Ad Hoc Networks (ad + hoc_network)

Distribution by Scientific Domains

Kinds of Ad Hoc Networks

  • mobile ad hoc network
  • wireless ad hoc network


  • Selected Abstracts


    A zone co-operation approach for efficient caching in mobile ad hoc networks

    INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 9 2006
    Narottam Chand
    Abstract Mobile Ad hoc NETwork (MANET) presents a constrained communication environment due to fundamental limitations of client resources, insufficient wireless bandwidth and users' frequent mobility. Caching of frequently accessed data in such environment is a potential technique that can improve the data access performance and availability. Co-operative caching, which allows the sharing and co-ordination of cached data among clients, can further explore the potential of the caching techniques. In this paper, we propose a novel scheme, called zone co-operative (ZC) for caching in MANETs. In ZC scheme, one-hop neighbours of a mobile client form a co-operative cache zone. For a data miss in the local cache, each client first searches the data in its zone before forwarding the request to the next client that lies along routing path towards server. As a part of cache management, cache admission control and value -based replacement policy are developed to improve the data accessibility and reduce the local cache miss ratio. An analytical study of ZC based on data popularity, node density and transmission range is also performed. Simulation experiments show that the ZC caching mechanism achieves significant improvements in cache hit ratio and average query latency in comparison with other caching strategies. Copyright 2006 John Wiley & Sons, Ltd. [source]


    A study of a routing attack in OLSR-based mobile ad hoc networks

    INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 11 2007
    Bounpadith Kannhavong
    Abstract A mobile ad hoc network (MANET) is a collection of mobile nodes which are able to communicate with each other without relying on predefined infrastructures or central administration. Due to their flexibilities and easy deployment, MANET can be applied in situation where network infrastructures are not available. However, due to their unique characteristics such as open medium and the lack of central administration, they are much more vulnerable to malicious attacks than a conventional infrastructured wireless network. MANET employs routing to provide connectivity for mobile nodes that are not within direct wireless transmission range. Existing routing protocols in MANET assume a trusted and cooperative environment. However, in hostile environment, mobile nodes are susceptible to various kinds of routing attacks. In this paper, we show that an OLSR MANET node is prone to be isolated by malicious attack called Node Isolation attack. After analysing the attack in detail, we present a technique to mitigate the impact of the attack and improve the performance of the network when the attack is launched. The results of our implementations illustrate that the proposed solution can mitigate the attack efficiently. Copyright 2007 John Wiley & Sons, Ltd. [source]


    Using temporal correlation for fault localization in dynamically changing networks

    INTERNATIONAL JOURNAL OF NETWORK MANAGEMENT, Issue 4 2008
    Maitreya Natu
    A mobile ad hoc network creates a dynamic environment where node mobility can cause periodic changes in routes. Most existing fault localization algorithms assume availability of a complete and/or deterministic dependency model. Such assumptions cannot be made in the dynamically changing networks. This paper is aimed at developing a fault diagnosis architecture and algorithm to address the issue of dynamically changing dependencies in networks. We propose an architecture to capture the changes in dependencies and introduce a temporal correlation algorithm to perform fault diagnosis with the dynamically changing dependency information. We present an experimental evaluation of our work through simulation results using Qualnet. Copyright 2007 John Wiley & Sons, Ltd. [source]


