1 |
Messaging and positioning in a dynamic TETRA environmentEidlert, Fredrik January 2009 (has links)
Advanced communication with capabilities such as voice, data, and messaging usually requires an infrastructure with base stations, servers, and etcetera. The TETRA technology offers such communication not only in TMO (infrastructure-based network) but also in DMO where all nodes communicate directly (or via a repeater) with each other. This master’s thesis concerns messaging (specifically short messages) in a dynamic multi link TETRA DMO network. It examines what type of messaging technique to use and how to do path selection. The messages will be clear text, status, and GPS location information. The solution is implemented as a part of the ISIS software (which is developed by Know IT Dataunit). The planned multi link-part of the thesis could not be tested, so there is no implementation or evaluation of this. The evaluation of the implementation concerning sending and reception of messages shows that the proposed solution fulfils the demands for this kind of product. During a four day long test, messages (short text messages and positioning messages) were sent and received while a normal number of voice conversations took place, without packet loss. / Avancerad kommunikation med funktioner såsom röstsamtal, dataöverföring samt meddelandetjänster kräver ofta en infrastruktur med basstationer, servrar etcetera. TETRA-tekniken erbjuder sådan kommunikation, inte bara i TMO (infrastrukturbaserade nätverk), utan även i DMO där alla noder kommunicerar direkt (eller via en repeater) med varandra. Detta examensarbete undersöker hanteringen av meddelanden (framförallt korta meddelanden) i ett dynamiskt multilänkat TETRA nätverk. Det som behandlas är vilken typ av meddelande som bör användas samt hur man väljer väg. De meddelanden som hanteras är klartextmeddelanden, status samt GPS positionsmeddelanden. Den lösning som tagits fram är implementerad som en del i ISIS programvaran (som är utvecklad av Know IT Dataunit). Multilänkdelen kunde inte testas, därför gjordes aldrig någon implementering eller utvärdering. Utvärderingen av implementeringen som hanterar sändning och mottagning av meddelanden visar att den föreslagna lösningen uppfyller de krav man kan ställa på en sådan produkt. Under ett fyra dagar långt test skickades meddelanden (korta textmeddelanden samt positioneringsmeddelanden) medan ett normalt antal röstsamtal pågick, utan någon förlust av paket.
|
2 |
A cross-layer and multi-metric routing decision making framework for MANETsOsathanunkul, Kitisak January 2013 (has links)
Mobile Ad hoc Networks (MANETs) are re-emerging as a popular networking facility for wireless device users. A growing number of diversified applications are now accessible via wireless devices. The different applications may have different Quality of Service (QoS) requirements, which may better be satisfied by using different routing methods or metric types. Existing ad hoc network routing solutions do not consider various application-level requirements when making a routing decision. They typically make routing decisions based upon limited information acquired at the network layer. Most of the existing routing protocols make use of a single routing metric. Using a single metric type and/or information, only acquired at the network layer may not be able to accommodate different QoS requirements, imposed by diversified user-level applications or application-level data types.The aim of this thesis is to design an efficient routing function for ad hoc networks while at the same time satisfying users‟ and/or applications‟ QoS and security requirements. To achieve this, the thesis investigates and specifies routing requirements that could best support application-level QoS and security requirements in MANETs. It also investigates and critically analyses the state of the art in MANET routing, and the mechanisms used for protecting the routing functions. To overcome the weaknesses and advance the state of the art in MANET routing, this thesis proposes two major solutions. The first solution is the Secure ETX (SETX) routing protocol. It is a secure routing solution that can provide routing functions efficiently in malicious MANET environment. The SETX protocol provides a security mechanism to counter black hole attacks in MANETs on the ETX metric acquisition process. Simulation studies have been carried out and discussed in the thesis. Simulation results show that the SETX protocol can provide a marked improvement in network performances in the presence of black hole attacks, and it can do so with a negligible level of additional overhead.The second solution is a novel routing decision making called the Flexible Routing Decision (FRD) framework. The FRD framework supports routing decision making by using multiple metric types (i.e. multi-criteria routing decision making) and uses a cross-layer approach to support application-level QoS requirements. This allows users to use different routing metrics types, making the most appropriate routing decision for a given application. To accommodate the diversified application-level QoS requirements, multiple routing metric types have been identified and interpreted in the FRD framework design. The FRD framework has overcome some weaknesses exhibited by existing single metric routing decision making, used in MANETs. The performance of a routing decision making of FRD is also evaluated using NS2 simulation package. Simulation results demonstrate that the FRD framework outperforms the existing routing decision making methods.
