11,321 research outputs found

    Enhanced Ad Hoc On-Demand Distance Vector Routing Protocol For Mobile Ad Hoc Network Internet Connectivity

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    An ad hoc network is a collection of wireless mobile nodes dynamically forming a temporary network without the use of any existing network infrastructure or centralized administration and consists of mobile nodes that use a wireless interface to communicate with each other. These mobile nodes serve as both hosts and routers so they can forward packets on behalf of each other. Hence, the mobile nodes are able to communicate beyond their transmission range by supporting multi hop communication. However, the fact that there is no central infrastructure and that the devices which can move randomly gives rise to various kinds of problems, such as routing and security and quality of service (QoS). In this thesis the problem of routing is considered. An Ad-Hoc network has certain characteristics, which impose new demand on the routing protocol the most important characteristic is the dynamic topology, which is a consequence of node mobility. Nodes can changes position quite frequently, which means that we need a routing protocol that quickly adapts to topology changes. The nodes in ad hoc network can consist of laptops and PDA (Personal Digital Assistants) and are often very limited in resources such as CPU capacity, storage capacity, battery power and bandwidth. This means that routing protocol should try to minimize control traffic, such as period update message. Instead the routing protocol should be reactive, thus only calculate routes upon receiving a specific request. The Internet Engineering Task Force (IEFT) currently has a working group called mobile Ad hoc network (MANET) that is working on routing specification for Ad hoc networks. This thesis evaluates some of the routing protocols such as AODV (Ad hoc on demand Distance vector) and DSR (Dynamic Sources Routing) and DSDV (Destination Sequenced Distance vector) for performance testing and an enhanced implementation of AODV, which is able to detect Internet gateway in the proactive, reactive, and hybrid situation. This evaluation is done by means of simulation using NS-2 developed by University California Berkeley. There are several ad hoc routing protocols, such as AODV, DSR, and DSDV that propose solutions for routing within a mobile ad hoc network. However, since there is an interest in communication between not only mobile devices in an ad hoc network, but also between a mobile device in an ad hoc network and a fixed device in a fixed network (e.g. the Internet), the ad hoc routing protocols need to be modified. In this thesis the ad hoc routing protocol AODV is used and modified to examine the interconnection between a mobile ad hoc network and the Internet. For this purpose Network Simulator 2, NS 2, has been used. Moreover, three proposed approaches for gateway discovery are implemented; propose a forwarding algorithm, and route determination algorithm for default route and host route in MANET are investigated

    A Cross Layer Routing Protocol for OFDMA Based Mobile Ad Hoc Networks.

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    PhDMobile ad hoc networks are of growing interest because of their unique characteristics and advantages in many practical applications. QoS provision acts as a major challenge in the routing protocol design in the real-world mobile ad hoc networks, especially for the real-time services. OFDM is a new technology which has many advantages over the other modulation schemes. Because of its prominent features, many popular wireless standards have adopted it as physical layer modulation, such as IEEE 802.11 series, WiMAX, 3GPP LTE etc, and it is extended to multiuser environment known as OFDMA. So far none of the existing ad hoc routing protocols fully account for the OFDMA based mobile ad hoc networks. In this thesis, a QoS routing protocol is proposed for OFDMA based mobile ad hoc networks. A signal strength-based sub-channel allocation scheme is proposed in the routing protocol aiming to reduce the signalling overhead and cochannel interference. The performance of the proposed routing protocol is compared with other alternative proposals through simulations using OPNET simulator. Moreover, a partial time synchronization and a null subcarrier based frequency synchronization algorithms are also proposed for OFDMA based ad hoc network to further support and facilitate the proposed sub-channel allocation scheme and routing protocol

    Xcast Based Routing Protocol For Push To Talk Application In Mobile Ad Hoc Networks

