AAS Precoder Selection Using Dual CSI-RS Capacity Feedback
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Solution Overview
Problem
Existing precoder selection methods in active antenna systems (AAS) for 4G LTE and 5G NR are not reliably selecting between codebook-based and non-codebook-based precoders based on spectral efficiency, leading to suboptimal performance in various RF conditions, especially in medium to high mobility scenarios.
Innovation Solution
A UE-assisted precoder selection method that involves configuring two sets of CSI-RS resources for codebook-based and non-codebook-based precoders, obtaining corresponding CSI reports, estimating channel capacities, and selecting the best precoder based on these capacities, using multiple CSI-RS resource configurations and reports transmitted to the base station.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If codebook-based precoder is used, then implementation is simpler with predefined codebooks, but spectral efficiency is suboptimal in medium to high mobility scenarios
Solution Approach 1:
The patent implements dynamic precoder selection that adapts between codebook-based and non-codebook-based precoding methods based on real-time channel conditions and mobility scenarios. The system dynamically determines which precoding approach to use by evaluating channel state information and selecting the optimal method, thereby resolving the contradiction between implementation simplicity and spectral efficiency across varying operational conditions.
2Productivity
If non-codebook-based precoder is used, then spectral efficiency is improved through adaptive precoding, but implementation complexity increases with advanced algorithms
Solution Approach 1:
The system dynamically selects between codebook-based and non-codebook-based precoding methods based on evaluated channel conditions. When channel conditions warrant the use of advanced algorithms for improved spectral efficiency, the system activates non-codebook-based precoding with methods such as MRT, ZF, or MMSE. This dynamic approach allows the system to implement complexity only when necessary to achieve spectral efficiency improvements.
Solution Approach 2:
The patent changes the operational parameters of the precoding system by selecting different precoding methods (MRT, ZF, MMSE) based on channel conditions. The system adjusts the complexity level by parameter selection, choosing simpler codebook-based methods when appropriate and transitioning to more complex non-codebook-based methods when spectral efficiency requires it, thereby managing the trade-off between complexity and performance.
3Ease of operation
If existing precoder selection methods are used, then system operation is maintained, but reliable selection between precoder types is not achieved in varying RF conditions
Solution Approach 1:
The patent implements a feedback mechanism where the system evaluates channel state information and uses this feedback to reliably select between codebook-based and non-codebook-based precoders. The base station receives CSI from the UE, processes this information to determine channel conditions and mobility scenarios, and uses this feedback to make informed decisions about precoder selection. This feedback loop ensures reliable precoder selection across varying RF conditions while maintaining system operation.
Data Source
AI summary
Systems and methods for User Equipment (UE)-assisted precoder selection are provided. In one embodiment, a method implemented in a base station for transmitting data to a UE includes transmitting, to the UE, Channel State Information Reference Signal (CSI-RS) on two sets of CSI-RS resources; receiving, from the UE, two sets of CSI; estimating a first channel capacity for the codebook-based precoder based on the first set of CSI and a second channel capacity for the non-codebook-based precoder based on the second set of CSI; selecting one precoder from the codebook-based precoder and the non-codebook-based precoder based on the first channel capacity and the second channel capacity; and performing data transmission to the UE using the selected precoder. Embodiments of the proposed solution enable selecting a best precoder from the codebook-based precoder and the non-codebook-based precoder.