can be guaranteed. With the objective of yielding efficient utilization of the network resources, i.e., fibers and OXCs, circuit redundancy is achieved by means of shared path protection (SPP) switching, in combination with differentiated reliability (DiR). The resulting optimal routing and wavelength assignment problem is proven to be NP-complete. To produce suboptimal solutions in polynomial time, a heuristic technique is presented, which makes use of a time-efficient method to estimate the end-to-end circuit availability in the presence of multiple (link and node) failures. Using the proposed heuristic, a selection of representative OXC architectures and optical switching technologies is examined to assess the influence of the node equipment choice on the overall network performance.     

Methods for optimizing the location of base stations for indoor wireless communications

When designing wireless communication systems, it is very important to know the optimum locations for the base station antennas. In this paper, a model has been developed to set up an optimization problem, the solution of which provides the information for the optimum location of the base station antennas particularly for an indoor environment. Several methods for the optimization of the cost function are presented and the final results are compared with each other. This methodology can be applied for the design and planning of the location of base station antennas for indoor wireless communication systems. Two numerical examples have been presented to illustrate the application of this methodology.     

浅析TD-SCDMA位置更新对接通率的影响

本文从4个方向分析由位置更新导致的呼叫不可达,并一一给以优化解决意见.     

全分布式位置管理策略的负载和位置更新性能研究

分布式位置管理策略及其分布式数据库结构与传统位置管理策略和HLR－VLR结构有显著区别,本文基于一种对DDB结构新的性能估计方法,从用户的移动性概率分布出发,对DDB结构下的数据库负载和位置更新性能进行了研究。     

A practical method of optimizing system life cycle costs vs availability

The effect will be shown, on availability and life cycle costs by equipment reliability, maintainability, system configuration and technician response time to equipment failures. Guidelines will be given to assist the project manager in determining best system parameters for minimizing life cycle costs for a particular application.     

基于用户感知的WCDMA网络位置更新优化

本文从提升用户感知的角度出发,通过开展WCDMA网络位置更新优化,减少用户位置更新次数,达到延长手机待机时间、减少网络空口信令负荷、提高网络接通率的目的.     

On identifying SRLG failures in all-optical networks

Fast and unambiguous failure localization (UFL) is a desired feature in all-optical networks in order to provision high availability services. To save monitoring resources for signalling-free UFL, the paper studies a novel algorithm to localize any SRLG failure via monitoring-trails (m-trails) together with the working lightpaths. The feasibility conditions on the proposed m-trail allocation problem are discussed while different m-trail sharing strategies are introduced and compared via simulation. The problem of selecting an optimal set of working lightpaths is shown to be NP-complete and the simulation results verify the proposed algorithm with respect to monitoring resource consumption and running time.     

JDBC驱动程序工作方式分析与比较

随着企业对信息系统应用需求的不断深化,Java EE开发技术也随之不断演化。JDBC提供了应用程序与数据库的连接服务。如何根据企业应用系统的环境和特征,选择合适的JDBC数据库驱动程序工作方式,是开发者在设计系统与后台数据库连接时,首先需要考虑的问题。本文通过对JDBC四个常用的驱动程序工作方式进行分析与比较,旨在为Java EE开发者提供一定的参考。     

On parallelizing and optimizing the implementation of communicationprotocols

We present a method for the automatic derivation of efficient protocol implementations from a formal specification. Optimized efficient protocol implementation has become an important issue in telecommunications systems engineering as recently network throughput has increased much faster than computer processing power. Efficiency will be attained by two measures. First, the inherent parallelism in protocol specifications will be exploited. Second, the order of execution of the operations involved in the processing of the protocol data will be allowed to differ from the order prescribed in the specification, thus allowing operations to be executed jointly and more efficiently. The method will be defined formally which is useful when implementing it as a tool     

高频单站定位误差特性分析及精度优化构想

从降低高频单站定位误差、提高系统整体性能角度出发,系统性地分析了高频单站定位误差源——电离层虚高、测量仰角和方位角——对定位误差影响的规律。基于误差特性分析结果,提出了优化定位精度的构想:一是通过选择合理的电离层模型,并基于探测数据进行实时修正来提高电离层虚高准确度;二是通过选择优质测向体制和天线场地、研究基于电离层斜向探测等技术的测向校正方法来提高测向准确度;三是应用迭代算法用以克服方法近似所带来的误差。通过方法可行性,论证了优化构想和电离层斜向探测技术对提高高频单站定位精度的重要意义。     

Performance of improved probabilistic location update scheme forcellular mobile networks

This paper suggests an improved probabilistic location update (IPLU) scheme for advanced cellular mobile networks. The location management cost with IPLU is analyzed, and various performance characteristics of IPLU are investigated. It is shown that IPLU has the parameter q that can be used as a control parameter to achieve the best performance when the unit location update cost (U) and the unit paging cost (P) are given. In addition, this paper provides some recommendable values of q in two cases, P>U and P⩽U. As a result, we demonstrate a merit of IPLU, that is, simple implementation with an acceptable performance level, especially, under the future cellular mobile network environments where a vast number of microcells/picocells exist and the relative user mobility is very high     

A crossing-tier location update/paging scheme in hierarchical cellular networks

Location update/paging strategies have been widely studied in the traditional single-tier cellular networks. We propose and evaluate a novel crossing-tier location update/paging scheme that can be used in a hierarchical macrocell/microcell cellular network. Location update is proceeded only in the macrocell tier, where a location area (LA) is made up by larger macrocells. A mobile user will stay in such a LA for longer time. Therefore, the cost on location update can be reduced due to the decreased frequency of location update. To reduce the paging delay, the paged mobile user will be searched in the macrocell tier only when the paging load is not high. Otherwise, it will be searched in the microcell tier, where a sequential searching method is applied. The operation for the scheme is simple, as the macrocell/microcell cellular network has the advantage because a mobile user can receive a signal from both a microcell and the overlaid macrocell. Analytical models have been built for cost and delay evaluation. Numerical results show that, at relatively low cost, the crossing-tier scheme also achieves low paging delay.     

