Mobile Agents in the Mobile Telephone Network Management

The paper discusses the application of mobile agents in the management of mobile telephone (cellular) networks. We propose the use of mobile agents for collecting subscriber information, such as location area identifier and cell identifier. By using a subscriber profile containing these data the signaling messages caused by location update could be reduced. We also propose a method to improve the quality of network coverage by collecting measurements data by a mobile agent in the mobile station (mobile phone) or at the mobile switching center. By analyzing these data the network provider would be able to discover areas without proper radio signal coverage (black holes), thereby avoiding expensive and time-consuming measurements done by specially equipped vehicles. In addition, we discuss the basic infrastructure requirements for deployment of the mobile agent technology in cellular networks.     

Mobile Agents for Wireless Computing: The Convergence of Wireless Computational Models with Mobile-Agent Technologies

Wireless mobile computing breaks the stationary barrier and allows users to compute and access information from anywhere and at anytime. However, this new freedom of movement does not come without new challenges. The mobile computing environment is constrained in many ways. Mobile elements are resource-poor and unreliable. Their network connectivity is often achieved through low-bandwidth wireless links. Furthermore, connectivity is frequently lost for variant periods of time. The difficulties raised by these constraints are compounded by mobility that induces variability in the availability of both communication and computational resources. These severe restrictions have a great impact on the design and structure of mobile computing applications and motivate the development of new software models. To this end, a number of extensions to the traditional distributed system architectures have been proposed [26]. These new software models, however, are static and require a priori set up and configuration. This in effect limits their potential in dynamically serving the mobile client; the client cannot access a site at which an appropriate model is not configured in advance. The contribution of this paper is twofold. First, the paper shows how an implementation of the proposed models using mobile agents eliminates this limitation and enhances the utilization of the models. Second, new frameworks for Web-based distributed access to databases are proposed and implemented.     

An Efficient Multicast Routing Protocol in Wireless Mobile Networks

Providing multicast service to mobile hosts in wireless mobile networking environments is difficult due to frequent changes of mobile host location and group membership. If a conventional multicast routing protocol is used in wireless mobile networks, several problems may be experienced since existing multicast routing protocols assume static hosts when they construct the multicast delivery tree. To overcome the problems, several multicast routing protocols for mobile hosts have been proposed. Although the protocols solve several problems inherent in multicast routing proposals for static hosts, they still have problems such as non-optimal delivery path, datagram duplication, overheads resulting from frequent reconstruction of a multicast tree, etc. In this paper, we summarize these problems of multicast routing protocols and propose an efficient multicast routing protocol based on IEFT mobile IP in wireless mobile networks. The proposed protocol introduces a multicast agent, where a mobile host receives a tunneled multicast datagram from a multicast agent located in a network close to it or directly from the multicast router in the current network. While receiving a tunneled multicast datagram from a remote multicast agent, the local multicast agent may start multicast join process, which makes the multicast delivery route optimal. The proposed protocol reduces data delivery path length and decreases the amount of duplicate copies of multicast datagrams. We examined and compared the performance of the proposed protocol and existing protocols by simulation under various environments and we got an improved performance over the existing proposals.     

Proxies + Path Prediction: Improving Web Service Provision in Wireless–Mobile Communications

Mobile computing is considered of major importance to the computing industry for the forthcoming years due to the progress in the wireless communications area. A proxy-based architecture for accelerating Web browsing in wireless customer premises networks is presented. Proxy caches, maintained in base stations, are constantly relocated to follow the roaming user. A cache management scheme is proposed, which involves the relocation of full caches to the most probable cells but also percentages of the caches to less likely neighbors. Relocation is performed according to the output of a user movement prediction algorithm based on a learning automaton. The simulation of the scheme shows considerable benefits for the end user.     