    Urban mesh and ad hoc mesh networks

    INTERNATIONAL JOURNAL OF NETWORK MANAGEMENT, Issue 2 2008
    Anders Nilsson Plymoth
    Mesh networking is currently gaining much attention, within both academia and industry. Mesh networking allows cheap and fast deployment of wireless services. It is regarded as a very promising solution for urban deployment scenarios as well as for temporary emergency response situations. Another related promising field is that of ad hoc wireless networking, which consists of mobile nodes that dynamically create and maintain a network without the need for any infrastructure. We propose a solution and architecture for urban mesh ad hoc networks, a network that combines mesh networking with ad hoc networks for urban environments. We present four types of ad hoc mesh and ad hoc mesh networks. The most general one consists of mesh nodes, called mesh points (MP), that act as a type of access point for user nodes (UN). The MPs have at least two interfaces: one which is used to communicate with UNs, and one which is used to maintain the mesh access network and transport data. These two interfaces can basically use any type of technology (IEEE 802.11 a/b/g, WiMax, etc.), and for capacity reasons it is generally regarded that the best solution is to let the mesh interface operate on a separate high-capacity channel or channels. An intricate part of these types of networks are routing and location services. In our solution, UN devices operate in ad hoc mode running an ad hoc routing protocol. This allows UNs that wish to communicate to connect directly in an ad hoc manner, or through an MP. An important question is therefore whether two UNs that wish to communicate should connect through the mesh or connect directly. We show that from a capacity point of view whether a UN should route its packets to the closest available MP, or through a ad hoc network, depends on the environment the network is located, the amount traffic and the type of protocols used. Since MPs need to know where to route packets within the mesh, i.e., locating the MP closest to the destination UN, each UN run a small application that registers the UN to the mesh network. In addition to the above features we have developed a new MAC that quickly queries two candidate nodes, which picks the candidate with the currently best radio conditions. This enable nodes to cope with deep dips in signal strength due to fast fading, a well-known problem in urban environments. We show that this new protocol achieves significantly lower delays. We also show that in dense urban environments performance and battery lifetime can be improved if ad hoc technologies are used. Copyright 2007 John Wiley & Sons, Ltd. [source]


    A heterogeneous-network aided public-key management scheme for mobile ad hoc networks

    INTERNATIONAL JOURNAL OF NETWORK MANAGEMENT, Issue 1 2007
    Yuh-Min Tseng
    A mobile ad hoc network does not require fixed infrastructure to construct connections among nodes. Due to the particular characteristics of mobile ad hoc networks, most existing secure protocols in wired networks do not meet the security requirements for mobile ad hoc networks. Most secure protocols in mobile ad hoc networks, such as secure routing, key agreement and secure group communication protocols, assume that all nodes must have pre-shared a secret, or pre-obtained public-key certificates before joining the network. However, this assumption has a practical weakness for some emergency applications, because some nodes without pre-obtained certificates will be unable to join the network. In this paper, a heterogeneous-network aided public-key management scheme for mobile ad hoc networks is proposed to remedy this weakness. Several heterogeneous networks (such as satellite, unmanned aerial vehicle, or cellular networks) provide wider service areas and ubiquitous connectivity. We adopt these wide-covered heterogeneous networks to design a secure certificate distribution scheme that allows a mobile node without a pre-obtained certificate to instantly get a certificate using the communication channel constructed by these wide-covered heterogeneous networks. Therefore, this scheme enhances the security infrastructure of public key management for mobile ad hoc networks. Copyright 2006 John Wiley & Sons, Ltd. [source]


    Study of MANET routing protocols by GloMoSim simulator

    INTERNATIONAL JOURNAL OF NETWORK MANAGEMENT, Issue 6 2005
    Ashwini K. Pandey
    This paper compares ad hoc on-demand distance vector (AODV), dynamic source routing (DSR) and wireless routing protocol (WRP) for MANETs to distance vector protocol to better understand the major characteristics of the three routing protocols, using a parallel discrete event-driven simulator, GloMoSim. MANET (mobile ad hoc network) is a multi-hop wireless network without a fixed infrastructure. Following are some of our key findings: (1) AODV is most sensitive to changes in traffic load in the messaging overhead for routing. The number of control packets generated by AODV became 36 times larger when the traffic load was increased. For distance vector, WRP and DSR, their increase was approximately 1.3 times, 1.1 times and 7.6 times, respectively. (2) Two advantages common in the three MANET routing protocols compared to classical distance vector protocol were identified to be scalability for node mobility in end-to-end delay and scalability for node density in messaging overhead. (3) WRP resulted in the shortest delay and highest packet delivery rate, implying that WRP will be the best for real-time applications in the four protocols compared. WRP demonstrated the best traffic scalability; control overhead will not increase much when traffic load increases. Copyright 2005 John Wiley & Sons, Ltd. [source]


