Quasi-Colocation Signaling for Wireless Device Control Signal Reception
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Solution Overview
Problem
In New Radio (NR) networks, user equipment (UE) faces challenges in assuming quasi-colocation (QCL) between system synchronization blocks (SSB) and other control signals, leading to suboptimal energy efficiency and performance due to varying network deployments, where QCL assumptions may not always be valid.
Innovation Solution
The proposed solution involves signaling the QCL status between reference signals and control signals to UE, allowing it to optimize control signal reception by using or ignoring QCL assumptions based on received configuration, thereby maximizing energy efficiency and performance in various deployments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If UE assumes QCL between SSB and control signals, then detection performance improves, but energy efficiency deteriorates when QCL assumption is invalid
Solution Approach 1:
The UE dynamically adjusts its QCL assumption behavior based on received indication information. When the indication suggests QCL is valid, the UE uses QCL assumptions to improve detection performance. When the indication suggests QCL is invalid, the UE ignores QCL assumptions to avoid performance degradation, thereby optimizing energy efficiency. This dynamic adaptation resolves the contradiction between detection performance and energy efficiency.
2Device complexity
If UE uses QCL assumptions for control signal reception, then processing complexity reduces, but reliability deteriorates when QCL is not valid
Solution Approach 1:
The network provides indication information as feedback to the UE regarding whether QCL assumptions are valid for control signal reception. The UE uses this feedback to determine whether to apply QCL assumptions. When feedback indicates QCL is valid, the UE uses QCL to reduce processing complexity. When feedback indicates QCL is invalid, the UE ignores QCL to maintain reception reliability, thus resolving the contradiction between processing complexity and reliability.
3Productivity
If network provides QCL indication signaling, then UE reception optimization improves, but signaling overhead increases
Solution Approach 1:
The network changes the parameter of QCL indication signaling by providing explicit indication information about QCL validity. This parameter change enables the UE to optimize its reception strategy appropriately. The indication signaling, while adding some overhead, provides critical information that allows the UE to avoid unnecessary processing when QCL is invalid or to apply QCL optimizations when valid, thereby improving overall reception productivity relative to the signaling overhead incurred.
Data Source
AI summary
According to some embodiments, a method for use in a network node comprises: determining a quasi-colocation (QCL) status between a reference signal (e.g., initial access signal such as system synchronization block (SSB), or a tracking reference signal (TRS)) and a control signal (e.g., a paging signal, a random access response (RAR), or a channel such as physical downlink control channel (PDCCH) or physical downlink shared channel (PDSCH)); and signaling the QCL status to a wireless device. A method for use in a wireless device may comprise: receiving a QCL status between a reference signal and a control signal; receiving the reference signal; estimating one or more signal parameters based on the received reference signal; and when the reference signal and the control signal are QCL, receiving the control signal using the estimated signal parameters to optimize reception of the control signal.