Unlicensed Band Synchronization Signal Acquisition via PBCH Payload Timing
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Solution Overview
Problem
In wireless communication systems, especially those operating in unlicensed bands, base stations face challenges in consistently transmitting synchronization signals due to unavailability of the band, leading to difficulties in timing information acquisition for user equipment.
Innovation Solution
The method involves user equipment receiving synchronization signals/physical broadcast channel blocks in the unlicensed band, using timing information from the payload and demodulation reference signals, with the size of the payload determined by the numerology applied, to acquire frame, slot, or index timing information, and performing initial access based on this information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If base station transmits synchronization signals in unlicensed band, then user equipment can acquire timing information, but base station cannot consistently occupy the band due to unlicensed band availability issues
Solution Approach 1:
The base station performs channel sensing and prepares synchronization signal transmission in advance. The UE is pre-configured with candidate positions for SS/PBCH blocks and can perform blind detection at these positions, allowing timing information acquisition even when the base station cannot continuously occupy the band.
Solution Approach 2:
The system dynamically adapts to unlicensed band availability by allowing the base station to transmit synchronization signals only when the channel is available. The UE compensates for this dynamic behavior through blind detection at multiple candidate positions and uses numerology-based payload size determination to handle varying transmission conditions.
2Reliability
If base station transmits synchronization signals at multiple candidate positions, then user equipment can find timing information, but transmission overhead and complexity increase
Solution Approach 1:
The synchronization signal transmission is segmented into multiple SS/PBCH blocks at different candidate positions within a synchronization raster. Each block contains essential timing information, and the UE can select the first successfully detected block, dividing the complex acquisition task into manageable detection steps.
Solution Approach 2:
The SS/PBCH block structure is designed to be universal and self-contained, carrying multiple functions including timing information, numerology indication, and band availability signaling within a single block. This multi-functionality reduces the need for additional signaling mechanisms.
3Measurement precision
If payload size is increased to include more timing information, then timing acquisition accuracy improves, but processing time and complexity increase
Solution Approach 1:
The patent extracts only the essential timing information elements needed for initial access into the PBCH payload, such as system frame number and slot timing. Less critical information is either omitted or provided through separate signaling mechanisms, reducing payload size and processing requirements while maintaining sufficient precision for synchronization.
Solution Approach 2:
The payload size and content are dynamically adjusted based on the numerology applied to the unlicensed band. Different numerologies (subcarrier spacings) have different payload configurations optimized for their specific timing requirements, allowing efficient use of processing resources while maintaining appropriate precision for each scenario.
Data Source
AI summary
The present disclosure provides an operation method of a terminal and a base station in a wireless communication system supporting an unlicensed band, and an apparatus supporting same. As a specific example, the present disclosure comprises an operation method of a terminal and an operation method of a base station corresponding thereto, by which a terminal can obtain timing information relating to a unlicensed band on the basis of a PBCH payload in a synchronization signal/physical broadcast channel (SS/PBCH) block and a demodulation reference signal (DMRS) sequence for the PBCH.