Inter-cell coordination of discontinuous transmission and reception for energy-efficient radio resource management in 5G-advanced
Creators: name: Borja Zambrano, Juan Guillermo
Publisher: name: RWTH Aachen University
Year: 2024
Subjects: subject: 004

description: Masterarbeit, Rheinisch-Westfälische Technische Hochschule Aachen, 2023; Aachen : RWTH Aachen University 1 Online-Ressource : Illustrationen (2024). doi:10.18154/RWTH-2023-07392 = Masterarbeit, Rheinisch-Westfälische Technische Hochschule Aachen, 2023
description: As mobile broadband use has become essential for society, the demand for mobile data has been continuously increasing throughout the years and it is expected to continue growing in the future at an even faster pace with 5G slowly taking over the traffic from the previous generations [1]. In this regard, 5G networks have been developed to cope with the increasing traffic demand, e.g. with more capable radios or denser network deployments, but this has posed a challenge on how to contain the network energy consumption so that it does not grow excessively as well. Current mobile networks are often dimensioned to handle high loads during peak traffic hours and to provide very high quality of service for the user in the right conditions, but this often results in low average network utilization, which generates an energy consumption imbalance between low and high load periods as the energy usage is not proportional to the actual traffic demand. To this end, this thesis proposes a technique in the time domain to decrease the base station energy consumption by enabling advanced sleep modes (ASMs) in a systematic way. This technique is called Cell Discontinuous Transmission and Reception (Cell DTX/DRX) and it defines two cell operational periods: An active period where transmissions and receptions take place as needed, and an inactive period where the cell does not transmit or receive anything and ASMs are activated to reduce radio power consumption. The Cell DTX/DRX scheme is evaluated through system-level simulations for a mixed traffic scenario in a single-cell network under varying load and its performance is analysed in terms of achievable energy saving gains, service impact as well as perceived user experience impact for different Cell DTX/DRX parameters. This scheme presents promising energy saving gains of up to 50% in a single-cell network under low load without compromising the user experience. The energy saving gains achieved under light load and mediumload are in the order of 30-40% and 10-20%, respectively, without compromising the quality of experience for the users. In general, the Cell DTX/DRX scheme offers an interesting and configurable trade-off between network energy saving and user performance without affecting cell performance or cell coverage. Additionally, this workproposes two coordinated implementation strategies for scaling up the Cell DTX/DRX scheme to a multi-cell network, as inter-cell interference needs to be considered in this case. By coordinating cell activity periods, additional energy saving gains of about 2-3% can be achieved compared to the case in which all cells are active or inactive at the same time. Furthermore, the main benefit from coordinating the Cell DTX/DRX patterns between neighbouring cells is the reduction on the user performance impact, since the inter-cell interference levels are reduced. If the Cell DTX/DRX scheme would be implemented in today's 5G networks that are on average often low utilized, it is possible to expect network energy saving gains of around 20% throughout a day by the Cell DTX/DRX scheme, even with conservative Cell DTX/DRX configurations and without compromising user experience.
description: Published by RWTH Aachen University, Aachen