• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 72
  • 13
  • 9
  • 6
  • 5
  • 3
  • 2
  • 1
  • 1
  • Tagged with
  • 132
  • 132
  • 89
  • 63
  • 62
  • 59
  • 56
  • 56
  • 29
  • 26
  • 23
  • 20
  • 20
  • 15
  • 15
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

On routing protocols for mobile social networks

Altamimi, Ahmed B. 18 October 2011 (has links)
A mobile social network (MSN) is defined as a mobile network that uses social relationships to allow its nodes to communicate. Many wireless networks including ad hoc networks do not reflect a real world deployment because of routing implementation difficulties. However, with the enormous use of social network sites (SNSs) including Twitter and Facebook, MSNs are expected to make the implementation of routing easier. Thus, some research activity has been devoted to routing protocols in such networks. This task is very challenging, thus only a few MSN routing protocols have been proposed in the literature. However, these protocols suffer from either a low delivery ratio or high memory requirements. This thesis presents a new routing protocol (Status) for MSNs which has excellent performance in terms of delivery ratio and memory requirements. Status takes advantage of the online status of a node to make forwarding decisions. Status has a low overhead ratio, low average delay and low computational complexity at the node level. All of these features are examined in this thesis. Simulation results are presented which show that Status outperforms other routing protocols such as Epidemic and PRoPHET with a realistic mobility model, namely, the shortest path movement based model (SPMBM). Status does not have high memory requirements since it does not store the online status of other nodes. Instead, an instance check is done when two nodes meet. Since messages are forwarded without probability calculations based on contact history, Status also has low computational complexity. / Graduate
2

Multipath route construction methods for wireless sensor networks

Rizvi, Saad 06 June 2013 (has links)
Routing plays an important role in energy constrained Wireless Sensor Networks (WSNs). To conserve energy in WSN, energy-efficiency of the routing protocol is an important design consideration. These protocols should maximize network lifetime and minimize energy consumption. In this thesis, a novel multipath routing protocol is proposed for WSNs, which constructs multiple paths based on residual energy of the nodes. The protocol allows the source node to select a path for data transmission from the set of discovered multiple paths based on cumulative residual energy or variance. Choosing a next-hop node based on energy, and using an alternative path for routing achieves load balancing. The results show that the proposed algorithm M-VAR has lower residual energy variance (96%, 90%, 72%, 12% less) and longer network lifetime (404%, 205%, 115%, 10%) than basic Directed Diffusion, load-balanced Directed Diffusion (LBDD-ED-RD), multipath Directed Diffusion (MDD-CRE), and the proposed algorithm M-CRE, respectively.
3

Multipath route construction methods for wireless sensor networks

Rizvi, Saad 06 June 2013 (has links)
Routing plays an important role in energy constrained Wireless Sensor Networks (WSNs). To conserve energy in WSN, energy-efficiency of the routing protocol is an important design consideration. These protocols should maximize network lifetime and minimize energy consumption. In this thesis, a novel multipath routing protocol is proposed for WSNs, which constructs multiple paths based on residual energy of the nodes. The protocol allows the source node to select a path for data transmission from the set of discovered multiple paths based on cumulative residual energy or variance. Choosing a next-hop node based on energy, and using an alternative path for routing achieves load balancing. The results show that the proposed algorithm M-VAR has lower residual energy variance (96%, 90%, 72%, 12% less) and longer network lifetime (404%, 205%, 115%, 10%) than basic Directed Diffusion, load-balanced Directed Diffusion (LBDD-ED-RD), multipath Directed Diffusion (MDD-CRE), and the proposed algorithm M-CRE, respectively.
4

Implementation and performance measurement and analysis of OLSR protocol /

Sinky, Hassan Hussein. January 1900 (has links)
Thesis (M.S.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 28-29). Also available on the World Wide Web.
5

An investigation of Routing Protocols in Wireless Mesh Networks (WMNs) under certain Parameters / En undersökning av Routing Protocols i Wireless Mesh Networks (WMNs) under vissa parametrar

