A Unified Multiple Access Framework for Next Generation Mobile Networks By Removing Orthogonality (MANGO)

Lead Research Organisation: Lancaster University
Department Name: Computing & Communications

Abstract

An 8-fold increase in global mobile data traffic is predicted from 2015 to 2020, and it is expected that 50 billion devices will be connected through the mobile networks by 2020, given the expected surge in mobile connectivity and Internet of Things (IoT) applications. A combination of multiple approaches would be required to satisfy ever-growing demand of mobile data traffic, i.e., significant enhancement in spectrum efficiency, extension of available spectrum to higher frequency bands, and network densification using small cells.

The design of novel radio access technologies is an important aspect in improving spectrum efficiency in a cost-effective manner for future mobile networks. Radio access technologies are typically characterised by orthogonal multiple access schemes, e.g., frequency division multiple access (FDMA), time division multiple access (TDMA), code division multiple access (CDMA), and orthogonal FDMA (OFDMA) that provide the means for multiple users to access and share the radio resources simultaneously. One of the key issues with the orthogonal multiple access (OMA) schemes, for example, OFDMA used by 3GPP-LTE, is that when some bandwidth resources, such as subcarrier channels, are allocated to users with poor channel condition, it results in lower spectrum efficiency.

Motivated by the spectral inefficiency of OMA techniques, non-orthogonal multiple access (NOMA) has been recognised recently as a promising multiple access technique to significantly enhance the spectral efficiency and is envisioned to be a key component of the next generation mobile networks. The dominant NOMA schemes are grouped in two categories: power-domain or code-domain NOMA. In power-domain NOMA, users are allocated different power levels according to their channel conditions to obtain the maximum gain in system performance whereas in code-domain NOMA, different users are assigned different codes, and are then multiplexed over the same time-frequency resources. However, NOMA techniques still involve several critical challenges such as lack of insightful understanding of the performance limits of NOMA and a large gap in the performance evaluation of NOMA transceivers under single-/multiple antennas, single-/multi-cell cases, which makes their immediate deployment prohibitive.

This visionary project tackles the issue of NOMA techniques' deployment in next generation mobile networks by establishing a unified theoretical framework and developing sophisticated digital signal processing algorithms to realise the concept of NOMA in single-/multiple antenna, single-/multi-cell scenarios. The novelty of this project lies in a) information theoretical analysis with practical constraints, b) less-computationally complex transceiver design for power-domain and code-domain NOMA c) joint precoding design for single- and multi-cell NOMA networks, d) NOMA applications in cognitive radio and IoT systems and e) system level performance evaluations in next generation mobile network scenarios.

The project will be performed in partnership with leaders in future mobile network research and standardisation (Samsung, Nokia Bell Labs, MobileVCE) and in defence and emergency services (QinetiQ). The project consortium maintains a very strong track record in wireless communications, MIMO signal processing, and information theory with a right mix of theoretical and practical skills. Given the novelty and originality of the topic, the research outcomes will be of considerable value to transform the future of mobile networks and give the industry a fresh and timely insight into the development of NOMA based radio access in next generation mobile networks, advancing UK's research profile of wireless communication in the world. It is further believed that the successful completion of this project will lead to radically changes in the design of the physical layer of wireless communication systems and have a tremendous impact on standardisation.

Publications

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Related Projects

Project Reference Relationship Related To Start End Award Value
EP/P009719/1 01/08/2017 09/04/2018 £298,535
EP/P009719/2 Transfer EP/P009719/1 10/04/2018 31/07/2020 £244,458
 
Description Multiple access (MA) technologies are key to the successful evolution of modern mobile networks, and form the very core of the way in which the radio technology of the cellular systems work. All past generations of cellular systems rely on various forms of orthogonal MA in the time, frequency or code domains, even though it has been known since Shannon's work on the multiple access channel that this is sub-optimal. Only recently has non-orthogonal multiple access (NOMA) been considered for practical implementation, but it has been quickly envisioned as a key component for 5G wireless systems. Furthermore, the superior spectral efficiency of NOMA has also led recent standardization activities to include NOMA in 4G LTE-A. Despite the solid theoretical underpinning, and now this rapid pace of standardization, there are still important questions about the performance of NOMA particularly in presence of practical constraints such as limited feedback, interference and dynamic network topology, which introduce new challenges and will limit versatile adoption of NOMA in wireless communications. This project has successfully explored these challenging practical problems in NOMA, culminating in the formulation of both new fundamental theories and advanced technologies that contribute to the development of the next-generation mobile networks, as can be shown by the publications attached..
Exploitation Route Our research outcomes have been shared with the research community by publishing our works in international leading journals, including the preprints of our articles in arxiv and Researchgate, and presenting various tutorials and keynotes in international conferences.
Sectors Digital/Communication/Information Technologies (including Software)

URL https://personalpages.manchester.ac.uk/staff/zhiguo.ding/index
 
Description The world has witnessed an exponential growth in the number and demand of wireless devices, and an increase in the array of wireless broadband network applications that has permeated virtually all aspects of our daily lives. The importance of wireless communication on the quality of our lives and on our economy cannot be overstated. However, this progress cannot be sustained with the current wireless communication network technologies, and this fact has spurred research innovations towards the next generation of wireless systems, typically termed 5G technologies. Non-orthogonal multiple access (NOMA) represents such a key paradigm shift that will help meet these demands in next-generation mobile networks is the design of new types of multiple access techniques which provide more innovative ways of sharing the spectrum among massive users and devices. Since its invention at 2013, NOMA has been quickly recognized as a promising multiple access (MA) technique for 5G which is to be deployed in 2020. A simplified version of NOAM, termed Multi-User Superposition Transmission (MUST), has also been proposed to 4G LTE-A in 2015. The NOMA principle has also been applied to system beyond telecommunications, e.g., recently NOMA has also been used in digital TV systems, where it is termed Layered Division Multiplexing. Our research in NOMA has successfully set an agenda to fully exploit the potentials of the NOMA principle for revolutionizing wireless systems, and recently received three Best Paper Awards from three IEEE societies, including IEEE Vehicular Technology Society (VTS) Jack Neubauer Memorial Award 2018, IEEE Communication Society (COMSOC) Henrich Hertz Best Letter Award 2018, and IEEE Signal Processing Society (SPS) Best Signal Processing Letter Award 2018.
First Year Of Impact 2019
Sector Digital/Communication/Information Technologies (including Software)
Impact Types Societal