NB-IoT Wireless Device Measurement Adaptation for Power Reduction

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Solution Overview

Problem

Narrow Band Internet of Things (NB-IoT) devices face challenges in reducing activity time to achieve low power consumption, which is essential for prolonged battery life, as existing methods struggle to efficiently perform measurements across synchronized and asynchronous cells without increasing radio activity time.

Innovation Solution

A method where a wireless device determines whether signals from different cells occur simultaneously and adapts measurement procedures by using either NB-SSS or NB-RS based on synchronization status, and a network node adjusts transmit timings and DRX cycles to facilitate reduced activity time, allowing for interleaved measurements across cells.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the wireless device performs measurements on both synchronized and asynchronous cells using conventional methods, then measurement accuracy is maintained, but radio activity time increases leading to higher power consumption

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidpower consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent segments the measurement process into two distinct paths based on cell synchronization status: for synchronized cells, the device uses NB-SSS signals only, while for asynchronous cells, it uses NB-RS signals only. This segmentation allows the device to perform measurements on multiple cells without requiring simultaneous transceiver activity, thereby reducing overall radio activity time and power consumption while maintaining measurement accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic adaptation of measurement procedures by determining the synchronization status of each cell and selectively applying different measurement methods. The wireless device dynamically adjusts its measurement strategy based on whether cells are synchronized or asynchronous, optimizing the balance between measurement precision and power consumption for each specific scenario.

Inventive Principle:
Principle #15Dynamics

2Duration of action of stationary object

If the wireless device reduces activity time to lower power consumption, then battery life is extended, but the ability to perform accurate measurements across multiple cells is compromised

Engineering Contradiction:
Improvebattery lifeVSAvoidmeasurement accuracy
Core Design Contradiction:
Duration of action of stationary objectVSMeasurement precision

Solution Approach 1:

By segmenting measurements into synchronized cell measurements (using NB-SSS) and asynchronous cell measurements (using NB-RS), the patent enables the wireless device to complete all necessary measurements within a reduced activity window. The device can interleave these measurements efficiently, ensuring accurate measurement of multiple cells while keeping the transceiver active for shorter durations, thus extending battery life.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs preliminary determination of cell synchronization status to pre-plan the measurement sequence. By knowing in advance which cells are synchronized and which are asynchronous, the device can organize its measurement activities to minimize radio activity time while ensuring all necessary measurements are performed accurately before returning to sleep mode.

Inventive Principle:
Principle #10Preliminary action

3Use of energy by moving object

If the wireless device uses NB-SSS for measurements in synchronized cells, then power consumption is reduced, but measurement capability is lost for asynchronous cells

Engineering Contradiction:
Improvepower consumptionVSAvoidmeasurement capability
Core Design Contradiction:
Use of energy by moving objectVSAdaptability or versatility

Solution Approach 1:

The patent applies local quality by using different measurement approaches tailored to the specific characteristics of each cell type: NB-SSS is used specifically for synchronized cells where it provides sufficient measurement capability with lower power consumption, while NB-RS is used specifically for asynchronous cells where it ensures accurate measurement despite higher power requirements. This localized optimization maintains overall system adaptability while reducing total power consumption.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the measurement parameter (signal type) based on cell synchronization status. By switching between NB-SSS and NB-RS depending on whether the cell is synchronized or asynchronous, the device adapts its measurement capability to match the specific conditions of each cell, maintaining versatility while optimizing power consumption for each measurement scenario.

Inventive Principle:
Principle #35Parameter changes

4Use of energy by moving object

If the network node adjusts transmit timings to facilitate reduced activity time, then wireless device power consumption decreases, but network coordination complexity increases

Engineering Contradiction:
Improvepower consumptionVSAvoidnetwork coordination complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent merges the timing adjustment functionality into the existing self-organizing network (SON) framework and automatic neighbor relation (ANR) mechanisms. By combining these timing adjustment functions with existing network coordination procedures, the patent reduces network coordination complexity while still enabling the transmit timing adjustments necessary for reduced device activity time and lower power consumption.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3453125B1Wireless device and method therefor, and computer program
Publication Date: 2019.11.20 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3453125B1 patent drawingFigure 1~3
  • EP3453125B1 patent drawingFigure 4~6
  • EP3453125B1 patent drawingFigure 7~8

AI summary

A method of a wireless device arranged to perform measurements of signals wirelessly transmitted from at least one network node and being associated with a first cell and a second cell, respectively, is disclosed. The signals to be measured comprise signals of a first type and a second type. The method comprises determining whether the signals of the first type associated with the first cell and the second cell occur simultaneously. If the signals of the first type associated with the first cell and the second cell occur simultaneously, the method comprises measuring the signal of the first type associated with the first cell and measuring the signal of the second type associated with the second cell. If the signals of the first type associated with the first cell and the second cell does not occur simultaneously, the method comprises measuring the signal of the first type associated with the first cell and the signal of the first type associated with the second cell. A method of a network node is also disclosed, as well as a wireless device and a network node, and computer programs therefor.