基于阈值的两级指针推进的移动性管理策略

提出了基于阈值的两级指针推进策略(TPFT,two-level pointer forwarding with thresholds)将一部分VLR(visitor location register)中的移动用户选为移动代理(MA,mobile agent),在MA之间建立第一级指针链;在MA与VLR之间建立第二级指针链,两级指针链均设定长度阈值。将该策略与“基本位置管理策略”及“通行用户指针推进策略”和“带门槛的指针推进策略”的开销进行比较得出:选择适当的两级阈值,TPFT策略的开销优于上述策略。同时,TPFT策略是将系统中对HLR(home location register)的修改与查询的信号量分布到各个MA中,提高了系统效率。     

移动位置业务在3G网络中的实现

移动位置业务作为一种移动增值业务,随着3G技术的发展越来越受到关注。叙述了移动位置业务中采用的主要定位技术并进行综合比较,通过描述该业务的网络架构和基本信令流程,说明该业务在3G网络中的实现方案,展望移动位置业务的发展前景,并指出影响业务发展的关键因素。     

LEO卫星网位置管理策略研究

本文总结了传统的 LEO卫星网的位置管理策略 ,并提出了 LEO网基于卫星自主定位的距离门限位置管理方案。该方案定位直接通过本网络卫星实现 ,减小了移动终端的代价和复杂度。另外 ,该方案虽然增加了定位开销 ,但是大大减小了位置更新和寻呼开销     

基于3G的M-Government模型及数据同步问题研究

电子政务代表了政务实施发展的趋势和方向,移动电子政务是电子政务的延伸和发展.3G网络作为新一代移动通信系统,推动了移动电子政务的发展,3G网络的各种优势带动了移动政务各种应用的推广.本文提出了基于3G网络的移动电子政务模型,并与基于2G的模型进行了比较.此外,本文还研究了移动电子政务中必须考虑到的数据同步问题,并提出了一个切实可行的模型.     

基于3G的M—Government模型及数据同步问题研究

电子政务代表了政务实施发展的趋势和方向，移动电子政务是电子政务的延伸和发展。3G网络作为新一代移动通信系统，推动了移动电子政务的发展，3G网络的各种优势带动了移动政务各种应用的推广。本文提出了基于3G网络的移动电子政务模型，并与基于2G的模型进行了比较。此外，本文还研究了移动电子政务中必须考虑到的数据同步问题，并提出了一个切实可行的模型。     

基于代价函数的动态分布式解析映射机制

针对身份与位置的动态解析映射问题,依据终端的移动模式和通信特征,提出了一种基于代价函数的动态分布式移动解析映射机制。该机制将移动终端的通信状态划分为移动更新、均衡传输和解析查询3种通信模式,以最小化解析映射代价为目标,分别提出了基于分布式多播、一致性散列协同和主动式域内共享的解析映射方法,设计了对应的注册更新、解析查询和数据路由解析优化策略。仿真结果表明,该机制实现了移动过程中解析映射代价的最小化,具有较小的解析时延,对网络结构的动态变化具有良好的适应性。     

基于任务的访问控制模型在移动核心网的应用

随着移动通信技术广泛应用,现有移动核心网面临的安全威胁越来越突出。首先介绍了基于任务的访问控制模型(TBAC),进而研究并设计了一个适合在移动核心网中应用的基于任务的访问控制模型(M-TBAC)。该模型通过定义完整的模型元素和任务状态,能动态地控制网络中各个网元访问归属位置寄存器(HLR)的权限,具有较好的安全性和可扩展性。     

摩托罗拉在京设3G研发中心

摩托罗拉在北京开设了一个研发中心，以促进全球化3G网络解决方案的开发。该中心的研究对象为摩托罗拉的全球移动通讯系统(UMTS，Universal Mobile Telecommunications System)和基于HSDPA的移动宽带技术。     

一种3G中基于三层数据库的呼叫建立机制研究

基于3G网络三层数据库结构中GLR (Gateway Location Register)服务区远大于VLR (Visitor Location Register)服务区的情况,考虑被呼业务本地化(即本地移动用户呼叫本地移动用户的比例占总呼叫数的比例大),通过在GLR中设置缓存的方法,给出了一种新的呼叫建立机制。建立分析模型得到新机制的总代价函数和总时间延迟函数,并同基本呼叫建立机制以及2G网络基于VLR缓存的呼叫建立机制进行了对比分析,验证了新呼叫建立机制的优越性。     

动态网络空间中的k-NN查询

随着无线通讯应用的持续增长和定位技术的发展,如何有效率的应答大量移动对象的查询请求以及基于位置的服务(1location-based services LBS)变得越来越重要,k-NN查询是其中的重要服务功能.本文提出了一种解决动态网络中静态对象k-NN查询算法,该算法先将网络以目标对象为中心进行网络划分,通过定位原始...     