Enhanced efficiency and frequency assignment by optimizing the base stations location in a mobile radio network

Most mobile radio networks have been planned based on the classical cellular concept. However, alternative planning strategies that lead to more efficient network configurations are necessary due to the fact that the traffic density is generally far from constant throughout the service area, making necessary the relocation of base stations inside the traffic hotspots. If the traffic is characterized in a discrete way, the optimization of base stations location resembles vector quantization, a well-known problem in signal processing. In this paper, we use this analogy to propose a mobile radio network planning algorithm. Simulation results show that higher trunking efficiency as well as improved frequency assignment can be obtained if an existing mobile radio network is redesigned using the presented strategy. Raúl Chávez-Santiago was born in Oaxaca City, Mexico. He obtained the B.Sc. degree in communications and electronics engineering in 1997 from the School of Mechanical and Electrical Engineering (ESIME-IPN), and the M.Sc. degree in electrical engineering in 2001 from the Center of Research and Advanced Studies of the National Polytechnic Institute (CINVESTAV-IPN) in Mexico City. He has professional experience as Computer Networking Engineer, and Research and Teaching Assistant. Currently, he is completing his studies toward the Ph.D. degree at Ben-Gurion University (BGU) of the Negev, Israel. In 2002, he received the URSI Young Scientist Award. His main research interests are the optimal planning of radio communication networks, the electromagnetic compatibility of terrestrial and satellite radio systems, and the efficient use of the radio spectrum. He is an IEEE and IEICE student member, and a URSI radio scientist. Avi Raymond was born in Yavne, Israel. He received the B.Sc. and M.Sc. degrees in electrical engineering from Ben-Gurion University (BGU) of the Negev in 2000 and 2005, respectively. He worked for two years in a communication company in the field of Telephony and Broadband Services. He also worked as a Research Assistant in the communications laboratory at BGU. He currently works at Elta Electronic Industries Ltd. as System Engineer and pursues studies toward a second M.Sc. degree in systems engineering at the Technion Institute of Technology, Haifa, Israel. His research interests are the optimization algorithms for frequency assignment in cellular networks. Vladimir Lyandres was born in 1944, in Vologda, Russia. He received the M.Sc. degree in communications engineering in 1966 and the Ph.D. degree in communications theory in 1972 from the State University of Telecommunications (SUT), Saint Petersburg, Russia. He was with SUT until 1990 holding a position of Senior Scientific Associate and working on research and development of digital transmission systems, modeling of radio communication channels and algorithms of frequency planning for broadcasting and cellular systems. Since 1991 he holds a position of Researcher at the communications laboratory and Professor at the Department of Electrical and Computer Engineering, Ben-Gurion University (BGU) of the Negev, Israel. His research interests include synthesis of Markov models, combinatorial optimization, and adaptive power loading. He is a senior member of IEEE and member of IEICE.     

More efficient location tracking in PCS systems using a noveldistributed database system

In personal communication services (PCS), the complete location information and subscribers' profiles are kept in a database called the home location register (HLR). Another database, the visitor location register (VLR), is used to store partial location information. When a mobile user is called, the system queries the HLR to determine the location of the called party. Distributed databases have been introduced to improve the efficiency of querying the HLR. This paper presents an alternative means of constructing a distributed database. The proposed database design employs fixed pointers to link distributed data. Each database contains a portion of the system's information as well as several pointers. The pointers identify the location of real data, enabling the system to obtain the required information efficiently. The database of the proposed design is markedly smaller than the fully distributed databases since each database of the proposed design stores only partial information. Subscriber information is stored only in one database, thus allowing a single database, rather than multiple databases, to be updated. The single update presented herein notably reduces the signal traffic load. If the caller is in the registration area of some HLR, which holds the called party's information, the response time is significantly decreased since the transactions are served only by the local database. This phenomenon is referred to as the calling locality. The proposed method effectively shares the database and the network loading that originates from several databases' tracking mobile users in a PCS system. According to the results presented, this method is highly effective for systems with a heavy load and high calling locality. The single update feature of the proposed design reduces the traffic in the signaling link and the processing load of a database. However, the proposed method includes no fault tolerance and therein differs from the fully distributed design     

User mobility pattern scheme for location update and paging in wireless systems

The user mobility pattern (UMP) scheme is introduced for location update and paging in wireless systems where mobile terminals (MTs) maintain their history data in a database called user mobility history (UMH). During a location update, a UMP is derived from UMH and registered to the network. Unless the MT detects that it has moved out of the registered UMP, it does not perform any other location update. On the other hand, cells are paged selectively according to the cell entry times in the registered UMP upon a call arrival for the MT. The related data structures and the protocols for the UMP scheme are presented in the paper. The experimental results show that the UMP scheme outperforms the time-based and movement-based location update schemes as well as the blanket, selective, and velocity paging schemes.