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Associate Professor Sarah Johnson

ARC Future Fellow

School of Elect Engineering and Computer Science (Electrical and Computer Engineering)

A Key to a Secure Future

Associate Professor Sarah Johnson with mathematical equations

In a digital age where information privacy is key, University of Newcastle Associate Professor Sarah Johnson is cracking the code on keeping business, government, defence and your secrets secure. A/Prof Johnson is an expert on error correction codes which improve the reliability and quality of digital technologies such as television, DVD players, mobile phones and the Internet.

In partnership with Quintessence Labs and researchers at the Australian National University, A/Prof Johnson is developing next generation quantum key distribution (QKD) technology that will enable two parties to produce a random shared key known only to them. The key can then be used to encrypt and decrypt messages to guarantee secure transmission of data.

Information like email, network security, e-commerce, credit-card, security numbers and sensitive company documents are some of the applications QKD could be used for, according to A/Prof Johnson.

"Banks, government, defence forces and the corporate world are just some of the areas set to benefit from the information protection solutions we are designing," A/Prof Johnson said.

"Technology is a major part of today's critical infrastructure from health to power to e-commerce. Data security is of the utmost importance, whether it's a company protecting itself from espionage attacks or a country guarding against cyber-terrorism," she said.

One of the greatest challenges of cryptography is ensuring that a third party does not get access to the secret key and therefore confidential information. Specialising in iterative error-correcting coding, A/Prof Johnson role is to ensure that the transfer of the key is clear, reliable and secure.

A fundamental aspect of digital communications, error-correction coding uses complex mathematical algorithms to eliminate 'noise' or errors during transmission – such as interference from storms or competing digital devices.

Current methods for secure communications are in danger of becoming cracked in the future by quantum computers that can factor large numbers, which is why QKD technology is gaining so much attention, as the Australian Research Council (ARC) Future Fellow explains.

"In the case of quantum cryptography, we're not just using error-correction coding to clean up 'noise', we're using it to detect interference and the presence of any third party 'listening in'," she said.

"The very nature of a quantum mechanical system means that if anyone even observes or listens in on the quantum channel, it alters the state of the photons and thus the message, alerting the users to interference.

Quantum cryptographic systems can be used in optical fibre networks, wireless point to point, satellite uploads. As Australia moves toward a National Broadband Network (NBN), technologies like QKD will become increasingly important.

"QKD technology is the way of the future and has already been used to protect bank transfers, ballot results and computer networks in Europe. For example, Geneva residents used quantum cryptography to transmit their voting results for the 2007 parliamentary elections.

"It has been quite expensive to use QKD, but the new type of continuous variable QKD we are investigating uses standard telecommunications-type receivers rather than single photon detectors making it significantly cheaper to produce."

The QKD technology is part of a $300,000 ARC Linkage Grant with an expected product date by 2016.

"With technology expanding so rapidly, there is a growing need for better and faster error correction," said A/Prof. Johnson, "Ultimately, new error correction codes can be incorporated into the next generation of communications equipment and we're currently studying best case scenarios for networks where multiple users can use a system together securely."  

Johnson authored a book in 2010 titled Iterative Error Correction, which discusses the theory, design and implementation of powerful coding techniques known as turbo, low-density parity-check and repeat-accumulate codes. 

Based at the University of Newcastle's Centre for Complex Dynamic Systems and Control and the Signal Processing and Microelectronics Group, A/Prof Johnson is also working on improving digital communication, like mobiles and wi-fi networks, through her specialty in iterative error correction coding.  

In addition to her error-correction coding work, A/Prof Johnson has been collaborating with leading neuroscientists at the University of Newcastle over the past 18 months through her work with the Priority Research Centre for Bioinformatics, Biomarker Discovery and Information-Based Medicine

Creating solutions using mathematical algorithms across three different projects, A/Prof Johnson is aiming to improve current medical image processing, create a new imaging device and, ultimately, make steps towards a virtual reality system for medical research.

"Working towards improving the imaging and building a new imaging device is an interesting project because it involves quite a lot of different technological areas and collaborating with colleagues in computer science, electrical engineering and biomedical science."

Whether it is protecting or unveiling information, A/Prof Johnson is helping deliver the keys to a clearer image of the future.

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Sarah Johnson

A Key to a Secure Future

In a digital age where information privacy is key, University of Newcastle Associate Professor Sarah Johnson is cracking the code

Read more

Technology troubleshooter

Dr Sarah Johnson designs complex computer codes that work behind the scenes to ensure digital communications are clearly conveyed.

Sarah Johnson in the server room 

Dr Sarah Johnson enjoys solving mathematical problems and her research field of error correction coding provides an endless array of numerical challenges. Error correction technologies are fundamental to digital communications, from DVD players to the National Broadband Network, and in most cases work imperceptibly in the background to correct corruptions in transmission so quickly that users are never aware of a problem.

"Just about any time we communicate, whether it is a text message to a friend or a critical communication, we are using error correction to get that message through," Johnson advises.

Error correction detects and rectifies corruptions caused to digital communications by what is broadly termed 'noise'– interference from factors such as stormy weather, physical barriers in the landscape or competition with nearby digital devices. It does not always work, as evidenced when mobile phone reception fails or a television picture momentarily drops out, but without it our communications would be far less reliable.

Johnson's research with the University's Signal Processing and Microelectronics group focuses on developing new error correction codes for next-generation communication technologies. "With digital technology expanding so rapidly, there is a growing need for better and faster error correction," she explains. "Technology that was unimaginable 10 years ago is now pushing the boundaries of our current approaches to correcting digital errors."

Designing error correction codes involves complex algorithmic computations but Johnson describes the fundamental process as adding extra numerical information to a digital message – a 'checking sequence' that bears a mathematical relationship to the original message – which can then be used to detect errors and recover the original data.

