共查询到20条相似文献,搜索用时 15 毫秒
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M. S. Obaidat C. Ben Ahmed N. Boudriga 《International Journal of Communication Systems》1999,12(3):153-166
The growing fields of wireless networks and asynchronous transfer mode (ATM) are merging to form wireless ATM networks. This paper addresses dynamic bandwidth allocation, connection admission procedures, routing, and location management strategies in wireless ATM. More precisely, we investigate the issue of extending the private Network to Network Interface, PNNI, and protocols to support mobility. PNNI‐based hierarchical routing, hand‐off, location management and routing schemes are proposed to integrate wireless capabilities into ATM networks. These schemes provide fast and efficient hand‐off connection processing mechanism and a reduction in the connection disruption time during a connection hand‐off session. They also provide a predictable resource requirement of the mobile system during its connection. During a connection hand‐off, misrouted cells can be re‐routed to their destinations. This substantially reduces the overhead due to end‐to‐end re‐transmissions invoked at higher layers. An analytical model is developed to illustrate the hand‐off algorithm. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献
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The mobility feature of mobile stations (MSs) imposes a large burden on network traffic control as a result of location management. Design issues of location management include MS registration (updating) and call setup (paging). Previous approaches introduced several network topologies for updating and paging procedures, but most of them focused on a single problem: either updating optimization or paging optimization. In this paper, we design and integrate two mechanisms, distributed temporary location caches (TLCs) and distributed home location registers (HLRs), to reduce database access delay and to decrease network signaling traffic in both updating and paging for low power, low tier micro cellular systems. By using TLCs, our approach can improve the performance of updating and paging in comparison with previous approaches. Experimental results based on our analytic model show that our location management procedures have lower HLR access rate, lower registration cost, and lower call setup cost than other approaches. 相似文献
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Yan Yan Baoxian Zhang Jun Zheng Jian Ma 《Wireless Communications and Mobile Computing》2010,10(7):899-911
In wireless sensor networks (WSNs), a mobile sink can help eliminate the hotspot effect in the vicinity of the sink, which can balance the traffic load in the network and thus improve the network performance. Location‐based routing is an effective routing paradigm for supporting sink mobility in WSNs with mobile sinks (mWSNs). To support efficient location‐based routing, scalable location service must be provided to advertise the location information of mobile sinks in an mWSN. In this paper, we propose a new hierarchical location service for supporting location‐based routing in mWSNs. The proposed location service divides an mWSN into a grid structure and exploits the characteristics of static sensors and mobile sinks in selecting location servers. It can build, maintain, and update the grid‐spaced network structure via a simple hashing function. To reduce the location update cost, a hierarchy structure is built by choosing a subset of location servers in the network to store the location information of mobile sinks. The simulation results show that the proposed location service can significantly reduce the communication overhead caused by sink mobility while maintaining high routing performance, and scales well in terms of network size and sink number. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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Hang‐Wen Hwang Chien‐Chao Tseng Ming‐Feng Chang 《Wireless Communications and Mobile Computing》2003,3(3):311-327
Owing to the increasing population of mobile subscribers, the rapidly expanding signaling traffic has become a challenge to the mobility management in PCS networks. Multiple database schemes to reduce signal traffic and to solve the bottleneck problem of the single home location register (HLR) architecture have been proposed by many researchers. However, in most of the multiple location databases or HLR systems, extra signaling is required for the multiple database updates. We propose a batch‐update strategy, instead of the immediate update method, for the location‐tracking schemes with replication to reduce the signaling overhead. In this paper, we first introduce a distributed HLRs architecture in which each HLR is associated with a localized set of VLRs and the location registrations and queries are processed locally. Then we propose our batch‐update strategy and present two pointing schemes for inter‐HLR call deliveries. The numerical result shows that our approach can effectively decrease the signaling cost of location registration and call delivery compared with the IS‐41 standard. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
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Youn‐Hee Han Sang‐Cheol Han KwonWoo Yang Chong‐Sun Hwang Young‐Sik Jeong 《International Journal of Communication Systems》2001,14(10):961-978
