Location Management Scheme Research Articles

Handling Mobility in Wireless Sensor and Actor Networks

In Wireless Sensor and Actor Networks (WSANs), the collaborative operation of sensors enables the distributed sensing of a physical phenomenon, while actors collect and process sensor data and perform appropriate actions. WSANs can be thought of as a distributed control system that needs to timely react to sensor information with an effective action. In this paper, coordination and communication problems in WSANs with mobile actors are studied. First, a new location management scheme is proposed to handle the mobility of actors with minimal energy expenditure for the sensors, based on a hybrid strategy that includes location updating and location prediction. Actors broadcast location updates limiting their scope based on Voronoi diagrams, while sensors predict the movement of actors based on Kalman filtering of previously received updates. The location management scheme enables efficient geographical routing, and based on this, an optimal energy-aware forwarding rule is derived for sensor-actor communication. Consequently, algorithms are proposed that allow controlling the delay of the data-delivery process based on power control, and deal with network congestion by forcing multiple actors to be recipients for traffic generated in the event area. Finally, a model is proposed to optimally assign tasks to actors and control their motion in a coordinated way to accomplish the tasks based on the characteristics of the events. Performance evaluation shows the effectiveness of the proposed solution.

Paging and Location Management in IEEE 802.16j Multihop Relay Network

IEEE 802.16j is an emerging wireless broadband networking standard that integrates infrastructure base stations with multihop relay technology. Based on the idle mode operation in IEEE 802.16j, we propose a novel location management and paging scheme. It integrates the paging area-based and the timer-based location update mechanism. In paging area-based scheme, an idle mode mobile station updates when it moves to a new paging area. In timer-based scheme, an idle mode MS updates when the location update timer expires. In this work, we formulate the mathematical model to evaluate the performance of the proposed paging scheme. A new random walk mobility model that is suitable for modeling in multihop relay network is created. Optimization of location update timer is also investigated.

A Dynamic Location Management Scheme for Wirless Networks Using Cascaded Correlation Neural Network

A Dynamic Location Management Scheme for Wirless Networks Using Cascaded Correlation Neural Network

A new strategy for managing user's locations in PCS networks using hot spots topology: discussion and analysis

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.

Air data systems - integrated multi system wireless networks

Aircraft data networks are fast becoming more of a necessity due to their support for user mobility. Many aircraft manufacturers are planning to deploy data networks within their airplanes and provide internet connectivity to their passengers. While a data network within the aircraft and passenger access to it causes some security concerns, it open up some safety enhancement opportunities. With internet connectivity within the airplane, the activity within the airplane can be monitored in real-time from the ground station. Also, using the high bandwidth satellite links, the flight critical data could be downloaded to a server in the ground station in real-time flight or periodically, thereby enabling real-time flight status monitoring. In a multi-system 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. An integrated framework is developed for location management in such a multi-system, fourth generation (4G) 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. Ill. 2, bibl. 8 (in English; summaries in English, Russian and Lithuanian).

Imprecision-Tolerant Location Management for Object-Tracking Wireless Sensor Network

An important issue of wireless sensor networks is object tracking, where the key steps include event detection, target classification, location estimation and location management. The main theme of this paper is location management. Because imprecision is an inherent property in object-tracking sensor networks, this paper focuses on the scenarios where users can tolerate a certain degree of imprecision in their query results. We intend to develop a location management scheme that can achieve two goals. First, multiple precision levels are provided. Second, the query cost is proportional to the precision level. To achieve these two goals, we propose a tree-based imprecision-tolerant location management scheme that includes three major components: (1) update and query mechanisms that can support imprecision-tolerant queries, (2) the approach to taking the statistics of imprecision-tolerant queries and (3) a tree construction algorithm that can reduce the query cost and minimize the increment of update cost. Performance evaluations are conducted through simulations to verify the proposed scheme.

A Novel Location Management Scheme for Wireless Mesh Networks

Conventional location management schemes are not designed for Wireless mesh networks and result in considerable signaling cost if used directly in the circumstance. In this paper, a Cluster-based location management scheme is introduced, which takes adequately into account the characteristic of the mesh structure. Numerical result reveals that the proposed scheme enables to significantly lessen the signaling cost.

A Cooperative Location Management Scheme for Mobile Ad Hoc Networks

A mobile ad hoc network (MANET) is a kind of wireless ad hoc network. It is a self-configuring network of mobile routers connected by wireless links. Since MANETs do not have a fixed infrastructure, it is a chal-lenge to design a location management scheme that is both scalable and cost-efficient. In this paper, we propose a cooperative location management scheme, called CooLMS, for MANETs. CooLMS combines the strength of grid based location management and pointer forwarding strategy to achieve high scalability and low signaling cost. An indepth formal analysis of the location management cost of CooLMS is presented. In particular, the total location management cost of mobile nodes moving at variable velocity is estimated using the Gauss_Markov mobility model for the correlation of mobility velocities. Simulation results show CooLMS performs better than other schemes under certain circumstances.

