Associate ProfessorMahyar Shirvanimoghaddam

Project Opportunities

Title: Non-orthogonal multiple access for massive Internet of Things

Summary of opportunity:

Non-orthogonal multiple access (NOMA) has been identified as a key technology in the fifth generation of mobile wireless standards to improve the network capacity. This project aims at designing novel NOMA schemes for massive IoT systems in order to accommodate a large number of devices within limited radio resources. Channel coding techniques and advanced multiuser processing techniques are explored in this project.In this project, we will answer this fundamental question "which transmission strategy is more effective: i) dynamically allocating more resource blocks for the random access procedure to detect each active IoT device and then allocating dedicated data channels and transmitting at full power (orthogonal transmission), or ii) limiting the number of resource blocks allocated to the random access channel and allowing devices to simultaneously transmit their messages at the same data channel (non-orthogonal transmission), with the expense of higher complexity at the base station, but with lower transmission power over a longer time, or iii) remove the random access phase altogether and allow devices to transmit multiple times through several resource blocks (grant-free non-orthogonal transmission)". A trade-off between the system complexity and throughput, access delay, and random access efficiency will be derived for both coordinated and uncoordinated multiple access strategies.

Opportunity synopsis:

In the near future our everyday physical objects will be transformed to information sources, communicating with each other and the underlying data transport infrastructure. This will create an ecosystem of connected devices and revolutionize the way we live today and open new roads for creativity and innovations. Around 50 billion devices will be installed by 2020 and they will generate an enormous data traffic. Providing connectivity and handling such a traffic are beyond the capabilities of current wireless standards, calling for breakthrough innovations in communication strategies. This project develops novel communication strategies for future wireless systems to support a large number of devices and diverse service requirements.

This program is supported under an Australian Research Council Discovery Project Grant with collaboration of Prof. Mischa Dohler, King's College London, and Dr Gianluigi Liva, German Aerospace Centre.

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Project Opportunities

Title: Design of Novel Channel Coding Techniques for Short Packet Transmission in Massive Internet of Things

Summary of opportunity:

In this project, the channel code design problem for massive Internet of Things (IoT) is considered by taking into account the unique characteristic of massive IoT, i.e., short length and bursty nature. Our aim is to develop practical coding strategies for both contention-based and grant-free access schemes.
 

Opportunity synopsis:

In the near future our everyday physical objects will be transformed to information sources, communicating with each other and the underlying data transport infrastructure. This will create an ecosystem of connected devices and revolutionize the way we live today and open new roads for creativity and innovations. Around 50 billion devices will be installed by 2020 and they will generate an enormous data traffic. Providing connectivity and handling such a traffic are beyond the capabilities of current wireless standards, calling for breakthrough innovations in communication strategies. This project develops novel communication strategies for future wireless systems to support a large number of devices and diverse service requirements. Current wireless standards have been designed and optimized for human-based traffic, that is long packets are used for sending the data. However, in massive IoT, devices usually generate small packets, therefore using the existing standards would be wasteful of resources. More specifically, new channel coding techniques should be designed for small packets in massive IoT applications.In contention based random access, the transmission phase consists of allocating individual users to dedicated, orthogonal resource blocks.

The codeword length in massive IoT is assumed to be only few kbs and the objective is then to design short block length codes that achieve high rate efficiency in the given time and frequency resources. To meet this requirement structured (algebraic) low-density parity-check codes will be developed. We will also develop a multi-level Raptor code, where multiple devices are transmitting at the same data channel using the same Raptor code and degree distribution function, but with different power levels. The received signal at the BS can then be realized as the coded symbols of a superimposed multi-layer Raptor code, where a multi-stage decoder and SIC are used to decode the devices' messages.

The new work required here includes a degree distribution design for multi-layer Raptor codes with short message lengths, as the current analysis and design of Raptor codes are for asymptotic case when the message length goes to infinity and designing an optimal power control strategy to maximize the throughput and the number of devices which can be supported in a given number of resource blocks.

This program is with collaboration of Professor Mischa Dohler, King's College London, and Dr Gianluigi Liva, German Aerospace Centre.

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Project Opportunities

Title: Channel Code Design in Short Block Length Regime: Capacity Analysis and Code Design

Summary of opportunity:

Ultra-reliable and low latency communications is central to the development of next generation's mobile communications and many emerging mission critical applications. The project will develop the fundamental sciences, enabling transmission and channel coding technologies, which will be essential for building and rolling out of future ultra-reliable and low latency wireless networks. The project outcomes will open up new research trajectories in the design of future mission critical communication systems and provide the foundations and tools for transforming, modernising and safeguarding Australia's national critical infrastructure.

Opportunity synopsis:

Rateless codes can automatically adapt to the channel condition without requiring channel state information (CSI) feedback and retransmission, thus effectively reducing the latency. Existing rateless codes have been constructed based on graphs. Short block length will introduce short cycles in the graph, significantly degrading the decoding performance of belief propagation decoders, used for
decoding graph based rateless codes. In our recent initial investigation, we showed that BCH codes outperform other codes under ML decoding in terms of block error probability in the short block-length region and perform close to the PPV normal approximation bound. However, the existing binary BCH codes are fixed-rate and for a given block-length, there are only a limited number of code rates for BCH codes. Although several methods such as puncturing, shortening or extension can be used to generate codes from a mother code, the generated codes will not be optimal. In this project, we will design a rateless semi-structured channel coding scheme to achieve the analytical bounds.we also develop a structured analog Fountain code (SAFC) specifically designed for short block-lengths. Each coded symbol of SAFC will be a weighted sum of a subset of information symbols. We will select the subset of information symbols and design the weights row by row with each row corresponding to a SAFC symbol. The design objective here is to maximise the minimum Euclidian distance for SAFC.