    AODV-RIP: improved security in mobile ad hoc networks through route investigation procedure

    CONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 7 2010
    Byung-Seok Kang
    Abstract Most routing protocols in mobile ad hoc networks (MANETs) place an emphasis on finding paths in dynamic networks without considering security. As a result, there are a number of attacks that can be used to manipulate the routing in MANET. A malicious node that sends a modified control message to an intermediate node can disturb the network using a control message. To solve this problem, we introduce AODV protocol with route investigation procedure (AODV-RIP). It uses two additional control messages to defeat security attacks that can occur in AODV routing protocol. When an intermediate node that is on the path between the source node and the destination node receives a control message, it sends a Rroute Investigation Request (IREQ) message to the destination node in order to check the reliability of the control message. According to the existence of Route Investigation Reply (IREP), the intermediate node decides whether it transmits the control message to the source node or not. Consequently, the intermediate node that receives the control message confirms that it is using two additive control messages: IREQ and IREP. Through this investigation procedure, the source node can obtain a reliable path for transmitting data packets to an intentional destination node. The simulation results show an improvement in the packet delivery ratio and end-to-end delay at the expense of a moderate increase of the control message overhead compared with the current routing protocols. Copyright 2009 John Wiley & Sons, Ltd. [source]


    On the connectivity of Bluetooth-based ad hoc networks

    CONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 7 2009
    P. Crescenzi
    Abstract We study the connectivity properties of a family of random graphs that closely model the Bluetooth's device discovery process, where each device tries to connect to other devices within its visibility range in order to establish reliable communication channels yielding a connected topology. Specifically, we provide both analytical and experimental evidence that when the visibility range of each node (i.e. device) is limited to a vanishing function of n, the total number of nodes in the system, full connectivity can still be achieved with high probability by letting each node connect only to a ,small' number of visible neighbors. Our results extend previous studies, where connectivity properties were analyzed only for the case of a constant visibility range, and provide evidence that Bluetooth can indeed be used for establishing large ad hoc networks. Copyright 2008 John Wiley & Sons, Ltd. [source]


    A study on video performance of multipoint-to-point video streaming with multiple description coding over ad hoc networks

    ELECTRICAL ENGINEERING IN JAPAN, Issue 4 2010
    Keisuke Utsu
    Abstract Supporting multimedia applications over wireless networks has become a very active research topic recently because video applications are forecast to receive high demand in future wireless networks, such as ad hoc networks. However, enabling video transmission over wireless ad hoc networks is more challenging than over other wireless networks due to node mobility, interference, and the absence of a supporting infrastructure. This paper addresses the problem of video transmission over ad hoc networks. We propose to combine Multiple Description Coding (MDC) with multiple source transport (Multipoint-to-Point transfer: MP2P) in order to maintain smooth video streaming over wireless ad hoc networks. In this paper, we describe a comprehensive simulation and test bed experiment designed to show the effect of the proposed MP2P video transfer with MDC for two description cases of video streaming over wireless ad hoc networks. The results show that the proposed mechanism successfully improves video transfer performance in terms of video packet reachability and throughput. 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 170(4): 43,50, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20999 [source]


    Dynamic zone topology routing protocol for MANETs

    EUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 4 2007
    Mehran Abolhasan
    The limited scalability of the proactive and reactive routing protocols have resulted in the introduction of new generation of routing in mobile ad hoc networks, called hybrid routing. These protocols aim to extend the scalability of such networks beyond several hundred to thousand of nodes by defining a virtual infrastructure in the network. However, many of the hybrid routing protocols proposed to date are designed to function using a common pre-programmed static zone map. Other hybrid protocols reduce flooding by grouping nodes into clusters, governed by a cluster-head, which may create performance bottlenecks or a single point of failures at each cluster-head node. We propose a new routing strategy in which zones are created dynamically, using a dynamic zone creation algorithm. Therefore, nodes are not restricted to a specific region. Additionally, nodes perform routing and data forwarding in a cooperative manner, which means that in the case failure, route recalculation is minimised. Routing overheads are also further reduced by introducing a number of GPS-based location tracking mechanisms, which reduces the route discovery area and the number of nodes queried to find the required destination. Copyright 2006 AEIT [source]


