Ad Hoc Networks Research

Last Updated: Sat Jan 21 18:38:15 UTC 2012

Ad Hoc Networks Research

Radio Frequency Propagation, Radar Datalinking, Routing,
Smart Networks, GNSS Protocols, Network Performance Modelling

Introduction

Ad Hoc Networks are self organising, self healing, distributed networks which most often employ wireless transmission techniques. My ongoing research in this area is divided into several domains. The first is airborne ad hoc networking (my doctoral research topic), the second is Suburban Ad Hoc networking and the related topic of Smart Ad Hoc Networks, and the third is in networked military systems.

My research in this area by necessity spans a number of areas of physics, engineering and computer science. These include radiofrequency propagation effects in “radar-like” and urban geometries, antenna parametrisation, satellite navigation support protocols, routing strategies and protocols, and network performance modelling. Related research I have performed includes radar performance modelling and vehicle signature modelling.

The Suburban Ad Hoc (Area) Networking group focusses its research activities on techniques for implementing Suburban Ad Hoc Networks. These are self organising, quasi-static ad hoc (typically wireless) networks which provide an alternative technology for providing high speed digital connectivity to households, small businesses and distributed campuses. Specific areas of research interest include security, low level routing protocols, access controls and propagation behaviour.

Smart Ad Hoc Networks

Smart Ad Hoc Networks are capable of analysing the radio propagation environment they operate in to optimise performance. This typically requires that the network nodes have positioning capability as well as memory to recall geographically local conditions. GNSS systems are the most affordable approach to providing network nodes with positioning capability.

Airborne Ad Hoc Networks

Airborne Ad Hoc Networks (AAHN) are a form of ad hoc network in which the transceivers and routers are carried by airborne platforms, such as conventional aircraft, High Altitude Long Endurance or conventional Uninhabited Aerial Vehicles, tethered aerostats or dirigibles. As such the AAHN has many quite different characteristics compared to conventional 'terrestrial' ad hoc networks. While AAHNs offer enormous footprint coverage for each node, compared to conventional solutions, this is achieved at the expense of unique problems in antenna placement, transceiver design, protocol design and integration.

Research Publications

Summary of all publications : Click Here

Lynch, David, Jr and Kopp, Carlo, Multifunctional Radar Systems for Fighter Aircraft , in Radar Handbook, Third Edition, Ed. Merrill I Skolnik, McGraw Hill Companies, Columbus OH USA, pp. 1-46, Hardcover, 1200 pages, URI: http://www.scitechpublishing.com/index.asp?PageAction=VIEWPROD&ProdID=408

For 17 years Radar Handbook has been the yardstick by which all other radar books are measured. Covering the entire scope of the field—from basic theory to real world applications—this trusted resource offers the unmatched expertise of more than 30 world leaders in every major area of radar technology. Complete with five brand new chapters, the third edition has been thoroughly updated to cover the latest trends and advances in this dynamic field. Classic chapters from the previous edition have also been revised by a new generation of radar experts to ensure this edition will withstand the test of time as efficiently as previous editions have.

M R. Tyson, C. Kopp, The Lightweight Global Navigation Satellite System (GNSS) Support Protocol (LGSP), Internet-Draft, Experimental, Network Working Group, Internet Engineering Task Force, December 19, 2007, URI: http://tools.ietf.org/html/draft-tyson-lgsp-01

This document presents the Lightweight GNSS (Global Navigation Satellite System) Support Protocol (LGSP). The Lightweight GNSS Support Protocol (LGSP) is being developed in order to provide a comprehensive solution which solves the problems inherent in traditional radio-based Differential GPS (DGPS) protocols. LGSP will also provide additional support for GNSS user equipment, such as a GPS almanac retrieval method, allowing compatible units to perform faster almanac acquisition, thus resulting in less time until an initial position measurement can be established. Other supporting features include alternative distribution of GPS navigation messages and differential correction messages, a hierarchical mirroring architecture, redundant backup operation and load balancing functions.

