Terminal Pathloss Reference Signal Selection for Uplink Power Control
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Solution Overview
Problem
In future radio communication systems, such as NR, the limited number of candidates for power control parameters for uplink transmissions (e.g., PUCCH, PUSCH, SRS) indicated by downlink control information (DCI) can lead to deterioration of system performance if not appropriately determined.
Innovation Solution
A terminal that determines a reference signal for pathloss reference for the PUSCH based on the reception of a MAC CE or the transmission of a random access channel, and transmits the PUSCH using transmission power based on this reference signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the number of candidates for power control parameters is limited as indicated by DCI, then the device complexity is reduced, but the system performance deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-configuring multiple pathloss reference signals (PL-RS) with different pathloss values before transmission. The network pre-assigns these reference signals to different spatial relations or beams, allowing the terminal to quickly select from pre-prepared options without complex real-time calculations, thus maintaining low device complexity while ensuring optimal power control for different transmission scenarios
Solution Approach 2:
The patent implements dynamics by enabling the terminal to dynamically select among multiple pre-configured pathloss reference signals based on current transmission conditions. The terminal can switch between different PL-RS candidates depending on the spatial relation, beam direction, or channel conditions, making the power control adaptable to changing environments without increasing the number of candidates indicated by DCI
2Device complexity
If the parameter for transmission power control is not appropriately determined, then the device complexity is reduced, but the system performance deteriorates
Solution Approach 1:
The patent applies feedback by using pathloss measurements from reference signals to determine appropriate transmission power. The terminal measures the pathloss based on received reference signals (such as CSI-RS or SSB) and feeds this information back into the power control calculation. This feedback mechanism ensures that the transmission power is appropriately determined based on actual channel conditions without requiring complex device processing
Solution Approach 2:
The patent implements parameter changes by allowing the pathloss reference signal parameter to change based on different transmission scenarios. The network can configure multiple PL-RS with different reference signal IDs, and the terminal selects the appropriate one based on the current spatial relation or beam. This parameter flexibility enables appropriate power control determination without increasing device complexity
Data Source
AI summary
A terminal according to one aspect of the present disclosure includes: a control section that determines a reference signal for pathloss reference for a physical uplink shared channel (PUSCH), based on any one of reception of a medium access control control element (MAC CE) and transmission of a random access channel; and a transmitting section that transmits the PUSCH by using transmission power based on the reference signal for pathloss reference. According to one aspect of the present disclosure, a parameter for transmission power control can be appropriately determined.