|
3 |
USING LABVIEW TO DESIGN A FAULT-TOLERANT LINK ESTABLISHMENT PROTOCOLHoran, Stephen, Deivasigamani, Giriprassad 10 1900 (has links)
International Telemetering Conference Proceedings / October 18-21, 2004 / Town & Country Resort, San Diego, California / The design of a protocol for a satellite cluster link establishment and management that accounts for link corruption, node failures, and node re-establishment is presented in this paper. This protocol will need to manage the traffic flow between nodes in the satellite cluster, adjust routing tables due to node motion, allow for sub-networks in the cluster, and similar activities. This protocol development is in its initial stages and we will describe how we use the LabVIEW Sate Diagram tool kit to generate the code to design a state machine representing the protocol for the establishment of inter-satellite communications links.
|
4 |
Game theory for dynamic spectrum sharing cognitive radioRaoof, Omar January 2010 (has links)
‘Game Theory’ is the formal study of conflict and cooperation. The theory is based on a set of tools that have been developed in order to assist with the modelling and analysis of individual, independent decision makers. These actions potentially affect any decisions, which are made by other competitors. Therefore, it is well suited and capable of addressing the various issues linked to wireless communications. This work presents a Green Game-Based Hybrid Vertical Handover Model. The model is used for heterogeneous wireless networks, which combines both dynamic (Received Signal Strength and Node Mobility) and static (Cost, Power Consumption and Bandwidth) factors. These factors control the handover decision process; whereby the mechanism successfully eliminates any unnecessary handovers, reduces delay and overall number of handovers to 50% less and 70% less dropped packets and saves 50% more energy in comparison to other mechanisms. A novel Game-Based Multi-Interface Fast-Handover MIPv6 protocol is introduced in this thesis as an extension to the Multi-Interface Fast-handover MIPv6 protocol. The protocol works when the mobile node has more than one wireless interface. The protocol controls the handover decision process by deciding whether a handover is necessary and helps the node to choose the right access point at the right time. In addition, the protocol switches the mobile nodes interfaces ‘ON’ and ‘OFF’ when needed to control the mobile node’s energy consumption and eliminate power lost of adding another interface. The protocol successfully reduces the number of handovers to 70%, 90% less dropped packets, 40% more received packets and acknowledgments and 85% less end-to-end delay in comparison to other Protocols. Furthermore, the thesis adapts a novel combination of both game and auction theory in dynamic resource allocation and price-power-based routing in wireless Ad-Hoc networks. Under auction schemes, destinations nodes bid the information data to access to the data stored in the server node. The server will allocate the data to the winner who values it most. Once the data has been allocated to the winner, another mechanism for dynamic routing is adopted. The routing mechanism is based on the source-destination cooperation, power consumption and source-compensation to the intermediate nodes. The mechanism dramatically increases the seller’s revenue to 50% more when compared to random allocation scheme and briefly evaluates the reliability of predefined route with respect to data prices, source and destination cooperation for different network settings. Last but not least, this thesis adjusts an adaptive competitive second-price pay-to-bid sealed auction game and a reputation-based game. This solves the fairness problems associated with spectrum sharing amongst one primary user and a large number of secondary users in a cognitive radio environment. The proposed games create a competition between the bidders and offers better revenue to the players in terms of fairness to more than 60% in certain scenarios. The proposed game could reach the maximum total profit for both primary and secondary users with better fairness; this is illustrated through numerical results.
|
5 |
A Control Layer Algorithm for Ad hoc Networks in Support of Urban Search and Rescue (USAR) ApplicationsRamarathinam, Venkatesh 30 March 2004 (has links)
Ad hoc networks have gained significant importance and gathered huge momentum within the wireless network research community. We explore the novel idea of applying ad hoc networking for urban search and rescue operations. Several algorithms have been proposed and implemented for routing in ad hoc networks and their performance have been thoroughly analyzed. But none of the prior work deals specifically for search and rescue operations, which entail certain specific criteria such as prevention of node loss, maximizing the area of coverage and constant and instantaneous access to a main controller.
In this thesis, we propose a centralized and adaptive algorithm tailored for efficient performance of mobile nodes assisting in search and rescue operations. The proposed algorithm assists in finding and maintaining stable links between the mobile nodes and base station, while optimizing the area of coverage and energy efficiency of the nodes. The algorithm is implemented using ns (network simulator), and its performance is compared with that of a widely used ad hoc routing protocol, Ad hoc On-demand Distance Vector (AODV) routing protocol. We use frequency of link breakages, network throughput and routing overhead as our performance metrics. This algorithm can also be extended to provide support for routing among mobile nodes.
|
6 |
The localized Delaunay triangulation and ad-hoc routing in heterogeneous environmentsWatson, Mark Duncan 03 January 2006
Ad-Hoc Wireless routing has become an important area of research in the last few years due to the massive increase in wireless devices. Computational Geometry is relevant in attempts to build stable, low power routing schemes. It is only recently, however, that models have been expanded to consider devices with a non-uniform broadcast range, and few properties are known. In particular, we find, via both theoretical and experimental methods, extremal properties for the Localized Delaunay Triangulation over the Mutual Inclusion Graph. We also provide a distributed, sub-quadratic algorithm for the generation of the structure.
