5G-NR and E-UTRA Modem Timing Exchange for SFTD

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Solution Overview

Problem

In non-standalone 5G-NR and 4G E-UTRA network arrangements, efficient determination of System Frame Timing Difference (SFTD) measurements is challenging due to distinct time references between the 5G-NR and 4G E-UTRA modems, often from different vendors, requiring both modems to perform timing measurements independently.

Innovation Solution

The 5G-NR modem provides timing information to the 4G E-UTRA modem via a software interface, enabling the E-UTRA modem to determine and forward SFTD information on behalf of the 5G-NR modem, leveraging shared network time synchronization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If both 5G-NR modem and 4G E-UTRA modem perform timing measurements independently, then measurement accuracy is maintained, but processing complexity and power consumption increase

Engineering Contradiction:
ImproveSFTD measurement accuracyVSAvoiddigital signal processing cycles
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces an intermediary mechanism where the 5G-NR modem provides timing information to the 4G E-UTRA modem through a software interface. This allows the 4G modem to perform SFTD calculations using timing data from the 5G modem, eliminating the need for both modems to independently perform all timing measurements. The intermediary interface enables coordinated measurement operations that reduce overall processing complexity while maintaining measurement accuracy.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If both modems perform independent timing measurements, then measurement reliability is ensured, but power consumption increases

Engineering Contradiction:
Improvetiming measurement reliabilityVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent merges the timing measurement functionality by having the 5G-NR modem perform timing measurements and then share this information with the 4G E-UTRA modem through a software interface. Instead of both modems performing identical independent measurements, the system combines the measurement operations, with the 5G modem doing the actual timing measurement and the 4G modem using this data for SFTD calculations. This merging approach maintains measurement reliability while significantly reducing power consumption by eliminating redundant measurement operations.

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If timing measurements are performed by both modems, then measurement completeness is achieved, but die area increases

Engineering Contradiction:
Improvetiming measurement completenessVSAvoiddie area
Core Design Contradiction:
Measurement precisionVSArea of moving object

Solution Approach 1:

The patent extracts the timing measurement functionality from the 4G E-UTRA modem and assigns it to the 5G-NR modem. The 4G modem no longer needs to perform timing measurements independently but instead receives timing information from the 5G modem through the software interface. This extraction allows the 4G modem to focus solely on SFTD calculations using the provided timing data, thereby reducing the overall die area required for timing measurement hardware while maintaining measurement completeness.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP3897071B1E-utran and 5gnr modem arrangement for sftd
Publication Date: 2025.10.15 NXP USA INC
  • EP3897071B1 patent drawingFigure 1~2
  • EP3897071B1 patent drawingFigure 3~4
  • EP3897071B1 patent drawingFigure 5~6

AI summary

A 5G-NR modem for a non-standalone network and including a cell search module configured to: determine first timing information comprising first times indicative of the time of receipt of a respective one or more first radio frames from a first, 5G-NR, base station, each radio frame having a first system frame number, the first times measured relative to a network time; provide for sending of system frame timing difference information for the first base station by sending said first timing information to a second, E-UTRA, modem for determination and forwarding of the SFTD information using said first timing information and second timing information determined by the E-UTRA modem, the second timing information comprising second times indicative of the time of receipt of a respective one or more second radio frames from a second, E-UTRA, base station, each radio frame having a second system frame number.