A Global

The Mobile

Better energy efficiency for 5G

 January 2021

By Jean-Michel Cornily, Orange, 3GPP WG SA5 Rapporteur Rel-17 work item ‘Enhancements on EE for 5G networks’.

As part of the global trend to reduce the impact of ICT equipment on the environment and the constant desire to reduce the network operator’s operational expenses, 3GPP has been working for years on standards for the energy efficiency of mobile networks - by following a two-step approach: (1) Defining Energy Efficiency (EE) KPIs & methods to measure them and (2) By defining use cases and solutions for Energy Saving (ES).

The energy efficiency of a mobile network can be defined by its performance divided by its energy consumption, where the definition of performance depends on the network entity it applies to. For a unit of energy consumed by the mobile network, the higher its performance is, the higher its energy efficiency is.

Historically, the focus has been put on the Radio Access Network (RAN) since it’s commonly agreed that it constitutes the most energy consuming part of the mobile network; its performance is assessed by the traffic data volume carried by base stations (cf. ETSI standard ES 203 228).

Work is now ongoing to define the performance of a 5G core network and of network slices. In the Network Slice as a Service (NSaaS) model, a customer may express requirements to a provider about the energy efficiency of the network slice they want to order (cf. GSMA NG.116). The performance of a network slice is defined in terms of data volume for enhanced Mobile Broadband (eMBB), the reduction of latency for Ultra Reliable Low Latency Communications (URLLC), number of registered subscribers or active user equipment for massive IoT.

enjoy SA5 image final2To build such energy efficiency KPIs, 3GPP-defined performance measurements are collected from network elements / functions via OA&M standardized APIs. When it comes to measuring the energy consumption of network elements / functions, 3GPP relies on ETSI defined methods (cf. ETSI standard ES 202 336-12) for base stations and servers. Given there is no standardized method yet to measure the energy consumption of virtualized network functions, work is ongoing in 3GPP to propose methods to estimate it.

As for energy saving, it can be orchestrated at two levels:

a) Distributed ES, when the intelligence to realize the energy saving is located in the network elements / functions, e.g. base stations;
b) Centralized ES, when the intelligence is provided by a management function in the OSS.

The energy saving logic is fed by performance measurements and, in 5G, by analytics such as traffic load prediction or user equipment mobility prediction, provided by a Management Data Analytics Function (MDAF) or the NetWork Data Analytics Function (NWDAF).

This effort is a part of the industry-wide activity on 5G, spanning an eco-system that also includes energy efficiency related output from GSMA, ETSI, ITU-T and NGMN.

Further Reading

 TS28.310 Management and orchestration; Energy efficiency of 5G 
 TS28.552  Management and orchestration; 5G performance measurements 
 TS28.554 Management and orchestration; 5G end to end Key Performance Indicators (KPI) 
 TS28.622 Telecommunication management; Generic Network Resource Model (NRM) Integration Reference Point (IRP); Information Service (IS)

This article was created and published for the January 2021 edition of the ETSI magazine - Enjoy!

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