Communications and Networks Research Lab


Researchers in the Communications and Networking Laboratory are actively engaged in addressing key challenges that face the future generation broadband communication networks.

More specifically, researchers in the wireless communications and networking area are investigating design and fundamental information-theoretic analysis of energy efficient next generation wireless networks that can deliver very high data rates anytime anywhere, via the MIMO-OFDM technology proposed for the new wireless communication standards such as Long-Term Evolution — Advanced (LTE-A), and re-thinking of cellular network design via a hierarchical structure involving macro, micro, pico and femto-cells.¬†Emerging technologies such as cognitive radios are also being investigated to address the problem of spectrum scarcity. A number of researchers are also investigating how to design more energy efficient wireless video communication networks.

Researchers in the optical communications domain are investigating the problem of reducing the carbon footprint of the next generation Internet (for more information, see Centre for Energy-Efficient Telecommunications), along with the design and analysis of broadband networks that seamlessly integrate wireless and optical communications technologies via Passive optical networking (PON). Networking researchers are investigating practical inference methods for Internet measurement, sophisticated accurate clock synchronization techniques over the Internet and aspects of Information-theoretic security.

More details on these and other related projects can be found in the following list of projects.


Achieving cost effective abatement from Australian electricity generation

Researchers: Michael Brear, Chris Manzie, Tansu Alpcan, Dragan Nesic

Whilst several studies have modelled the Australian electricity network's response to emissions trading, they do not typically examine the effects of weather and the dynamics of different plant closely. As such, significant opportunities and challenges involved in integrating higher penetration renewables and complementary technologies into the national network have not been systematically identified.

This two year study will therefore answer two specific questions.
1. What combination of technologies will achieve the lowest cost for successively deeper levels of abatement from the national network?

2. How effectively will the National Electricity Market (NEM) function at each abatement target under its current rules?

Answering Question 1 requires the first, integrated optimisation of the network. Each abatement level will be achieved by some technology combination, with scenarios established in a technologically-neutral framework. Question 2 will then use common, economic modelling approaches to examine in particular the NEM spot price and participant bidding with higher penetration renewables.

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Codes over rings

Researchers: Margreta Kuijper

This project focuses on algebraic codes over finite rings of the type Z_{p^r}. In recent years, novel linear algebraic tools were developed that overcome the difficulties of the presence of zero divisors in such rings.

Current research is focused on further application of these fundamental ideas. We consider the design of efficient algorithms for decoding of Reed-Solomon codes over rings; network coding over finite rings; shortest recurrence algorithms for sequences over rings; non-Hamming metric decoding over finite rings.

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Easing the squeeze: dynamic and distributed resource allocation with cognitive radio

Researchers: Tansu Alpcan, Subhrakanti Dey

The radio spectrum is a scarce and valuable natural resource which is being squeezed by the rapid growth in wireless communications. Cognitive radios make efficient use of radio spectrum by dynamically reusing frequencies. This requires cognitive radios to sense the local environment and to control the interference caused to existing users of the spectrum. In this project we will design novel dynamic and distributed resource allocation algorithms for cognitive radios in order to significantly improve their performance. We will do so using techniques from extreme value theory, game theory and mechanism design and large random
matrix theory.

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Gigabit wireless access using millimeter-wave over optical fiber systems

Researchers: Masud Bakaul, Thas Nirmalathas, Christina Lim, Stan Skafidas

Millimeter-wave radio-over-fiber (RoF) systems are widely considered as a disruptive technology for Gigabit/s wireless communications. In these systems, the benefits of optical fiber and mm-wave radio technologies are combined to provide an alternative approach for high-speed wireless access to customers. An optical fiber feeder network is used to interconnect a large number of remote antenna base stations (BSs) to the local Exchange (central office, CO), where most of the switching and signal processing equipment are installed. Usual distances between the CO and the BSs and the BSs and the customers are 5-50 km and 10 -1000 meters respectively. This project explores various system technologies and architectures in simplification of optically modulated millimeter-wave generations, transports and detections that enable Gigabit wireless access potentially at low-costs.

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Gigabit wireless: setting the standard for tomorrow's broadband

Researchers: Jamie Evans, Margreta Kuijper, Subhrakanti Dey, Brian Krongold, Feng Li, Phil Yeoh

This project will impact the future international standards for wireless broadband access. The research team will meet the challenge of designing an integrated wireless access technology that offers the maximum possible data rate for mobile users while providing competitive data rates for wireless access to the home. This will be achieved by exploiting a new wireless technology (MIMO-OFDM) that provides a superior air interface to current generation systems. We will enhance this technology with novel approaches to resource allocation and network architecture design that have the potential to drastically increase the system capacity.

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Internet Measurement

Researchers: Darryl Veitch

Internet Measurement is a rich field devoted to the development of accurate experimental, measurement, analysis and inference techniques to shine light into the vast unknown that is `what is going on in the Internet'. 

