Base Station Synchronization Channel Interference Reduction

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Solution Overview

Problem

In LTE systems, the detection likelihood of the secondary synchronization channel (S-SCH) is reduced due to interference from adjacent cells in an inter-station synchronous system, leading to degraded transmission characteristics and increased cell search time.

Innovation Solution

The use of multiple primary synchronization channel (P-SCH) sequences and different transmission intervals for cells, along with scramble code randomization across cells, improves the detection likelihood of the S-SCH by reducing interference and enhancing channel estimation accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If multiple P-SCH sequences and different transmission intervals are used for cells, then the detection likelihood of S-SCH is improved and cell search time is reduced, but the device complexity and signal processing requirements increase

Engineering Contradiction:
Improvecell search timeVSAvoidbase station signal processing complexity
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

The synchronization signal transmission is segmented into multiple P-SCH sequences with different transmission intervals. Different cells use different sequences and intervals, dividing the overall synchronization process into distinct segments that can be detected more reliably without requiring the mobile station to process all sequences simultaneously at the same interval.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The transmission interval of P-SCH sequences is made dynamic rather than uniform across all cells. Each cell can be configured with different transmission intervals, allowing the system to adapt to varying conditions and improve S-SCH detection likelihood while managing base station processing loads through intelligent resource allocation.

Inventive Principle:
Principle #15Dynamics

2Object-affected harmful factors

If scramble code randomization is applied across cells, then interference from adjacent cells is reduced and S-SCH detection is improved, but the processing load for mobile stations increases

Engineering Contradiction:
Improveinterference from adjacent cellsVSAvoidmobile station processing load
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

Scramble code randomization is applied locally to each cell individually rather than using a uniform approach across all cells. Each cell is assigned a specific scramble code sequence that is randomized independently, which reduces interference from adjacent cells while allowing mobile stations to process each cell's synchronization signal with targeted complexity rather than uniformly high complexity for all cells.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2184873B1Base station apparatus, transmitting method, and radio communication system
Publication Date: 2012.07.25 NTT DOCOMO INC
  • EP2184873B1 patent drawingFigure 1~2
  • EP2184873B1 patent drawingFigure 3
  • EP2184873B1 patent drawingFigure 4

AI summary

A base station apparatus is disclosed for use in a mobile communication system including multiple cells having multiple sectors. The base station apparatus includes a synchronization channel generation unit configured to generate a synchronization channel for use in cell search by a user apparatus and a transmitting unit configured to wirelessly transmit a signal including the synchronization channel. The synchronization channel includes a primary synchronization channel and a secondary synchronization channel. The primary synchronization channel includes multiple types of sequences, and the secondary synchronization channel transmitted in a sector of a cell includes a code derived from a predefined generation polynomial equation corresponding to the primary synchronization channel.