NB-IoT Radio Base Station Power Saving State

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current energy-saving approaches in mobile networks fail to efficiently manage power consumption when a switched-off cell lacks adjacent coverage cells, as they cannot effectively detect user equipment (UE) needs for service without adjacent cells to switch back on.

Innovation Solution

Implementing a power saving state in radio base stations (RBS) where only essential signaling is periodically transmitted, allowing the RBS to switch off and wake up when needed by user equipment, with adaptive switch-on and switch-off periods to conserve energy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the RBS switches off the transmitter to save power, then energy consumption is reduced, but the ability to detect and serve UEs is impaired

Engineering Contradiction:
Improvepower consumptionVSAvoiddetection of UE access requests
Core Design Contradiction:
Use of energy by moving objectVSDifficulty of detecting and measuring

Solution Approach 1:

The transmitter is switched off periodically between transmission time intervals (TTIs) rather than continuously. The RBS transmits during specific TTIs and remains off during others, creating a periodic pattern that balances power savings with periodic availability for serving UEs.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The RBS uses feedback from UE access requests (random access preambles) to dynamically adjust its operation. When an access request is detected during the off period, the RBS switches on to serve the UE, and this feedback mechanism ensures the system responds to actual demand rather than operating on fixed schedules alone.

Inventive Principle:
Principle #23Feedback

2Reliability

If the RBS transmits signaling frequently to maintain network accessibility, then UEs can be served, but energy consumption increases

Engineering Contradiction:
Improvenetwork accessibilityVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

System information is transmitted periodically at specific TTIs rather than continuously. This periodic transmission maintains network accessibility by providing UEs with necessary system information at regular intervals while consuming power only during these specific transmission windows.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The RBS dynamically adjusts its transmission schedule based on actual network conditions and UE demand. The system can transition between different operational states (fully on, partially on with periodic transmission, or fully off) depending on whether UEs are present and what level of service is required.

Inventive Principle:
Principle #15Dynamics

3Use of energy by moving object

If the RBS operates in transmit standby mode with reduced signaling, then power is saved, but UEs cannot detect the cell for initial access

Engineering Contradiction:
Improvepower consumptionVSAvoidcell detection by UEs
Core Design Contradiction:
Use of energy by moving objectVSEase of operation

Solution Approach 1:

The RBS transmits essential synchronization signals and system information periodically at predetermined TTIs. This periodic transmission ensures that UEs can detect the cell and acquire necessary system information during these transmission windows, while the RBS consumes minimal power during the intervals between transmissions.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP3606186B1Energy efficient operation of radio network nodes and wireless communication devices in NB-iot
Publication Date: 2023.08.09 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3606186B1 patent drawingFigure 1
  • EP3606186B1 patent drawingFigure 2
  • EP3606186B1 patent drawingFigure 3

AI summary

A radio network node may operate in a normal or restricted operating state. In the restricted operating state, the radio network node may have just enough activity to enable UEs to detect the cell. The radio access node may transition to the normal operating state in response to messaging from a wireless communication device, such as reception of a random access preamble.