Ahmad, Waqas, Aslam, Muhammad Kashif January 2009 (has links)
Wireless Mesh Networks (WMNs) are bringing revolutionary change in the field of wireless networking. It is a trustworthy technology in applications like broadband home networking, network management and latest transportation systems. WMNs consist of mesh routers, mesh clients and gateways. It is a special kind of wireless Ad-hoc networks. One of the issues in WMNs is resource management which includes routing and for routing there are particular routing protocols that gives better performance when checked with certain parameters. Parameters in WMNs include delay, throughput, network load etc. There are two types of routing protocols i.e. reactive protocols and proactive protocols. Three routing protocols AODV, DSR and OLSR have been tested in WMNs under certain parameters which are delay, throughput and network load. The testing of these protocols will be performed in the Optimized Network Evaluation Tool (OPNET) Modeler 14.5. The obtained results from OPNET will be displayed in this thesis in the form of graphs. This thesis will help in validating which routing protocol will give the best performance under the assumed conditions. Moreover this thesis report will help in doing more research in future in this area and help in generating new ideas in this research area that will enhance and bring new features in WMNs. / Wireless Mesh Networks (WMNs) bringar revolutionerande förändring inom området för trådlösa nätverk. Det är en pålitlig teknik i tillämpningar såsom bredband hemma nätverk, nätverkshantering och senaste transportsystem. WMNs består av mesh routrar, kunder mesh och gateways. Det är en speciell typ av trådlöst ad-hoc-nätverk. En av frågorna i WMNs är resurshushållning som inkluderar routing och routing det finns särskilda routingprotokoll som ger bättre prestanda vid kontroll med vissa parametrar. Parametrar i WMNs omfatta dröjsmål, genomströmning, belastningen på nätet etc. Det finns två typer av routingprotokoll dvs reaktiva protokoll och proaktiva protokoll. Tre routingprotokoll AODV, DSR och OLSR har testats i WMNs under vissa parametrar som är försenade, genomströmning och belastningen på nätet. Testning av dessa protokoll kommer att utföras i den optimerade Network Evaluation Tool (OPNET) Modeler 14.5. De erhållna resultaten från OPNET kommer att visas i denna avhandling i form av grafer. Denna uppsats kommer att bidra till att godkänna vilka routingprotokoll kommer att ge bäst resultat enligt den antagna förhållanden. Dessutom kommer denna uppsats rapport kommer att bidra till att göra mer forskning i framtiden på detta område och bidra till att generera nya idéer inom detta forskningsområde som kommer att öka och att nya funktioner i WMNs. / +46762749245
6

Performance analysis and protocol design of opportunistic routing in multi-hop wireless networks.

