Moving Cell Synchronization Signal Frequency Mapping

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Solution Overview

Problem

In high-density wireless environments, moving cells in 5G communication systems face challenges with unnecessary handovers and channel quality measurements due to congestion, leading to delays and inefficient resource allocation.

Innovation Solution

A method for transmitting a synchronization signal by a moving cell base station, where the synchronization signal sequence is mapped to a different frequency region than that used by legacy user equipment, utilizing a Zadoff-Chu sequence with a dedicated root index to prevent interference and facilitate efficient handovers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If moving cells use the same frequency region as legacy user equipment for synchronization signals, then legacy user equipment can detect and measure the signals, but interference occurs leading to unnecessary handovers and measurement delays

Engineering Contradiction:
Improvehandover reliabilityVSAvoidhandover delay
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The frequency region for synchronization signals is segmented into different parts: legacy user equipment uses the original frequency region while moving cells use a different frequency region. This segmentation prevents interference between the two types of user equipment, allowing moving cells to perform handovers without unnecessary delays caused by detecting legacy cell synchronization signals.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The synchronization signal transmission for moving cells is extracted from the common frequency region and placed in a dedicated frequency region. This extraction eliminates the interference problem that would otherwise cause legacy user equipment to incorrectly detect moving cells as target cells for handover, thereby preventing unnecessary handover delays.

Inventive Principle:
Principle #2Taking out (Extraction)

2Productivity

If moving cells transmit synchronization signals on the same frequency region, then signal detection is possible, but interference increases causing unnecessary measurements and handovers

Engineering Contradiction:
Improvecommunication efficiencyVSAvoidinterference
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The solution moves the synchronization signal transmission from the same frequency dimension to a different frequency dimension. By allocating a dedicated frequency region for moving cells, the system adds frequency dimension separation, which eliminates interference while maintaining signal detectability, thus improving communication efficiency without generating harmful interference.

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

3Reliability

If a dedicated frequency region is allocated for moving cells, then interference with legacy user equipment is minimized, but frequency resource allocation becomes more complex

Engineering Contradiction:
Improvecommunication reliabilityVSAvoidfrequency allocation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The frequency region for moving cells is predetermined and pre-configured in the system. This preliminary allocation of frequency resources eliminates the need for complex real-time frequency allocation decisions, reducing system complexity while ensuring reliable communication by preventing interference from the outset.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3130094B1Method and apparatus for transmitting synchronization signals for a moving cell
Publication Date: 2020.12.23 LG ELECTRONICS INC
  • EP3130094B1 patent drawingFigure 1
  • EP3130094B1 patent drawingFigure 2
  • EP3130094B1 patent drawingFigure 3

AI summary

Disclosed is a method of transmitting a synchronization signal from a moving cell base station in a wireless communication system. The present invention includes mapping a moving cell synchronization signal sequence generated on a basis of a sequence assigned for a moving cell to a frequency region and transmitting the mapped moving cell synchronization signal sequence. Moreover, the moving cell synchronization signal sequence may be mapped to the frequency region different from a prescribed frequency region for transmitting a synchronization signal for a user equipment unsupportive of the moving cell.