Intelligent Handoff for Mobile Wireless Internet

This paper presents an intelligent mobility management scheme for Mobile Wireless InterNet – MWIN. MWIN is a wireless service networks wherein its core network consisting of Internet routers and its access network can be built from any Internet-capable radio network. Two major standards are currently available for MWIN, i.e., the mobile IP and wireless LAN. Mobile IP solves address mobility problem with the Internet protocol while wireless LAN provides a wireless Internet access in the local area. However, both schemes solve problems independently at different layers, thereby some additional problems occur, e.g., delayed handoff, packet loss, and inefficient routing. This paper identifies these new problems and performs analyses and some real measurements on the handoff within MWIN. Then, a new handoff architecture that extends the features of both mobile IP and wireless LAN handoff mechanism was proposed. This new architecture consists of mobile IP extensions and a modified wireless LAN handoff algorithm. The effect of this enhancement provides a linkage between different layers for preventing packet loss and reducing handoff latency. Finally, some optimization issues regarding network planning and routing are addressed.     

Dynamic Location Management for Mobile Computing

This paper presents a dynamic and individualized location update scheme that considers each user's mobility patterns. The mobility patterns are used to create individualized location areas for each user. The proposed scheme is flexible and can be used in network with arbitrary cell topologies. The scheme, along with other existing schemes is simulated using realistic users' mobility and call arrival patterns, and network topology. The simulated environment consists of 90 cells representing the geographical area of the San Francisco bay, and 66,550 mobile users representing the typical classes of users that are normally present in a real cellular network. Results show the proposed scheme gives lower overall signaling costs, resulting in savings on the limited radio bandwidth that may have otherwise been used for location updates and paging.     

地铁环境下支持移动IP无线接入点的研究与设计

根据地铁环境下无线通信的特殊性,对无线接入进行了重新设计。研究并继衷了传统移动IP的思想,并对其进行了一定的修改,将移动代理大部分职能与无线接入点进行分离,实现了移动节点与无线接入点之间快速正确切换的功能,在不同的网段中移动时实现了漫游功能,并且实现了有、无线网络的连接畅通。最后描述了系统的测试结果以及存在的不足。     

Hyper-Erlang Distribution Model and its Application in Wireless Mobile Networks

This paper presents the study of the hyper-Erlang distribution model and its applications in wireless networks and mobile computing systems. We demonstrate that the hyper-Erlang model provides a very general model for users' mobility and may provide a viable approximation to fat-tailed distribution which leads to the self-similar traffic. The significant difference from the traditional approach in the self-similarity study is that we want to provide an approximation model which preserves the Markovian property of the resulting queueing systems. We also illustrate that the hyper-Erlang distribution is a natural model for the characterization of the systems with mixed types of traffics. As an application, we apply the hyper-Erlang distribution to model the cell residence time (for users' mobility) and demonstrate the effect on channel holding time. This research may open a new avenue for traffic modeling and performance evaluation for future wireless networks and mobile computing systems, over which multiple types of services (voice, data or multimedia) will be supported.     

mPERSONA: Personalized Portals for the Wireless User: An Agent Approach

The needs of the wireless and mobile user regarding information access and services are quite different than those of the desktop user. This need is not about browsing the Web but about receiving personalized services that are highly sensitive to the immediate environment and requirements of the user. Personalization appears to be the most appropriate solution to this need. It comes into aid by creating personalized portals that are specific for the wireless user, which (a) are focus on the local content and (b) directly tones down factors that break up the functionally of the Internet/wireless services when viewed through wireless devices; factors like the click count, user response time (the choice factor) and the size of the wireless network traffic. In this paper we present a flexible personalization system for the wireless user that takes into consideration user mobility, the local environment and the user and device profile. The system utilizes the various characteristics of mobile agents to support flexibility, scalability, modularity and user mobility. We present metrics appropriate to the wireless environment, and an initial performance evaluation indicating improvement ranging from 33% up to, for certain metrics, 60%.     