January 2008 (has links)
Luk, Chun Pong. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 122-125). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgement --- p.iv / Chapter 1 --- Introduction / Motivation --- p.1 / Chapter 1.1 --- Background and Motivation --- p.1 / Chapter 1.2 --- Performance Analysis of Opportunistic Routing in Multi-hop Wireless Network --- p.3 / Chapter 1.3 --- Opportunistic Routing Protocol Design --- p.5 / Chapter 1.4 --- Chapter Summary --- p.6 / Chapter 2 --- Literature Review --- p.8 / Chapter 2.1 --- Introduction --- p.8 / Chapter 2.2 --- Opportunistic Routing Protocols --- p.9 / Chapter 2.2.1 --- Challenges of the Opportunistic Routing Protocol Design --- p.9 / Chapter 2.2.2 --- Overview of Existing Opportunistic Routing Protocols --- p.11 / Chapter 2.2.3 --- Forwarding Set Selection Algorithms --- p.12 / Chapter 2.2.4 --- Actual Forwarder Determination --- p.13 / Chapter 2.2.5 --- Duplicate Suppression Strategies --- p.14 / Chapter 2.2.6 --- Variations of Opportunistic Routing Protocols --- p.16 / Chapter 2.3 --- Performance Evaluation and Analysis of Opportunistic Routing --- p.16 / Chapter 2.4 --- Routing in Networks with Directional Antennas --- p.19 / Chapter 2.4.1 --- Performance Analysis of the use of Directional Antenna in Routing --- p.20 / Chapter 2.4.2 --- Existing Routing and MAC protocols for Networks with Directional Antennas --- p.21 / Chapter 2.5 --- Chapter Summary --- p.22 / Chapter 3 --- Performance Analysis of Opportunistic Routing in Multi-hop Wireless Network --- p.24 / Chapter 3.1 --- Introduction --- p.24 / Chapter 3.2 --- Analytical Derivation of the Expected Progress per Transmission of Opportunistic Routing --- p.25 / Chapter 3.2.1 --- Problem Formulations and Assumptions --- p.26 / Chapter 3.2.2 --- Reception Probability of a Node in a Given Region --- p.28 / Chapter 3.2.3 --- Radio Channel Models --- p.30 / Chapter 3.2.4 --- Average Progress per Transmission --- p.32 / Chapter 3.3 --- Validation and Analytical Results --- p.34 / Chapter 3.3.1 --- Results Validation --- p.34 / Chapter 3.3.2 --- Baseline Models --- p.35 / Chapter 3.3.3 --- Results and Analysis --- p.36 / Chapter 3.4 --- Further Extension of the Model --- p.40 / Chapter 3.5 --- Chapter Summary --- p.42 / Chapter 4 --- Opportunistic Routing in Multi-hop Wireless Networks with Directional Antennas --- p.44 / Chapter 4.1 --- Introduction --- p.44 / Chapter 4.2 --- Performance Analysis of Opportunistic Routing in Networks with Directional Antennas --- p.46 / Chapter 4.2.1 --- Network Model --- p.46 / Chapter 4.2.2 --- Radio Channel Models --- p.47 / Chapter 4.2.3 --- Antenna Models --- p.49 / Chapter 4.2.4 --- Expected Progress per Transmission with Directional Antenna --- p.51 / Chapter 4.2.5 --- Simulation Setup --- p.52 / Chapter 4.2.6 --- Results and Analysis --- p.54 / Chapter 4.3 --- Maximizing the Gain of Opportunistic Routing by Adjusting Antenna Beamwidth and Direction --- p.60 / Chapter 4.3.1 --- Introduction and Motivation --- p.60 / Chapter 4.3.2 --- Network Models --- p.61 / Chapter 4.3.3 --- Algorithms --- p.61 / Chapter 4.3.4 --- Results and Discussions --- p.66 / Chapter 4.3.5 --- Section Summary --- p.71 / Chapter 4.4 --- Chapter Summary --- p.72 / Chapter 5 --- Impact of Interference on Opportunistic Routing --- p.74 / Chapter 5.1 --- Introduction --- p.74 / Chapter 5.2 --- Interference Model --- p.75 / Chapter 5.3 --- MAC Protocols --- p.76 / Chapter 5.4 --- Simulation Results and Discussions --- p.78 / Chapter 5.4.1 --- Simulation Setup --- p.78 / Chapter 5.4.2 --- Baseline Models --- p.78 / Chapter 5.4.3 --- Results and Analysis --- p.79 / Chapter 5.5 --- Chapter Summary --- p.84 / Chapter 6 --- Threshold-based Opportunistic Routing Protocol --- p.86 / Chapter 6.1 --- Introduction --- p.86 / Chapter 6.2 --- Limitations of Existing Opportunistic Routing Protocols --- p.87 / Chapter 6.3 --- System Model --- p.89 / Chapter 6.4 --- Operating Principles of TORP --- p.91 / Chapter 6.5 --- Protocol Details --- p.93 / Chapter 6.5.1 --- Forwarding Set Computation --- p.93 / Chapter 6.5.2 --- Update of Forwarding Set and Remaining Transmission Counts --- p.97 / Chapter 6.5.3 --- Forwarding Threshold Computation and Details of the Packet Forwarding Process --- p.100 / Chapter 6.5.4 --- Node State --- p.101 / Chapter 6.5.5 --- Packet Format --- p.101 / Chapter 6.5.6 --- Batched Acknowledgement --- p.102 / Chapter 6.6 --- Advantages of TORP --- p.102 / Chapter 6.6.1 --- Distributed Forwarding Set Computation --- p.102 / Chapter 6.6.2 --- Threshold-based Forwarding --- p.103 / Chapter 6.6.3 --- MAC-Independence --- p.104 / Chapter 6.7 --- Protocol Extensions --- p.104 / Chapter 6.7.1 --- Implicit ACK --- p.104 / Chapter 6.7.2 --- Progress Recovery --- p.105 / Chapter 6.7.3 --- Modification of TORP for Large Networks --- p.106 / Chapter 6.8 --- Results and Discussions --- p.106 / Chapter 6.8.1 --- Simulation Setup --- p.106 / Chapter 6.8.2 --- Baseline Models --- p.107 / Chapter 6.8.3 --- Performance Evaluations and Analysis --- p.108 / Chapter 6.9 --- Chapter Summary --- p.116 / Chapter 7 --- Conclusion and Future Works --- p.118 / Chapter 7.1 --- Conclusion --- p.118 / Chapter 7.2 --- Future Work --- p.120 / Bibliography --- p.122
7