Recently, hierarchical architecture for location databases has been proposed in order to accommodate the growing number of personal communication systems users. With the three‐level hierarchical database architecture, which is compatible with the current cellular mobile systems, newly developed additional databases, including the regional location database (RLR), are positioned between the HLR and the VLRs. We propose an efficient cache scheme, the double T‐thresholds location cache scheme, which could reduce the network and database costs to lookup a portable using the three‐level architecture. This scheme extends the existing T‐threshold location cache scheme, which is effective only under the two‐level architecture of location databases currently adopted by IS‐41 and GSM. The idea behind our proposed scheme is to use two pieces of cache information, VLR and RLR, which serve the called portables. These two pieces are required in order to exploit not only the locality of a registration area (RA), but also the locality of a regional registration area (RRA), a wide area covered by the RLR. We also use two threshold values in order to determine whether the two pieces are obsolete. In order to model the RRA residence time, the branching Erlang‐∞ distribution is introduced. The cost analysis presented in this paper shows that the double T‐thresholds location cache scheme significantly reduces the network and database costs for most patterns of portables. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
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As a special type of wireless sensor network, the chain‐type wireless sensor networks can be used to monitor narrow and long regions, such as roads, underground mine tunnels, rivers, and bridges. In this study, a perpendicular bisector division (PB) method was first presented, in which the location may be divided into more location sub‐areas by a perpendicular bisector of each of two location nodes. Compared with the triangulation division method in Approximate Point‐in‐Triangulation Test (APIT), the computable complexity of PB is lower, and the number of division areas is larger. Furthermore, in order to locate targets under rare location nodes, a virtual location node‐perpendicular bisector division (VPB) was presented by a virtual location node based on the geographic shape of the monitored area. Virtual location nodes increase the density of location nodes, which can improve the accuracy of the location in the location algorithm. Second, two range‐free location algorithms were proposed: the location algorithm based on PB (LAPB) and the location algorithm based on VPB (LAVPB). In the end, the location errors performance of APIT, LAPB, and LAVPB for locating miners in an underground mine tunnel was tested. The results show that LAPB and LAVPB have higher location accuracy and are more robust than APIT. LAVPB is more suitable for locating targets in harsh environments. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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Jahanzeb Faizan Hesham EL‐Rewini Mohamed Khalil 《Wireless Communications and Mobile Computing》2008,8(4):483-500
Mobile IPv6 is an enabling platform for creating IP mobility in the evolution path towards next generation service offerings. However, Mobile IPv6 does not provide reliability and load balancing in the network. In this paper, we introduce ‘Virtual HA Reliability Protocol.’ It is an extension to Mobile IPv6 that introduces reliability and load balancing in the Mobile IPv6‐based networks. It also provides solutions to the problems caused due to Home Agent failures in Mobile IPv6. These problems are: delayed failure detection, service interruption in the upper layer applications, increased workload on the Mobile Node, message overhead over the air interface, and IPsec Security Associations re‐establishment. We also present the results of several experiments to assess the performance of our solution. The results show that our solution provides transparent Home Agent failure detection and recovery mechanisms. As a result, there is a significant reduction in message exchange over the air interface. Also, our solution provides high service availability in the upper layer applications. Moreover, there is reduced workload on the Mobile Node. Finally, the load balancing mechanism of our solution provides efficient, dynamic, and transparent load balancing among the multiple Home Agents. Thus our solution improves the overall Mobile IPv6 and upper layer applications performance. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
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H. C. Leligou P. Trakadas S. Maniatis P. Karkazis T. Zahariadis 《Wireless Communications and Mobile Computing》2012,12(12):1091-1103
As the applications of wireless sensor networks proliferate, the efficiency in supporting large sensor networks and offering security guarantees becomes an important requirement in the design of the relevant networking protocols. Geographical routing has been proven to efficiently cope with large network dimensions while trust management schemes have been shown to assist in defending against routing attacks. Once trust information is available for all network nodes, the routing decisions can take it into account, i.e. routing can be based on both location and trust attributes. In this paper, we investigate different ways to incorporate trust in location‐based routing schemes and we propose a novel way of balancing trust and location information. Computer simulations show that the proposed routing rule exhibits excellent performance in terms of delivery ratio, latency time and path optimality. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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In this paper, we present a mobility management scheme for real-time multimedia sessions over heterogeneous wireless networks.
