Aperiodic CSI Requests Across Aggregated LTE Component Carriers
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Solution Overview
Problem
In LTE systems, there is a need for methods and apparatuses to determine which component carriers (CCs) a user equipment (UE) should provide channel state information (CSI) reports for, especially when carrier aggregation is supported with multiple CCs, as existing methods are inadequate for aperiodic CSI reporting across multiple CCs.
Innovation Solution
The UE determines the set of CCs for CSI reporting based on various methods, including bitmaps, subframe and system frame number mapping, cyclic shifts of demodulation reference signals, carrier indicator fields, and redefined resource allocation fields in the DCI format, to accurately convey CSI reports for the appropriate CCs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single UL CC is used for aperiodic CSI reporting for multiple DL CCs, then resource utilization is improved, but the ability to determine which specific DL CCs require CSI reporting becomes complex
Solution Approach 1:
The patent implements feedback mechanisms where the network signals CSI reporting configurations to the UE, and the UE provides CSI feedback for specific DL CCs based on this configuration. This resolves the contradiction by automating the determination process through structured feedback loops, allowing efficient resource utilization on a single UL CC while eliminating the complexity of manual determination for multiple DL CCs.
Solution Approach 2:
The patent introduces configurable parameters such as CSI reporting offsets, periodicities, and triggering conditions that can be dynamically adjusted. These parameter changes enable flexible control over which DL CCs require CSI reporting on the single UL CC, resolving the determination complexity while maintaining efficient resource utilization.
2Productivity
If carrier aggregation with multiple CCs is implemented, then system capacity is improved, but the overhead for managing CSI reporting across multiple CCs increases
Solution Approach 1:
The patent merges CSI reporting for multiple DL CCs into a single UL CC, consolidating what would otherwise be separate reporting channels. This combining approach maintains the high system capacity enabled by carrier aggregation while significantly reducing the signaling overhead that would result from managing separate CSI reporting for each CC.
Solution Approach 2:
The patent creates a universal CSI reporting mechanism on the UL CC that can handle multiple DL CCs through configurable parameters and triggers. This multi-functional approach allows a single reporting channel to serve multiple purposes, reducing overhead while supporting the enhanced capacity of carrier aggregation.
3Measurement precision
If aperiodic CSI reporting is used for multiple CCs, then reporting accuracy is improved, but the complexity of managing reporting triggers and timing increases
Solution Approach 1:
The patent implements preliminary configuration of CSI reporting parameters, triggers, and timing relationships before actual CSI reporting occurs. By pre-configuring which DL CCs should trigger CSI reporting on the UL CC and establishing timing relationships in advance, the system achieves accurate aperiodic reporting while reducing the complexity of real-time management.
Solution Approach 2:
The patent introduces dynamic triggering mechanisms where CSI reporting on the UL CC is activated based on real-time conditions such as scheduling decisions, channel changes, or network requests. This dynamic approach maintains high reporting accuracy by adapting to current conditions while simplifying management through event-driven operation rather than complex predetermined schedules.
Data Source
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AI summary
A method, computer program product, and apparatus are provided in which a request for a channel state information (CSI) report is received on a component carrier of a plurality of component carriers. The request indicates a set of component carriers of the plurality of component carriers for which to provide the CSI report. In addition, a CSI report including feedback for each of the indicated component carriers in the set of component carriers is transmitted. A method, computer program product, and apparatus are provided in which a request for a CSI report on a component carrier of a plurality of component carriers is transmitted. The request indicates a set of component carriers of the plurality of component carriers for which to receive the CSI report. In addition, a CSI report including feedback for each of the indicated component carriers in the set of component carriers is received.