An Automatic Solution to Checking Compatibility between Routing Metrics and Protocols

Liu, Chang 19 January 2016 (has links)
Routing metrics are important mechanisms to adjust routing protocols' path selection according to the needs of a network system. However, if a routing metric design does not correctly match a particular routing protocol, the protocol may not be able to find an optimal path; routing loops can be produced as well. Thus, the compatibility between routing metrics and routing protocols is increasingly significant with the widespread deployment of wired and wireless networks. However, it is usually difficult to tell whether a routing metric can be perfectly applied to a particular routing protocol. Manually enumerating all possible test cases is very challenging and often infeasible. Therefore, it is highly desirable to have an automatic solution so that one can avoid putting an incompatible combination of routing metric and protocol into use. In this thesis, the above issue has been addressed by developing two automated checking systems for examining the compatibility between real world routing metric and protocol implementations. The automatic routing protocol checking system assumes that some properties of routing metrics are given and the system's job is to check if a new routing protocol is able to achieve optimal, consistent and loop- free routing when it is combined with metrics that hold the given metric properties. In contrast to the protocol checking system, the automatic routing metric checking system assumes that a routing protocol is given and the checking system needs to verify if a new metric implementation will be able to work with this protocol. Experiments have been conducted to verify the correctness of both protocol and metric checking systems. / Master of Science
8

Secure Ad Hoc Routing Protocols With Detection, Identification And Self-Healing Capabilities

Ayeegoundanpalayam Kulasekaran, Sivakumar 11 December 2009 (has links)
Devices taking part in mobile ad hoc networks (MANET) co-operate with each other to route packets by strictly adhering to the ad hoc routing protocol in use. Malicious nodes taking part in co-operative routing can launch a wide variety of attacks to reduce the utility of MANETs. The aim of secure routing protocols is to ensure that MANETs can continue to function even in the face of malicious nodes. Secure routing protocols should have measures to dissuade attackers by detecting inconsistencies, identifying the perpetrator responsible for the inconsistency, and provide means to inhibit the role of misbehaving nodes. Most existing secure routing protocols try to achieve only first step, viz., detection of inconsistencies. This dissertation research investigates and proposes efficient strategies that substantially enhance the scope of assurances provided by secure MANET routing protocols while keeping the overhead low.
9

The optimisation and performance evaluation of routing protocols in cognitive radio based wireless mesh networks