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    Mobile ad-hoc networks comprise a type of wireless network that can be easily created without the need for network infrastructure or administration. These networks are organized and administered into temporary and dynamic network topologies. Unfortunately, mobile ad-hoc networks suffer from some limitations related to insufficient bandwidth. The proliferation of new IP Multimedia subsystem services (IMs), such as Push-to-talk (PTT) applications consume large amounts of bandwidth, resulting in degraded QoS performance of mobile ad-hoc networks. In this thesis, a Priority XCAST based routing protocol (P-XCAST) is proposed for mobile ad-hoc networks to minimize bandwidth consumption. P-XCAST is based on demand route requests and route reply mechanisms for every destination in the PXCAST layer. To build the network topology and fill up the route table for nodes, the information in the route table is used to classify the XCAST list of destinations according to similarities on their next hop. Furthermore, P-XCAST is merged with a proposed Group Management algorithm to handle node mobility by classifying nodes into two types: group head and member. The proposed protocol was tested using the GloMoSim network simulator under different network scenarios to investigate Quality of Service (QoS) performance network metrics. P-XCAST performance was better by about 20% than those of other tested routing protocols by supporting of group size up to twenty receivers with an acceptable QoS. Therefore, it can be applied under different network scenarios (static or dynamic). In addition Link throughput and average delay was calculated using queuing network model; as this model is suitable for evaluating the IEEE 802.11 MAC that is used for push to talk applications. The analytical results for link throughput and average delay were used to validate the simulated results

    QoS in Node-disjoint Routing for Ad Hoc Networks

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    PhDA mobile ad hoc network (MANET) is a collection of mobile nodes that can communicate with each other without using any fixed infrastructure. It is necessary for MANETs to have efficient routing protocol and quality of service (QoS) mechanism to support multimedia applications such as video and voice. Node-Disjoint Multipath Routing Protocol (NDMR) is a practical protocol in MANETs: it reduces routing overhead dramatically and achieves multiple node-disjoint routing paths. Because QoS support in MANETs is important as best-effort routing is not efficient for supporting multimedia applications, this thesis presents a novel approach to provide that support. In this thesis NDMR is enhanced to provide a QoS enabled NDMR that decreases the transmission delay between source and destination nodes. A multi-rate mechanism is also implemented in the new protocol so that the NDMR QoS can minimise the overall delays. It is shown that these approaches lead to significant performance gains. A modification to NDMR is also proposed to overcome some of the limitations of the original

    Novel Method of Improving Quality of Service for Voice over Internet Protocol Traffic in Mobile Ad Hoc Networks

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    In recent years, the application of Mobile Ad-hoc Network (MANET) with Voice over Internet Protocol (VoIP) has been increased.  However, the level of Quality of Service (QoS) for VoIP traffic in MANET, while there is no infrastructure, will reduce when dealing with a large number of calls. In this type of dynamic environment, the developing of a new infrastructure becomes more costly and time-consuming. In this paper, we proposed an efficient method, called the Quality of Service-Nearest Neighbor (QoS-NN), to improve the QoS level for VoIP in order to manage the huge number of calls over MANET network. We utilized the Ad-hoc On-demand Distance Vector (AODV) protocol as the underlying routing protocol to implement our proposed method. We evaluated the proposed QoS-NN method using Network Simulator version 2 (NS2). The performance of the proposed QoS-NN method was compared with Lexicographic order method. The comparison was evaluated in terms of R-factor, end-to-end delay, packet loss ratio, and packet delivery ratio performance metrics. In addition, the proposed method evaluated under different network parameters such as VoIP CODECs, node mobility speed, number of calls and number of nodes. The comparison results indicate that the proposed QoS-NN outperform the Lexicographic order method

    Intelligent Routing and Flow Control In MANETs

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    Improving the performance of the Mobile Ad hoc NETworks (MANETs) is a challenge. MANETs present several constraints such as dynamic topology, wireless link communication and limited resources like bandwidth and energy. Routing without taking into account these constraints degrades performance and aggravates congestion problem. This paper proposes a new solution combining QoS (Quality of Service) routing protocol and flow control mechanism. This QoS routing protocol selects the routes with more resources in an intelligent manner rather than diffusion. It returns the best route offering a higher transmission rate, a less delay and a more stability. This protocol uses a new metric to compute the most stable route. To reinforce the congestion avoidance, we add a flow control mechanism to adjust the sender\u27s transmission rate for each route. The solution is modeled by the ant systems. The results obtained under the Network Simulator (NS2.31) show that our QoS routing protocol improves the network performance compared to QoS-AODV protocol. The addition of flow control mechanism produces significant improvements in network system performance