A University of Newcastle electrical engineering scholar, Johnson was awarded her PhD in 2003 and launched her research career with a fellowship at NICTA, Australia's Information and Communications Technology Research Centre of Excellence. She is now a senior researcher at the University, supported by an Australian Research Council (ARC) Future Fellowship. Her specialty field is iterative error correction coding, which has widespread application in cellular communications, digital video broadcasting and wi-fi networks.

Johnson has published in high-impact IEEE (Institute of Electrical and Electronics Engineers) journals and authored a book in 2009 titled Iterative Error Correction, through Cambridge University Press. It discusses the theory, design and implementation of powerful coding techniques known as turbo, low-density parity-check and repeat-accumulate codes.

Johnson also has a strong research interest in information theory – the analysis of the limits of error correction coding – and is working on an ARC-funded project with a University of Newcastle colleague, Dr Lawrence Ong, studying best-case scenarios for multiple-user communication networks.

"It is relatively easy to determine the best-case scenario for error correction in a traditional situation where there is only one person sending and one receiving," Johnson asserts. "It is a lot more complicated to design and understand fundamental limits in networks that have multiple people trying to communicate at the same time, which is increasingly the way people communicate today." 

In a novel project, Johnson has a commercial consultancy with cyber defence company QuintessenceLabs to design a unique cryptography application for their ultra-secure electronic key systems.

"Error correction plays a vital role in so many technologies that there is an endless stream of applications for the work I do. There are so many exciting problems that keep me motivated every day."

Visit the Centre for Bioinformatics, Biomarker Discovery and Information-Based Medicine

Sarah Johnson in the server room

Technology troubleshooter

Dr Sarah Johnson designs complex computer codes that work behind the scenes to ensure digital communications are clearly conveyed.

Read more

Career Summary

Biography

Sarah Johnson received the B.E. and Ph.D. degrees in Electrical Engineering from the University of Newcastle in 1999 and 2004 respectively. She then held a postdoctoral position with the Wireless Signal Processing Program, National ICT Australia before returning to the University of Newcastle where she is now an Australian Research Council Future Fellow. Her research concentrates on the fields of coding and information theory. 

A/Prof Johnson has authored a book, Iterative Error Correction Codes, published by Cambridge University Press and published over 70 technical papers. Her research has been supported by five Australian Research Council (ARC) DP grants, an ARC Future Fellowship, an ARC Linkage Project and industry-sponsored projects.

Research Expertise
I perform research in the fields of digital communications and information theory. The field of digital communications is concerned with the reliable transmission and storage of digital data while information theory investigates the fundamental theoretical limits of this task. This includes: The design, analysis and application of iterative error correction codes. These codes enable the communication of a digital message without error (or with as few errors as possible) despite an imperfect communications medium. Such codes are used in a large range of applications including mobile phones, digital television, wireless local area networks, deep space communications, longhaul optical communications and hard disk storage. The design of communication strategies for next generation digital networks, focusing in particular on cooperation in multi-terminal relay networks.

Teaching Expertise
Undergraduate teaching in computer and telecommunications engineering including Introduction to Computer Engineering, Introduction to Telecommunications and Advanced Telecommunications Supervision of honors students and postgraduate students.

Administrative Expertise
Technical program committee member for national and international conferences.



Qualifications

  • PhD (Electrical Engineering), University of Newcastle
  • Bachelor of Engineering (Electrical), University of Newcastle

Keywords

  • Computer Engineering
  • Error Correction Coding
  • Iterative error correction
  • Low-density parity-check codes
  • Network information theory
  • Repeat-accumulate codes
  • Telecommunications
  • Telecommunications Engineering

Languages

  • English (Fluent)

Fields of Research

CodeDescriptionPercentage
080401Coding and Information Theory70
090609Signal Processing10
100510Wireless Communications20

Professional Experience

UON Appointment

DatesTitleOrganisation / Department
15/05/2015 - Associate ProfessorUniversity of Newcastle
School of Elect Engineering and Computer Science
Australia

Academic appointment

DatesTitleOrganisation / Department
1/01/2013 - Membership - Organising Committee IEEE International Conference on CommunicationsOrganising Committee IEEE International Conference on Communications
Australia
1/01/2013 - Membership - International Technical Program Committee IEEE Information Theory Workshop (ITW)International Technical Program Committee IEEE Information Theory Workshop (ITW)
Australia
1/01/2013 - Membership - International Technical Program Committee IEEE International Symposium on Turbo CodesInternational Technical Program Committee IEEE International Symposium on Turbo Codes
Australia
1/03/2012 - 1/12/2015Future FellowUniversity of Newcastle
Australia
1/01/2012 - 31/12/2012Membership - International Technical Program Committee IEEE International Symposium on Turbo CodesInternational Technical Program Committee IEEE International Symposium on Turbo Codes
Australia
1/01/2012 - 31/12/2012Membership - International Technical Program Committee IEEE PIMRCInternational Technical Program Committee IEEE PIMRC
Australia
1/06/2007 - 1/03/2012Senior Research Fellow
UoN Research Fellowship
University of Newcastle
Australia
1/01/2006 - 31/12/2006Membership - International Technical Program Committee IEEE VTC International Technical Program Committee IEEE VTC
Australia
1/06/2004 - 1/06/2007Australian Postdoc Fellowship (APD)
ARC - Research Fellowships Scheme
Australia Research Council
Australia
1/01/2004 - Membership - Institute of Electrical and Electronic Engineers (IEEE)Institute of Electrical & Electronic Engineers (IEEE)
Australia
1/08/2003 - 1/07/2004Research FellowNational ICT Australia
Australia

Awards

Research Award

YearAward
2007Pro Vice-Chancellor’s Award for Research Excellence
University of Newcastle
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Publications

For publications that are currently unpublished or in-press, details are shown in italics.


