IoT Synchronization Channel Segmentation for Shared Spectrum

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Solution Overview

Problem

Existing wireless communication systems face challenges in efficiently transmitting synchronization signals over shared spectra, particularly for Internet of Things (IoT) communications, where narrowband receivers may struggle to receive synchronization signals that occupy more than one resource block.

Innovation Solution

The proposed solution involves dividing the bandwidth allocated to synchronization signals into multiple resource blocks and transmitting variants of a base synchronization sequence over these blocks. This allows narrowband user equipment (UE) to receive and synchronize with a serving cell by obtaining system acquisition information from any one resource block, while UEs capable of receiving multiple blocks can combine them for improved accuracy and reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If synchronization signals are transmitted over multiple resource blocks to meet regulatory bandwidth requirements, then the bandwidth coverage and signal robustness are improved, but narrowband UEs cannot receive the full synchronization signal

Engineering Contradiction:
Improvebandwidth coverageVSAvoidcompatibility with narrowband UEs
Core Design Contradiction:
Area of stationary objectVSAdaptability or versatility

Solution Approach 1:

The synchronization signal is segmented into multiple parts, each transmitted over a different resource block. Each resource block contains a complete or partial synchronization sequence that can be independently received and processed by UEs, allowing narrowband UEs to acquire synchronization information from a single resource block while wideband UEs can utilize multiple resource blocks for enhanced performance

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different resource blocks are designed with specific local characteristics optimized for different UE types. Each resource block contains synchronization sequences with properties suitable for its specific frequency location, enabling UEs to receive adequate synchronization information from any single resource block regardless of their bandwidth capability

Inventive Principle:
Principle #3Local quality

2Reliability

If synchronization sequences are designed for robustness with large frequency offset using interleaved ZC sequences, then the signal reliability is improved, but the sequence length and processing complexity increase

Engineering Contradiction:
Improvesignal robustnessVSAvoidsequence processing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The robust synchronization sequence is divided into multiple segments, with each segment transmitted over a separate resource block. This segmentation reduces the processing complexity for narrowband UEs that only need to process one segment, while maintaining the overall robustness through the distributed structure across multiple resource blocks

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Narrowband UEs perform partial action by processing only a single resource block containing a segment of the synchronization sequence, which is sufficient for their needs. Wideband UEs can perform excessive action by combining multiple resource blocks to achieve enhanced robustness and accuracy

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP3639418B1Synchronization channel and system acquisition for internet of things communications in a shared spectrum
Publication Date: 2025.06.18 QUALCOMM INC
  • EP3639418B1 patent drawingFigure 1
  • EP3639418B1 patent drawingFigure 2
  • EP3639418B1 patent drawingFigure 3A~3B

AI summary

Methods, systems, and devices for wireless communication are described. A base station may identify a first synchronization sequence and generate a second synchronization sequence based at least in part on the first synchronization sequence. The base station may map the first synchronization sequence to a first resource block of a synchronization channel associated with a first frequency sub-band of a shared radio frequency spectrum band and the second synchronization sequence to a second resource block associated with a second frequency sub-band of the synchronization channel. The base station may then transmit the first synchronization sequence and the second synchronization sequence concurrently over the synchronization channel using the first resource block and the second resource block according to the mapping. In some cases, the second synchronization may be generated by applying a first phase shift to the first synchronization sequence.