Optimal dynamic mobility management for PCS networks

We study a dynamic mobility management scheme: the movement-based location update scheme. An analytical model is applied to formulate the costs of location update and paging in the movement-based location update scheme. The problem of minimizing the total cost is formulated as an optimization problem that finds the optimal threshold in the movement-based location update scheme. We prove that the total cost function is a convex function of the threshold. Based on the structure of the optimal solution, an efficient algorithm is proposed to find the optimal threshold directly. Furthermore, the proposed algorithm is applied to study the effects of changing important parameters of mobility and calling patterns numerically     

Joint distribution of numbers of location updates and cell boundary crossings in movement-based location management schemes

The movement-based location management (LM) scheme is a well-known dynamic LM scheme that is relatively easy to implement. In this letter, we derive the joint probability distribution of the number of cell boundary crossings and number of location updates of a mobile terminal, assuming Poisson call arrivals and generally distributed cell residence time, under movement-based LM. The derived movement statistics are used to bound the movement threshold so that the number of location updates is kept within a reasonable range. Numerical results are presented.     

Optimal fractional movement-based scheme for PCS location management

In this letter, we propose a fractional movement-based location update scheme for personal communication service networks. Similar to the well-known fractional guard channel scheme for channel assignments, in our proposed scheme, the movement threshold is a real number with a fraction instead of an integer. We prove analytically that there is a unique optimal fractional movement threshold that minimizes the total cost of location updates and paging per call arrival.     

Dynamic hierarchical database architecture for location managementin PCS networks

This paper introduces a dynamic hierarchical database architecture for location management in personal communications service (PCS) networks. The proposed scheme allows the dynamic adjustments of user location information distribution based on the mobility and calling patterns of the mobile terminals (MTs). A unique distribution strategy is determined for each MT, and location pointers are set up at selected remote locations which indicate the current location of the MTs. This method effectively reduces the signaling and database access overhead for location registration and call delivery. Besides, the required processing is handled by a distributed network of directory registers and centralized coordination is not necessary. The functions of the other network elements, such as the home location register (HLR) and the visitor location registers (VLRs), remain primarily unchanged. This greatly facilitates the deployment of this scheme in current PCS networks     

Hybrid Scheme with Adaptive Replication and Mobility Anchoring Point (MAP) in Wireless Networks

Replication strategy is mostly useful for replicating the mobile user’s profile at selected locations from which some callers have higher calling rate. Location management scheme also include replication strategy to reduce the location lookup cost of called mobile user. It plays important role in personal communication services in order to reduce call setup cost, call setup time, and increases the QoS (quality of service). In prior replication schemes, called user’s location profile is placed at some fixed and limited number of visitor location registers (VLRs) based on call history of the caller. In prior hybrid schemes location update and replication strategies are combined together. These prior hybrid schemes apply pointer forwarding strategy and replication. But these schemes have limitations like holding “loose” form of location profile and higher location update cost. We have proposed a new hybrid scheme which includes adaptive replication of updated user’s location profile and mobility anchoring point (MAP) for location update. The main objective of the proposed scheme is to reduce call setup cost and call setup time. In order to achieve the objective, adaptive replication is applied at certain visitor location registers (VLRs) according to movement of caller. The replica is kept updated at MAP and replicated to neighbor VLRs as per movement of the caller. We have presented fluid-flow based analytical modeling which shows that proposed scheme outperforms the prior hybrid scheme.     

Determination of the Registration Point for Location Update by Dynamic Programming in PCS

Location management is important to effectively keep track of mobile terminals with reduced signal flows and database queries. Even though dynamic location management strategies are known to show good performance, we in this paper consider the static location management strategy which is easy to implement. A system with single home location register and pointer forwarding is assumed. A mobile terminal is assumed to have memory to store the IDs of visitor location registers (VLRs) each of which has the forwarding pointer to identify its current location. To obtain the registration point which minimizes the database access and signaling cost from the current time to the time of power-off probabilistic dynamic programming formulation is presented. A Selective Pointer Forwarding scheme is proposed which is based on one-step dynamic programming. The proposed location update scheme determines the least cost temporary VLR which point forwards the latest location of the mobile. The computational results show that the proposed scheme outperforms IS-41, pure Pointer Forwarding, and One-step Pointer Forwarding at the expense of small storage and a few computations at the mobile terminals.     

