Multi-Configuration CSI Reporting Complexity Reduction
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Solution Overview
Problem
Current CSI reporting mechanisms in LTE Rel-13 require significant computational complexity for UEs configured with multiple CSI processes, especially during aperiodic reporting, as they need to compute and transmit CSI reports for both Class A and Class B configurations within a single CSI process, leading to increased overhead and complexity.
Innovation Solution
The method involves configuring a wireless device with multiple CSI reporting configurations, allowing it to compute and report CSI feedback for only one configuration at a time, with primary configurations taking precedence over subordinate ones, and enabling the eNB to request CSI reports for a single CSI process or resource, reducing computational complexity and overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a UE is configured with multiple CSI processes (Class A and Class B) to support rich CSI feedback with multiple ports and codebooks, then the CSI feedback capability is improved, but the computational complexity in the UE increases significantly
Solution Approach 1:
The patent segments the CSI feedback capability into two separate reporting mechanisms: one for Class A CSI processes and another for Class B CSI processes. Each segment can be independently configured and reported, allowing the UE to handle them separately rather than computing all CSI reports simultaneously, thus reducing computational complexity while maintaining versatile CSI feedback capability.
Solution Approach 2:
The patent introduces dynamic switching between different CSI reporting configurations based on eNB requests and channel conditions. The UE can dynamically select which CSI process (Class A or Class B) to report based on current operational requirements, allowing flexible adaptation without maintaining full computational capability for all configurations simultaneously.
2Loss of information
If the UE computes and transmits CSI reports for both Class A and Class B configurations within a single CSI process, then comprehensive CSI coverage is achieved, but the reporting overhead and processing time increase
Solution Approach 1:
The patent implements periodic reporting mechanisms where Class A and Class B CSI reports are transmitted at different periodicities. Class A reports can be transmitted less frequently with longer periodicity, while Class B reports are transmitted more frequently with shorter periodicity. This allows comprehensive CSI coverage to be maintained over time while reducing the immediate processing burden and reporting overhead at any single time instant.
3Measurement precision
If two CSI processes are used to support Hybrid CSI reporting, then accurate beamforming weights can be determined, but the UE must calculate CSI for two reports which increases computational complexity
Solution Approach 1:
The patent applies preliminary action by having the UE pre-compute and store CSI measurements for both Class A and Class B configurations during periods when full computation is feasible. When the eNB requests CSI reports, the UE can retrieve pre-computed values or partially processed data, reducing the real-time computational burden while maintaining accurate beamforming weight determination.
Data Source
AI summary
Systems and methods for low complexity multi-configuration Channel State Information (CSI) reporting are provided. In some embodiments, a method of operating a wireless device in a cellular communications network to provide CSI feedback from multiple CSI reporting configurations is provided. The method includes receiving a first and second CSI reporting configuration and then reporting updated CSI in a CSI report for only one of the first CSI reporting configuration and the second CSI reporting configuration. In this way, rich CSI feedback with many ports, different codebooks, mixed beamformed and non-precoded CSI-RS configurations, etc., can be supported while requiring less computational complexity in the wireless device.