UE CSI-RS Timing Synchronization Without Target Cell SSB Info

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Solution Overview

Problem

User Equipment (UE) in 5G networks face challenges in performing CSI-RS measurements on target cells when the associated Synchronization Signal Block (SSB) information is absent from the measurement configuration, leading to potential timing misalignments and measurement inaccuracies.

Innovation Solution

The UE receives a measurement configuration message indicating CSI-RS measurements on target cells without SSB information, using additional synchronization methods such as determining the time and frequency resources based on indications of SSB transmission status, performing SFTD measurements, or adjusting search windows to accurately measure CSI-RS.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the measurement configuration message does not include SSB information for the target cell, then the device complexity is reduced and the measurement process is simplified, but timing misalignment occurs leading to measurement inaccuracies

Engineering Contradiction:
Improvemeasurement configuration complexityVSAvoidCSI-RS measurement accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent applies preliminary action by performing SFTD measurements and determining timing offsets before conducting CSI-RS measurements. The UE calculates the timing difference between serving cell and target cell SSBs in advance, then uses this pre-determined offset to accurately locate CSI-RS resources without requiring SSB information in the measurement configuration message.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If the UE performs additional synchronization methods such as SFTD measurements, then timing and frequency alignment is improved, but the measurement time and processing complexity increase

Engineering Contradiction:
Improvetiming alignment accuracyVSAvoidmeasurement processing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies partial action by performing only the necessary SFTD measurements specifically for timing offset calculation, rather than complete synchronization procedures. The UE selectively executes partial synchronization tasks (timing offset estimation, frequency offset compensation) only when SSB information is absent, reducing overall processing time while maintaining measurement precision.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP4173424B1User equipment timing synchronization for CSI-RS based radio resource management
Publication Date: 2026.01.21 APPLE INC
  • EP4173424B1 patent drawingFigure 1
  • EP4173424B1 patent drawingFigure 2
  • EP4173424B1 patent drawingFigure 3

AI summary

A user equipment (UE) is served by a serving cell of a network and is configured to measure channel state information reference signals (CSI-RS) from a target cell. The UE receives, from the serving cell, a measurement configuration message indicating the UE is to measure CSI-RS from a target cell of the network, wherein the measurement configuration message does not include Synchronization Signal Block (SSB) information for the target cell but further comprises an indication of whether the target cell transmits SSBs. The UE determines, based on at least the measurement configuration message, a time and frequency resource on which the CSI-RS of the target cell are to be transmitted and measures the CSI-RS of the target cell.