1,903 research outputs found

    Airborne Directional Networking: Topology Control Protocol Design

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    This research identifies and evaluates the impact of several architectural design choices in relation to airborne networking in contested environments related to autonomous topology control. Using simulation, we evaluate topology reconfiguration effectiveness using classical performance metrics for different point-to-point communication architectures. Our attention is focused on the design choices which have the greatest impact on reliability, scalability, and performance. In this work, we discuss the impact of several practical considerations of airborne networking in contested environments related to autonomous topology control modeling. Using simulation, we derive multiple classical performance metrics to evaluate topology reconfiguration effectiveness for different point-to-point communication architecture attributes for the purpose of qualifying protocol design elements

    End-to-End Resilience Mechanisms for Network Transport Protocols

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    The universal reliance on and hence the need for resilience in network communications has been well established. Current transport protocols are designed to provide fixed mechanisms for error remediation (if any), using techniques such as ARQ, and offer little or no adaptability to underlying network conditions, or to different sets of application requirements. The ubiquitous TCP transport protocol makes too many assumptions about underlying layers to provide resilient end-to-end service in all network scenarios, especially those which include significant heterogeneity. Additionally the properties of reliability, performability, availability, dependability, and survivability are not explicitly addressed in the design, so there is no support for resilience. This dissertation presents considerations which must be taken in designing new resilience mechanisms for future transport protocols to meet service requirements in the face of various attacks and challenges. The primary mechanisms addressed include diverse end-to-end paths, and multi-mode operation for changing network conditions

    Continued study of NAVSTAR/GPS for general aviation

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    A conceptual approach for examining the full potential of Global Positioning Systems (GPS) for the general aviation community is presented. Aspects of an experimental program to demonstrate these concepts are discussed. The report concludes with the observation that the true potential of GPS can only be exploited by utilization in concert with a data link. The capability afforded by the combination of position location and reporting stimulates the concept of GPS providing the auxiliary functions of collision avoidance, and approach and landing guidance. A series of general recommendations for future NASA and civil community efforts in order to continue to support GPS for general aviation are included

    Proposition of a Novel Multipath-Routing Protocol for Manets Connected Via Positioning of UAVS Using Ant Colony Optimization Meta-Algorithms

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    In the forthcoming operational theatre, combat radio nodes will be strategically positioned to facilitate a myriad of manoeuvres, constituting a dynamic mobile ad-hoc network (MANET), where communication among participating nodes is achieved collaboratively without fixed base stations. However, due to the nodes' mobility, the cohesive formation may fragment into smaller clusters, while conversely, multiple smaller groups might amalgamate into larger entities. In such a dynamic milieu, the integration of unmanned aerial vehicles (UAVs) emerges as a potent solution to enhance network coverage and connectivity among disparate groups. Sending of information all over the MANETs is dependent mostly on methodologies of routing, where the on-request unitary paths procedures to route like AODV and AOMDV (which stands for routing via multiple roads) play crucial roles. Leveraging authentic topographic data becomes imperative to ascertain precise connectivity metrics among nodes, while devising an efficient resource allocation strategy for reliable communication via UAVs warrants attention. Given the predominance of line-of-sight links between UAVs and ground nodes, substantial traffic is anticipated despite less amount of information sectional resources. Furthermore, diverse quality-of-service requirements of network traffic necessitate prioritization based on tactical imperatives. In these studies, formulations have been done for Unmanned Flying Vehicle localizing problems geared towards maximal connectivity inside groups along with information section allocating problems aimed at increasing utilities of GC to maximum levels, demonstrating superiority over conventional methodologies through numerical analysis validating the efficacy of our proposed scheme. Wireless connections implemented rapid growths in recent times essentially network of MANET, showcasing significant developments of science and technology

    Identification of Technologies for Provision of Future Aeronautical Communications

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    This report describes the process, findings, and recommendations of the second of three phases of the Future Communications Study (FCS) technology investigation conducted by NASA Glenn Research Center and ITT Advanced Engineering & Sciences Division for the Federal Aviation Administration (FAA). The FCS is a collaborative research effort between the FAA and Eurocontrol to address frequency congestion and spectrum depletion for safety critical airground communications. The goal of the technology investigation is to identify technologies that can support the longterm aeronautical mobile communication operating concept. A derived set of evaluation criteria traceable to the operating concept document is presented. An adaptation of the analytical hierarchy process is described and recommended for selecting candidates for detailed evaluation. Evaluations of a subset of technologies brought forward from the prescreening process are provided. Five of those are identified as candidates with the highest potential for continental airspace solutions in L-band (P-34, W-CDMA, LDL, B-VHF, and E-TDMA). Additional technologies are identified as best performers in the unique environments of remote/oceanic airspace in the satellite bands (Inmarsat SBB and a custom satellite solution) and the airport flight domain in C-band (802.16e). Details of the evaluation criteria, channel models, and the technology evaluations are provided in appendixes

    Examining Ambiguities in the Automatic Packet Reporting System

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    The Automatic Packet Reporting System (APRS) is an amateur radio packet network that has evolved over the last several decades in tandem with, and then arguably beyond, the lifetime of other VHF/UHF amateur packet networks, to the point where it is one of very few packet networks left on the amateur VHF/UHF bands. This is proving to be problematic due to the loss of institutional knowledge as older amateur radio operators who designed and built APRS and other AX.25-based packet networks abandon the hobby or pass away. The purpose of this document is to collect and curate a sufficient body of knowledge to ensure the continued usefulness of the APRS network, and re-examining the engineering decisions made during the network’s evolution to look for possible improvements and identify deficiencies in documentation of the existing network
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