    Evaluasi Kinerja Protokol Perutean AODV dan SDGR+R pada VANET dengan Studi Kasus Pelabuhan Lembar

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    The Vehicular ad-hoc Network (VANET) is a subclass of Mobile ad-hoc networks (MANETs).VANET is a wireless network created from the concept of building a vehicle network (node) toexchange data information (data communication). There is a new concept technique forVANET communication used, namely the use of the concept of Software Defined Network(SDN) on VANET. For data communication between vehicles, a routing protocol required. Themost common routing protocol used on VANET since 2003 is AODV. In 2014 several studieswere using the SDN paradigm tried on VANET technology to improve the performance ofQuality of Service (QoS), one of which is a Geographic-based SDN, called SDGR in 2016.Multicast is a method of routing data on a network that allows one node or a group of nodes tocommunicate efficiently with the receiving node. The multicast concept supports one-to-manyrouting in nodes that send packet data to a group of nodes. The development of the SDGRrouting protocol using the idea of multicast technique to SDGR based on the Direction calledSDGR + R carried out in 2019. This study uses a case study of vehicle transportationsimulations in the Lamber Port area of Lombok. The simulation results knew that SDGR + Ris better than AODV in terms of service quality (QoS) at a latency of 15.58% and packet deliveryratio (PDR) of 47.78%

    On-demand security and QoS optimization in mobile ad hoc networks

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    Scope and Method of Study: Security often comes with overhead that will impact link Quality of Service (QoS) performance. In this dissertation, we propose an on-demand security and QoS optimization architecture in mobile ad hoc networks that automatically adapts network security level to changes in network topology, traffic condition, and link QoS requirements, so as to keep the security and QoS at optimum conditions. In order to achieve the overall objective, we introduce three basic frameworks: a policy based plug-in security framework, a multi-layer QoS guided routing algorithm, and a Proportional Integral Derivative (PID) feedback control based security and QoS optimization framework. The research has been evaluated with the network simulator ns-2. Finally, we propose an attack tree and state machine based security evaluation mechanism for ad hoc networks: a new security measurement metric.Findings and Conclusions: Simulations have been done for small and large network sizes, low and high communication ratios, as well as low and high mobility scenarios. The simulations show that the proposed on-demand security and QoS optimization architecture can produce similar performance to non-secure QoS routing protocol under various traffic loads. It provides more secure ad hoc networks without compromising the QoS performance, especially under light and medium traffic conditions

    Last mile mobile hybrid optical wireless access network routing enhancement

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    This study focuses on mobile ad hoc networks (MANETs) that support Internet routing protocol imposing stringent resource consumption constraints of Quality of service (QoS). The mobile Internet causes the on-going issue of inefficient use of the MANET resources due to its random nature of wireless environments. In this paper, the new improved architecture of the last mile mobile hybrid optical-wireless access network (adLMMHOWAN) is proposed and designed to tackle the arised issues. The proposed design is based on a unified wireless-wired network solution required the deployment of MANET-based wireless fidelity (WiFi) technology at the wireless front-end and wavelengths division multiplexing passive optical network (WDM PON) at the optical backhaul. The critical performance metrics such as network capacity and energy consumption based on modified AODVUU routing protocol using OMNeT++ software is analyzed with 2 scenarios, namely the number of nodes and mobility speed. This mode of communication results in better QoS network capacity of 47.07% improvement, with 26.85% reduction of lower energy resource consumption for mobile wireless front-end over passive optical network backhaul architecture when compared with the existing work of oRiq scheme that focus on improvement in MANETs
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