Cost analysis and minimization of movement-based location management schemes in wireless communication networks: a renewal process approach

The paper makes new contributions to cost analysis and minimization of movement-based location management schemes in wireless communication networks. The main contributions of the paper are three-fold. First, we consider two different call handling models, that is, the call plus location update (CPLU) model and the call without location update (CWLU) model. We point out that all existing analysis of location update cost of a movement-based location management scheme (MBLMS) do not accurately capture the essence of the two models. Second, we analyze the exact location update cost of an MBLMS under both CPLU and CWLU models using a renewal process approach which has rarely been used before. We find that the location update cost of an MBLMS under the CWLU model is much easier to analyze than that of an MBLMS under the CPLU model. Furthermore, an MBLMS operated under the CWLU model has lower location update cost than an MBLMS operated under the CPLU model. Third, we are able to derive a closed form solution to the movement threshold that minimizes the total cost of location management in an MBLMS for the CPLU model when the inter-call time has an arbitrary distribution and the cell residence time has an Erlang distribution, and for the CWLU model when both inter-call time and cell residence time have arbitrary distributions. Such closed form solutions have not been available in the existing literature.     

Movement-based location update and selective paging for PCSnetworks

This paper introduces a mobility tracking mechanism that combines a movement-based location update policy with a selective paging scheme. Movement-based location update is selected for its simplicity. It does not require each mobile terminal to store information about the arrangement and the distance relationship of all cells. In fact, each mobile terminal only keeps a counter of the number of cells visited. A location update is performed when this counter exceeds a predefined threshold value. This scheme allows the dynamic selection of the movement threshold on a per-user basis. This is desirable as different users may have very different mobility patterns. Selective paging reduces the cost for locating a mobile terminal in the expense of an increase in the paging delay. We propose a selective paging scheme which significantly decreases the location tracking cost under a small increase in the allowable paging delay. We introduce an analytical model for the proposed location tracking mechanism which captures the mobility and the incoming call arrival patterns of each mobile terminal. Analytical results are provided to demonstrate the cost-effectiveness of the proposed scheme under various parameters     

Information-Theory Based Optimal Location Management Schemes for Integrated Multi-System Wireless Networks

In a multisystem environment where a mobile node can utilize multiple interfaces and simultaneously connect to multiple providers, new opportunities exist for efficient location management strategies spanning heterogeneous cellular wireless networks. In this paper, an integrated framework is developed for location management in such a multi-system, fourth generation (4 G) wireless networks. This information-theoretic framework allows each individual sub-system to operate fairly independently, and does not require the knowledge of individual sub-network topologies. An efficient location management in such a loosely coupled network is designed by having a mobile node view its movement as a vector-valued sequence, and then transmit this sequence in an entropy coded form to the network. We demonstrate how an intelligent, integrated paging strategy must consider the joint residence probability distribution of a mobile node in multiple sub-networks. We prove that the determination of an optimal paging sequence is NP-complete, and also propose an efficient greedy heuristic to compute the paging sequence, both without and with bounds on the paging delay. Three different location tracking strategies are proposed and evaluated; they differ in their degrees of centralized control and provide tradeoff between the location update and paging costs. Simulation experiments demonstrate that our proposed schemes can result in more than 50% savings in both update and paging costs, in comparison with the basic movement-based, multi-system location management strategy.     

Mobile location management in ATM networks

This paper presents two mobile location management algorithms for ATM (asynchronous transfer mode) networks based on the PNNI (private network-to-network interface) standard. The first solution is called the mobile PNNI scheme because it builds on the PNNI routing protocol. It uses limited-scope (characterized by a parameter S) reachability updates, forwarding pointers, and a route optimization procedure. The second solution is called the LR (location registers) scheme because it introduces location registers (such as the cellular home and visitor location registers) into the PNNI standards-based hierarchical networks. This scheme uses a hierarchical arrangement of location registers with the hierarchy limited to a certain level S. Analytical models are set up to compare the average move, search, and total costs per move of these two schemes for different values of the CMR (call-to-mobility ratio), and to provide guidelines for selecting parameters of the algorithms. Results show that at low CMRs (CMR<0.025), the LR scheme performs better than the mobile PNNI scheme. We also observe that the two schemes show a contrasting behavior in terms of the value to be used for the parameter S to achieve the least average total cost. At low CMRs, the parameter S should be high for the mobile PNNI scheme, but low for the LR scheme, and vice versa for high CMRs