    Error-aware and energy-efficient routing approach in MANETs

    INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 1 2009
    Liansheng Tan
    Abstract The lifetime of a network is the key design factor of mobile ad hoc networks (MANETs). To prolong the lifetime of MANETs, one is forced to attain a tradeoff of minimizing the energy consumption and load balancing. In MANETs, energy waste resulting from retransmission due to high bit error rate (BER) and high frame error rate (FER) of wireless channel is significant. In this paper, we propose two novel protocols termed multi-threshold routing protocol (MTRP) and enhanced multi-threshold routing protocol (EMTRP). MTRP divides the total energy of a wireless node into multiple ranges. The lower bound of each range corresponds to a threshold. The protocol iterates from the highest threshold to the lowest one and chooses those routes with bottleneck energy being larger than the current threshold during each iteration. This approach thus avoids overusing certain routes and achieves load balancing. If multiple routes satisfy the threshold constraint, MTRP selects a route with the smallest hop count to further attain energy efficiency. Based on MTRP, EMTRP further takes channel condition into consideration and selects routes with better channel condition and consequently reduces the number of retransmissions and saves energy. We analyze the average loss probability (ALP) of the uniform error model and Gilbert error model and give a distributed algorithm to obtain the maximal ALP along a route. Descriptions of MTRP and EMTRP are given in pseudocode form. Simulation results demonstrate that our proposed EMTRP outperforms the representative protocol CMMBCR in terms of total energy consumption and load balancing. Copyright 2008 John Wiley & Sons, Ltd. [source]


    A study of a routing attack in OLSR-based mobile ad hoc networks

    INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 11 2007
    Bounpadith Kannhavong
    Abstract A mobile ad hoc network (MANET) is a collection of mobile nodes which are able to communicate with each other without relying on predefined infrastructures or central administration. Due to their flexibilities and easy deployment, MANET can be applied in situation where network infrastructures are not available. However, due to their unique characteristics such as open medium and the lack of central administration, they are much more vulnerable to malicious attacks than a conventional infrastructured wireless network. MANET employs routing to provide connectivity for mobile nodes that are not within direct wireless transmission range. Existing routing protocols in MANET assume a trusted and cooperative environment. However, in hostile environment, mobile nodes are susceptible to various kinds of routing attacks. In this paper, we show that an OLSR MANET node is prone to be isolated by malicious attack called Node Isolation attack. After analysing the attack in detail, we present a technique to mitigate the impact of the attack and improve the performance of the network when the attack is launched. The results of our implementations illustrate that the proposed solution can mitigate the attack efficiently. Copyright 2007 John Wiley & Sons, Ltd. [source]


    A survey of current architectures for connecting wireless mobile ad hoc networks to the Internet

    INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 8 2007
    Habib M. Ammari
    Abstract Connecting wired and wireless networks, and particularly mobile wireless ad hoc networks (MANETs) and the global Internet, is attractive in real-world scenarios due to its usefulness and praticality. Because of the various architectural mismatches between the Internet and MANETs with regard to their communication topology, routing protocols, and operation, it is necessary to introduce a hybrid interface capable of connecting to the Internet using Mobile IP protocol and to MANETs owing to an ad hoc routing protocol. Specifically, the approaches available in the literature have introduced updated versions of Mobile IP agents or access points at the edge of the Internet to help MANET nodes get multi-hop wireless Internet access. The main differences in the existing approaches concern the type of ad hoc routing protocol as well as the switching algorithm used by MANET nodes to change their current Mobile IP agents based on specific switching criteria. This paper surveys a variety of approaches to providing multi-hop wireless Internet access to MANET nodes. Copyright 2006 John Wiley & Sons, Ltd. [source]


