Aperiodic CSI Reporting via Reference Subframe Designation
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Solution Overview
Problem
In LTE TDD systems, dynamic changes in uplink-downlink subframe configurations lead to interference issues, preventing effective reporting of aperiodic channel state information (CSI) for certain downlink subframe sets due to the lack of available CSI measurement resources.
Innovation Solution
A base station device and user equipment method that allows for aperiodic CSI reporting by designating a reference subframe within the downlink subframe set for CSI measurement, ensuring that the base station receives the CSI measurement result, even when traditional CSI measurement resources are not available, by using higher layer signaling to notify the user equipment of the reference subframe.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If dynamic TDD subframe configuration is used to improve transmission efficiency and quality of service, then the system can adapt to varying traffic conditions, but interference occurs between uplink and downlink subframes of local and neighboring cells, preventing effective CSI reporting for certain downlink subframe sets
Solution Approach 1:
The patent divides downlink subframes into multiple sets (first downlink subframe set and second downlink subframe set) based on their interference characteristics with neighboring cells. Each set can be independently configured for CSI reporting, allowing the system to handle interfered and non-interfered subframes differently, thus resolving the contradiction between dynamic adaptation and interference avoidance.
2Device complexity
If traditional CSI measurement resources are used in dynamic TDD configurations, then the measurement process remains simple, but available CSI measurement subframe resources are insufficient when downlink subframes are interfered with by uplink subframes
Solution Approach 1:
The patent pre-configures multiple downlink subframe sets and establishes corresponding CSI reporting configurations before actual CSI reporting occurs. The base station notifies the UE of the reference subframe through higher layer signaling in advance, allowing the UE to prepare appropriate measurement resources and reporting strategies before interference conditions arise, thus maintaining simple measurement processes while ensuring sufficient measurement resources.
3Loss of information
If aperiodic CSI reporting is triggered for all downlink subframes, then complete channel state information is obtained, but the timing relationship between triggering and reporting cannot be established when no suitable measurement subframe is available
Solution Approach 1:
The patent introduces a reference subframe concept that acts as an intermediary between the triggered aperiodic CSI and the actual measurement reporting. When a downlink subframe is interfered with, the system identifies a suitable reference subframe from the same or different subframe set that can serve as the measurement basis, allowing the timing relationship to be established through this intermediate reference point while maintaining complete CSI information.
Data Source
AI summary
A base station device, user equipment, and a method for reporting channel state information are disclosed. The base station device receives at least one piece of aperiodic channel state information (CSI) from user equipment, where the at least one piece of aperiodic CSI corresponds to an aperiodic CSI measurement result on a first reference subframe, the aperiodic CSI measurement result on the first reference subframe is an aperiodic CSI measurement result of a first downlink subframe set, and the first reference subframe is a subframe in the first downlink subframe set. The base station device effectively receives an aperiodic channel state measurement result of the downlink subframe set.