一种分层多跳无线网中的移动性管理策略

该文介绍一种分层多跳无线网与其他骨干网络互连情况下的网络层移动性管理方案。它使用了包含逻辑家乡代理的宏移动性管理和将位置管理与路由和寻呼机制结合起来的微移动性管理的思想,以提高网络在战场等特殊情况下使用的可靠性和抗毁性,减小位置管理的开销,节省无线信道的带宽。     

A Novel Routing Protocol for Supporting QoS for Ad Hoc Mobile Wireless Networks

The main purposes of this article are to lessen the influence of the fastchanging network topology, rapidly varying bandwidth information, and the increasing size of routing tables onquality of service routing. Based on DSDV (Destination-Sequenced Distance-Vector) routing protocol formaintaining up-to-date routing information, the related research has to update routing tables when networktopology changes; moreover, the routing tables must be updated periodically even though the networktopology has not changed. To put emphasis on QoS routing, they also have to exchange routing tables by thetime of bandwidth information changes. Furthermore, the size of routing tables increases with the numberof mobile nodes; therefore, the precious wireless bandwidth is wasted on transmitting the large-scalerouting tables. In this article, we propose an on-demand-based QoS routing protocol to mitigate theseproblems and to achieve the QoS requirement. The goal of this article is to discover an optimal routewith minimum time delay for transmitting real-time data from a source node hop by hop to adestination node under some predefined constraints. Our contributions are as follows: our researchprovides a rigorous bandwidth definition and bandwidth application, a broad view of bandwidth calculationand reservation, minimizing the size of control packets and the number of control packet transmissions,and an efficient QoS routing protocol.     

基于无线传感网络的移动机器人通信研究

文章对无线传感网络在机器人设计中的应用进行了研究,提出了一种基于Ad hoc网络的分布式无线令牌环协议的机器人通信系统实现方案,分析了其在机器人通信系统应用中的可行性.文中给出了基于无线传感网络的机器人通信系统的软硬件设计方案,并对其在移动机器人通信系统中的应用问题进行了探讨,最终提出了无线传感器网络应用于移动机器人通信系统的实现方法.     

On-Demand Multicast Routing Protocol in Multihop Wireless Mobile Networks

An ad hoc network is a dynamically reconfigurable wireless network with no fixed infrastructure or central administration. Each host is mobile and must act as a router. Routing and multicasting protocols in ad hoc networks are faced with the challenge of delivering data to destinations through multihop routes in the presence of node movements and topology changes. This paper presents the On-Demand Multicast Routing Protocol (ODMRP) for wireless mobile ad hoc networks. ODMRP is a mesh-based, rather than a conventional tree-based, multicast scheme and uses a forwarding group concept; only a subset of nodes forwards the multicast packets via scoped flooding. It applies on-demand procedures to dynamically build routes and maintain multicast group membership. ODMRP is well suited for ad hoc wireless networks with mobile hosts where bandwidth is limited, topology changes frequently, and power is constrained. We evaluate ODMRP performance with other multicast protocols proposed for ad hoc networks via extensive and detailed simulation.     

移动代理技术在Ad Hoc无线网络中的应用研究

Ad Hoc无线网络是一组具有路由和转发功能的移动节点组成的一个多跳的临时性自治系统,是一种无中心的无线网络。现有的主动路由协议或者按需路由协议都不能很好地满足Ad Hoc网络的需要。介绍了Ad Hoc无线移动网络和移动代理技术。在分析了现有的2种路由协议后,提出了在按需路由协议中加入移动代理技术来增强Ad Hoc无线网络的性能。在这些结果的基础上,提出了移动代理通信协议。     

基于嵌入式移动机器人无线通讯系统的实现

无线通讯系统是移动机器人的一个重要组成部分,在机器人自主能力有限的情况下,借助上位机与机器人进行无线通信是控制机器人的一种可行方案。文中以轮式移动机器人作为控制平台,利用nRF905无线射频收发模块,实现了移动机器人的无线通讯系统。文中详细阐述了机器人无线通信系统的硬件及软件设计,该系统具有成本低、实时性强、通信可靠等特点。     

