Internet Connectivity for Ad Hoc Mobile Networks

The growing deployment rate of wireless LANs indicates that wireless networking is rapidly becoming a prevalent form of communication. As users become more accustomed to the use of mobile devices, they increasingly want the additional benefit of roaming. The Mobile IP protocol has been developed as a solution for allowing users to roam outside of their home networks while still retaining network connectivity. The problem with this solution, however, is that the deployment of foreign agents is expensive because their coverage areas are limited due to fading and interference. To reduce the number of foreign agents needed while still maintaining the same coverage, ad hoc network functionality can cooperate with Mobile IP such that multihop routes between mobile nodes and foreign agents can be utilized. In this work, we present a method for enabling the cooperation of Mobile IP and the Ad hoc On-Demand Distance Vector (AODV) routing protocol, such that mobile nodes that are not within direct transmission range of a foreign agent can still obtain Internet connectivity. In addition, we describe how duplicate address detection can be used in these networks to obtain a unique co-located care-of address when a foreign agent is not available.     

Stimulating Node Cooperation in Mobile Ad hoc Networks

Mobile Ad hoc Networks (MANETs) rely on the cooperation of nodes for packet routing and forwarding. Much of the existing work in MANETs assume that mobile nodes (possibly owned by selfish users) will follow prescribed protocols without deviation. However, a user may misbehave due to several advantages resulting from noncooperation, the most obvious being power saving. As such, the network availability is severely endangered. Hence, enforcing the cooperation among nodes becomes a very important issue. Several different approaches have been developed to detect non-cooperative nodes or deal with the non-cooperative behavior of mobile nodes in MANETs. These protocols are first surveyed in details in this paper. It is found that the proposed approaches have several concerns that prevent them from really enforcing the node cooperation in MANETs. Thus, a new scheme that can stimulate and also enforce nodes to cooperate in a selfish ad hoc environment is presented. We also present a mechanism to detect and exclude potential threats of selfish mobile nodes. The simulation results indicate that by using the proposed scheme, MANETs can be robust against nodes’ misbehaving and the performance of the network is enhanced many folds when compared to other existing schemes.

自组织网中的Anycasting研究

移动无线自组织网络正成为研究的热点,最近在网络通信中提出了一种为任播(anycasting)的通信模式,这里介绍了自组织网中任播的概念以及应用,说明了如何在网络层通过路由实现任播功能。     

On Address Privacy in Mobile Ad Hoc Networks

The network addresses of principals in a mobile ad hoc network (MANET) are conventionally assumed to be public information. This may cause devastating consequences for MANETs deployed in hostile environments. For example, attackers can easily locate a target principal based his known network address and then launch a pinpoint attack. This paper identifies address privacy as a new security requirement to prevent attackers from ascertaining network addresses of MANET principals. We further present Swarms, the first solution to satisfying this requirement. Swarms eliminates the conventionally explicit one-on-one mappings between MANET principals and network addresses and allows any two principals to communicate while blind to each other’s address. We quantitatively measure the address privacy offered by Swarms via an entropy-based information-theoretic metric.

Cross-Layering Approaches in Wireless Ad Hoc Networks

Wireless ad hoc networks are temporary formed, infrastructureless networks. Due to the unstable channel conditions and network connectivity, their characteristics impose serious challenges in front of network designers. The layering approach to network design does not fit the ad hoc environment well. Therefore, various cross-layering approaches, where protocol layers actively interact, exchange inherent layer information and fine tune their parameters according to the network status are becoming increasingly popular. This paper presents an in-depth analysis of the latest cross-layering approaches for wireless ad hoc networks supported by several examples. A special emphasis is put on the link and network layer related cross-layer designs. Several link adaptation and efficient service discovery schemes are elaborated through analytical and simulation studies. Their performance shows the potentials of the cross-layering for boosting system characteristics in wireless ad hoc networks. Liljana Gavrilovska currently holds a position of full professor at Faculty of Electrical Engineering, University “St. Cyril and Metodij” – Skopje, Macedonia. She is chief of Telecommunications Laboratory and teaches undergraduate courses in telecommunication networks, data transmission and switching and traffic theory, and graduate courses in wireless, mobile and personal networks, teletraffic engineering and planning, and broadband multiservices networks. In 2000 she joined the Center for PersonKommunikation, Aalborg University, Denmark, as a visiting professor and during 2001--2002 she held a position of associate research professor at the same university. Currently she holds a part-time position of associated research professor with Center for Teleinfrastructur (CTIF). Prof. Gavrilovska was involved in several EU (ACTS ASAP, IST PACWOMAN, MAGNET, TEMPUS) and national/international projects. She published numerous conference and journal papers and participated in several workshops. At the moment she is working on the book “Ad Hoc Networking Towards Seamless Communications” together with prof. R. Prasad. Her research interests include wireless and personal area networks, ad hoc networking, networking protocols, traffic analysis, QoS, and optimization techniques. She is a senior member of IEEE and serves as a Chair of Macedonian Communication Chapter.     