M R Tyson, C Kopp and R D Pose: RF propagation environment awareness (RPEA) for smart mobile ad-hoc networks, Journal of Battlefield Technology, vol 11, issue 3, Argos Press Pty Ltd, Red Hill ACT Australia, pp. 21-27.

Urban canyon environments represent a significant challenge to wireless communications, a satisfactory solution for which remains to be proven. We present RF Propagation Environment Awareness (RPEA), utilising ‘smart’ ad hoc, or self-forming and self-healing networks that are capable of storing and exploiting local propagation geometry information. An empirical radio propagation environment model, comprising a loss model specific to the local urban topology, is used to optimise network operation. This model is constructed over time from prior experience operating in the area of interest, and can be used to estimate the lifetime of a wireless connection, given current node kinematic behaviour, and location relative to attenuating objects in the environment. This lifetime can in turn be used to evaluate Quality of Service parameters for network routes, and to select optimal routes with the longest lifetime. We propose one technique to learn about the RF propagation environment, and evaluate the utility of RPEA.

M R Tyson and C Kopp, LGSP: A lightweight GNSS support protocol for military and civil applications, Journal of Battlefield Technology, vol 11, issue 1, Argos Press Pty Ltd, Red Hill ACT Australia, pp. 23-30.

We present a Lightweight GNSS (Global Navigation Satellite System) Support Protocol (LGSP), which has been devised at Monash University. LGSP aims to comprehensively address limitations in the traditional GNSS model, such as low signal availability in urban environments, receiver initialisation delays and bandwidth restrictions, by offering an alternative secure distribution channel for GNSS data. This gives compatible receivers an alternate means for acquiring GNSS data, resulting in enhanced robustness, efficiency and availability of GNSS systems. Development of LGSP is nearing completion, and a protocol specification has been released as an Internet Draft to the IETF. This paper presents the rationale behind the development of LGSP and discusses the protocol’s architecture, message formats and definitions.

C Kopp, Fifteen constraints on the capability of high-capacity mobile military networked systems, Journal of Battlefield Technology, vol 10, ed 2, Argos Press Pty Ltd, Australia, pp. 15-20.

The network centric warfare (NCW) model represents one of the defining trends in information age military technique. Its aim is to improve situational awareness and ‘accelerate the observation-orientation-decision-action (OODA) loop’. While much literature exists which extols the virtues of NCW, the problem of what constraints exist on the capabilities of such systems has been explored much less frequently. This paper identifies no less than fifteen constraints on the capability of networked military systems, implemented with tactical datalinks, and explores their respective causes and implications.

M R Tyson, C Kopp and R D Pose, RF Propagation Environment Awareness (RPEA) for Smart Mobile Ad-Hoc Networks, Proceedings of the Military Communications and Information Systems 2008 Conference (MilCIS 2008), 18 November 2008 to 20 November 2008, MilCIS, pp. 1-6, URI: http://www.milcis.com.au/milcis2008pdf/Reviewed papers/Tyson-final.pdf

Urban canyon environments represent a significant challenge to wireless communications, a satisfactory solution for which remains to be proven. We present RF Propagation Environment Awareness (RPEA), utilising ‘smart’ ad hoc, or self-forming and self-healing networks that are capable of storing and exploiting local propagation geometry information. An empirical radio propagation environment model, comprising a loss model specific to the local urban topology, is used to optimise network operation. This model is constructed over time from prior experience operating in the area of interest, and can be used to estimate the lifetime of a wireless connection, given current node kinematic behaviour, and location relative to attenuating objects in the environment. This lifetime can in turn be used to evaluate Quality of Service parameters for network routes, and to select optimal routes with the longest lifetime. We propose one technique to learn about the RF propagation environment, and evaluate the utility of RF Propagation Environment Awareness.