This project pursues several strands, including:

  • Active probing:  this is the practice of sending streams of `probe' packets into the network, to infer network behaviour through observing their end-to-end experience (if they are lost, delayed..).  The current focus is to explore the `convex network' approach to solving problems in optimal probing (getting the most information per-probe).
  • Traffic Sampling:  in high speed environments like inside routers in the Internet core there are far too many packets to measure them all.  We research optimal sampling, sketching, and `skampling' techniques to measure metrics like the flow-size distribution at ultra high-speed with minimum variance.
  • Optimal Traceroute:  Traceroute is a well-known tool for measurement of the paths that packets take when traversing the Internet. The project refines its operation to provide statistical guarantees when used for topology discovery.

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Internet of Things for Creating Smart Cities: Designing an urban information architecture

Researchers: Jayavardhana Gubbi Lakshminarasimha, Marimuthu Palaniswami, Jayavardhana Gubbi, Slaven Marusic

The project aims to create a Smart City capability through seamless urban environment monitoring via large-scale sensing, data analytics and information representation. Interconnection of sensing and actuating devices as an ‘internet of things’ addresses the ability to share information across platforms through a unified framework, developing a common operating picture for city management. The interpretation of events and visualisation of information for end-users will ensure sustainability and higher quality of life in the urban environment. Major outcomes will include energy-efficient sensing, network quality of service, cloud computing for sensor networks and high level analytics to detect and interpret events for decision making.

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Large scale multiple antennas for energy-efficient heterogeneous wireless networks

Researchers: Phee Lep Yeoh, Brian Krongold

This project investigates new network architectures for future wireless broadband inspired by recent advances in large scale multiple antenna technology and heterogeneous networks. The aim is to support flexible and scalable wireless services across diverse network regions with energy-efficient management of radio spectrum and interference. Targeted applications include smart energy metering, intelligent transport systems, mobile health monitoring and green data centres. Outcomes of the research will be new wireless protocols and algorithms drawing upon the foundations of random matrix theory, game theory, and large system analysis, which will offer fundamental insights into large scale multiple antennas for heterogeneous wireless networks.

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Network Timing System

Researchers: Darryl Veitch, Julien Ridoux

This project aims to develop the next generation system for computer clock synchronisation for the Internet.  Our goal is to replace the incumbent, the `NTP' system, currently used by (almost) every computer on earth.

All computers incorporate a software clock, essential to software applications. An inexpensive and convenient way to synchronise such clocks is over a network, however the approach the Internet currently depends upon is unreliable, inflexible, and ignores major sources of error. This project will define and solve the key research problems underpinning an optimal and maintainable system for network timekeeping, and implement and test the outcomes under realistic conditions over the Internet. The result will be software clocks of high accuracy and reliability supporting applications like cloud computing, tele-medicine, smart grids, and network measurement, well positioned to become the next generation timekeeping system for the Internet.

This project builds on the existing testbed and RADclock synchronisation client developed under the SyncLab project.  Open Source software is available for download at  Support for RADclock has been accepted into FreeBSD, the operating system of choice for servers.

Current directions:

  • Virtualised OSs     ( timing architecture for virtual machines )

               Virtualisation-friendly timing including live migration;  testing on Xen, VMware Player

  • Asymmetry measurement and mitigation   ( large error, largely ignored )

               Tightening bounds via spatial diversity; OS calibration; server recommendation service 

  • Server heath monitor   ( remote assessment of time-server quality )

               Exploiting known RADclock performance to detect server anomalies

  • Timing system health   ( evaluating systemic anomalies and performance )

               Mapping and evaluating public stratum-1 servers; assessing vulnerabilities

  • IEEE-1588 (PTP) support   ( exploiting 1588 masters for software clocks )

               Benchmarking 1588-capable RADclock against alternatives; contributions to standard

  • Unidirectional feed-forward algorithms   ( currently RADclock is bidirectional )

               Currently only feedback algorithms exist, unstable to noise (latency variability)

  • RADclock performance   ( formal analysis and performance enhancement )

               Statistical analysis of algorithms (for optimisation, calibration..);  LAN-specific enhancements

  • Adoption   ( building momentum towards replacing the NTP system )

              Accepted into FreeBSD 10.0; visibility with Linux stakeholders; adoption by CAIDA’s Ark monitors

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Network Tomography

Researchers: Darryl Veitch, Julien Ridoux, Salman Malik

Internet Tomography is the name given to a class of statistical inference problems where Internet measurements made over accessible `slices' of the network are used to infer quantities over other, inaccessible slices. Classic examples include measuring aggregrate traffic at routers inside the network to infer end-to-end traffic demand, or measuring end-to-end delays at measurement stations at the edge of the network to infer delays at nodes inside it. 