Flooding-Based Geocasting Protocols for Mobile Ad Hoc Networks

Geocasting is a variation on the notion of multicasting. A geographical area is associated with each geocast, and the geocast is delivered to the nodes within the specified geographical area. Thus, geocasting may be used for sending a message that is likely to be of interest to everyone in a specified area. In this paper, we propose three geocasting protocols for ad hoc networks, obtained as variations of a multicast flooding algorithm, and then evaluate these approaches by means of simulations. Proposed geocasting algorithms attempt to utilize physical location information to decrease the overhead of geocast delivery.     

一种解决ad hoc网络中自私节点安全问题的方法

移动ad hoc网络（MANET）路由和分组转发功能需要节点间的相互合作，自私节点为节约能量而不参与合作，将会影响网络的正常工作．因此本文将针对自私节点危害和解决方法展开分析，并提出一种改进解决方法——基于可信任中心服务器和邻居监测的合作增强机制，该方法不但能够激励节点间的相互合作，而且有效地解决了自私节点改变用户身份的欺骗攻击．最后，仿真结果表明这种合作增强机制对自私节点安全问题是有效的，并且易于实用化．     

ABRP: Anchor-based Routing Protocol for Mobile Ad Hoc Networks

Ad hoc networks, which do not rely on any infrastructure such as access points or base stations, can be deployed rapidly and inexpensively even in situations with geographical or time constraints. Ad hoc networks are attractive in both military and disaster situations and also in commercial uses like sensor networks or conferencing. In ad hoc networks, each node acts both as a router and as a host. The topology of an ad hoc network may change dynamically, which makes it difficult to design an efficient routing protocol. As more and more wireless devices connect to the network, it is important to design a scalable routing protocol for ad hoc networks. In this paper, we present Anchor-based Routing Protocol (ABRP), a scalable routing protocol for ad hoc networks. It is a hybrid routing protocol, which combines the table-based routing strategy with the geographic routing strategy. However, GPS (Global Positioning System) (Kaplan, Understanding GPS principles and Applications, Boston: Artech House publishers, 1996) support is not needed. ABRP consists of a location-based clustering protocol, an intra-cell routing protocol and an inter-cell routing protocol. The location-based clustering protocol divides the network region into different cells. The intra-cell routing protocol routes packets within one cell. The inter-cell routing protocol is used to route packets between nodes in different cells. The combination of intra-cell and inter-cell routing protocol makes ABRP highly scalable, since each node needs to only maintain routes within a cell. The inter-cell routing protocol establishes multiple routes between different cells, which makes ABRP reliable and efficient. We evaluate the performance of ABRP using ns2 simulator. We simulated different size of networks from 200 nodes to 1600 nodes. Simulation results show that ABRP is efficient and scales well to large networks. ABRP combines the advantages of multi-path routing strategy and geographic routing strategy—efficiency and scalability, and avoids the burden—GPS support.     

移动无线ad hoc网络吞吐量的计算

在网络拓扑满足网络各种不同性能指标下,本文提出了一种新的转发策略和功率控制策略来估计ad hoc网络的吞吐量.实验结果证明:该方法能够有效的估算和提高ad hoc网络的吞吐量.     

A Mutual Exclusion Algorithm for Ad Hoc Mobile Networks

A fault-tolerant distributed mutual exclusion algorithm that adjusts to node mobility is presented, along with proof of correctness and simulation results. The algorithm requires nodes to communicate with only their current neighbors, making it well-suited to the ad hoc environment. Experimental results indicate that adaptation to mobility can improve performance over that of similar non-adaptive algorithms when nodes are mobile.     

