Discovery Signal Design for Small Cell Clusters

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Solution Overview

Problem

In wireless networks, small cell clusters experience signal interference and resource inefficiency due to always-on signal transmission, leading to PCI confusion and collision, which hampers network coverage and resource management.

Innovation Solution

A discovery signal with a base sequence and orthogonal sequence is transmitted with optimized periodicity and time density, allowing user equipment to distinguish between small cell clusters and identify the correct cell, thereby mitigating interference and conserving resources.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If small cells transmit always-on signals to provide continuous network coverage, then network coverage is improved, but signal interference and PCI confusion increase

Engineering Contradiction:
Improvenetwork coverage areaVSAvoidsignal interference
Core Design Contradiction:
Area of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The patent implements periodic discovery signals instead of always-on transmissions. Small cells transmit discovery signals at specific intervals (periodic action) rather than continuously, which reduces signal interference and PCI confusion while still providing network coverage. The periodic transmission allows user equipment to detect and identify small cells during designated discovery periods without constant interference.

Inventive Principle:
Principle #19Periodic action

2Reliability

If small cells transmit always-on signals to ensure continuous service, then network service availability is improved, but power consumption increases

Engineering Contradiction:
Improvenetwork service availabilityVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by stationary object

Solution Approach 1:

The patent employs periodic discovery signal transmission where small cells activate only during designated discovery periods rather than maintaining continuous transmission. This periodic operation significantly reduces power consumption while ensuring network service availability is maintained during the periodic windows when discovery signals are transmitted.

Inventive Principle:
Principle #19Periodic action

3Measurement precision

If discovery signals are transmitted with high time density to improve cell identification accuracy, then cell identification precision is improved, but resource efficiency deteriorates

Engineering Contradiction:
Improvecell identification accuracyVSAvoidresource efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent implements periodic discovery signals with optimized timing that provide sufficient cell identification accuracy during designated discovery periods without requiring continuous high-density transmissions. The periodic structure allows user equipment to accurately identify cells during these windows while conserving network resources during non-discovery periods.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP2946606B1Discovery signal in cluster-based small cell
Publication Date: 2024.09.18 APPLE INC
  • EP2946606B1 patent drawingFigure 1
  • EP2946606B1 patent drawingFigure 2
  • EP2946606B1 patent drawingFigure 3

AI summary

The embodiments described herein relate to a user equipment ("UE") and a plurality of nodes in a wireless network. A UE may be adapted to receive from a node a discovery signal that includes a base sequence. The base sequence may distinguish a first group of collocated nodes, comprising a first cell cluster, from a second group of collocated nodes, comprising a second cell cluster. The UE may further be adapted to receive from the node an orthogonal sequence, also included in the discovery signal. The orthogonal sequence may distinguish a first cell from other collocated cells so that cells within a cell cluster are separately identifiable. In further embodiments, the conjugate of sequences may be used to increase the amount of sequences available to distinguish cells and/or cell clusters. Other embodiments are described herein.