Cross-Carrier CFI Configuration via RRC Signaling
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Solution Overview
Problem
The existing LTE-Advanced system faces challenges in managing Control Format Indicator (CFI) values during cross-carrier scheduling, leading to false detections and adverse effects on system performance due to the lack of effective CFI configuration management across component carriers.
Innovation Solution
The proposed method involves Radio Resource Control (RRC) configuring CFI values for cross-carrier scheduled component carriers using specific modes, such as configuring RRC signaling for each component carrier or subframe type, to manage CFI values independently or uniformly across carriers, ensuring accurate CFI indication and reducing false detections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If CFI values are not configured for cross-carrier scheduled component carriers, then the system complexity is reduced, but false detections occur and system performance deteriorates
Solution Approach 1:
The patent applies preliminary action by configuring CFI values through RRC signaling before cross-carrier scheduling operations occur. The network pre-configures CFI values for component carriers that will be cross-carrier scheduled, storing them in the UE's buffer. This advance configuration ensures that when cross-carrier scheduling happens, the UE already has the correct CFI values ready, eliminating false detections while maintaining clear management through predefined configuration rules.
2Measurement precision
If CFI values are configured for each component carrier, then CFI indication accuracy is improved, but signaling overhead increases
Solution Approach 1:
The patent applies local quality by configuring CFI values selectively based on specific conditions rather than uniformly for all component carriers. The network configures CFI values only for component carriers that meet specific criteria (e.g., those that will be cross-carrier scheduled), and uses different configuration approaches for different subframe types within carriers. This targeted configuration ensures accurate CFI indication where needed while minimizing unnecessary signaling overhead for carriers that don't require it.
3Ease of operation
If CFI values are configured uniformly across all component carriers, then configuration management is simplified, but false detections occur in cross-carrier scheduling scenarios
Solution Approach 1:
The patent applies dynamics by making the CFI configuration approach adaptive rather than static. The network dynamically selects whether to configure CFI values for specific component carriers based on the actual cross-carrier scheduling configuration. When cross-carrier scheduling is enabled for a component carrier, the network configures CFI values for it; when it's not enabled, no CFI configuration is performed. This dynamic approach maintains ease of operation through clear conditional rules while ensuring reliability by configuring CFI values only when actually needed for cross-carrier scheduling.
Data Source
AI summary
A method for transmitting control format indicator values includes RRC configuring CFI values and transmitting signalings related thereto with one of multiple modes. The modes include configuring one RRC signaling for each component carrier which can be cross-carrier scheduled for user equipment, to indicate a CFI value of each subframe of said component carrier; configuring one RRC signaling respectively for each of subframe types designated by all component carriers which can be cross-carrier scheduled for user equipment, to indicate a CFI value of each designated subframe type; configuring one RRC signaling respectively for each designated subframe type of each component carrier which can be cross-carrier scheduled for user equipment, to indicate a CFI value of each subframe type designated; and configuring one RRC signaling for each user equipment for which cross-carrier scheduling can be performed, to indicate the CFI values of all component carriers which can be cross-carrier scheduled.