PUCCH Format Selection for Periodic CSI Reporting
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Solution Overview
Problem
In wireless communication systems, particularly in LTE-Advanced with carrier aggregation, transmitting channel state information (CSI) from a large number of secondary cells to a base station using a primary cell's PUCCH/PUSCH leads to an excessively increased payload, inefficiently utilizing resources.
Innovation Solution
A method where a user equipment (UE) selects a PUCCH format supporting multiple periodic CSI reports based on predetermined thresholds and priorities, and transmits CSI reports and HARQ ACKs efficiently, using bundling and priority-based transmission to manage the payload effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a large number of secondary cells are configured in one primary cell for carrier aggregation, then the data transmission capacity is improved, but the payload of information on secondary cells transmitted through the primary cell's PUCCH/PUSCH is excessively increased
Solution Approach 1:
The patent divides the transmission of CSI information into two parts: periodic CSI reports transmitted through PUCCH and aperiodic CSI reports transmitted through PUSCH. This segmentation allows the system to handle large payload requirements by distributing information across different transmission channels with different capabilities.
Solution Approach 2:
The patent introduces dynamic selection between PUCCH and PUSCH for CSI transmission based on payload size, cell configuration, and traffic conditions. The system dynamically switches transmission modes to optimize the balance between capacity utilization and payload management, rather than using a fixed transmission method.
2Loss of information
If all periodic CSI reports from multiple secondary cells are transmitted through the primary cell's PUCCH, then complete channel state information is provided to the base station, but the PUCCH payload becomes excessively large reducing transmission efficiency
Solution Approach 1:
The patent segments CSI reporting into periodic reports on PUCCH and aperiodic reports on PUSCH. Periodic reports provide essential CSI information regularly, while aperiodic reports provide additional detailed information when needed, ensuring information completeness without overloading the PUCCH.
Solution Approach 2:
The patent uses the PUSCH as an intermediary channel to handle excessive CSI payload. When PUCCH payload exceeds thresholds, the system triggers aperiodic CSI reporting through PUSCH, which has higher payload capacity, thereby maintaining transmission efficiency while preserving information completeness.
3Quantity of substance
If a PUCCH format supporting multiple periodic CSI reports is selected, then the payload capacity is increased to accommodate more secondary cells, but the complexity of PUCCH format selection and management is increased
Solution Approach 1:
The patent changes the parameter of PUCCH format selection based on measurable conditions such as payload size thresholds, cell configuration counts, and channel conditions. This parameter-based selection approach automates the decision process and reduces complexity by using clear decision criteria rather than manual configuration.
Solution Approach 2:
The patent implements feedback mechanisms where the UE monitors payload size and transmission outcomes, and automatically adjusts PUCCH format selection and triggers aperiodic reporting accordingly. This closed-loop feedback reduces complexity by making the system self-adjusting based on actual transmission conditions.
4Productivity
If carrier aggregation with many secondary cells is implemented to improve data rate, then the system throughput is increased, but the resource utilization on the primary cell becomes inefficient due to excessive control information
Solution Approach 1:
The patent segments control information transmission between PUCCH and PUSCH, allowing efficient use of primary cell resources. By offloading excessive CSI payload to PUSCH transmissions, the primary cell's control channel capacity is preserved for essential signaling, improving overall resource utilization efficiency.
Solution Approach 2:
The patent dynamically adjusts the distribution of CSI transmission between PUCCH and PUSCH based on current system conditions, payload size, and resource availability. This dynamic adaptation optimizes resource utilization efficiency while maintaining the high throughput benefits of carrier aggregation with many secondary cells.
Data Source
AI summary
The present invention relates to a periodic channel state information (CSI) reporting method performed by a terminal in a wireless communication system, and provides a method comprising: determining whether to select a first physical uplink control channel (PUCCH) format; and if the first PUCCH format is selected, transmitting, on the basis of the first PUCCH format, a periodic CSI report and a hybrid automatic repeat request (HARQ) ACK, wherein the first PUCCH format is a PUCCH format supporting multiple periodic CSI reports.