    Integration of mobility and intrusion detection for wireless ad hoc networks

    INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 6 2007
    Bo Sun
    Abstract One of the main challenges in building intrusion detection systems (IDSs) for mobile ad hoc networks (MANETs) is to integrate mobility impacts and to adjust the behaviour of IDSs correspondingly. In this paper, we first introduce two different approaches, a Markov chain-based approach and a Hotelling's T2 test based approach, to construct local IDSs for MANETs. We then demonstrate that nodes' moving speed, a commonly used parameter in tuning IDS performances, is not an effective metric to tune IDS performances under different mobility models. To solve this problem, we further propose an adaptive scheme, in which suitable normal profiles and corresponding proper thresholds can be selected adaptively by each local IDS through periodically measuring its local link change rate, a proposed unified performance metric. We study the proposed adaptive mechanism at different mobility levels, using different mobility models such as random waypoint model, random drunken model, and obstacle mobility model. Simulation results show that our proposed adaptive scheme is less dependent on the underlying mobility models and can further reduce false positive ratio. Copyright 2006 John Wiley & Sons, Ltd. [source]


    Power aware scalable multicast routing protocol for MANETs

    INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 10 2006
    R. Manoharan
    Abstract Multicasting is an effective way to provide group communication. In mobile ad hoc networks (MANETs), multicasting can support a wide variety of applications that are characterized by a close degree of collaboration. Since MANETs exhibit severe resource constraints such as battery power, limited bandwidth, dynamic network topology and lack of centralized administration, multicasting in MANETs become complex. The existing multicast routing protocols concentrate more on quality of service parameters like end-to-end delay, jitter, bandwidth and power. They do not stress on the scalability factor of the multicast. In this paper, we address the problem of multicast scalability and propose an efficient scalable multicast routing protocol called ,Power Aware Scalable Multicast Routing Protocol (PASMRP)' for MANETs. PASMRP uses the concept of class of service with three priority levels and local re-routing to provide scalability. The protocol also ensures fair utilization of the resources among the nodes through re-routing and hence the lifetime of the network is increased. The protocol has been simulated and the results show that PASMRP has better scalability and enhanced lifetime than the existing multicast routing protocols. Copyright 2005 John Wiley & Sons, Ltd. [source]


    A zone co-operation approach for efficient caching in mobile ad hoc networks

    INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 9 2006
    Narottam Chand
    Abstract Mobile Ad hoc NETwork (MANET) presents a constrained communication environment due to fundamental limitations of client resources, insufficient wireless bandwidth and users' frequent mobility. Caching of frequently accessed data in such environment is a potential technique that can improve the data access performance and availability. Co-operative caching, which allows the sharing and co-ordination of cached data among clients, can further explore the potential of the caching techniques. In this paper, we propose a novel scheme, called zone co-operative (ZC) for caching in MANETs. In ZC scheme, one-hop neighbours of a mobile client form a co-operative cache zone. For a data miss in the local cache, each client first searches the data in its zone before forwarding the request to the next client that lies along routing path towards server. As a part of cache management, cache admission control and value -based replacement policy are developed to improve the data accessibility and reduce the local cache miss ratio. An analytical study of ZC based on data popularity, node density and transmission range is also performed. Simulation experiments show that the ZC caching mechanism achieves significant improvements in cache hit ratio and average query latency in comparison with other caching strategies. Copyright 2006 John Wiley & Sons, Ltd. [source]


    An efficient MAC protocol for multi-channel mobile ad hoc networks based on location information

    INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 8 2006
    Yu-Chee Tseng
    Abstract This paper considers the channel assignment problem in a multi-channel MANET environment. We propose a scheme called GRID, by which a mobile host can easily determine which channel to use based on its current location. In fact, following the GSM style, our GRID spends no communication cost to allocate channels to mobile hosts since channel assignment is purely determined by hosts' physical locations. We show that this can improve the channel reuse ratio. We then propose a multi-channel MAC protocol, which integrates GRID. Our protocol is characterized by the following features: (i) it follows an ,on-demand' style to access the medium and thus a mobile host will occupy a channel only when necessary, (ii) the number of channels required is independent of the network topology, and (iii) no form of clock synchronization is required. On the other hand, most existing protocols assign channels to a host statically even if it has no intention to transmit [IEEE/ACM Trans. Networks 1995; 3(4):441,449; 1993; 1(6): 668,677; IEEE J. Selected Areas Commun. 1999; 17(8):1345,1352], require a number of channels which is a function of the maximum connectivity [IEEE/ACM Trans. Networks 1995; 3(4):441,449; 1993; 1(6): 668,677; Proceedings of IEEE MILCOM'97, November 1997; IEEE J. Selected Areas Commun. 1999; 17(8):1345,1352], or necessitate a clock synchronization among all hosts in the MANET [IEEE J. Selected Areas Commun. 1999; 17(8):1345,1352; Proceedings of IEEE INFOCOM'99, October 1999]. Through simulations, we demonstrate the advantages of our protocol. Copyright 2005 John Wiley & Sons, Ltd. [source]


    The CSMA/DM LAN protocol

    INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 8 2006
    Wuxu Peng
    Abstract We propose an extension of the classical CSMA/CD protocol that eliminates its three main drawbacks. The new protocol, called dual-mode CSMA/CD (CSMA/DM), operates in two modes, light mode and heavy mode. The light mode of CSMA/DM is almost the same as the original CSMA/CD protocol and is primarily used when the LAN load is light. The heavy mode is a collision free mode and is applied when the LAN load is heavy. The proposed modification to CSMA/CD is minimal while performance gain is significant. CSMA/DM automatically switches between its two modes based on the observed LAN load. Under heavy mode, the monitor station in a CSMA/DM LAN allocates bandwidth to those busy stations without collisions. The newly added priority scheme in the heavy mode allows stations to reserve bandwidth for their high priority frames. Compared with the current collision-free fast Ethernet and Gigabit Ethernet, CSMA/DM has the advantage of not needing any extra switches or hubs while maintaining comparable performance. Its priority scheme provides more flexibility on bandwidth distribution than in fast Ethernet and Gigabit Ethernet. It can also be easily adapted for high-speed wireless LANs. More importantly, CSMA/DM should be a good alternative of the widely used CSMA/CA (collision avoidance) in mobile ad hoc networks (MANET) and sensor networks. Copyright 2005 John Wiley & Sons, Ltd. [source]


    A new distributed approximation algorithm for constructing minimum connected dominating set in wireless ad hoc networks

    INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 8 2005
    Bo Gao
    Abstract In recent years, constructing a virtual backbone by nodes in a connected dominating set (CDS) has been proposed to improve the performance of ad hoc wireless networks. In general, a dominating set satisfies that every vertex in the graph is either in the set or adjacent to a vertex in the set. A CDS is a dominating set that also induces a connected sub-graph. However, finding the minimum connected dominating set (MCDS) is a well-known NP-hard problem in graph theory. Approximation algorithms for MCDS have been proposed in the literature. Most of these algorithms suffer from a poor approximation ratio, and from high time complexity and message complexity. In this paper, we present a new distributed approximation algorithm that constructs a MCDS for wireless ad hoc networks based on a maximal independent set (MIS). Our algorithm, which is fully localized, has a constant approximation ratio, and O(n) time and O(n) message complexity. In this algorithm, each node only requires the knowledge of its one-hop neighbours and there is only one shortest path connecting two dominators that are at most three hops away. We not only give theoretical performance analysis for our algorithm, but also conduct extensive simulation to compare our algorithm with other algorithms in the literature. Simulation results and theoretical analysis show that our algorithm has better efficiency and performance than others. Copyright 2005 John Wiley & Sons, Ltd. [source]