Locating mobile nodes using heuristics with fuzzy logic handoff

In wireless and mobile networks ensuring smooth handoff and tracing exact location of destination node and that too without wasting much time and bandwidth of constrained network is much essential. Several related techniques have been proposed in literature. Each has its own advantages/disadvantages. In this paper, we have proposed, first, a fuzzy logic based handoff management scheme that also handles some basic network management activities like call transferring after allotting a suitable wireless or radio link to the incoming node. It also proposes a location management scheme based on simple heuristics technique like time and probability.

Modeling and Cost Analysis of Movement-Based Location Management for PCS Networks With HLR/VLR Architecture, General Location Area and Cell Residence Time Distributions

Location management plays a central role in guaranteeing the effective operation of personal communication service (PCS) networks. In current PCS networks, a two-tier system of home location register (HLR) and visitor location register (VLR) databases is commonly used for location management. To improve the performance of PCS networks, several dynamic location management schemes have been proposed. Among the existing dynamic schemes, the movement-based location management may be the most practical due to its effectiveness and easy implementation under the framework of current PCS networks. To implement location management in PCS networks, cost analysis is a crucial aspect. However, most of the existing cost analyses for the movement-based scheme are too simple and not available for PCS networks with the HLR/VLR architecture. One reason for this is the complexity and the difficulty associated with the problem. Li et al. and Rodriguez-Dagnino et al. challenged this task by considering the HLR/VLR architecture. However, the cost analysis developed by Li et al. was carried out under the assumption that the cell and location area (LA) residence times are exponentially distributed. Rodriguez-Dagnino et al. furthered Li et al.'s work by assuming that the LA residence time follows a hyperexponential distribution and that the cell residence time is generally distributed. However, Li et al. and Rodriguez-Dagnino et al. failed to consider VLR location updates that are caused by terminal movements between LAs. In this paper, we relax the restrictions imposed on the distributions of the cell and LA residence times and propose an analytical model to study the movement-based scheme with HLR/VLR architecture. The issue of VLR location updates that are caused by movements between LAs is addressed carefully and successfully. Analytical formulas for the costs of HLR and VLR location updates are derived using a unified approach. Numerical study suggests that the total cost is a convex function of the movement threshold and is sensitive to the variances of the cell and LA residence times. The result presented in this paper can serve as a guideline for the system design and the implementation of the movement-based scheme for PCS networks.

GrLS: Group-Based Location Service in Mobile Ad Hoc Networks

In this paper, we propose a group-based location service protocol named GrLS for mobile ad hoc networks (MANETs). The novelty of GrLS is in its exploitation of group mobility to improve the efficiency of the location service. GrLS uses different location management strategies for single nodes and for groups of nodes. A single node is responsible for recruiting its own location servers and performing location update. On the other hand, in a group of nodes, only the group leader recruits the location servers and updates its location to a specific home region called group home region. Since the location update cost normally dominates the location service cost for all practical purposes, the overhead of the location service protocol is significantly reduced. Furthermore, when the nodes join or leave groups, GrLS can provide seamless location service handoff. To the best of our knowledge, GrLS is the first location service protocol in MANETs that has explored group mobility and developed group location management for mobile nodes. Both theoretical analysis and simulation results show that GrLS can achieve a higher success ratio of location query and better load balance with much lower overhead than the existing protocols without considering group mobility.

Performance Analysis of Profile-Based Location Caching with Fixed Local Anchor for Next-Generation Wireless Networks

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.

Optimization of Distance-Based Location Management for PCS Networks

Location management (LM) is an important function in a personal communication network to track movements of mobile terminals (MTs) for call delivery. It is well-known that the total signaling cost of a distance-based LM scheme is the lowest among dynamic location management schemes for PCS networks. In this paper, we derive the joint probability distribution of two random variables: the moving distance of an MT and the number of location updates resulting from the moving distances exceeding the distance threshold. As special cases, the probability distributions of an MT's moving distances and the number of location updates during an LM interval are obtained. These statistics are generally applicable to irregular cell topologies and general cell residence time distributions. Based on the derived statistics, the optimal distance thresholds for distance based LM schemes with blanket paging and sequential paging are solved analytically. Numeric results show that our optimized distance-based LM scheme outperforms some well-known LM schemes in total LM cost.