Kola, Lesiba Morries January 2017 (has links)
Thesis (MSc.) -- University of Limpopo, 2017 / The notion of ubiquitous computing, Internet of things (IoT), big data, cloud computing and other emerging technologies has brougt forward the innovative paradigms and incredible developments in wireless communication technologies. The Wireless Mesh Networks (WMNs) technology has recently emerged as the promising high speed wireless technology to provide the last mile broadband Internet access and deliver flexible and integrated wireless communication solutions. The WMNs has the potential to enable people living in rural, peri-urban areas and small businesses to interconnect their networks and share the affordable Internet connectivity. The recent multimedia applications developed, such as voice over Internet protocol (VoIP), online gaming, cloud storage, instant messaging applications, and video sharing applications require high speed communication media and networks. These applications have witnessed enormous growth in the recent decade and continue to enhance communication amongst the users. Hence, the WMNs must have adequate capacity to support high bandwidth and real-time and multimedia applications. While the wireless communications networks are dependent on the radio frequency (RF) spectrum, the traditional wireless technologies utilise the RF spectrum bands inefficiently, resulting in sporadic and underutilisation of the RF spectrum. This inefficient usage of RF spectrum calls for novel techniques to leverage the available RF spectrum amongst different players in the wireless communication arena. There have been developments on integration of the WMNs with cognitive ratios to allow unlicensed users of RF spectrum to operate in the licensed portions of spectrum bands. This integration will provide the required bandwidth to support the required high speed broadband communication infrastructure. In this dissertation, we focus our research on the routing layer in a multi-hop wireless network environment. We addressed the routing challenges in both the WMNs and the cognitive radio based wireless mesh networks (CR-WMNs). The primary focus was to identify the routing protocols most suitable for the dynamic WMN environment. Once identified, the routing protocol was then ported to the CR-WMN environment to evaluate its performance given all the dynamics of cognitive radio environment. vi We further proposed the routing protocol called the extended weighted cumulative expected transmission time (xWCETT) routing protocol for the CR-WMNs. The design of our proposed xWCETT routing protocol is based on the multi-radio multi-channel architecture as it gives the base framework matching the cognitive radio environment. The xWCETT integrates features from the Ad-hoc On-demand Distance Vector (AODV) routing protocol and the weighted cumulative expected transmission time (WCETT) routing metric. The xWCETT was implemented using the Cognitive Radio Cognitive Network (CRCN) patch ported in network simulator (NS2) to incorporate the shared and dynamic spectrum access features. We compared the performance of our proposed xWCETT routing protocol with the AODV, dynamic source routing (DSR), the optimised link source routing (OLSR), Destination Sequences Distance Vector (DSDV), and the CRCN-WCETT routing protocols. The extensive simulation and numerical results show that the proposed xWCETT protocol obtained on average, around 10% better performance results in the CR-WNNs as compared to its routing counterparts. The comparative analysis and evaluation was performed in terms of the average end-to-end latency, throughput, jitter, packet delivery ratio, as well as the normalised routing load. The performance results obtained indicates that the proposed xWCETT routing protocol is a promising routing solution for dynamic CR-WMNs environment. / National Research Foundation (NRF)
10

ROUTING IN MOBILE AD-HOC NETWORKS: SCALABILITY AND EFFICIENCY

Bai, Rendong 01 January 2008 (has links)
Mobile Ad-hoc Networks (MANETs) have received considerable research interest in recent years. Because of dynamic topology and limited resources, it is challenging to design routing protocols for MANETs. In this dissertation, we focus on the scalability and efficiency problems in designing routing protocols for MANETs. We design the Way Point Routing (WPR) model for medium to large networks. WPR selects a number of nodes on a route as waypoints and divides the route into segments at the waypoints. Waypoint nodes run a high-level inter-segment routing protocol, and nodes on each segment run a low-level intra-segment routing protocol. We use DSR and AODV as the inter-segment and the intra-segment routing protocols, respectively. We term this instantiation the DSR Over AODV (DOA) routing protocol. We develop Salvaging Route Reply (SRR) to salvage undeliverable route reply (RREP) messages. We propose two SRR schemes: SRR1 and SRR2. In SRR1, a salvor actively broadcasts a one-hop salvage request to find an alternative path to the source. In SRR2, nodes passively learn an alternative path from duplicate route request (RREQ) packets. A salvor uses the alternative path to forward a RREP when the original path is broken. We propose Multiple-Target Route Discovery (MTRD) to aggregate multiple route requests into one RREQ message and to discover multiple targets simultaneously. When a source initiates a route discovery, it first tries to attach its request to existing RREQ packets that it relays. MTRD improves routing performance by reducing the number of regular route discoveries. We develop a new scheme called Bilateral Route Discovery (BRD), in which both source and destination actively participate in a route discovery process. BRD consists of two halves: a source route discovery and a destination route discovery, each searching for the other. BRD has the potential to reduce control overhead by one half. We propose an efficient and generalized approach called Accumulated Path Metric (APM) to support High-Throughput Metrics (HTMs). APM finds the shortest path without collecting topology information and without running a shortest-path algorithm. Moreover, we develop the Broadcast Ordering (BO) technique to suppress unnecessary RREQ transmissions.

Page generated in 0.0882 seconds