RF Carrier Positioning via Synchronization Channel Offset

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Solution Overview

Problem

In wireless communication systems, particularly in 5G networks, the large number of possible RF carrier positions due to wider frequency bands leads to unmanageable cell search times, and existing solutions fail to provide precise knowledge of RF carrier position and bandwidth, potentially causing RF emissions to spill over regulatory limits.

Innovation Solution

A method in wireless devices and network nodes that identifies a synchronization channel part of an RF carrier, determines its position using system information, and adjusts subcarrier spacing to reduce the number of possible RF channel positions and prevent emissions from exceeding regulatory limits by blanking subcarriers when necessary.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a fine carrier raster with 100 kHz separation is used to provide precise RF carrier positioning, then manufacturing precision is improved, but device complexity increases due to unmanageable cell search times

Engineering Contradiction:
ImproveRF carrier positioning precisionVSAvoidcell search complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent divides the RF carrier positioning into two stages: first identifying the synchronization channel position on a coarse raster, then determining the actual RF carrier position using an offset value. This segmentation reduces cell search complexity while maintaining positioning precision by breaking down the fine search task into a coarse search plus offset calculation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary identification of the synchronization channel position on a coarse raster before determining the final RF carrier position. This preliminary action reduces the search space for the actual carrier position, making the overall process more manageable while maintaining precision through the subsequent offset application.

Inventive Principle:
Principle #10Preliminary action

2Loss of time

If the number of possible RF carrier positions is limited to reduce cell search time, then loss of time is reduced, but measurement precision deteriorates due to inability to precisely determine RF carrier position and bandwidth

Engineering Contradiction:
Improvecell search timeVSAvoidRF carrier position and bandwidth knowledge
Core Design Contradiction:
Loss of timeVSMeasurement precision

Solution Approach 1:

The patent introduces a synchronization channel as an intermediary element with a fixed coarse raster. The wireless device first acquires this intermediary signal, then uses it as a reference to determine the actual RF carrier position and bandwidth through offset values and system information, thereby maintaining measurement precision while reducing search time.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the mechanical approach of directly searching all possible RF carrier positions with a signal processing approach: first acquiring the synchronization channel, then calculating the RF carrier position through offset values. This substitution maintains precision while dramatically reducing the time required.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If synchronization channel positions are fixed on a coarse raster to reduce cell search time, then productivity is improved, but manufacturing precision deteriorates as RF carrier position cannot be precisely determined

Engineering Contradiction:
Improvecell search efficiencyVSAvoidRF carrier position determination
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent adds another dimension to the positioning system by introducing an offset parameter that operates independently from the coarse synchronization channel raster. This allows the system to maintain the coarse raster for efficiency while adding a fine-tuning dimension through the offset value to achieve precise RF carrier positioning.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

4Ease of operation

If RF carrier positions are constrained to align with subcarrier grid to simplify system design, then ease of operation is improved, but manufacturing precision deteriorates causing RF emissions to potentially exceed regulatory limits

Engineering Contradiction:
Improvesystem design simplicityVSAvoidRF carrier positioning accuracy
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent makes the RF carrier positioning dynamic by allowing the offset value to be adjusted based on system information and regulatory requirements. Rather than being fixed to the subcarrier grid, the offset can be dynamically determined to ensure precise positioning within the licensed block while maintaining compliance with emission limits.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3602948B1Channel raster and numbering
Publication Date: 2022.05.04 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3602948B1 patent drawingFigure 1
  • EP3602948B1 patent drawingFigure 2
  • EP3602948B1 patent drawingFigure 3

AI summary

A method in a wireless device (310) is disclosed. The method comprises identifying (704) a synchronization channel part of a radio frequency (RF) carrier in an operating band. The method comprises obtaining (708) system information for use in determining a position of the RF carrier in the operating band relative to the identified synchronization channel part of the RF carrier. The method comprises determining (712), based on the obtained system information, the position of the RF carrier in the operating band relative to the identified synchronization channel part of the RF carrier.