Book (1 outputs)

YearCitationAltmetricsLink
2010Johnson SJ, Iterative Error Correction: Turbo, Low-Density Parity-Check and Repeat-Accumulate Codes, Cambridge University Press, Cambridge, UK, 356 (2010) [A2]

Chapter (1 outputs)

YearCitationAltmetricsLink
2003Johnson SJ, Weller SR, 'Low-density parity-check codes: Design and decoding', Wiley Encyclopedia of Telecommunications, Wiley Interscience, Brisbane 1-18 (2003) [B1]
Co-authorsSteven Weller

Journal article (29 outputs)

YearCitationAltmetricsLink
2015Johnson SJ, Walker FR, 'Strategies to improve quantitative assessment of immunohistochemical and immunofluorescent labelling.', Scientific reports, 5 10607 (2015)
DOI10.1038/srep10607
Co-authorsRohan Walker
2015Johnson SJ, Walker FR, 'Strategies to improve quantitative assessment of immunohistochemical and immunofluorescent labelling', Scientific Reports, 5 (2015)

Binary image thresholding is the most commonly used technique to quantitatively examine changes in immunolabelled material. In this article we demonstrate that if implicit assumpt... [more]

Binary image thresholding is the most commonly used technique to quantitatively examine changes in immunolabelled material. In this article we demonstrate that if implicit assumptions predicating this technique are not met then the resulting analysis and data interpretation can be incorrect. We then propose a transparent approach to image quantification that is straightforward to execute using currently available software and therefore can be readily and cost-effectively implemented.

DOI10.1038/srep10607
Co-authorsRohan Walker
2015Jones KA, Zouikr I, Patience M, Clarkson AN, Isgaard J, Johnson SJ, et al., 'Chronic stress exacerbates neuronal loss associated with secondary neurodegeneration and suppresses microglial-like cells following focal motor cortex ischemia in the mouse.', Brain Behav Immun, (2015)
DOI10.1016/j.bbi.2015.02.014Author URL
Co-authorsNeil Spratt, Rohan Walker
2014Patience MJ, Zouikr I, Jones K, Clarkson AN, Isgaard J, Johnson SJ, et al., 'Photothrombotic Stroke Induces Persistent Ipsilateral and Contralateral Astrogliosis in Key Cognitive Control Nuclei', Neurochemical Research, (2014)

While astrocytes are recognised to play a central role in repair processes following stroke, at this stage we do not have a clear understanding of how these cells are engaged duri... [more]

While astrocytes are recognised to play a central role in repair processes following stroke, at this stage we do not have a clear understanding of how these cells are engaged during the chronic recovery phase. Accordingly, the principal aim of this study was to undertake a quantitative multi-regional investigation of astrocytes throughout the recovery process. Specifically, we have induced experimental vascular occlusion using cold-light photothrombotic occlusion of the somatosensory/motor cortex in adult male C57B6 mice. Four weeks following occlusion we collected, processed, and immunolabelled tissue using an antibody directed at the glial fibrillary acidic protein (GFAP), an astrocyte specific cytoskeletal protein marker. We investigated GFAP changes in 13 regions in both the contra- and ipsi-lateral hemispheres from control and occluded animals. Specifically, we examined the infra-limbic (A24a), pre-limbic (A25), anterior cingulate (A32), motor (M1 and M2) cortices, the forceps minor fibre tract, as well the shell of the accumbens, thalamus, cingulate cortex (A29c), hippocampus (CA1-3) and lateral hypothalamus. Tissue from occluded animals was compared against sham treated controls. We have identified that the focal occlusion produced significant astrogliosis (p < 0.05), as defined by a marked elevation in GFAP expression, within all 13 sites assessed within the ipsilateral (lesioned) hemisphere. We further observed significant increases in GFAP expression (p < 0.05) in 9 of the 13 contralesional sites examined. This work underscores that both the ipsilateral and contralesional hemispheres, at sites distal to the infarct, are very active many weeks after the initial occlusion, a finding that potentially has significant implications for understanding and improving the regeneration of the damaged brain.