    QoS routing through alternate paths in wireless ad hoc networks

    INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 3 2004
    Baoxian Zhang
    Abstract Quality of service (QoS) routing plays an important role in QoS provisioning for mobile ad hoc networks. This work studies the issue of route selection subject to QoS constraint(s). Our method searches for alternate routes with satisfied QoS requirement(s) to accommodate each communication request when the shortest path connecting the source,destination pair of the request is not qualified. In order to effectively reduce protocol overhead, a directed search mechanism is designed to limit the breadth of the searching scope, which aims at achieving a graceful tradeoff between the success probability in QoS route acquisition and communication overhead. Efficient hop-by-hop routing protocols are designed for route selection subject to delay and bandwidth constraint, respectively. Simulation results show that the designed protocols can achieve high performance in acquiring QoS paths and in efficient resource utilization with low control overhead. Copyright 2004 John Wiley & Sons, Ltd. [source]


    Virtual base stations for wireless mobile ad hoc communications: an infrastructure for the infrastructure-less

    INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 8 2001
    Hossam Hassanein
    Abstract In this paper, we propose a new protocol for wireless mobile ad hoc networks, which establishes a dynamic wireless mobile infrastructure. The proposed protocol, namely, the virtual base stations (VBS) protocol, mimics and maintains the operation of the conventional fixed infrastructure in cellular networks. In the VBS protocol, a mobile node is elected from a set of nominees to act as a temporary base station within its zone. We provide proofs for the correctness of the VBS protocol, and show lower and upper bounds for its global convergence time. Likewise, we study the characteristics and performance of VBS by means of simulation. It is shown that VBS scales well to large networks of mobile stations, and that it outperforms other infrastructure-formation protocols in terms of stability. The VBS protocol would facilitate the development of a comprehensive and promising framework for quality of service (QoS) management in wireless mobile ad hoc networks once the proper integration of the MAC protocol with the routing and call admission control mechanisms is established. The VBS architecture lays the groundwork for assigning bandwidth, and/or implementing priorities, and hence for QoS-based routing by conveying the quality of a path prior to call setup. Copyright 2001 John Wiley & Sons, Ltd. [source]


    Design of multichannel MAC protocols for wireless ad hoc networks

    INTERNATIONAL JOURNAL OF NETWORK MANAGEMENT, Issue 5 2009
    Shou-Chih Lo
    Medium access control (MAC) protocols coordinate channel access between wireless stations, and they significantly affect the network throughput of wireless ad hoc networks. MAC protocols that are based on a multichannel model can increase the throughput by enabling more simultaneous transmission pairs in the network. In this paper, we comprehensively compare different design methods for multichannel MAC protocols. We classify existing protocols into different categories according to the channel negotiation strategies they employ. The common problems that may be encountered in multichannel design are discussed. We then propose a hybrid protocol that combines the advantages of the two methods of a common control channel and a common control period. The simulation results show that our proposed protocol can significantly outperform two representative protocols. Copyright 2008 John Wiley & Sons, Ltd. [source]


    A proactive management algorithm for self-healing mobile ad hoc networks

    INTERNATIONAL JOURNAL OF NETWORK MANAGEMENT, Issue 3 2008
    Adel F. Iskander
    The ability to proactively manage mobile ad hoc networks (MANETs) is critical for supporting complex services such as quality of service, security and access control in these networks. This paper focuses on the problem of managing highly dynamic and resource-constrained MANET environments through the proposal of a novel proactive management algorithm (PMA) for self-healing MANETs. PMA is based on an effective integration of autonomous, predictive and adaptive distributed management strategies. Proactive management is achieved through the distributed analysis of the current performance of the mobile nodes utilizing an optimistic discrete event simulation method, which is used to predict the mobile nodes' future status, and execution a proactive fault-tolerant management scheme. PMA takes advantage of distributed parallel processing, flexibility and intelligence of active packets to minimize the management overhead, while adapting to the highly dynamic and resource-constrained nature of MANETs. The performance of the proposed architecture is validated through analytical performance analysis and comparative simulation with the Active Virtual Network Management Protocol. The simulation results demonstrate that PMA not only significantly reduces management control overhead, but also improves both the performance and the stability of MANETs. Copyright 2007 John Wiley & Sons, Ltd. [source]