Most approaches in the current literature use Mobile IP (MIP) or Session Initiation Protocol (SIP) to maintain real-time sessions
during mobility. In this paper, we analyze MIP and SIP in terms of the mobility rate, packet loss and packet overheads in
the user plane and propose a mechanism by which the network can choose the optimum protocol for mobility management. We perform
the analysis for constant bit rate (CBR) as well as for variable bit rate (VBR) traffic. We show that for CBR traffic, the
proposed mechanism leads to 12–35% improvement in the system capacity, while for VBR traffic, capacity improvements ranging
from about 35–50% can be obtained. Our proposed approach and the analysis are applicable to handovers between different IP
domains both in homogeneous as well as in heterogeneous wireless networks. 相似文献
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We propose an integrated resource management approach that can be implemented in next generation wireless networks that support multimedia services (data, voice, video, etc.). Specifically, we combine the use of position-assisted and mobility predictive advanced bandwidth reservation with a call admission control and bandwidth reconfiguration strategy to support flexible QoS management. We also introduce a mobile agent based framework that can be used to carry out the functions of geolocation and of the proposed resource management in wireless networks. A model is also developed to obtain the optimal location information update interval in order to minimize the total cost of the system operation. The comparison of the achievable performance results of our proposed scheme with the corresponding results of a conventional system that supports advanced bandwidth reservation only, as means of supporting the QoS requirements, demonstrate that our integrated scheme can alleviate the problem of overreservation, support seamless operation throughout the wireless network, and increase significantly the system capacity. 相似文献
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Yuh‐Shyan Chen Wei‐Han Hsiao Kau‐Lin Chiu 《International Journal of Communication Systems》2009,22(12):1515-1541
In wireless/mobile networks, users freely and frequently change their access points (APs) while they are communicating with other users. To support the mobility of mobile nodes (MNs), Mobile IPv6 (MIPv6) is used to inform the information of MN's home address and current care‐of‐address (CoA) to its home agent. MIPv6 suffers from a long delay latency and high packet losses (PLs) because MIPv6 does not support micromobility. A Hierarchical Mobile IPv6 (HMIPv6) is proposed which provides micromobility and macromobility to reduce handoff latency (HL) by employing a hierarchical network structure. In this paper, we propose a cross‐layer partner‐based fast handoff mechanism based on HMIPv6, called the PHMIPv6 protocol. Our PHMIPv6 protocol is a cross‐layer, layer‐2 + layer‐3, and cooperative approach. A cooperative node, called a partner node (PN), is adopted in the PHMIPv6 protocol. A new layer‐2 trigger scheme used in the PHMIPv6 protocol accurately predicts the next AP and then invites a cooperative PN in the area of the next AP. With the cooperation of the PN, the CoA can be pre‐acquired and duplicate address detection operation can be pre‐executed by the PN before the MN initializes the handoff request. The PHMIPv6 protocol significantly reduces the handoff delay time and PLs. In the mathematical analysis, we verified that our PHMIPv6 protocol offers a better HL than the MIPv6, HMIPv6, and SHMIPv6 protocols. Finally, the experimental results also illustrate that the PHMIPv6 protocol actually achieves performance improvements in the handoff delay time, PL rate, and handoff delay jitter. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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Y. Mallikarjuna Rao M. V. Subramanyam K. Satya Prasad 《International Journal of Communication Systems》2018,31(11)
