COMBINATION OF NON-ORTHOGONAL MULTIPLE-ACCESS TECHNIQUES AND MASSIVE MULTI-INPUT, MULTI-OUTPUT ANTENNAS

The 5G generation mobile network is predicted to account for 45% of the total global information traffic by 2025 although this network has only been commercialized since the end of 2020. The increase in information traffic comes from the record increase in the number of users, Internet connected terminals and especially the emergence of more and more smartphones with many applications requiring large transmission traffic. This is posing a huge challenge for the next generation mobile communication networks in terms of ensuring transmission capacity and performance simultaneously. Specifically, mobile communication networks of the next generation 5G (beyond 5G) must meet the following important criteria:

- Data capacity increase 1000 times

- The number of users increase 10 times

- Energy consumption reduce 10 times

- Processing latency reduce 10 times

Therefore, to meet the requirements of the new generation mobile network, many advanced techniques have been proposed. In which, the technique of massive multiple input multiple output antenna (MIMO) and non-orthogonal multiple access (NOMA) technique are two techniques that are currently attracting the attention of research community in the field of telecommunications because of their outstanding advantages. While NOMA research is being considered to become standardized in the next generation of mobile networks, massive MIMO is already a technology in the 5G standard set and is considered one of the core technologies in later generations. However, most of the previous studies have focused on only one of the two techniques and there are very few studies that combine these two techniques in a complete system.

In a recent collaborative study involving University of Science and Technology – The University of Danang (DUT), an information system that integrates NOMA and massive MIMO techniques in real-time channel conditions for mobile networks such as 5G and post-5G networks have been proposed, helping to exploit the advantages of these two techniques.

More specifically, this study presents a mathematical model and builds an expression to calculate the maximum channel capacity of a NOMA - massive MIMO system and develops algorithms to optimize the performance of a multi-user system in case the transmit channel is not ideal. The research results of the topic are urgent and practical in exploiting the system, helping to optimize the performance of using spectrum, providing simultaneous multi-access to a large number of users/devices in the context of a large number of users/devices in limited physical resources (frequency, time ..)

The results of the study were published in the journal IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY (vol. 70, no. 5) May, 2021. This is a journal ranked Q1 (Scimago/ISI) and in the top 2% of the telecommunications industry. The main author of the paper is Dr. Le Thi Phuong Mai, lecturer at the Faculty of Electronics and Telecommunications Engineering, DUT.

[Word explanation]

Non-orthogonal multiple access techniques change the way of transmission compared to previous generations of networks (from 1G to 4G) by distributing different power levels or assigning low-density or low cross-correlation codes for different users. As a result, this transmission technique is capable of meeting the needs of massive connectivity, allowing to increase the ability to provide access to many people / devices without affecting inherently limited physical resources, especially in the context of the Internet of Things (IoT) era.

Massive MIMO technology allows the design of a large number of antennas at base stations (from 64 antennas or more), which is considered a breakthrough technology for mobile networks in greatly increasing the transmission channel capacity. The transmission of a system using massive MIMO can under ideal conditions increase indefinitely, proportional to the number of antennas at the base station.

Fig. Dr. Le Thi Phuong Mai

[Biography]

- Dr. Le Thi Phuong Mai graduated with a PhD in Telecommunication from Sapienza University of Rome in 2019 and is currently researching and teaching at the Faculty of Electronics and Telecommunications Engineering, University of Science and Technology – The University of Danang. She has authored over 20 international articles, including articles from prestigious scientific journals (Q1/Scimago, ISI), and been head of 01 ministerial-level project.

- Le Thi Phuong Mai is honored to be one of 30 scientists to receive a post-doctoral scholarship in Vietnam from VINIF in 2021.