DOI10.1007/s11064-014-1487-8
Co-authorsRohan Walker
2014Kongsui R, Beynon SB, Johnson SJ, Mayhew J, Kuter P, Nilsson M, Walker FR, 'Chronic stress induces prolonged suppression of the P2X7 receptor within multiple regions of the hippocampus: A cumulative threshold spectra analysis', Brain, Behavior, and Immunity, 42 69-80 (2014) [C1]
DOI10.1016/j.bbi.2014.05.017
CitationsScopus - 1
Co-authorsRohan Walker
2014Asadi B, Ong L, Johnson SJ, 'On Index Coding in Noisy Broadcast Channels with Receiver Message Side Information', IEEE COMMUNICATIONS LETTERS, 18 640-643 (2014) [C1]
DOI10.1109/LCOMM.2014.020414.132589Author URL
CitationsScopus - 1Web of Science - 1
Co-authorsLawrence L Ong
2014Kongsui R, Beynon SB, Johnson SJ, Walker FR, 'Quantitative assessment of microglial morphology and density reveals remarkable consistency in the distribution and morphology of cells within the healthy prefrontal cortex of the rat', JOURNAL OF NEUROINFLAMMATION, 11 (2014) [C1]
DOI10.1186/s12974-014-0182-7Author URL
CitationsWeb of Science - 1
Co-authorsRohan Walker
2014Johnson SJ, Lechner G, Chandrasetty VA, 'Memory-efficient quasi-cyclic spatially coupled low-density parity-check and repeat-accumulate codes', IET Communications, 8 3179-3188 (2014) [C1]
DOI10.1049/iet-com.2014.0384
2014Ong L, Johnson SJ, Kellett CM, 'On the capacity of the binary-symmetric parallel-relay network', TRANSACTIONS ON EMERGING TELECOMMUNICATIONS TECHNOLOGIES, 25 217-230 (2014) [C1]
DOI10.1002/ett.2561Author URL
CitationsWeb of Science - 4
Co-authorsLawrence L Ong, Chris Kellett
2013Tynan RJ, Beynon SB, Hinwood M, Johnson SJ, Nilsson M, Woods JJ, Walker FR, 'Chronic stress-induced disruption of the astrocyte network is driven by structural atrophy and not loss of astrocytes', Acta Neuropathologica, 126 75-91 (2013) [C1]
DOI10.1007/s00401-013-1102-0Author URL
CitationsScopus - 15Web of Science - 12
Co-authorsRohan Walker
2013Timo R, Lechner G, Ong L, Johnson S, 'Multi-Way Relay Networks: Orthogonal Uplink, Source-Channel Separation and Code Design', IEEE TRANSACTIONS ON COMMUNICATIONS, 61 753-768 (2013) [C1]
DOI10.1109/TCOMM.2012.121112.110730Author URL
CitationsScopus - 4Web of Science - 3
Co-authorsLawrence L Ong
2013Ong L, Lechner G, Johnson SJ, Kellett CM, 'The Three-User Finite-Field Multi-Way Relay Channel with Correlated Sources', IEEE TRANSACTIONS ON COMMUNICATIONS, 61 3125-3135 (2013) [C1]
DOI10.1109/TCOMM.2013.061913.120987Author URL
CitationsScopus - 1
Co-authorsLawrence L Ong, Chris Kellett
2013Johnson S, Lechner G, 'Spatially Coupled Repeat-Accumulate Codes', IEEE COMMUNICATIONS LETTERS, 17 373-376 (2013) [C1]
DOI10.1109/LCOMM.2013.010313.122343Author URL
CitationsScopus - 3Web of Science - 1
2012Ong LL, Kellett CM, Johnson SJ, 'On the equal-rate capacity of the AWGN multiway relay channel', IEEE Transactions on Information Theory, 58 5761-5769 (2012) [C1]
CitationsScopus - 14Web of Science - 10
Co-authorsLawrence L Ong, Chris Kellett
2012Ong LL, Motani M, Johnson SJ, 'On capacity and optimal scheduling for the half-duplex multiple-relay channel', IEEE Transactions on Information Theory, 58 5770-5784 (2012) [C1]
CitationsScopus - 7Web of Science - 3
Co-authorsLawrence L Ong
2012Ong LL, Johnson SJ, Kellett CM, 'The half-duplex AWGN single-relay channel: Full decoding or partial decoding?', IEEE Transactions on Communications, 60 3156-3160 (2012) [C1]
CitationsScopus - 2Web of Science - 1
Co-authorsLawrence L Ong, Chris Kellett
2012Ong LL, Johnson SJ, 'The capacity region of the restricted two-way relay channel with any deterministic uplink', IEEE Communications Letters, 16 396-399 (2012) [C1]
DOI10.1109/LCOMM.2012.011312.112198
CitationsScopus - 3Web of Science - 1
Co-authorsLawrence L Ong
2011Ong LL, Johnson SJ, Kellett CM, 'The capacity region of multiway relay channels over finite fields with full data exchange', IEEE Transactions on Information Theory, 57 3016-3031 (2011) [C1]
DOI10.1109/TIT.2011.2120010
CitationsScopus - 37Web of Science - 30
Co-authorsChris Kellett, Lawrence L Ong
2011Johnson SJ, Ong LL, Kellett CM, 'Joint channel-network coding strategies for networks with low-complexity relays', European Transactions on Telecommunications, 22 396-406 (2011) [C1]
CitationsScopus - 4Web of Science - 5
Co-authorsChris Kellett, Lawrence L Ong
2010Ong LL, Johnson SJ, Kellett CM, 'An optimal coding strategy for the binary multi-way relay channel', IEEE Communications Letters, 14 330-332 (2010) [C1]
DOI10.1109/LCOMM.2010.04.092427
CitationsScopus - 31Web of Science - 24
Co-authorsLawrence L Ong, Chris Kellett
2009Johnson SJ, 'A finite-length algorithm for LDPC codes without repeated edges on the binary erasure channel', IEEE Transactions on Information Theory, 55 27-32 (2009) [C1]
DOI10.1109/tit.2008.2008118
CitationsScopus - 1
2009Johnson SJ, 'Burst erasure correcting LDPC codes', IEEE Transactions on Communications, 57 641-652 (2009) [C1]
DOI10.1109/tcomm.2009.03.060468
CitationsScopus - 11Web of Science - 7
2009Johnson SJ, Weller SR, 'Practical interleavers for repeat-accumulate codes', IEEE Transactions on Communications, 57 1225-1228 (2009) [C1]
DOI10.1109/tcomm.2009.05.060382
CitationsScopus - 5Web of Science - 2
Co-authorsSteven Weller
2008Johnson SJ, Weller SR, 'Combinatorial interleavers for systematic regular repeat-accumulate codes', IEEE Transactions on Communications, 56 1201-1206 (2008) [C1]
DOI10.1109/tcomm.2008.041247
CitationsScopus - 9Web of Science - 8
Co-authorsSteven Weller
2006Johnson SJ, Weller SR, 'Constraining LDPC degree distributions for improved error floor performance', IEEE Communications Letters, 10 103-105 (2006) [C1]
DOI10.1109/LCOMM.2006.02001.
CitationsScopus - 11Web of Science - 6
Co-authorsSteven Weller
2004Johnson SJ, Weller SR, 'Codes for iterative decoding from partial geometies', IEEE Transactions on Communications, 52 236-243 (2004) [C1]
DOI10.1109/TCOMM.2003.822737
CitationsScopus - 30Web of Science - 21
Co-authorsSteven Weller
2003Johnson SJ, Weller SR, 'Resolvable 2-Designs for Regular Low-Density Parity-Check Codes', IEEE Transactions on Communications, 51 1413-1419 (2003) [C1]
DOI10.1109/TCOMM.2003.816946
CitationsScopus - 29Web of Science - 22
Co-authorsSteven Weller
2003Johnson SJ, Weller SR, 'A Family if Irregular LDPC Codes with low Encoding Complexity', IEEE Communication Letters, 7 79-81 (2003) [C1]
DOI10.1109/LCOMM.2002.808375
CitationsScopus - 71Web of Science - 57
Co-authorsSteven Weller
2003Weller SR, Johnson SJ, 'Regular low-density parity-check codes from oval designs', European Transactions on Teleconmmunications, 14 399-409 (2003) [C1]
DOI10.1002/ett.939
CitationsScopus - 13Web of Science - 12
Co-authorsSteven Weller
Show 26 more journal articles