Wireless mesh networks (WMNs) have been the recent advancements and attracting more academicians and industrialists for their seamless connectivity to the internet. Radio resource is one among the prime resources in wireless networks, which is expected to use in an efficient way especially when the mobile nodes are on move. However, providing guaranteed quality of service to the mobile nodes in the network is a challenging issue. To accomplish this, we propose 2 clustering algorithms, namely, static clustering algorithm for WMNs and dynamic clustering algorithm for WMNs. In these algorithms, we propose a new weight‐based cluster head and cluster member selection process for the formation of clusters. The weight of the nodes in WMN is computed considering the parameters include the bandwidth of the node, the degree of node connectivity, and node cooperation factor. Further, we also propose enhanced quality of service enabled routing protocol for WMNs considering the delay, bandwidth, hopcount, and expected transmission count are the routing metrics. The performance of the proposed clustering algorithms and routing protocol are analyzed, and results show high throughput, high packet delivery ratio, and low communication cost compared with the existing baseline mobility management algorithms and routing protocols. 相似文献
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A speed-adaptive strategy for location management cost reduction in cellular networks 总被引:1,自引:0,他引:1
A speed adaptive location management scheme will greatly reduce the cost of tracking mobile stations, because mobile stations
can travel at a wide range of speeds. Recently, an elegant distance- and time-based scheme has been proposed. The scheme uses
a look-up table which describes the relationship between the distance and the time: the distance decreases while the time
increases. In the scheme, the paging area for a mobile station will be automatically reduced if the mobile station does not
update its location over a certain time period. Therefore, the scheme performs well when a mobile station travels at a low
speed. However, it does not perform well when the incoming call arrival rate is high or when the speed of a mobile station
is high. To overcome those drawbacks, a novel speed-adaptive scheme is proposed in this paper. The proposed scheme uses an
enhanced look-up table that consists of two parts: the distance in the first part increases while the time increases; in the
second part, the distance decreases with the increasing time. By introducing the first part, the proposed scheme reduces the
paging cost for a call arriving shortly after a location update, and adapts to the speed range of a mobile station. To reduce
the paging cost further, a paging angle is introduced for high-speed mobile stations. Numerical simulations using various
activity-based models and random walk models show that the proposed scheme performs well for mobile stations traveling at
both high and low speeds.
Zhijun Wang is a Ph.D. candidate in the Department of Computer Science at the University of Alabama. He received his M.S. in computer
science from the University of Alabama in 2002. He also had a formal training in physics and obtained his B.S. in physics
from Tianjin University in 1993 and his M.S. in physics from Yale University in 1998. His current research interests include
location management in cellular networks and routing in ad hoc networks.
Jingyuan Zhang received the bachelor’s degree from Shandong University in 1984, the master’s degree from Zhejiang University in 1987, and
the doctoral degree from Old Dominion University in 1992, all in computer science. He is currently an assistant professor
with the Department of Computer Science at the University of Alabama. Prior to joining the University of Alabama, he was an
instructor with Ningbo University, an assistant professor with Elizabeth City State University, and a principal computer scientist
with ECI Systems and Engineering.
Dr. Zhang’s current research interests include wireless networks and mobile computing, single display groupware, graphics,
and parallel processing. He is a member of the IEEE. 相似文献
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《Journal of Location Based Services》2013,7(4):237-255
To become truly ubiquitous, next generation location-based services (LBS) will have to rely on mobile platforms upon which multiple sensors and measurement systems have been integrated to provide continuous, three-dimensional positioning and orientation. Such technologies are explored today for example in mobile mapping systems, vehicle navigation systems and mobile robot navigation. Next-generation LBS also need theoretically sound methods to translate position into location information. The article addresses this problem: the transformation of position into meaningful and reliable location, and the transformation of location knowledge into positioning constraints. It suggests by this way an intelligent location model that integrates sensor fusion with spatial knowledge fusion via a feedback cycle. It is shown that this feedback cycle consists of three layers: spatial constraints, temporal constraints and spatiotemporal constraints. 相似文献