GMZRP: Geography-aided Multicast Zone Routing Protocol in Mobile Ad Hoc Networks

This paper presents the design and evaluation of a highly efficient on-demand multicast routing protocol for mobile ad hoc networks (MANETs). The protocol, called Geography-aided Multicast Zone Routing Protocol (GMZRP), eliminates as much as possible duplicate route queries by using a simple yet effective strategy for propagating the multicast route request (MRREQ) packets. GMZRP is the first hybrid multicast protocol taking the advantages of both topological routing and geographical routing. It partitions the network coverage area into small zones and guarantees that each geographic zone is queried only once. GMZRP maintains a multicast forwarding tree at two levels of granularities, i.e., the zone granularity and the node granularity. By doing this, it can easily handle route breakage since the zone level information can help recover the link failure at the node level. The results of the performance evaluation of GMZRP using simulation show that, comparing with the well-known multicast protocol ODMRP (On-Demand Multicast Routing Protocol), GMZRP has much lower protocol overhead in terms of query packets and, meanwhile, achieves competing packet delivery ratio and shorter delivery latency.

移动自组织网路由稳定性分析

针对移动自组织网络中的路由建立和维护问题,研究了衡量路由稳定性的准则,以节点的不确定性特征作为路由选择的标准,提出了基于局部拓扑结构变化熵度量的稳定路由选择策略,并在此基础上设计了一种稳定路由协议。通过NS-2仿真软件对路由选择策略和路由协议进行了验证,仿真结果表明所提出的稳定路由选择策略和路由协议能够有效地提高移动自组织网络的性能。     

一种节省能量的移动Ad Hoc网络组播选路协议

鉴于现有基于网孔的移动Ad Hoc网络组播选路协议都滑考虑如何有效使用电池能量的问题，本文提出了一种节省能量组播选路协议（E^2MRP),E^2MRP协议的两个主要特征是：（1）在创建和维护中继组（RG）的过程中交替采用分组平均能量消耗最少和最大节点花费最小两种标准，（2）采用基于图的组播结构，本文通过仿真分析大大降低了节点的能量消耗，特别是在节移动性较低，组播成员较少时更是如此。     

Dynamic Task-Based Anycasting in Mobile Ad Hoc Networks

Mobile ad hoc networks (MANETs) have received significant attention in the recent past owing to the proliferation in the numbers of tetherless portable devices, and rapid growth in popularity of wireless networking. Most of the MANET research community has remained focused on developing lower layer mechanisms such as channel access and routing for making MANETs operational. However, little focus has been applied on higher layer issues, such as application modeling in dynamic MANET environments. In this paper, we present a novel distributed application framework based on task graphs that enables a large class of resource discovery based applications on MANETs. A distributed application is represented as a complex task comprised of smaller sub-tasks that need to be performed on different classes of computing devices with specialized roles. Execution of a particular task on a MANET involves several logical patterns of data flow between classes of such specialized devices. These data flow patterns induce dependencies between the different classes of devices that need to cooperate to execute the application. Such dependencies yield a task graph (TG) representation of the application.We focus on the problem of executing distributed tasks on a MANET by means of dynamic selection of specific devices that are needed to complete the tasks. In this paper, we present simple and efficient algorithms for dynamic discovery and selection (instantiation) of suitable devices in a MANET from among a number of them providing the same functionality. This is carried out with respect to the proposed task graph representation of the application, and we call this process Dynamic Task-Based Anycasting. Our algorithm periodically monitors the logical associations between the selected devices, and in the event of a disruption in the application owing to failures in any component in the network, it adapts to the situation and dynamically rediscovers the affected parts of the task graph, if possible. We propose metrics for evaluating the performance of these algorithms and report simulation results for a variety of application scenarios differing in complexity, traffic, and device mobility patterns. From our simulation studies, we observed that our protocol was able to instantiate and re-instantiate TG nodes quickly and yielded high effective throughput at low to medium degrees of mobility and not much below 70% effective throughput for high mobility scenarios.     