Conference (34 outputs)

YearCitationAltmetricsLink
2014Ong L, Johnson SJ, Kellett CM, 'Optimal coding functions for pairwise message sharing on finite-field multi-way relay channels', 2014 IEEE International Conference on Communications, ICC 2014 (2014) [E1]

This paper considers the finite-field multi-way relay channel with pairwise message sharing, where multiple users exchange messages through a single relay and where the users may ... [more]

This paper considers the finite-field multi-way relay channel with pairwise message sharing, where multiple users exchange messages through a single relay and where the users may share parts of their source messages (meaning that some message parts are known/common to more than one user). In this paper, we design an optimal functional-decode-forward coding scheme that takes the shared messages into account. More specifically, we design an optimal function for the relay to decode (from the users on the uplink) and forward (back to the users on the downlink). We then show that this proposed function-decode-forward coding scheme can achieve the capacity region of the finite-field multi-way relay channel with pairwise message sharing. This paper generalizes our previous result for the case of three users to any number of users. © 2014 IEEE.

DOI10.1109/ICC.2014.6883595
Co-authorsLawrence L Ong, Chris Kellett
2014Asadi B, Ong L, Johnson SJ, 'The capacity of three-receiver AWGN broadcast channels with receiver message side information', IEEE International Symposium on Information Theory - Proceedings (2014) [E1]

This paper investigates the capacity region of three-receiver AWGN broadcast channels where the receivers (i) have private-message requests and (ii) know the messages requested by... [more]

This paper investigates the capacity region of three-receiver AWGN broadcast channels where the receivers (i) have private-message requests and (ii) know the messages requested by some other receivers as side information. We classify these channels based on their side information into eight groups, and construct different transmission schemes for the groups. For six groups, we characterize the capacity region, and show that it improves both the best known inner and outer bounds. For the remaining two groups, we improve the best known inner bound by using side information during channel decoding at the receivers. © 2014 IEEE.