M R Tyson and C Kopp, Defining functional requirements for a lightweight GNSS support protocol (LGSP), Proceedings of the 6th IEEE/ACIS International Conference on Computer and Information Science, 11 July 2007 to 13 July 2007, IEEE Computer Society, Los Alamitos CA USA, pp. 241-246, URI: http://ieeexplore.ieee.org/

Monash University is developing a Lightweight GNSS (Global Navigation Satellite System) Support Protocol (LGSP). This protocol aims to comprehensively address limitations in the traditional GNSS model, such as low signal availability in urban environments, receiver initialisation delays and bandwidth restrictions, by offering an alternative secure distribution channel for GNSS data. This gives compatible receivers an alternate means for acquiring GNSS data, resulting in enhanced robustness, efficiency and availability of GNSS systems. Development of LGSP has progressed, and a protocol specification is being prepared for release as an Internet draft to the IETF. This paper discusses motivations for the creation of LGSP, and presents key constraints and aims in the development of the protocol.

M R Tyson and C Kopp, LGSP: A lightweight GNSS support protocol for military and civil applications, Proceedings of the Military Communications and Information Systems 2007 Conference (MilCIS 2007), 20 November 2007 to 22 November 2007, MilCIS, pp. 1-6, URI: http://www.milcis.com.au/milcis2007pdf/2.4b-3 Tyson.pdf

We present a Lightweight GNSS (Global Navigation Satellite System) Support Protocol (LGSP), which is being developed by Monash University. LGSP aims to comprehensively address limitations in the traditional GNSS model, such as low signal availability in urban environments, receiver initialisation delays and bandwidth restrictions, by offering an alternative secure distribution channel for GNSS data. This gives compatible receivers an alternate means for acquiring GNSS data, resulting in enhanced robustness, efficiency and availability of GNSS systems. Development of LGSP is nearing completion, and a protocol specification is being released as an Internet draft to the IETF. This paper presents motivations behind the development of LGSP and discusses the protocol’s architecture and communications.

M R Tyson, R D Pose, C Kopp, S M Rokonuzzaman, M M Islam, Engineering a suburban ad-hoc network, Proceedings of the 7th Australian Information Warfare and Security Conference, 4 December 2006 to 5 December 2006, School of Computer and Information Science, Edith Cowan University, Perth WA Australia, pp. 120-130, URI: http://scissec.scis.ecu.edu.au/conference_proceedings/2006/iwar/Proceedings_IWAR_2006.pdf

The Monash Suburban Ad-Hoc Network (SAHN) project has devised a system that provides a highly secure and survivable ad-hoc network, capable of delivering broadband speeds to cooperating users within a fixed environment, such as a residential neighbourhood, or a campus. The SAHN differs from Mobile Ad Hoc Networks (MANETs) in that the environment is ‘quasi-static’, not mobile. That is, it is assumed that nodes are fixed, and will not move about: topology changes are very infrequent. Additionally, while many MANETs are designed for omnidirectional antennas, the SAHN provides for directional and electronically steered antennas. This paper investigates possible architectures for an implementation of the SAHN, and presents a real-world prototype. The prototype presented takes the form of a Linux kernel module, and a user-space daemon.

C Kopp and C S Wallace, TROPPO - A Tropospheric Propagation Simulator, School of Computer Science and Software Engineering, Monash University, Melbourne, 21pp. Technical Report 2004/161, URI: http://www.csse.monash.edu.au/publications/2004/tr-2004-161-full.pdf

An interesting problem which frequently arises in microwave communication and radar engineering is the calculation of microwave propagation losses through the troposphere and lower stratosphere. A wealth of detailed literature and software tools exists for calculating losses in propagation geometries which are characteristic of terrestrial satellite and point to point links, and surface based radar installations. The more general case is less frequently addressed. Given the inhomogeneous and widely variable physical properties of the atmosphere, the use of simplified models for solving the general propagation problem will mostly yield unsatisfactory results. We have developed and tested a general purpose numerical simulation tool for microwave propagation between stations of arbitrary altitude in the troposphere and stratosphere. Several existing models for atmospheric temperature, pressure and water vapour density, gaseous oxygen and water vapour losses, cloud losses and rain losses were adapted, and modified where appropriate to better fit empirical data and semi-empirical models. The accuracy of these models has been confirmed by comparison with published data.