This project researches a number of Internet Tomography problems.  The main focii currently are:

  • Exploiting sparsity for loss tomography (in a nutshell, working out how to predict loss `hotspot' locations assuming there aren't many of them).
  • Investigating joint compressibility for topology inference (working out how the network is connected by observing the similarities in the structure of observed packet losses at different locations).

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Precision Timekeeping Infrastructure: bridging the hardware/software divide

Researchers: Julien Ridoux, Darryl Veitch

Accurate time is essential for critical services from telecommunications to banking, and increasingly, must be performed with software clocks within computers, using hardware clocks accessed over the Internet. This project with Symmetricom Inc. will bridge the hardware/software divide to deliver reliable and cost effective access to precise timing. 

The project builds on the existing testbed and RADclock capabilities with the broader SyncLab project.  Its focus is on working to brings software based timekeeping on a LAN (Local Area Network) down to the 1 microsecond level.


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Scalable and energy-efficient deployment of video services over next generation networks

Researchers: Elaine Wong, Chien Aun Chan, Ampalavanapillai Nirmalathas, Christopher Leckie, Andre Gygax.

This project will build on existing research from the University of Melbourne to investigate the deployment of Internet Protocol Television (IPTV) video on demand services using peer-to-peer sharing in terms of economic factors and energy consumption issues for next generation networks such as the NBN.

IPTV is regarded as one of the most promising services that can generate new revenue opportunities for Internet service providers on next generation networks. Several research studies on IPTV trends have concluded that IPTV subscribers and traffic will increase by more than 50% per annum with an exponential growth.

Video on demand service, as an important element in IPTV services, allows users to choose any on demand video content at any time from the central video server with a high level of interactivity. The conventional approach of video on demand delivery establishes a dedicated connection between each user and the video server, even though a large number of users are watching the same video content. This is because many users will request the same content at different times throughout the day. As a consequence, IPTV services could overwhelm the Internet backbone and access networks with potentially hundreds of millions of users watching high bandwidth video streams with dedicated links. This not only has important ramifications for the traffic on the network, but also the energy consumption of the network.

The outcomes of the project will assist with the understanding of fundamental issues that influence the overall scalability of video streaming applications that are based on a hybrid peer-to-peer  mode of delivery. The project aims to provide insights into the design of cost-effective and energy-efficient IPTV deployments over next generation networks.

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The impact of the mass adoption of electric cars on the Australian electricity grid

Researchers: Iven Mareels, Doreen Thomas, Marcus Brazil, Kevin Prendergast, Tansu Alpcan, Julian de Hoog

This project will study the impact of the mass adoption of electric vehicles (EVs) on the electricity grid.  The success of the uptake of EVs promises significant greenhouse gas reduction but depends on making it convenient and affordable for motorists to move away from the use of fossil-fuelled vehicles.  The electricity grid infrastructure required to realise the full potential of EVs will be quantified, both from a traditional as well as a smart grid perspective.  The impact of this fleet on the power management of the distribution network and power quality will be analysed.

Specific research goals include:

  1. Identification of limitations in the current distribution network with respect to EV charging
  2. Development of an optimal charging policy for demand aggregators
  3. Evaluation of the benefits of the charging policy with respect to variable (green) power sources

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Trustworthy sensor networks - theory and implementation

Researchers: Marimuthu Palaniswami, Christopher Leckie, Yee Wei Law, Sutharshan Rajasegarar

Wireless sensor networks (WSNs) are increasingly being used in critical sectors of the economy: environment monitoring, healthcare, defence and critical infrastructure. However, networks that are deployed unattended in complex and dynamic environments are vulnerable to faults, interference or physical attack. The challenge for managing large-scale WSNs is to ensure the integrity of both the network and the data being collected. For WSNs to be widely accepted in real life, this project proposes new algorithms in security and trust management for assuring data quality, trustworthiness and availability, to be used in large-scale deployments.  
The fundamental importance of this project is that we are developing algorithms for wireless sensor networks (WSNs) that provide accurate and trustworthy data to Australian researchers and users, so that they have confidence in the analysis of their data. The algorithms developed in this proposal will become essential for any large scale WSN. The research significantly leverages the resources of our international partners who complement our work with several million dollars of investment. The result will put Australia on the international stage as a significant contributor to WSN technologies. By training PhD students, the project will also enrich local expertise in the technologies.  

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Uni TV

Researchers: Ken Clarke

UniTV is a project with a goal to make the University of Melbourne a significant player in the rapidly evolving broadband landscape. It is based on Internet Protocol Television (IPTV) which is a converged service bringing TV, communications, and education applications together. UniTV will deliver a huge variety of content plus educational and interactive services for The Melbourne Dental School as it's first channel. It is a new service model, different to that of traditional media players such as TV broadcasters and internet service providers, with the scope to become a multi-channel service across the educational and community spectrum.

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Contact Us

Assoc Prof Elaine Wong

Director, Communications and Networks