User Terminal PUCCH Resource Allocation for Cross-Carrier Scheduling
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Solution Overview
Problem
The existing systems face a performance decrease when cross-carrier scheduling (CCS) and physical uplink control channel (PUCCH) on secondary cells (SCells) are employed simultaneously, as there is no established method for determining PUCCH resources, leading to potential collisions and reduced overall system performance.
Innovation Solution
A user terminal is designed to determine PUCCH resources based on whether the PDCCH-receiving cell and the PUCCH-transmitting cell are the same, using either CCE or ARI indices, depending on this decision, to allocate PUCCH resources effectively, even when CCS spans across multiple cell groups.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If cross-carrier scheduling (CCS) and PUCCH on SCell are employed simultaneously, then system functionality and flexibility are improved, but PUCCH resource allocation becomes uncertain leading to resource collisions and performance degradation
Solution Approach 1:
The patent changes the parameter of PUCCH resource determination by introducing a conditional approach: when the PDCCH-receiving cell and PUCCH-transmitting cell are in the same cell group, use CCE index; when in different cell groups, use ARI index. This parameter change resolves the resource allocation uncertainty while maintaining system flexibility.
Solution Approach 2:
The patent implements dynamic resource allocation by making the PUCCH resource determination method adaptable to different cell group configurations. The system dynamically selects between CCE-based and ARI-based resource determination based on whether cells are in the same or different cell groups, preventing resource collisions while maintaining versatility.
2Adaptability or versatility
If PUCCH resources are determined without established methods, then implementation flexibility is maintained, but resource collisions occur reducing system performance
Solution Approach 1:
The patent applies preliminary anti-action by pre-establishing conditional rules to prevent PUCCH resource collisions before they occur. By defining clear determination methods based on cell group relationships, the system proactively avoids resource conflicts rather than reacting to them after occurrence.
Solution Approach 2:
The patent changes the resource determination parameter from undefined to conditionally-defined, using CCE index for same-cell-group scenarios and ARI index for different-cell-group scenarios. This parameter change eliminates implementation flexibility while preventing harmful resource collisions.
3Measurement precision
If conditional resource determination is implemented, then PUCCH resource allocation accuracy is improved, but device complexity increases
Solution Approach 1:
The patent segments the PUCCH resource determination process into two distinct conditional paths: one for cells in the same cell group (using CCE index) and another for cells in different cell groups (using ARI index). This segmentation improves allocation accuracy by matching the appropriate method to each scenario while keeping each individual path relatively simple.
Solution Approach 2:
The patent implements dynamic conditional determination that adapts the resource allocation method based on cell group relationships. While this adds conditional logic complexity, it achieves high allocation accuracy by selecting the appropriate determination method (CCE or ARI) based on the specific scenario.
Data Source
Figure 1A~1B
Figure 2
Figure 3A~3B
AI summary
The present invention is designed so 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 cells to which uplink control signals can be allocated, and which are configured in each CG, and controls the cell as a cell to transmit an uplink control signal, and, when information to indicate CCS is include 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 to transmit the uplink control signal are the same, and determines the resource to allocate to the uplink control signal based on this decision.