A Sliding-Frame Strategy for Distributed Location Management in Wireless Mobile Networks

This paper proposes a distributed location management strategy for wireless mobile networks. In the proposed strategy, a number of consecutively numbered location information databases (LIDs) are arranged into a frame. A frame of LIDs overlaps with the next frame except one database. The location information of a mobile host is replicated and stored in the databases in the same frame. When the location area of a mobile host changes, the new location information is stored in the next frame of databases. Thus, the proposed strategy is referred to as the sliding-frame strategy. The average communication cost and average database response time of the proposed sliding-frame strategy are analyzed and shown to be always lower than or equal to those of the strategy proposed by Krishnamurthi et al.

Dual home agent (DHA)-based location management scheme in integrated cellular–WLAN networks

For seamless integration of cellular and wireless local area network (WLAN) systems, we introduce a dual home agent (DHA)-based location management. The DHA maintains the location information both in the cellular and WLAN systems, and therefore unnecessary registration cost can be significantly reduced. In addition, a heuristic, which first looks for the called mobile node (MN) in the cellular system, is proposed to reduce the session setup latency. We analyze the registration cost, session setup delay, and registration delay. Numerical results demonstrate that Mobile IP with the DHA can reduce the registration cost significantly and allows a session setup delay that is comparable to that of the basic Mobile IP.

Location management scheme with WLAN positioning algorithm for integrated wireless networks

The recent decade has witnessed a rapid growth in wireless communications technology. This study presents a location management scheme for integrated wireless networks and a signal-based positioning algorithm for WLAN. The proposed location management scheme provides location information to obtain from a hierarchical location database to mobile users and LBS providers. Additionally, a signal-based positioning algorithm is developed for indoor positioning based on WLAN received signal strength indication (RSSI). Approximated distribution modeling is applied to calculate the probability of users appearing in training points. This mechanism not only locates a mobile client precisely, but also reduces the cost of locating. A performance evaluation is performed to indicate the effectiveness of the proposed location management method, and provide suitable parameter settings.

Design and Evaluation of DNS as Location Manager for HIP

Host Identity Protocol (HIP) is designed to provide secure and continuous communication by separating the identifier and locator roles of the Internet Protocol (IP) address. HIP also has efficient solutions to support host mobility. In this paper, we propose a location management scheme based on Domain Name System (DNS) for HIP. In the proposed scheme, a new DNS HIP resource record is used to translate a domain name into a host identity tag and an IP address. We also develop an analytical model to study the performance of DNS as location manager in terms of success rate, which takes into account the velocity of mobile nodes, the radius of a subnet, the regional network size, the packet transmission delay between the mobile node and the rendezvous server, and the packet processing delay at the DNS and the rendezvous server. The performance results show that for a reasonable range, the DNS is a feasible solution for location management with high success rate for HIP.

Quantitative analysis of location management and QoS in wireless networks

As a fundamental component in wireless networks, location management consists of two operations: location update and paging. These two supplementary operations enable the mobile user ubiquitous mobility. However, in case of failed location update, a significant consequence is the obsolete location identity in the network databases and thereafter the incapability in establishing the valid route for the potential call connection, which will seriously degrade the network quality-of-service (QoS). This issue is not theoretically studied in the literature. In this paper, we perform a quantitative analysis of the location management effect on QoS in the wireless networks. The metrics call blocking probability and the average number of blocked calls are introduced to reflect the QoS. For the sake of general applicability, the performance metrics are formulated with the relaxed tele-traffic parameters. Namely, the call inter-arrival time, cell residence time, location area residence time and location update inter-arrival time follow a general probability density function. The formulae are additionally specified in the static and several dynamic location management mechanisms. Numerical examples are presented to show the interaction between the performance metrics and location management schemes. The discussions on the sensitivity of tele-parameters are also given.

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.

Design, Validation, Simulation and Parametric Evaluation of a Novel Protocol for Locating Mobile Agents in Multiregion Environment

Mobile agents are processes that can be dispatched from source computer and be transported to remote servers for execution, have been widely argued to be an important enabling technology for future systems. Location management is a necessity for locating mobile agents in a network of mobile agent hosts for controlling, monitoring and communication during processing and it still represents an open research issue. The cost of location management strategies mainly depends on the cost of search and update. We concentrated on reducing the cost of update and improving the speed of processing of the agents. We proposed a location management technique applicable for multi-region environment in which mobile agent did not update its location at every migration. The technique named as Broadcasting with Search by Path Chase (BSPC). We used the tool time Petri net analyzer TINA to model, analyze and to simulate BSPC. We found that the BSPC behaves as expected and free from any deadlock. We measured the efficiency of BSPC and compared with some existing location management techniques by parametric evaluation. BSPC provided better scalability, location updating availability and interaction fault rate with theoretical considerations of network usage and network fault rate. It gave its best performance for applications of low CMR and having high migration rate of mobile agents within birth region.