Quality of Service in Mobile and Wireless Networks: The Need for Proactive and Adaptive Applications

Although there are already many fixed networked computers around the world, we will see several orders of magnitude more wireless and mobile devices connected to the Internet. Each car, truck, aircraft, but also many people will carry a plethora of different devices for communication. However, all mobile and wireless systems have in common that the quality of their connectivity may change rapidly over time. Still, users want to get the best quality possible or the quality they pay for respectively. In this paper we describe the implementation of adaptive and proactive applications that are supported by our architecture. The user can express his or her preference by simply clicking on a Q(uality)-button; the process of adaptation is performed without any user interaction. Feedback loops connecting applications, operating system, and network system realize the adaptation. We show how our architecture supports traditional adaptive applications and demonstrate the benefits of proactive applications in wireless and mobile environments.     

Route Maintenance in a Wireless Mobile Ad Hoc Network

A mobile ad-hoc network (MANET) is formed by a cluster of mobile hosts, without the infrastructure of base stations. To deal with the dynamic changing topology of a MANET, many routing protocols have been proposed. In this paper, we consider the route maintenance problem, which includes two parts: route deterioration and route breakage. In a MANET, a route may suddenly become broken because only one host roams away. Even if a route remains connected, it may become worse due to host mobility or a better route newly being formed in the system. Existing protocols, however, will stick with a fixed route once it is discovered, until it is expired or broken. In this paper, we show how to enhance several existing protocols with route optimization and local route recovery capability. So the routing paths can be adjusted on-the-fly while they are still being used for delivering packets and can be patched in minimum wireless bandwidth and delay while route errors occur.     

无线传感网络移动分簇路由策略

无线传感网络(WSN)路由协议中,分簇路由具有拓扑管理方便、能量高效和数据融合简单等优点,成为当前重点研究的路由技术。通过研究各种环境下的移动传感器网络,有效地降低能耗则是研究移动无线传感器网络的重要目的之一。针对无线传感网络中移动性问题,基于LEACH协议,利用移动传感器网络中节点距离、速度和剩余能量等因素提出了能量高效的移动分簇路由算法。实验结果表明此算法能够较好地支持节点移动,从而降低网络能耗,延长网络生存时间。     

Wireless resource virtualization: opportunities,challenges, and solutions

Wireless resource virtualization (WRV) is currently emerging as a key technology to overcome the major challenges facing the mobile network operators (MNOs) such as reducing the capital, minimizing the operating expenses, improving the quality of service, and satisfying the growing demand for mobile services. Achieving such conflicting objectives simultaneously requires a highly efficient utilization of the available resources including the network infrastructure and the reserved spectrum. In this paper, the most dominant WRV frameworks are discussed where different levels of network infrastructure and spectrum resources are shared between multiple MNOs. Moreover, we summarize the major benefits and most pressing business challenges of deploying WRV. We further highlight the technical challenges and requirements for abstraction and sharing of spectrum resources in next generation networks. In addition, we provide guidelines for implementing comprehensive solutions that are able to abstract and share the spectrum resources in next generation network. The paper also presents an efficient algorithm for base station virtualization in long‐term evolution (LTE) networks to share the wireless resources between MNOs who apply different scheduling polices. The proposed algorithm maintains a high‐level of isolation and offers throughput performance gain. Copyright © 2016 John Wiley & Sons, Ltd.     

Performance Analysis of Mobile Agents for Filtering Data Streams on Wireless Networks

Wireless networks are an ideal environment for mobile agents, since their mobility allows them to move across an unreliable link to reside on a wired host, next to or closer to the resources that they need to use. Furthermore, client-specific data transformations can be moved across the wireless link and run on a wired gateway server, reducing bandwidth demands. In this paper we examine the tradeoffs faced when deciding whether to use mobile agents in a data-filtering application where numerous wireless clients filter information from a large data stream arriving across the wired network. We develop an analytical model and use parameters from filtering experiments conducted during a US Navy Fleet Battle Experiment to explore the model's implications.