DOI10.1109/ISIT.2014.6875364
Co-authorsLawrence L Ong
2014Ong L, Asadi B, Johnson SJ, 'Coding schemes for a class of receiver message side information in AWGN broadcast channels', IEEE Information Theory Workshop (ITW), Hobart, Australia (2014) [E1]
DOI10.1109/ITW.2014.6970896
Co-authorsLawrence L Ong
2014Jayasooriya S, Johnson SJ, Ong L, Berretta R, 'Optimization of graph based codes for belief propagation decoding', Information Theory Workshop (ITW), 2014 IEEE, Hobart, Tas (2014) [E1]
DOI10.1109/ITW.2014.6970873
Co-authorsLawrence L Ong, Regina Berretta
2014Ye T, Veitch D, Johnson SJ, 'RA-inspired codes for efficient information theoretic multi-path network security', 2014 International Symposium on Information Theory and its Applications (ISITA), Melbourne (2014) [E1]
2012Lechner G, Johnson SJ, 'Absorbing sets and cycles', 2012 7th International Symposium on Turbo Codes and Iterative Information Processing, ISTC 2012, Gothenburg, Sweden (2012) [E1]
2012Ong LL, Timo R, Johnson SJ, 'The finite field multi-way relay channel with correlated sources: Beyond three users', 2012 IEEE International Symposium on Information Theory Proceedings (ISIT), Cambridge, Massachusetts (2012) [E1]
CitationsScopus - 1
Co-authorsLawrence L Ong
2012Ong LL, Johnson SJ, 'The capacity region of restricted multi-way relay channels with deterministic uplinks', 2012 IEEE International Symposium on Information Theory Proceedings (ISIT), Boston, Massachusetts (2012) [E1]
Co-authorsLawrence L Ong
2011Ong LL, Kellett CM, Johnson SJ, 'On achievable rate regions of the asymmetric AWGN two-way relay channel', 2011 IEEE International Symposium on Information Theory Proceedings (ISIT), St. Petersburg, Russia (2011) [E1]
DOI10.1109/ISIT.2011.6034256
Co-authorsChris Kellett, Lawrence L Ong
2011Ong LL, Timo R, Lechner G, Johnson SJ, Kellett CM, 'The finite field multi-way relay channel with correlated sources: The three-user case', 2011 IEEE International Symposium on Information Theory Proceedings (ISIT), St. Petersburg, Russia (2011) [E1]
CitationsScopus - 1
Co-authorsChris Kellett, Lawrence L Ong
2010Ong LL, Johnson SJ, Kellett CM, 'The binary-symmetric parallel-relay network', Proceedings of the 2010 IEEE International Symposium on Information Theory (ISIT 2010), Austin, TX (2010) [E1]
DOI10.1109/ISIT.2010.5513571
Co-authorsChris Kellett, Lawrence L Ong
2010Ong LL, Kellett CM, Johnson SJ, 'Capacity theorems for the AWGN multi-way relay channel', Proceedings of the 2010 IEEE International Symposium on Information Theory (ISIT 2010), Austin, TX (2010) [E1]
DOI10.1109/ISIT.2010.5513576
CitationsScopus - 20Web of Science - 16
Co-authorsChris Kellett, Lawrence L Ong
2010Ong LL, Johnson SJ, Kellett CM, 'The capacity of a class of multi-way relay channels', Proceedings of the 12th IEEE International Conference on Communications Systems (ICCS 2010), Singapore (2010) [E1]
DOI10.1109/ICCS.2010.5686491
CitationsScopus - 1
Co-authorsLawrence L Ong, Chris Kellett
2010Ong LL, Johnson SJ, Kellett CM, 'Functional-decode-forward for the general discrete memoryless two-way relay channel', Proceedings of the 12th IEEE International Conference on Communications Systems (ICCS 2010), Singapore (2010) [E1]
DOI10.1109/ICCS.2010.5686490
CitationsScopus - 3
Co-authorsChris Kellett, Lawrence L Ong
2010Hayes DF, Johnson SJ, Weller SR, 'Irregular repeat-accumulate-like codes with improved error floor performance', 2010 IEEE Information Theory Workshop, ITW 2010 - Proceedings, Dublin, IRELAND (2010) [E1]
DOI10.1109/CIG.2010.5592734
Co-authorsSteven Weller
2009Ong LL, Johnson SJ, Motani M, 'Optimal schedules for the D-node half duplex phase fading MRC', 2009 IEEE International Symposium on Information Theory (ISIT 2009), Seoul, Korea (2009) [E1]
DOI10.1109/isit.2009.5206072
CitationsScopus - 1
Co-authorsLawrence L Ong
2009Ong LL, Johnson SJ, Kellett CM, 'Achievable rate regions of the butterfly network with noisy links and end-to-end error correction', 2009 IEEE Information Theory Workshop (ITW 2009), Taormina, Sicily (2009) [E1]
DOI10.1109/ITW.2009.5351229
CitationsScopus - 1
Co-authorsChris Kellett, Lawrence L Ong
2007Johnson SJ, 'LDPC codes for correcting multiple erasure bursts', 8th Australian Communication Theory Workshop, AusCTW 2007 (2007)
2007Johnson SJ, Kellett CM, 'Joint Network and Channel Coding for Cooperative Networks', 2007 AUSTRALASIANTELECOMMUNICATION NETWORKS AND APPLICATIONS CONFERENCE, Christchurch, NEW ZEALAND (2007)
Author URL
Co-authorsChris Kellett
2006Johnson SJ, Weller SR, 'Practical Interleavers for Systematic Repeat-Accumulate Codes', 2006 IEEE 63rd Vehicular Technology Conference, Melbourne, VIC, Australia (2006) [E1]
CitationsScopus - 4
Co-authorsSteven Weller
2006Grant A, Kennedy R, Hanlen LW, Johnson SJ, Teal PD, 'Editorial remarks', Proceedings - 7th Australian Communications Theory Workshop, 2006 (2006)
2006Johnson SJ, 'Erasure Correcting LDPC Codes For Channels With Packet Losses', Proceedings of the NEWCOM-ACORN Joint Workshop, Vienna, September 2006, Vienna, Austria (2006) [E1]
2006Hanlen LW, Johnson SJ, Teal PD, 'Proceedings 7th Australian Communications Theory Workshop 2006', Proceedings 7th Australian Communications Theory Workshop 2006, Perth, Australia (2006) [E4]
2005Johnson SJ, Weller SR, 'Interleaver and Accumulator Design For Systematic Repeat-Accumulate Codes', Proceedings 6th Australian Communications Theory Workshop 2005 : 2-4 February 2005, The University of Queensland, Brisbane, Australia, Brisbane, Australia (2005) [E1]
Co-authorsSteven Weller
2005Johnson SJ, 'Finite-Length Repeat-Accumulate Codes on The Binary Erasure Channel', 2005 Asia-Pacific Conference on Communications, Perth, Western Australia, 3-5 October 2005, Perth, Australia (2005) [E1]
CitationsScopus - 3
2005Johnson SJ, Weller SR, 'Constructions for Irregular Repeat-Accumulate Codes', Proceedings of 2005 IEEE International Symposium on Information Theory, Adelaide, S. Aust (2005) [E1]
CitationsScopus - 4
Co-authorsSteven Weller
2004Johnson SJ, Weller SR, 'Structured low-density parity-check codes over non-binary fields', Proceedings of the 5th Australian Communication Theory Workshop 2004, Brisbane (2004) [E1]
Co-authorsSteven Weller
2003Johnson SJ, Weller SR, 'High-Rate LDPC Codes from Unital Designs', Proceedings for GLOBECOM 2003, San Francisco, USA (2003) [E1]
CitationsScopus - 5Web of Science - 3
Co-authorsSteven Weller
2003Johnson SJ, Weller SR, 'Can Cyclic Codes be Useful Low-Density Parity-Check Codes', Proceedings for AUSCTW 2003, Melbourne (2003) [E1]
Co-authorsSteven Weller
2003Brown RA, Johnson SJ, Weller SR, 'Performance of Space-Time Block Codes with Finite Geometry LDPC Outer Codes', Proceedings for AUSCTW 2003, University of Melbourne (2003) [E1]
Co-authorsSteven Weller
2002Johnson SJ, Weller SR, 'Codes for Iterative Decoding from Partial Geometries', International Symposium on Information Theory 2002, Switzerland (2002) [E1]
CitationsScopus - 4
Co-authorsSteven Weller
2002Johnson SJ, Weller SR, 'Quasi-cyclic LDPC Codes from Difference Families', Proceedings 3rd Australian Communications Theory Workshop 2002, Canberra, Australia (2002) [E1]
Co-authorsSteven Weller
2001Johnson SJ, Weller SR, 'Construction of Low-density Parity-check Codes from Kirkman Triple Systems', IEEE Global Telecommunications Conference, San Antonio, Texas, USA (2001) [E1]
CitationsScopus - 14Web of Science - 4
Co-authorsSteven Weller
2001Johnson SJ, Weller SR, 'Regular low-density parity-check codes from combinatorial designs', Proceedings 2001 IEEE Information Theory Workshop, Cairns, Australia (2001)
CitationsWeb of Science - 40
Co-authorsSteven Weller
Show 31 more conferences
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Grants and Funding