Checkerboard-Like Routing Protocol for Ad Hoc Mobile Wireless Networks

The main purposes of this article are to relieve broadcast problem, to immunize to some prerequisites, and to reduce the number of transmitted control packets. Broadcasting control packets network-wide is the most direct and common method for finding the required destination node in ad hoc mobile wireless networks; however, this causes a lot of waste of wireless bandwidth. To remedy the problem, routing protocols demanding some prerequisites are proposed; nonetheless, hardly can they be used if these prerequisites are missed or become stale. To efficiently reduce the number of transmitted control packets, our routing protocol partitions the network into interlaced gray districts and white districts by the aid of GPS and inhibits an intermediate node residing in a white district from re-transmitting the received control packets. However, a mobile node residing in a gray district is responsible for re-transmitting them till they reach the destination node. Our routing protocol does not demand any prerequisite except the use of GPS. Each mobile node can always obtain its own location information; furthermore, the information may neither be missed nor become stale. Our routing protocol is easy to be implemented, saves precious wireless bandwidth, and reduces almost half a number of control packets as compared with pure flooding routing protocols.Ying-Kwei Ho received the B.S. degree and M.S. degree in applied mathematics and in electrical engineering from the Chung-Cheng Institute of Technology in 1987 and 1993 respectively and the Ph.D. degree in computer engineering and science from the Yuan-Ze University, Taiwan, R.O.C. He joined the Army of Taiwan, R.O.C. in 1987 and worked as a software engineer. From 1993 to 1997, he was an instructor in the War Game Center of Armed Forces University, Taiwan, R.O.C. He is currently an assistant professor of the Department of Computer Science at Chung-Cheng Institute of Technology. His research interests include mobile computing, wireless network performance simulation and evaluation, and modeling and simulation.Ru-Sheng Liu received the B.S. degree in electrical engineering from the National Cheng-Kung University, Taiwan, in 1972 and the M.S. and Ph.D. degrees in computer science from the University of Texas at Dallas, Richardson, Texas, in 1981 and1985, respectively. He is currently an associate professor in the Department of Computer Engineering and Science at Yuan-Ze University, Chungli, Taiwan. His research interests are in the areas of mobile computing, internet technology, and computer algorithms.     

Performance Evaluation of Directional Adaptive Range Control in Mobile Ad Hoc Networks

This paper presents DARC (Directional Adaptive Range Control), a range control mechanism using directional antennas to be implemented across multiple layers. DARC uses directional reception for range control rather than directional transmission in order to achieve both range extension and high spatial reuse. It adaptively controls the communication range by estimating dynamically changing local network density based on the transmission activities around each network node. The experimental results using simulation with detailed physical layer, IEEE 802.11 DCF MAC, and AODV protocol models have shown the successful adaptation of communication range with DARC for varied network densities and traffic loads. DARC improves the packet delivery ratio by a factor of 9 at the maximum for sparse networks while it maintains the increased network capacity for dense networks. Further, as each node adaptively changes the communication range, the network delivers up to 20% more packets with DARC compared to any fixed range configurations.Mineo Takai is a Principal Development Engineer in the Computer Science Department at University of California, Los Angeles. He received his B.S., M.S. and Ph.D. degrees, all in electrical engineering, from Waseda University, Tokyo, Japan, in 1992, 1994 and 1997 respectively.Dr. Takai’s research interests include parallel and distributed computing, mobile computing and networking, and modeling and simulation of networked systems. He is a member of the ACM, the IEEE and the IEICE.Junlan Zhou received her B.S in Computer Science from Huazhong University of Science and Technology in 1998, her M.Eng in Computer Engineering from Nanyang Technological University in 2001 and her M.S in Computer Science from University of California, Los Angeles in 2003. She is currently a Ph.D candidate in the Computer Science Department at University of California, Los Angeles. Her research interests include modeling and simulation of wireless networks, protocol design and analysis of wireless networks, and broad areas of distributed computing.Rajive Bagrodia is a Professor of Computer Science at UCLA. He obtained a Bachelor of Technology in electrical engineering from the Indian Institute of Technology, Bombay and a Ph.D. in Computer Science from the University of Texas at Austin. Professor Bagrodia’s research interests include~wireless networks, performance modeling and~simulation, and nomadic computing. He has published over a hundred research papers on the preceding topics. The research has been funded by a variety of government and industrial sponsors including the National Science Foundation, Office of Naval Research, and the Defense Advanced Research Projects Agency. He is an associate editor of the ACM Transactions on Modeling and Computer Systems (TOMACS).     

