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

Lead Research Organisation: University of Edinburgh
Department Name: Sch of Engineering


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.


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Description We studied downlink sum rate maximization in non-orthogonal multiple access systems. Numerical examples reveal a superior performance, compared to conventional orthogonal schemes, achieving higher data rates combined with reduced transmit power.

We studied the NOMA scheme with full-duplex radio and published paper - K. Singh, K. Wang, S. Biswas, Z. Ding, F. Khan, and T. Ratnarajah, "Resource Optimization in Full Duplex Non-orthogonal Multiple Access Systems," IEEE Trans on Wireless Communications, Vol. 18, No. 9, pp. 4312-4325, Sep. 2019.
Exploitation Route Publications

We are currently working with local industry Calnex and international telecom industry Huawei and exploiting our research knowledge. Also including the research finding in our teaching syllabus (Advanced wireless communications and Array Signal Processing).
Sectors Digital/Communication/Information Technologies (including Software),Education

URL http://www.profratnarajah.org/
Description We are currently working with local industry Calnex and international telecom industry Huawei and exploiting our research knowledge. Also including the research finding in our teaching syllabus (Advanced wireless communications and Array Signal Processing and MIMO System). Obtained grant from Huawei £230K
First Year Of Impact 2019
Sector Digital/Communication/Information Technologies (including Software),Education
Impact Types Economic