Summary

Number of grants19
Total funding$3,306,282

Click on a grant title below to expand the full details for that specific grant.


20151 grants / $355,100

New strategies to transmit data: Coping with exponential growth in demand$355,100

Funding body: ARC (Australian Research Council)

Funding bodyARC (Australian Research Council)
Project TeamAssociate Professor Sarah Johnson, Doctor Lawrence Ong, Dr Gottfried Lechner
SchemeDiscovery Projects
RoleLead
Funding Start2015
Funding Finish2015
GNoG1400187
Type Of FundingAust Competitive - Commonwealth
Category1CS
UONY

20142 grants / $62,000

New error correction strategies for continuous variable quantum key distribution$42,000

Funding body: Quintessence Labs Pty. Ltd.

Funding bodyQuintessence Labs Pty. Ltd.
Project TeamAssociate Professor Sarah Johnson, Dr Thomas Symul, Dr Andrew Lance
SchemeLinkage Projects Partner Funding
RoleLead
Funding Start2014
Funding Finish2014
GNoG1201271
Type Of FundingAust Competitive - Commonwealth
Category1CS
UONY

Improving error correction performance through spatial coupling $20,000

Funding body: University of Newcastle

Funding bodyUniversity of Newcastle
Project TeamAssociate Professor Sarah Johnson
SchemeNear Miss Grant
RoleLead
Funding Start2014
Funding Finish2014
GNoG1301383
Type Of FundingInternal
CategoryINTE
UONY

20134 grants / $382,000

New error correction strategies for continuous variable quantum key distribution$300,000

Funding body: ARC (Australian Research Council)

Funding bodyARC (Australian Research Council)
Project TeamAssociate Professor Sarah Johnson, Dr Thomas Symul, Dr Andrew Lance
SchemeLinkage Projects
RoleLead
Funding Start2013
Funding Finish2013
GNoG1201139
Type Of FundingAust Competitive - Commonwealth
Category1CS
UONY

Improving error correction performance through spatial coupling$50,000

Funding body: University of Newcastle

Funding bodyUniversity of Newcastle
Project TeamAssociate Professor Sarah Johnson
SchemeNear Miss Grant
RoleLead
Funding Start2013
Funding Finish2013
GNoG1300453
Type Of FundingInternal
CategoryINTE
UONY

Integrated virtual reality jet ball system$20,000

Funding body: University of Newcastle - Faculty of Engineering & Built Environment

Funding bodyUniversity of Newcastle - Faculty of Engineering & Built Environment
Project Team
SchemeEquipment Grant
RoleLead
Funding Start2013
Funding Finish2013
GNo
Type Of FundingInternal
CategoryINTE
UONY

Image processing of neural cell morphology$12,000

Funding body: Faculty of Engineering

Funding bodyFaculty of Engineering
Project Team
SchemeStrategic Pilot Grant
RoleLead
Funding Start2013
Funding Finish2013
GNo
Type Of FundingInternal
CategoryINTE
UONY

20123 grants / $435,000

Compression of Digital Data: Bridging The Gap Between Theory and Practice$320,000

Funding body: ARC (Australian Research Council)

Funding bodyARC (Australian Research Council)
Project Team
SchemeDiscovery Project
RoleInvestigator
Funding Start2012
Funding Finish2014
GNo
Type Of FundingAust Competitive - Commonwealth
Category1CS
UONY

Error correction for quantum key distribution$100,000

Funding body: Enterprise Connect

Funding bodyEnterprise Connect
Project Team
SchemeResearchers in Business
RoleLead
Funding Start2012
Funding Finish2012
GNo
Type Of FundingOther Public Sector - Commonwealth
Category2OPC
UONY

2011 Emerging Research Leaders Program$15,000

Funding body: University of Newcastle

Funding bodyUniversity of Newcastle
Project TeamAssociate Professor Sarah Johnson
SchemeEmerging Research Leaders Program
RoleLead
Funding Start2012
Funding Finish2012
GNoG1201064
Type Of FundingInternal
CategoryINTE
UONY

20111 grants / $623,276

New high-performance iterative error correction codes$623,276

Funding body: ARC (Australian Research Council)

Funding bodyARC (Australian Research Council)
Project TeamAssociate Professor Sarah Johnson
SchemeFuture Fellowships
RoleLead
Funding Start2011
Funding Finish2011
GNoG1100437
Type Of FundingAust Competitive - Commonwealth
Category1CS
UONY

20101 grants / $150,000

Optimising Cooperation in Multiterminal Wireless Networks$150,000

Funding body: ARC (Australian Research Council)

