Dynamic PUCCH Format Selection for Expanded Carrier Aggregation
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Solution Overview
Problem
In existing LTE systems, the number of component carriers that can be configured per user terminal is limited, which restricts the potential for high-speed wireless communication, and the use of new PUCCH formats for uplink control information feedback has not been adequately addressed, leading to issues such as throughput reduction and communication quality deterioration.
Innovation Solution
A method for dynamically selecting and using multiple PUCCH formats and resources based on predetermined conditions, such as the number of cells and payload size, to effectively feed back uplink control information even when the number of component carriers is expanded beyond the existing limit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of component carriers is increased beyond five to enable ultra wideband unlicensed band operation, then the achievable peak rates are dramatically improved, but the existing PUCCH formats and resources become insufficient for feeding back uplink control information
Solution Approach 1:
The patent implements dynamic PUCCH format selection based on the number of component carriers. When the number of CCs exceeds a predetermined threshold (e.g., five), the system automatically switches from first PUCCH formats to second PUCCH formats that support larger payload sizes. This dynamic adaptation resolves the contradiction by adjusting the control channel capacity to match the data throughput requirements of expanded carrier aggregation.
Solution Approach 2:
The system changes the PUCCH format parameters (specifically the payload size capacity) based on the number of configured component carriers. The base station configures different PUCCH formats with different capacity characteristics, and the user terminal selects the appropriate format based on the current CC count. This parameter change enables the control information feedback mechanism to scale with the data channel capacity.
2Reliability
If multiple PUCCH formats are introduced to support expanded carrier aggregation, then uplink control information feedback capability is improved, but the device complexity and resource management burden increase
Solution Approach 1:
The base station performs preliminary configuration of multiple PUCCH formats and their corresponding resources before the user terminal needs to transmit uplink control information. The network side pre-defines the mapping between component carrier counts and appropriate PUCCH formats, so that when data transmission begins, the terminal can immediately select the correct format without complex real-time decision-making. This preliminary setup reduces the operational complexity during actual communication.
Solution Approach 2:
The system implements a feedback mechanism where the base station receives information about the number of configured component carriers from the user terminal, and based on this feedback, determines and notifies the appropriate PUCCH format for control information transmission. This closed-loop feedback approach ensures that the control channel capacity matches the actual data transmission requirements while maintaining manageable complexity through centralized control.
Data Source
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AI summary
The present invention is designed so that uplink control information can be fed back adequately even when the number of component carriers that can be configured in a user terminal is expanded from that of existing systems. A user terminal according to one aspect of the present invention, in which a plurality of component carriers can be configured, has a receiving section that receives downlink control information and/or RRC (Radio Resource Control) signaling, a transmission section that transmits uplink control information (UCI), which includes at least delivery acknowledgment information, in a specific resource, by using a specific PUCCH format (PF: Physical Uplink Control Channel Format), and a control section that selects the specific PF and the specific resource based on a payload size of at least a part of the UCI.