    Urban mesh and ad hoc mesh networks

    INTERNATIONAL JOURNAL OF NETWORK MANAGEMENT, Issue 2 2008
    Anders Nilsson Plymoth
    Mesh networking is currently gaining much attention, within both academia and industry. Mesh networking allows cheap and fast deployment of wireless services. It is regarded as a very promising solution for urban deployment scenarios as well as for temporary emergency response situations. Another related promising field is that of ad hoc wireless networking, which consists of mobile nodes that dynamically create and maintain a network without the need for any infrastructure. We propose a solution and architecture for urban mesh ad hoc networks, a network that combines mesh networking with ad hoc networks for urban environments. We present four types of ad hoc mesh and ad hoc mesh networks. The most general one consists of mesh nodes, called mesh points (MP), that act as a type of access point for user nodes (UN). The MPs have at least two interfaces: one which is used to communicate with UNs, and one which is used to maintain the mesh access network and transport data. These two interfaces can basically use any type of technology (IEEE 802.11 a/b/g, WiMax, etc.), and for capacity reasons it is generally regarded that the best solution is to let the mesh interface operate on a separate high-capacity channel or channels. An intricate part of these types of networks are routing and location services. In our solution, UN devices operate in ad hoc mode running an ad hoc routing protocol. This allows UNs that wish to communicate to connect directly in an ad hoc manner, or through an MP. An important question is therefore whether two UNs that wish to communicate should connect through the mesh or connect directly. We show that from a capacity point of view whether a UN should route its packets to the closest available MP, or through a ad hoc network, depends on the environment the network is located, the amount traffic and the type of protocols used. Since MPs need to know where to route packets within the mesh, i.e., locating the MP closest to the destination UN, each UN run a small application that registers the UN to the mesh network. In addition to the above features we have developed a new MAC that quickly queries two candidate nodes, which picks the candidate with the currently best radio conditions. This enable nodes to cope with deep dips in signal strength due to fast fading, a well-known problem in urban environments. We show that this new protocol achieves significantly lower delays. We also show that in dense urban environments performance and battery lifetime can be improved if ad hoc technologies are used. Copyright 2007 John Wiley & Sons, Ltd. [source]


    A heterogeneous-network aided public-key management scheme for mobile ad hoc networks

    INTERNATIONAL JOURNAL OF NETWORK MANAGEMENT, Issue 1 2007
    Yuh-Min Tseng
    A mobile ad hoc network does not require fixed infrastructure to construct connections among nodes. Due to the particular characteristics of mobile ad hoc networks, most existing secure protocols in wired networks do not meet the security requirements for mobile ad hoc networks. Most secure protocols in mobile ad hoc networks, such as secure routing, key agreement and secure group communication protocols, assume that all nodes must have pre-shared a secret, or pre-obtained public-key certificates before joining the network. However, this assumption has a practical weakness for some emergency applications, because some nodes without pre-obtained certificates will be unable to join the network. In this paper, a heterogeneous-network aided public-key management scheme for mobile ad hoc networks is proposed to remedy this weakness. Several heterogeneous networks (such as satellite, unmanned aerial vehicle, or cellular networks) provide wider service areas and ubiquitous connectivity. We adopt these wide-covered heterogeneous networks to design a secure certificate distribution scheme that allows a mobile node without a pre-obtained certificate to instantly get a certificate using the communication channel constructed by these wide-covered heterogeneous networks. Therefore, this scheme enhances the security infrastructure of public key management for mobile ad hoc networks. Copyright 2006 John Wiley & Sons, Ltd. [source]