SSB QCL Indication in NR-U Under SIB1 Association Constraints
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Solution Overview
Problem
In New Radio (NR)-based access to unlicensed spectrum (NR-U) systems, determining the Quasi-Co-Located (QCL) relationship between Synchronization Signal Blocks (SSBs) is challenging when an SSB is not associated with System Information Block 1 (SIB1), as existing methods require additional bits in the Physical Broadcast Channel (PBCH) to indicate the QCL parameter, leading to resource inefficiency and potential LBT failures.
Innovation Solution
The network device indicates the QCL parameter through specific bit fields in the PBCH, such as the SSB-SubcarrierOffset and pdcch-ConfigSIB1 information fields, depending on the association with SIB1, ensuring efficient indication of the QCL parameter and frequency-domain position of associated SSBs, thereby improving system performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If additional bits are added in PBCH to indicate QCL parameter for SSB not associated with SIB1, then QCL relationship determination accuracy is improved, but PBCH resource consumption increases
Solution Approach 1:
The patent applies different indication methods for different cases of SSB-SIB1 association. When SSB is associated with SIB1, QCL parameter is indicated using existing bit fields. When SSB is not associated with SIB1, the patent uses a specific indication manner involving SSB-SubcarrierOffset and pdcch-ConfigSIB1 information fields. This localized differentiation avoids uniformly increasing bits for all cases, thus resolving the contradiction between accuracy and resource consumption.
2Quantity of substance
If existing indication methods are used for QCL parameter, then PBCH resource utilization is maintained, but terminal device may fail to correctly receive QCL indication information
Solution Approach 1:
The patent changes the indication parameter selection based on the SSB-SIB1 association status. The network device determines which indication manner to use (first or second) depending on whether the SSB is associated with SIB1. This dynamic parameter selection ensures reliable QCL indication while maintaining efficient PBCH resource utilization, resolving the contradiction between resource efficiency and reception reliability.
Data Source
AI summary
Provided are a wireless communication method, a network device, and a terminal device. The network device may indicate a Quasi-Co-Located (QCL) parameter in different indication manners according to whether a Synchronization Signal Block (SSB) is associated with System Information Block 1 (SIB1), which is favorable for ensuring that the terminal device correctly receives QCL indication information. The method includes that: a network device determines SIB1 association indication information of a first SSB, the SIB1 association indication information being configured to indicate whether the first SSB is associated with SIB1; the network device determines whether the first SSB bears indication information of a QCL parameter and/or an indication manner for the QCL parameter in the first SSB based on whether the first SSB is associated with SIB1; and the network device sends the first SSB.