D3.2 – Initial Developments and Evaluation of the Proposed Enhancements and Optimization Strategies
Creators: name: Eger, Ory
name: Mohandoss, Govindarajan
name: Umbert Juliana, Anna
name: Sánchez González, Juan
name: Pérez-Romero, Jordi
name: Sallent Roig, José Oriol
name: Shasha, Eli
name: Globen, Baruch
name: Koffman, Israel
name: Berozashvili, Revaz
name: Castellanos, German
name: Sark, Vladica
name: Gutiérrez Terán, Jesús
name: Özates, Mert
name: Salvat Lozano, Josep Xavier
name: Ayala-Romero, Jose A.
name: Rossanese, Marco
name: Mursia, Placido
name: Municio, Esteban
name: Ghoraishi, Mir
Publisher: name: Zenodo
Year: 2024

description: BeGREEN D3.2 presents the initial developments and evaluation of the proposed physical (PHY) layer enhancements and optimisation strategies. While BeGREEN D3.1 described State-of-the-Art (SotA) on PHY mechanisms energy consumption and provided suggestions on innovative solutions and enhancements for this field, This document gets into the details of the specific solutions, indicates their potential for improving energy efficiency in cellular networks and presents some performance and power measurement results.

 A wide range of solutions and modules are discussed, each with its unique angle on the O-RAN/3GPP framework for 5G deployments, as well as forward looking to 6G. On the distributed unit (DU) and central unit (CU) accelerations, it is shown advanced architectures can be employed to reduce power consumption of modules with high computational complexity. Initial results of the comparative analysis of CU performance using x86 and Arm platforms indicates that while x86 shows better energy efficiency in scenarios with a limited number of simultaneous users, the Arm architecture excels in large-scale, high-throughput environments, achieving greater overall power savings. Specifically, as the data throughput increases, the energy savings with Arm become more pronounced compared to x86, as this is attributed to Arm's efficient handling of parallelized tasks. 

On terms of DU, for heavy processes algorithms, such as Low-Density Parity Check (LDPC) decoding, in the DU, it is observed that the Arm consumes less power, but is perform less processing than x86 for the same period. For Arm implementations with a larger vector length, much better ratios could be observed.

The radio unit (RU) consumes most energy in the radio access network (RAN) and in the cellular network, and thus the document explores several power saving techniques through simulation. It is observed that artificial intelligence (AI) based Digital-Pre-Distortion and Envelope Tracking can lead to more than 60% RF power amplifier (PA) energy saving. In addition, the PA blanking technique introduced in BeGREEN D3.1 that powers-off the RU PA when there is no data in the downlink stream, was developed and implemented on a commercial RU and a PA energy consumption reduction higher of more than 40% is achieved. 

The document introduced integrated sensing and communication (ISAC) to detect active users, and to assign resources based on the user distribution. To be used for extending the coverage of the RAN in urban areas, using Reconfigurable Intelligent Surface (RIS) is proposed and a practical autoconfiguring RIS integration is introduced, where its functionality and contribution in energy efficiency improvement is being evaluated. 

In the end, several strategies for interference management to improve the network energy efficiency are proposed and evaluated. The power consumption model for three different spectrum allocation strategies is developed. These differ in the way how the spectrum is shared and managed between the base station and the relay. The impact of these strategies on the system’s power consumption is currently being studied with simulations, and the results are expected in the upcoming BeGREEN D3.3.