Funding bodyARC (Australian Research Council)
Project TeamAssociate Professor Sarah Johnson
SchemeDiscovery Projects
RoleLead
Funding Start2010
Funding Finish2010
GNoG0189995
Type Of FundingAust Competitive - Commonwealth
Category1CS
UONY

20081 grants / $335,000

Iterative coding for next generation networks$335,000

Funding body: ARC (Australian Research Council)

Funding bodyARC (Australian Research Council)
Project TeamAssociate Professor Sarah Johnson, Associate Professor Christopher Kellett
SchemeDiscovery Projects
RoleLead
Funding Start2008
Funding Finish2008
GNoG0187513
Type Of FundingAust Competitive - Commonwealth
Category1CS
UONY

20072 grants / $529,312

2007 Research Fellowship$514,312

Funding body: University of Newcastle

Funding bodyUniversity of Newcastle
Project TeamAssociate Professor Sarah Johnson
SchemeResearch Fellowship
RoleLead
Funding Start2007
Funding Finish2007
GNoG0187099
Type Of FundingInternal
CategoryINTE
UONY

2007 Research Fellowship Project Grant$15,000

Funding body: University of Newcastle

Funding bodyUniversity of Newcastle
Project TeamAssociate Professor Sarah Johnson
SchemeFellowship Grant
RoleLead
Funding Start2007
Funding Finish2007
GNoG0188110
Type Of FundingInternal
CategoryINTE
UONY

20061 grants / $112,128

Construction methods and analysis tools for repeat-accumulate error correction codes$112,128

Funding body: ARC (Australian Research Council)

Funding bodyARC (Australian Research Council)
Project TeamAssociate Professor Sarah Johnson
SchemeDiscovery Projects
RoleLead
Funding Start2006
Funding Finish2006
GNoG0185285
Type Of FundingAust Competitive - Commonwealth
Category1CS
UONY

20051 grants / $50,000

Australian Communications Research Network (ACoRN)$50,000

Funding body: ARC (Australian Research Council)

Funding bodyARC (Australian Research Council)
Project TeamAssociate Professor Steven Weller, Professor Brett Ninness, Associate Professor Sarah Johnson
SchemeResearch Networks
RoleInvestigator
Funding Start2005
Funding Finish2005
GNoG0186088
Type Of FundingScheme excluded from IGS
CategoryEXCL
UONY

20042 grants / $272,466

Structured low-density parity-check codes for next-generation digital communications$257,466

Funding body: ARC (Australian Research Council)

Funding bodyARC (Australian Research Council)
Project TeamAssociate Professor Steven Weller, Associate Professor Sarah Johnson
SchemeDiscovery Projects
RoleInvestigator
Funding Start2004
Funding Finish2004
GNoG0183017
Type Of FundingAust Competitive - Commonwealth
Category1CS
UONY

Design and evaluation of repeat-accumulate error correction codes for digital communications$15,000

Funding body: University of Newcastle

Funding bodyUniversity of Newcastle
Project TeamAssociate Professor Sarah Johnson
SchemeEarly Career Researcher Grant
RoleLead
Funding Start2004
Funding Finish2004
GNoG0184996
Type Of FundingInternal
CategoryINTE
UONY
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Research Supervision

Current Supervision

CommencedResearch Title / Program / Supervisor Type
2015Application of Image Processing in Glial Cell Microscopy Image Analysis
Electrical Engineering, Faculty of Engineering and Built Environment
Principal Supervisor
2014The Design and Construction of an Intrinsic Optical Signal Brain Imaging System Combined with a Virtual Reality Setup to Investigate the Effects of Stroke in Mice
Electrical Engineering, Faculty of Engineering and Built Environment
Principal Supervisor
2014Capacity Analyses of Multi-source, Multi-destination, Multi-hop Cooperative Relay Networks
Electrical Engineering, Faculty of Engineering and Built Environment
Co-Supervisor
2013Broadcast Channels with Receiver Message Side Information
Electrical Engineering, Faculty of Engineering and Built Environment
Co-Supervisor
2013Analysis and Design of Multi-Edge Type Low-Density Parity-Check Codes for Multi-Point Communications
Electrical Engineering, Faculty of Engineering and Built Environment
Principal Supervisor
2011Investigating the Role of Microglia in Regulating Complex Behaviour
Human Biology, Faculty of Health and Medicine
Co-Supervisor

Past Supervision

YearResearch Title / Program / Supervisor Type
2005The Graphical Structure of Iterative Low-Density Parity-Check Decoding
Electrical Engineering, Australian National University
Co-Supervisor
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News

Australian Research Council (ARC)

ARC Discovery Project funding success

November 19, 2014

Associate Professor Sarah Johnson and Dr Lawrence Ong have been awarded more than $355,000 in ARC Discovery Project funding commencing in 2015 for their research project New strategies to transmit data: Coping with exponential growth in demand.

Secure Communications Grant

$300,000 for secure communications research

August 16, 2013

University of Newcastle wins $300,000 to make digital communications secure

Grants for creativity

Creative Industries

June 28, 2013

A study concerning Creativity and Cultural Production in the Hunter Region was announced today as one of six University of Newcastle projects awarded highly prestigious Australian Research Council Linkage Project Grants worth a total of $1.8 million.

Associate Professor Sarah Johnson

Position

ARC Future Fellow
School of Elect Engineering and Computer Science
Faculty of Engineering and Built Environment

Focus area

Electrical and Computer Engineering

Contact Details

Emailsarah.johnson@newcastle.edu.au
Phone(02) 4921 6028
Fax(02) 4921 6993

Office

RoomEA G14
BuildingEngineering A
LocationCallaghan
University Drive
Callaghan, NSW 2308
Australia
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