Cross-Carrier Scheduling Cell Group Selection
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Solution Overview
Problem
The existing systems face performance degradation when cross-carrier scheduling (CCS) and Physical Uplink Control Channel (PUCCH) on Secondary Cells (SCell) are employed simultaneously, leading to uncertainty about which cell should send uplink control information feedback, potentially decreasing overall system performance.
Innovation Solution
A user terminal is designed to receive downlink signals and select the appropriate cell for uplink control signal transmission based on whether the cross-carrier scheduling information is within the same cell group, ensuring accurate cell selection and reducing performance loss by determining if the cell receiving the PDCCH and the cell designated by CCS belong to the same cell group.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If cross-carrier scheduling and PUCCH on SCell are employed simultaneously, then resource allocation flexibility is improved, but system performance deteriorates due to uncertainty in UCI feedback transmission
Solution Approach 1:
The patent applies local quality by differentiating the feedback transmission behavior based on the cell group relationship. When the scheduled cell and scheduling cell belong to the same cell group, UCI is transmitted on the scheduled cell's PUCCH. When they belong to different cell groups, UCI is transmitted on the scheduling cell's PUCCH. This localized differentiation resolves the ambiguity while maintaining the flexibility of simultaneous CCS and PUCCH on SCell operation.
2Reliability
If cross-carrier scheduling information is transmitted via PDCCH on another cell, then control signal stability is improved, but cell selection complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-establishing the cell group affiliation information for each cell before cross-carrier scheduling operations. The user terminal and base station both have predetermined knowledge of which cells belong to which cell groups. When cross-carrier scheduling occurs, the terminal can immediately determine the appropriate PUCCH transmission cell by comparing the cell group affiliations, without requiring complex real-time analysis or additional signaling.
Data Source
Figure 1A~1B
Figure 2
Figure 3A~3B
AI summary
The present invention is designed to that the decrease of overall system performance can be reduced even when cross-carrier scheduling (CCS) and uplink control signal transmission in secondary cells are employed at the same time. A user terminal (20) according to an embodiment of the present invention provides a user terminal that communicates with a plurality of cell groups (CG), each group being formed with one or more cells to use different frequency bands, and that has a receiving section (203) that receives downlink signals transmitted from each cell, and a control section (401) that selects at least one cell, from the cells where uplink control signals can be allocated, which are configured in each CG, and controls the cell as a cell to transmit the uplink control signals, and, when information to indicate CCS is included in a downlink control signal that is received in the receiving section, the control section decides whether or not the cell having received the downlink control signal and the cell that is designated by the information to indicate CCS belong to the same CG, and selects the cell based on this decision.