|
7 |
The localized Delaunay triangulation and ad-hoc routing in heterogeneous environmentsWatson, Mark Duncan 03 January 2006 (has links)
Ad-Hoc Wireless routing has become an important area of research in the last few years due to the massive increase in wireless devices. Computational Geometry is relevant in attempts to build stable, low power routing schemes. It is only recently, however, that models have been expanded to consider devices with a non-uniform broadcast range, and few properties are known. In particular, we find, via both theoretical and experimental methods, extremal properties for the Localized Delaunay Triangulation over the Mutual Inclusion Graph. We also provide a distributed, sub-quadratic algorithm for the generation of the structure.
|
8 |
Wireless Mesh Networks: a comparative study of Ad-Hoc routing protocols toward more efficient routing / a comparative study of Ad-Hoc routing protocols toward more efficient routingAlibabaei, Navid January 2015 (has links)
Each day, the dream of seamless networking and connectivity everywhere is getting closer to become a reality. In this regard, mobile Ad-Hoc networks (MANETs) have been a hot topic in the last decade; but the amount of MANET usage nowadays confines to a tiny percentage of all our network connectivity in our everyday life, which connectivity through infrastructured networks has the major share. On the other hand, we know that future of networking belongs to Ad-Hocing , so for now we try to give our everyday infrastructure network a taste of Ad-Hocing ability; these types of networks are called Wireless Mesh Networks (WMN) and routing features play a vital role in their functionality. In this thesis we examine the functionality of 3 Ad-Hoc routing protocols known as AODV, OLSR and GRP using simulation method in OPNET17.5. For this goal we set up 4 different scenarios to examine the performance of these routing protocols; these scenarios vary from each other in amount of nodes, background traffic and mobility of the nodes. Performance measurements of these protocols are done by network throughput, end-end delay of the transmitted packets and packet loss ratio as our performance metrics. After the simulation run and gathering the results we study them in a comparative view, first based on each scenario and then based on each protocol. For conclusion, as former studies suggest AODV, OLSR and DRP are among the best routing protocols for WMNs, so in this research we don’t introduce the best RP based on the obtained functionality results, instead we discuss the network conditions that each of these protocols show their best functionality in them and suggest the best routing mechanism for different networks based on the analysis from the former part.
|
9 |
Simulation and Analysis of Wireless Ad Hoc Routing SchemesHåkansson, Mikael, Renman, Jan January 2004 (has links)
An Ad Hoc network is a wireless network without any stationary infrastructure of any kind. The nodes should be able to communicate with each other using wireless links, where a packet might traverse multiple links from the source to the destination. Every node in the network acts as a router, forwarding packet from one node to another. Since Ad Hoc networks are wireless and the nodes often battery driven, it is very important that the routing protocol in use can handle a large degree of node mobility and at the same time be very energy efficient. This is not an easy thing and a numerous routing protocols for wireless Ad Hoc networks have been proposed. Our goal was to simulate and make a literature study of three completely different routing protocols for wireless Ad Hoc networks: the Dynamic Source Routing protocol (DSR), the Topology Dissemination Based on Reverse-Path Forwarding protocol (TBRPF), and the Zone Routing Protocol (ZRP).
|
10 |
Security in low power wireless networks : Evaluating and mitigating routing attacks in a reactive, on demand ad-hoc routing protocol / Säkerheten i trådlösa lågenerginätverk : Utvärdering och begränsning av routing attacker i ett reaktivt ad-hoc routing protokollFredriksson, Tony, Ljungberg, Niklas January 2017 (has links)
Using low energy devices to communicate over the air presents many challenges to reach security as resources in the world of Internet Of Things (IoT) are limited. Any extra overhead of computing or radio transmissions that extra security might add affects cost of both increased computing time and energy consumption which are all scarce resources in IoT. This thesis details the current state of security mechanisms built into the commercially available protocol stacks Zigbee, Z-wave, and Bluetooth Low Energy, and collects implemented and proposed solutions to common ways of attacking systems built on these protocol stacks. Attacks evaluated are denial of service/sleep, man-in-the-middle, replay, eavesdropping, and in mesh networks, sinkhole, black hole, selective forwarding, sybil, wormhole, and hello flood. An intrusion detection system is proposed to detect sinkhole, selective forwarding, and sybil attacks in the routing protocol present in the communication stack Rime implemented in the operating system Contiki. The Sinkhole and Selective forwarding mitigation works close to perfection in larger lossless networks but suffers an increase in false positives in lossy environments. The Sybil Detection is based on Received Signal Strength and strengthens the blacklist used in the sinkhole and selective forwarding detection, as a node changing its ID to avoid the blacklist will be detected as in the same geographical position as the blacklisted node.
|
Page generated in 0.0799 seconds