LTE Channel State Information Transmission via Dynamic PUCCH Resource Selection
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Solution Overview
Problem
In LTE systems with carrier aggregation, multiple pieces of channel state information (CSI) cannot be simultaneously transmitted due to limited capacity of the physical uplink control channel (PUCCH), leading to reduced downlink data scheduling performance.
Innovation Solution
A method where user equipment (UE) determines an uplink subframe and channel resource to send feedback information, allowing multiple pieces of CSI to be transmitted by utilizing a second uplink channel resource with a larger codebook size, enabling simultaneous transmission of CSI across multiple carriers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiple pieces of periodic CSI are simultaneously configured in a same subframe, then the feedback coverage is improved, but the PUCCH capacity is exceeded causing CSI to be discarded or feedback period to be prolonged
Solution Approach 1:
The patent segments the feedback information by dividing it into two types: Type 1 feedback (ACK/NACK and first CSI) and Type 2 feedback (second CSI). This segmentation allows different feedback types to be handled through different mechanisms, enabling multiple CSI pieces to be transmitted simultaneously without exceeding PUCCH capacity constraints.
Solution Approach 2:
The patent introduces dynamic selection of PUCCH resources based on the type of feedback information. UE dynamically selects between first PUCCH resources (for Type 1 feedback) and second PUCCH resources (for Type 2 feedback) depending on the scheduling situation and feedback requirements, allowing flexible adaptation to different CSI transmission scenarios.
2Productivity
If only one piece of CSI is reported per subframe due to PUCCH capacity restrictions, then the PUCCH load is controlled, but the downlink data scheduling performance is lowered
Solution Approach 1:
The patent merges multiple feedback elements (ACK/NACK and multiple CSI pieces) into a unified feedback mechanism. By combining Type 1 and Type 2 feedback with appropriate multiplexing and resource allocation, the system can transmit multiple CSI pieces simultaneously while controlling PUCCH load, thereby improving downlink data scheduling performance.
Solution Approach 2:
The patent introduces an intermediary mechanism through the gNB's scheduling decisions and resource allocation. The gNB acts as an intermediary by determining which feedback type to request, allocating appropriate PUCCH resources, and coordinating between UE feedback capabilities and network requirements, enabling efficient transmission of multiple CSI pieces.
3Productivity
If more carriers are introduced to the CA system to increase data transmission rate, then the service coverage is improved, but the PUCCH capacity is further restricted due to increased ACK/NACK information
Solution Approach 1:
The patent creates a universal feedback framework that works across multiple carriers with different configurations. The Type 1 and Type 2 feedback mechanisms are designed to be carrier-agnostic, allowing the same PUCCH resource allocation and feedback processing to handle ACK/NACK and CSI from any number of aggregated carriers, thus supporting higher data transmission rates without proportionally increasing PUCCH complexity.
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AI summary
Embodiments of the present invention provide a channel state information transmission method, user equipment, and an access network device, to resolve at least a prior-art problem that multiple pieces of CSI cannot be simultaneously transmitted. The method includes: receiving, by UE, downlink data from an access network device; determining, by the UE, an uplink subframe used to send feedback information of the downlink data, where a first downlink subframe set associated with the uplink subframe includes a first subset and a second subset, and the first subset is a proper subset of the second subset; determining, by the UE, a channel resource used to send the feedback information, where the channel resource includes a first uplink channel resource or a second uplink channel resource; and if sending of r pieces of CSI is configured in the uplink subframe for the UE, a codebook size of the feedback information corresponds to the first subset, and the channel resource determined by the UE is the second uplink channel resource, sending, by the UE, the feedback information and t pieces of CSI of the r pieces of CSI on the second uplink channel resource.