C Kopp, The Properties of High Capacity Microwave Airborne Ad Hoc Networks, PhD Thesis, Monash University, 2000.

This dissertation demonstrates that substantial connectivity and network capacity can exist between aircraft participating in an ad hoc network under a range of weather conditions track densities and trac altitudes. Multiple hop connections spanning distances of several thousand kilometres with link capacities of up to Gigabits/s are shown to be feasible and to exhibit uninterrupted durations of hours. In summary it is shown that High Capacity Airborne Ad Hoc Networks are not only viable, but for many applications either competitive or superior to established LEO, MEO and GEO satellite communications, and extant airborne communication schemes.

Network Centric Warfare Publications (NCW)

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NCW101: An Introduction to Network Centric Warfare

Network Centric Warfare Textbook by Dr Carlo Kopp

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NCW101: An Introduction to Network Centric Warfare was produced to provide a broad and deep, yet accessible and affordable introductory text covering the fundamental ideas and technologies underpinning military networking. The intent of the text is to provide an objective view of military networking, devoid of the strong views often found in publications by advocates or detractors of NCW. Unlike other recent texts dealing with NCW, this work also covers key supporting technologies, information warfare impacts on networked systems, and many of the human factors problems arising in networked systems.

This book is a compilation of all twenty parts of the NCW101 series, and nine related technical essays, all of which were published in Strike Publications’ Defence Today journal between 2003 and 2008, and one research paper dealing with quantitative capability modeling of networked military systems.

The NCW101 series was produced with the intent of providing an accessible series of technical primers or tutorials for beginners in this area, the scope covering the whole gamut of digital networks, datalinks and communications technologies, the digitised Intelligence, Surveillance and Reconnaissance sensors feeding the network, and the full spectrum of Information Warfare applied against the sensor, network and operator.

Most of this material was written at an undergraduate level, with a qualitative rather than quantitative focus to maximize its accessibility and footprint. The book is suitable as an introductory text for both undergraduate and postgraduate students, as well as military staff college courses.

This text includes an extensive bibliography of related reference materials, intended to provide both professional readers and students of military networking with an accessible list of reading material.

Media

Defense Industry Daily - AESA Comlinks: DID Reader Has Done Prior Research

Airborne Ad Hoc Network Primer

Perhaps the best contextual comparison depicting the unique properties of the AAHN is its geometry compared to conventional satcom links. With most aircraft at the tropopause, and some in the stratosphere (UAVs) or lower troposhere, propagation related issues are far more pronounced against satcom systems, while latency is inherently better, especially where the network footprint is relatively modest.

This chart compares latency behaviours for satellite systems. The AAHN at shorter distances experiences latencies which are characteristic of terrestrial networks.

Propagation geometry chart for an AAHN link. The most interesting problems to solve arise in the Loss/Gain limited and Transition regions.

This chart depicts the coverage requirements for an AAHN antenna suite on a conventional aircraft.

Modelling long range link behaviour requires simulation of propagation losses. This plot was produced by the TROPPO simulator and depicts gaseous losses as a function of altitude, using the Van Vleck, Liege and Blake models.

Fine structure of the gaseous loss model in the Oxygen resonance region using the TROPPO simulator.

Gaseous loss rate model parameterised by frequency.

Gasous loss profiles for a link between an aircraft at 11 km altitude and a ground station, separated by a ground track distance of 380 km, using the TROPPO simulation and a nonlinear refracted path model.

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