NB-IoT Cell Reselection Core Network Data Buffering

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Solution Overview

Problem

Current Narrowband Internet of Things (NB-IoT) networks face challenges in maintaining mobility in connected mode, leading to high power consumption due to frequent handover procedures and potential downlink data loss during cell changes or reselections.

Innovation Solution

A core network device processes data by obtaining an indication message for terminal cell changes or reselections and sends downlink data to a target base station, implementing timers to manage data storage and transmission, ensuring data continuity and reducing storage burden.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the terminal performs measurement and measurement result reporting in connected mode to support handover decision-making, then handover capability is improved, but power consumption of the terminal increases

Engineering Contradiction:
Improvehandover capabilityVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The core network device performs preliminary actions by pre-configuring measurement parameters and thresholds before the terminal performs measurements. The network device prepares measurement configurations in advance, so when handover is needed, the terminal can quickly report results without extensive processing, reducing power consumption while maintaining handover capability.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If the core network device stores downlink data during cell reselection to prevent data loss, then data continuity is improved, but storage burden increases

Engineering Contradiction:
Improvedata continuityVSAvoidstorage burden
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The core network device performs preliminary actions by buffering downlink data before the terminal completes cell reselection. The data is stored in advance in the core network device, and only after the terminal successfully connects to the target base station is the data forwarded. This preliminary buffering ensures data continuity without requiring long-term storage, reducing overall storage burden.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The core network device acts as an intermediary between the data source and the terminal during cell reselection. It temporarily holds downlink data and forwards it to the target base station after successful handover, mediating the data transfer to ensure continuity while minimizing storage requirements through timely forwarding.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If the core network device sends downlink data to the target base station after cell reselection, then data delivery is improved, but data loss may occur during the transition

Engineering Contradiction:
Improvedata deliveryVSAvoiddata loss
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The core network device performs preliminary actions by buffering downlink data before the terminal completes cell reselection. This preliminary storage ensures that data is ready to be sent immediately after handover, improving data delivery while preventing loss during the transition period.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The core network device maintains continuous data availability by buffering downlink data throughout the cell reselection process. The data remains in the buffer continuously, ensuring uninterrupted delivery to the target base station once handover completes, thereby preventing data loss while maintaining productivity.

Inventive Principle:
Principle #20Continuity of useful action

Data Source

PatentEP3487225B1NB-iot cell reselection method and network devices
Publication Date: 2022.10.12 HUAWEI TECH CO LTD
  • EP3487225B1 patent drawingFigure 1
  • EP3487225B1 patent drawingFigure 2
  • EP3487225B1 patent drawingFigure 3

AI summary

Embodiments of this application provide a cell obtaining method and a terminal to reduce power consumption of the terminal. Technical solutions provided in the embodiments of this application are as follows: When a terminal is connected to a current source serving cell, the terminal obtains a first quality parameter of the current source serving cell; if the first quality parameter is less than a first preset threshold, the terminal determines a measurement cell set; the terminal measures each measurement cell in the measurement cell set to obtain each corresponding second quality parameter; and the terminal determines a target serving cell based on the second quality parameter.