----------Current Research Projects----------

Channel Coding for Beyond 5G

ARC Discovery Project 2022-2024

Significant improvements are required for ICT services if they are to meet the needs of rapid urbanization and industrial transformation while also addressing the current digital divide, which sees half of the world's population currently without sufficient access to the internet. The 6th-generation (6G) of mobile standards will be a key solution to the constantly increasing demands on our communications infrastructure. This project will develop novel communication strategies for 6G to service new applications with requirements way beyond what 5G can achieve. The outcomes of the project are expected to significantly improve users' data rate and enhance the reliability and coverage of mobile networks.

Short Code Design for Mission-Critical Communications

ARC Discovery Project 2019-2021

This project aims to develop fundamental science to enable transmission and channel coding technologies, which will be essential for building and rolling out of future ultra reliable and low latency wireless networks. Reliable and low latency communications are central to the development of the next generation mobile communications and many emerging critical applications. The project is expected to provide the foundations and tools for transforming, modernizing and safeguarding Australia's national critical infrastructure. The project is expected to provide novel applications such as smart grids, telemedicine, intelligent transportations, and industrial automation.

Communication Strategies for the Internet of Things

ARC Discovery Project 2018-2020

By 2020 there will be 25-50 billion embedded devices around the world, seamlessly monitoring their environments, processing information and communicating wirelessly with other devices. This massive growth in wirelessly connect devices will be driven by the internet of things, the name given to the ubiquitous connectivity of everything everywhere. The internet of things is expected to generate incremental revenue exceeding $300 billion. However, wireless cellular networks must be upgraded to accommodate these new devices. This project aims to facilitate expanded wireless connectivity by designing novel random access strategies and multilevel channel codes to enable new massive multiple access communication strategies for cellular networks.

The Idea Factory

Faculty of Engineering and IT, Educational Innovation Unit, 2018

This project aims at developing an interactive learning platform for students from the Faculty of Engineering and Sydney Business School to work together in solving real-world problems and explore both technical and business aspects of a real product. This project aims to close the gap between engineering and business students and provide a framework for effective collaboration through multiple specially designed modules to develop a real product. Students will be engaged during the design process and their feedback will be considered when designing the modules and platform.

Outcomes of this project were partly presented at the 2018 Australasian Association for Engineering Education. The paper is available here, "Developing Critical Thinking and Intellectual Design Skills via Collaborative Projects in Engineering and Business Postgraduate Studies". The project was also shortlisted for the 2020 Reimagine Education Award, in the category of Nurturing Employability.

Robust and Sustainable Communications for Massive Internet of Things

FEIT Early Career Researcher Development Fund 2019

In this project, I will design a novel communication strategy for IoT, leveraging recent advances in modern coding theory, multiuser detection, and my own achievements in multiple access techniques and massive modulation and channel coding. In general, the proposed scheme works for a large number of devices and provide different service requirements suitable for both massive and mission critical IoT. My primary results show that the proposed scheme can support up to 180 packets per second for the delay requirement of 1s, which is almost 13 times bigger than what is currently supported in cellular systems. This is equivalent to support more than 50000 devices per cell using the proposed scheme. The main project aims are Aim 1) deriving the fundamental limits of cellular

access for massive and critical IoT, Aim 2) designing massive modulation and coding using fountain codes to enable cellular IoT, Aim 3) optimizing the radio resource management to maximize the throughput and provide quality of service guarantee for mission critical IoT, and Aim 4) hardware development of the proposed scheme for massive IoT.

Channel Code Design for Ultra-Reliable and Low Latency Communication (URLLC)

Universities Australia, Australi-Germany Research Collaboration Scheme, 2017

Rateless codes can automatically adapt to the channel condition without requiring channel state information (CSI) feedback and retransmission, thus effectively reducing the latency. Existing rateless codes have been constructed based on graphs. Short block length will introduce short cycles in the graph, significantly degrading the decoding performance of belief propagation decoders, used fordecoding graph based rateless codes. In our recent initial investigation, we showed that BCH codes outperform other codes under ML decoding in terms of block error probability in the short block-length region and perform close to the PPV normal approximation bound. However, the existing binary BCH codes are fixed-rate and for a given block-length, there are only a limited number of code rates for BCH codes. Although several methods such as puncturing, shortening or extension can be used to generate codes from a mother code, the generated codes will not be optimal. In this project, we will design a rateless semi-structured channel coding scheme to achieve the analytical bounds.

By 2020 there will be 25-50 billion embedded devices around the world, seamlessly monitoring their environments, processing information and communicating wirelessly with other devices. This massive growth in wirelessly connect devices will be driven by the internet of things, the name given to the ubiquitous connectivity of everything everywhere. The internet of things is expected to generate incremental revenue exceeding $300 billion.

However, wireless cellular networks must be upgraded to accommodate these new devices. This project aims to facilitate expanded wireless connectivity by designing novel random access strategies and multilevel channel codes to enable new massive multiple access communication strategies for cellular networks.

By 2020 there will be 25-50 billion embedded devices around the world, seamlessly monitoring their environments, processing information and communicating wirelessly with other devices. This massive growth in wirelessly connect devices will be driven by the internet of things, the name given to the ubiquitous connectivity of everything everywhere. The internet of things is expected to generate incremental revenue exceeding $300 billion.

However, wireless cellular networks must be upgraded to accommodate these new devices. This project aims to facilitate expanded wireless connectivity by designing novel random access strategies and multilevel channel codes to enable new massive multiple access communication strategies for cellular networks.