Description
Network Energy Savings (NES) is a comprehensive framework within 3GPP 5G New Radio (NR) specifications focused on optimizing the energy efficiency of gNBs and the overall RAN. It operates by intelligently managing the operational state of network resources in response to real-time and predicted traffic conditions. The core principle involves transitioning network elements or specific radio resources into low-power states during periods of low demand, thereby reducing energy consumption without significantly impacting user experience or network availability.
The architecture of NES is integrated into the gNB's radio resource management (RRM) functions and is governed by policies that balance energy savings with key performance indicators (KPIs) like latency, throughput, and coverage. Key operational mechanisms include Cell DTX (Discontinuous Transmission), where a cell can temporarily mute its transmission signals, and Carrier Shutdown, which involves powering down entire carrier components. Furthermore, NES utilizes advanced sleep modes for radio units and supports dynamic adaptation of bandwidth parts (BWPs), allowing the gNB to operate with a narrower active bandwidth when full capacity is not required.
Implementation relies on coordination between the gNB-Central Unit (gNB-CU) and gNB-Distributed Unit (gNB-DU), as specified in the F1 interface. The gNB-CU makes centralised decisions based on aggregated load information and can instruct specific DUs to enter energy-saving states. These actions are often synchronized with the network's Self-Organizing Network (SON) functions for automated optimization. NES also defines specific signalling and measurement procedures, such as Energy Saving Indication messages and Energy Saving Assistance Information, to facilitate coordination between neighbouring gNBs, ensuring that coverage holes are not created when a cell reduces its activity.
Purpose & Motivation
NES was introduced to address the escalating energy costs and environmental impact of deploying and operating dense 5G networks. As 5G NR utilizes wider bandwidths, massive MIMO, and a higher density of cells to achieve its performance goals, the power consumption of the RAN has become a major concern for operators. Traditional networks often operated with fixed, always-on transmission patterns, leading to significant energy waste during low-traffic periods, such as overnight. NES provides the tools to make the network's energy consumption more proportional to its actual service load.
The creation of NES was motivated by both economic and regulatory pressures. Operators seek to reduce Operational Expenditure (OPEX), a substantial portion of which is energy costs. Simultaneously, there is growing societal and governmental demand for greener telecommunications. NES solves this by enabling a more elastic network infrastructure. It moves beyond simple, static power-saving modes to a dynamic, traffic-aware system that can make fine-grained adjustments. This allows operators to maintain service quality and coverage while achieving substantial energy reductions, which is critical for the sustainable rollout of 5G and future 6G networks.
Detected Changes Across Releases
from 3GPP Change RequestsSpecific changes extracted from the „Change history“ tables of 3GPP specifications (24 CRs across 4 releases). Complements the general historical overview above with the evidence-based evolution of this function.
In Release 15, the Network Energy Savings (NES) function was introduced to reduce operational expenses by enabling energy-saving states for cells. Specifically, it introduced intra-system and inter-system energy saving, where an NG-RAN node can autonomously switch a capacity booster cell to an inactive or dormant state based on cell load. The release also defined initial support for paging adaptation to increase gNB sleep time and introduced mechanisms for conditional handover and camping restrictions related to NES cell states.
- Energy Saving Support in R15 TS 38.300CR0152
In Release 16, the Network Energy Savings (NES) function introduced mechanisms to extend cell sleep times, notably through paging adaptation for UEs in RRC_IDLE and RRC_INACTIVE states by extending the values of N and Ns to create sparser paging frames. It also introduced the capability for an NG-RAN node to autonomously switch a capacity booster cell to an inactive or dormant state based on load, and defined NES-specific Conditional Handover events triggered via DCI. Furthermore, cells could bar UEs not capable of supporting cell DTX/DRX via SIB1 to facilitate energy-saving operations.
In Release 18, the Network Energy Savings (NES) function was newly introduced, establishing core mechanisms for NR. Key innovations included paging adaptation for UEs in RRC_IDLE and RRC_INACTIVE states to extend gNB sleeping time, and the ability for a cell to autonomously switch off or enter a dormant state based on load. The release also defined support for conditional handover with NES-specific events and introduced camping restrictions to bar UEs not capable of NES cell DTX/DRX.
- Introduction of Network Energy Savings TS 38.300CR0689
- Introduction of Network Energy Savings for NR TS 38.304CR0369
- Introduction of Network energy savings for NR TS 38.331CR4453
- Miscellaneous stage-2 corrections for network energy savings TS 38.300CR0870
- OAM Requirements on Energy Cost index TS 38.300CR0946
- Corrections for Network Energy Savings in 38.304 TS 38.304CR0390
+ 6 more changes
In Release 19, the Network Energy Savings (NES) function introduced paging adaptation for UEs in RRC_IDLE and RRC_INACTIVE states, extending paging parameters to allow gNBs longer sleep times. It also defined new conditional handover (CHO) triggering conditions specifically for NES events, allowing UEs to execute a handover when a source cell activates energy-saving measures like cell DTX/DRX. Furthermore, the release specified camping restrictions where cells can bar UEs not capable of supporting NES cell DTX/DRX.
- Introduction of Network Energy Savings Enhancements TS 38.300CR1013
- Introduction of Rel-19 network energy saving to TS 38.304 TS 38.304CR0442
- Introduction of enhancements for network energy efficiency TS 38.331CR5428
- Network Energy Savings Enhancements miscellaneous stage-2 corrections TS 38.300CR1042
- Network Energy Saving Enhancements rapporteur corrections TS 38.300CR1107
- Corrections for Network Energy Saving TS 38.331CR5559
+ 1 more changes
Explore further
Broader topics and technologies where NES plays a role.
Defining Specifications
3GPP specifications that define or reference NES, with the latest known release. Sourced from the 3GPP document catalog — see methodology.
| Specification | Title | Release |
|---|---|---|
| TS 38.300 vj00 | NG-RAN Overall Description | Rel-19 |
| TS 38.304 vj00 | UE RRC_IDLE and RRC_INACTIVE Procedures | Rel-19 |
| TS 38.306 vj00 | NR UE Radio Access Capability Parameters | Rel-19 |
| TS 38.331 vj00 | NR Radio Resource Control (RRC) Protocol Specification | Rel-19 |
| TS 38.401 vj10 | NG-RAN Architecture Specification | Rel-19 |