移动自组织网络环境中负载均衡策略研究

针对移动自组织网络中负载分布不均所导致的网络性能恶化问题,提出了一种基于分组转发行为不确定度量的网络负载计算方法,并以此为基础提出了负载均衡按需路由协议,通过监测分组转发过程中的行为变化特征,采用信息熵的形式对其进行量化和度量,并在路由发现过程中利用节点负载监测信息合理规避网络热点区域,以达到网络负载均衡分布的目的。仿真结果表明,基于负载均衡策略的路由协议能够有效提高分组递交成功率,降低分组传输延迟。     

Scalable Routing Protocol for Ad Hoc Networks

In this paper we present a scalable routing protocol for ad hoc networks. The protocol is based on a geographic location management strategy that keeps the overhead of routing packets relatively small. Nodes are assigned home regions and all nodes within a home region know the approximate location of the registered nodes. As nodes travel, they send location update messages to their home regions and this information is used to route data packets. In this paper, we derive theoretical performance results for the protocol and prove that the control packet overhead scales linearly with node speed and as N ^3/2 with increasing number of nodes. These results indicate that our protocol is well suited to relatively large ad hoc networks where nodes travel at high speed. Finally, we use simulations to validate our analytical model.     

Extending Global IP Connectivity for Ad Hoc Networks

Ad hoc networks have thus far been regarded as stand-alone networks without assumed connectivity to wired IP networks and the Internet. With wireless broadband communications and portable devices with appropriate CPU, memory and battery performance, ad hoc connectivity will become more feasible and demand for global connectivity through ad hoc networking is likely to rapidly grow. In this paper we propose an algorithm and describe a developed prototype for connectivity between an ad hoc network running the ad hoc on-demand distance-vector protocol and a wired IP network where mobile IP is used for mobility management. Implementation issues and performance metrics are also discussed.     

Towards Designing a Trusted Routing Solution in Mobile Ad Hoc Networks

Designing a trusted and secure routing solution in an untrustworthy scenario is always a challenging problem. Lack of physical security and low trust levels among nodes in an ad hoc network demands a secure end-to-end route free of any malicious entity. This is particularly challenging when malicious nodes collude with one another to disrupt the network operation. In this paper we have designed a secure routing solution to find an end-to-end route free of malicious nodes with collaborative effort from the neighbors. We have also extended the solution to secure the network against colluding malicious nodes, which, to the best of our knowledge, is the first such solution proposed. We have also proposed a framework for computing and distributing trusts that can be used with out trusted routing protocol. Our proposed framework is unique and different from the other schemes in that it tries to analyze the psychology of the attacker and quantifies the behavior in the computational model. Extensive simulation has been carried out to evaluate the design of our protocol. Partially funded by Department of Defense Award No. H98230-04-C-0460, Department of Transportation Project No. FL-26-7102-00 and National Science Foundation Grant Nos. ANI-0123950 and CCR-0196557. Tirthankar Ghosh is a PhD candidate in the Telecommunications and Information Technology Institute at Florida International University. His area of research is routing security and trust computation in wireless ad hoc and sensor networks. He received his Bachelor of Electrical Engineering from Jadavpur University, India and Masters in Computer Engineering from Florida International University. Dr. Niki Pissinou received her Ph.D. in Computer Science from the University of Southern California, her M.S. in Computer Science from the University of California at Riverside, and her B.S.I.S.E. in Industrial and Systems Engineering from The Ohio State University. She is currently a tenured professor and the director of the Telecommunication & Information Technology Institute at FIU. Previously Dr. Pissinou was a tenured faculty at the Center for Advanced Computer Studies at the University of Louisiana at Lafayette where she was also the director of the Telecommunication & Information & Technology Laboratory partially funded by NASA, and the co-director of the NOMAD: A Wireless and Nomadic Laboratory partially funded by NSF, and the Advanced Network Laboratory. Dr. Pissinou is active in the fields computer networks, information technology and distributed systems. Dr. Kami (Sam) Makki has earned his Ph.D. in Computer Science from the University of Queensland in Brisbane Australia, his Masters degree in Computer Science and Engineering from the University of New South Wales in Sydney Australia, and his Bachelor and Masters Degrees in Civil Engineering from the University of Tehran Iran. Before joining the department of Electrical Engineering and Computer Science at the University of Toledo he has held a number of academic positions and research appointments at the Queensland University of Technology in Brisbane, Royal Melbourne Institution of Technology in Melbourne and at The University of Queensland in Brisbane Australia. He is an active researcher in the fields of distributed systems, databases, mobile and wireless communications, and has more than 30 publications in peerreviewed journals and international proceedings. He has served as a chair and technical program committee member and reviewer for a number of IEEE and ACM sponsored technical conferences and has received a number of achievement awards.