Terminal Pathloss Calculation Using QCL Type A Reference Signals
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Solution Overview
Problem
In future radio communication systems, such as NR, the lack of clear pathloss reference signals (PL-RS) can lead to inadequate calculation of pathloss, resulting in poor UL signal transmission and system performance degradation, including decreased throughput.
Innovation Solution
A terminal equipped with a receiving section to receive configuration information and a control section that uses reference signals of QCL type A or D, depending on the transmission configuration indication state, for accurate pathloss calculation of uplink signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If QCL type D reference signal is not used as periodic reference signal in TCI state, then the system can support flexible beam management and spatial QCL, but pathloss calculation becomes unclear and UL signal transmission deteriorates
Solution Approach 1:
The patent introduces QCL type A reference signal as an intermediary to solve the pathloss calculation problem. When QCL type D reference signal is not periodic, the terminal uses QCL type A reference signal (which is periodic) as the pathloss reference signal. This intermediary approach allows the system to maintain both beam management flexibility and reliable pathloss calculation by using different reference signals for different purposes.
2Measurement precision
If the terminal uses QCL type A reference signal for pathloss calculation, then pathloss can be accurately calculated, but the system cannot utilize QCL type D for spatial QCL information
Solution Approach 1:
The patent segments the reference signal functions by introducing separate QCL type A and QCL type D reference signals. QCL type A reference signal is used specifically for pathloss calculation (periodic), while QCL type D reference signal is used for spatial QCL information (can be aperiodic). This segmentation allows both functions to be performed simultaneously without interference, resolving the contradiction between measurement precision and information loss.
3Reliability
If periodic reference signal is required for pathloss calculation, then accurate pathloss can be obtained, but system flexibility in reference signal configuration is reduced
Solution Approach 1:
The patent applies local quality by assigning different periodicity requirements to different reference signal types based on their specific functions. QCL type A reference signal is configured as periodic locally to ensure reliable pathloss calculation, while QCL type D reference signal can be configured flexibly (periodic or aperiodic) locally to support various beam management scenarios. This localized differentiation resolves the contradiction between reliability and flexibility.
Data Source
AI summary
A terminal according to one aspect of the present disclosure includes: a receiving section that receives configuration information related to an uplink signal; and a control section that uses, in a case where the configuration information satisfies an application condition and quasi-co-location (QCL) type D in a transmission configuration indication (TCI) state for a downlink channel is not a periodic reference signal, a reference signal of at least one of QCL type A and the QCL type D in the TCI state, for calculation of a pathloss of the uplink signal. According to one aspect of the present disclosure, it is possible to appropriately transmit a UL signal.