CSI Reporting Latency Reduction via Dynamic Reference Resource Selection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current LTE systems face challenges in reducing latency for channel state information (CSI) reporting, which affects the efficiency of data transmission and channel adaptation.
Innovation Solution
The method involves deriving channel state information based on different reference resources depending on whether the operation corresponds to regular or reduced latency based operations, and reporting this information to the network.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If traditional LTE CSI reporting procedures are used, then reporting accuracy is maintained, but reporting latency increases
Solution Approach 1:
The patent performs preliminary actions by determining the relationship between downlink and uplink timing ahead of time, and pre-configuring reference resource sets for different TTI lengths. This allows the UE to quickly select appropriate reference resources when CSI reporting is triggered, avoiding time-consuming calculations at reporting moment and thus reducing reporting latency while maintaining accuracy.
Solution Approach 2:
The patent introduces dynamic adaptability by configuring multiple reference resource sets corresponding to different TTI lengths and allowing the UE to dynamically select the appropriate reference resource based on the actual TTI length of the triggered CSI report. This dynamic selection mechanism enables the system to adapt to varying latency requirements while maintaining measurement precision through appropriate reference resource selection.
2Speed
If TTI length is reduced for faster reporting, then latency is reduced, but timing synchronization becomes more difficult
Solution Approach 1:
The patent performs preliminary timing relationship determination between downlink and uplink before CSI reporting is triggered. By pre-establishing the timing offset K1 and selecting reference resources based on predetermined TTI length relationships, the system simplifies the timing synchronization process for reduced TTI lengths, making faster reporting achievable without proportionally increasing synchronization complexity.
Solution Approach 2:
The patent changes the timing parameter K1 (offset between downlink grant and uplink CSI report) based on TTI length. By adjusting this parameter to account for reduced processing time in shorter TTIs, the system maintains proper timing synchronization while enabling faster reporting speeds. This parameter adaptation resolves the conflict between speed and synchronization complexity.
3Measurement precision
If multiple reference resource sets are configured for different TTI lengths, then reporting accuracy is improved, but configuration complexity increases
Solution Approach 1:
The patent segments the reference resources into multiple distinct sets, each corresponding to a specific TTI length. This segmentation allows the UE to select the most appropriate reference resource set for the current reporting scenario, ensuring measurement accuracy by using reference resources that match the actual TTI length characteristics, while the modular structure manages configuration complexity through organized grouping.
Solution Approach 2:
The patent creates a universal reference resource configuration framework that serves multiple TTI length requirements through a single configuration mechanism. By designing reference resource sets that can be universally applied across different TTI lengths with systematic indexing and selection rules, the system achieves multi-functionality that improves measurement accuracy for various scenarios while avoiding the need for entirely separate configurations for each TTI length.
Data Source
AI summary
A configuration can be received that configures a UE with a single configured CSI process for a serving cell. A highest CQI index value can be derived for which a single PDSCH TB with a combination of corresponding modulation scheme and TB size is received with a TB error probability not exceeding a target TB BLER value. The single PDSCH transport block can occupy a CSI reference resource. A CSI request can be received in either a subslot or a subframe. The CSI reference resource can be defined by the subslot in which the CSI request is received if the CSI request is received in the subslot. The CSI reference resource can be defined by the subframe in which the CSI request is received if the CSI request is received in the subframe.