SS/PBCH Block Reception in Unlicensed Bands via Valid Bit Rate Matching
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Solution Overview
Problem
Current 5G technologies face challenges in efficiently transmitting and receiving synchronization signal blocks in unlicensed bands, particularly in ensuring reliable communication for applications like virtual reality, augmented reality, automotive systems, smart cities, and industrial uses, which require low latency and high reliability.
Innovation Solution
A method and device for receiving a synchronization signal/physical broadcast channel (SS/PBCH) block in an unlicensed band, where a user equipment (UE) receives information on an actually transmitted SS/PBCH block and interprets valid bits to perform rate matching or mapping, ensuring efficient communication with base stations, other UEs, or autonomous driving vehicles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If synchronization signal blocks are transmitted in unlicensed bands using conventional methods, then transmission coverage is provided, but communication reliability and latency performance deteriorate for 5G applications
Solution Approach 1:
The synchronization signal block transmission is segmented into multiple candidate blocks with different time offsets. Instead of transmitting a single synchronization block, the system divides the transmission into multiple candidates (e.g., first candidate SSB, second candidate SSB) with predetermined time offsets, allowing the receiver to select the most reliable one based on channel conditions.
Solution Approach 2:
The transmission scheme dynamically adapts by indicating to the user equipment which candidate synchronization signal block was actually transmitted. This dynamic indication allows the system to flexibly handle varying channel conditions in unlicensed bands, improving reliability without requiring a fixed, complex transmission structure.
2Reliability
If multiple candidate synchronization signal blocks are transmitted with different time offsets, then communication reliability improves, but transmission time and complexity increase
Solution Approach 1:
Multiple candidate synchronization signal blocks are prepared in advance with predetermined time offsets before transmission. The transmission time offsets are pre-configured, allowing the receiver to efficiently search and identify the correct candidate without requiring extensive real-time processing, thus limiting time loss.
Solution Approach 2:
Instead of creating entirely different synchronization blocks, the system uses identical or similar synchronization signal content across multiple candidates, varying only the time offsets. This copying approach maintains reliability through redundancy while minimizing the additional time and processing required compared to creating unique blocks.
3Loss of time
If the index of actually transmitted synchronization signal block is indicated to user equipment, then latency performance improves, but device complexity increases
Solution Approach 1:
The indication of which candidate synchronization signal block was transmitted is extracted as a separate information element. This extracted indication is conveyed to the user equipment through dedicated signaling, allowing the receiver to quickly identify the correct candidate without having to decode complex modulation or perform extensive signal processing, thus reducing latency.
Solution Approach 2:
An indication mechanism acts as an intermediary between the transmitter and receiver for synchronization block identification. This intermediary provides a direct and efficient path for conveying which candidate block was transmitted, simplifying the overall system by providing a dedicated channel for this specific information rather than embedding it within the synchronization signal itself.
Data Source
AI summary
Disclosed is a method by which a terminal receives a synchronization signal/physical broadcast channel (SS/PBCH) block in an unlicensed band. Particularly, the method comprises: receiving information related to an actual transmitted SS/PBCH block (ATSS) transmitted by a base station; and receiving the SS/PBCH block on the basis of valid bits from among a plurality of bits included in the information related to the ATSS, wherein the number of valid bits can be based on an interval value between SS/PBCH blocks capable of assuming a quasi co-location (QCL).