User Equipment Radio Link Failure Detection Using Discontinuous Reference Signal Timers

Solution Overview

Problem

In LTE and NR communication systems, stable downlink synchronization and Radio Link Monitoring (RLM) measurements are challenging due to the discontinuous transmission of reference signals, leading to difficulties in detecting the reference signal during all unit periods.

Innovation Solution

A communication device and method that acquires and controls information about the communication quality based on discontinuously transmitted reference signals, allowing for the identification of transmission periods and enabling more stable synchronization and RLM measurements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If reference signals are transmitted discontinuously to save resources, then energy consumption and resource usage are reduced, but downlink synchronization and RLM measurement stability deteriorate

Engineering Contradiction:

Improveenergy consumptionVSAvoiddownlink synchronization stability

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The base station performs preliminary actions by transmitting reference signals at specific predetermined timings and notifying the terminal of these timings in advance. This allows the terminal to prepare for and accurately detect reference signals during discontinuous transmission periods, maintaining synchronization stability while enabling resource savings through discontinuous transmission.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements feedback mechanisms where the base station notifies the terminal of reference signal transmission timings. This feedback loop ensures the terminal can accurately track and detect reference signals even during discontinuous transmission, resolving the contradiction between resource saving and synchronization stability.

Inventive Principle:

Principle #23Feedback

2Productivity

If reference signals are transmitted discontinuously to reduce resource usage, then resource allocation efficiency is improved, but RLM measurement accuracy deteriorates

Engineering Contradiction:

Improveresource allocation efficiencyVSAvoidRLM measurement accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The base station performs preliminary actions by transmitting reference signals at specific predetermined timings and notifying the terminal of these timings in advance. This allows the terminal to prepare for and accurately detect reference signals during discontinuous transmission periods, maintaining synchronization stability while enabling resource savings through discontinuous transmission.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system changes the transmission parameter timing of reference signals from continuous to discontinuous at specific predetermined intervals. By carefully selecting these timing parameters and notifying the terminal, the system achieves resource allocation efficiency while maintaining sufficient measurement accuracy through strategic reference signal placement.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If reference signals are not included in all downlink wireless resources, then resource utilization is optimized, but detection reliability deteriorates

Engineering Contradiction:

Improveresource utilizationVSAvoidreference signal detection reliability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The base station performs preliminary actions by transmitting reference signals at specific predetermined timings and notifying the terminal of these timings in advance. This allows the terminal to prepare for and accurately detect reference signals during discontinuous transmission periods, maintaining synchronization stability while enabling resource savings through discontinuous transmission.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The notification mechanism acts as an intermediary between the base station's discontinuous reference signal transmission and the terminal's detection process. This intermediary provides the terminal with advance information about transmission timings, enabling reliable detection despite the discontinuous nature of the signals and achieving both resource optimization and detection reliability.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS11943800B2User equipment that determines radio link failure using timer and radio link quality, and corresponding base station

Publication Date: 2024.03.26 SONY GROUP CORP

AI summary

A user equipment that includes a radio transceiver that performs wireless communication in an unlicensed band, and circuitry that performs RLM using downlink physical signals, measures a radio link quality, evaluates the radio link quality against thresholds Qout and Qin, indicates out-of-sync to higher layers from a physical layer, indicates in-sync to the higher layers from the physical layer, starts a first timer when the out-of-sync is consecutively indicated to the higher layers from the physical layer, and determines that a radio link failure occurs in a case where the first timer expires without consecutive in-sync indications, and the first timer is different from a second timer used to determine whether a radio link failure occurs in a wireless communication in one or more serving cells in a licensed band.