FDD Precoder Refinement via Staggered Channel State Reporting
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Solution Overview
Problem
In frequency division duplex (FDD) wireless communication systems, the lack of ideal reciprocity between uplink (UL) and downlink (DL) channels leads to suboptimal precoding, resulting in performance degradation and transmission inaccuracies due to the inability to accurately configure precoders based on real-time channel estimates.
Innovation Solution
The system employs a method to refine precoders by transmitting timing parameters for channel coefficient and port attribute reports, allowing scheduling entities to update precoders based on explicit feedback from scheduled entities, thereby improving DL precoding performance by leveraging channel state reports across multiple timing parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If precoders are configured based on traditional channel estimates in FDD systems, then the system can maintain basic communication functionality, but the precoding accuracy deteriorates due to lack of ideal reciprocity between UL and DL channels
Solution Approach 1:
The patent implements a feedback mechanism where the scheduled entity provides explicit feedback containing channel state information to the scheduling entity. This feedback loop enables the scheduling entity to update and refine precoders based on actual channel conditions, resolving the accuracy issue caused by FDD reciprocity limitations.
Solution Approach 2:
The patent performs preliminary actions by transmitting timing parameters before actual channel coefficient reports. These timing parameters prepare the scheduling entity to correctly interpret and process subsequent channel state reports at the appropriate time, enabling accurate precoder refinement.
2Measurement precision
If the system transmits channel state reports at multiple timing parameters, then precoder refinement accuracy is improved, but the system complexity increases due to multiple timing configurations
Solution Approach 1:
The patent segments the channel state reporting process into multiple timing parameters, allowing different components of channel state information to be reported at different times. This segmentation enables precise precoder refinement while managing complexity through structured time-division of reporting.
Solution Approach 2:
The patent introduces dynamic timing parameters that can be adjusted based on channel conditions and system requirements. This dynamic approach allows the system to optimize reporting timing for each scenario, improving precision without requiring fixed complex configurations.
3Reliability
If explicit feedback with channel state reports is implemented, then DL precoding performance is improved, but the time delay increases due to feedback processing requirements
Solution Approach 1:
The patent performs preliminary actions by transmitting timing parameters in advance, which prepares the scheduling entity to process channel state reports more efficiently. This preliminary preparation reduces the actual processing delay while maintaining the performance benefits of explicit feedback.
Solution Approach 2:
The patent implements periodic channel state reporting at different timing parameters, allowing the system to update precoders periodically rather than continuously. This periodic approach reduces immediate processing delays while maintaining precoding performance through regular updates.
Data Source
AI summary
Aspects of the disclosure relate to the generation of channel state reports and precoding a wireless transmission based on frequency division duplex (FDD) reciprocity. A base station (B S) uses at least two precoders to transmit signals to A user equipment (UE). The UE generates a set of channel state reports, in which the UE transmits a first set of channel coefficients using a first timing, a set of port attributes using a second timing, and a second set of channel coefficients using a third timing. The first set of channel coefficients correspond to a first precoded portion of the wireless transmission, and the set of port attributes and the second set of channel coefficients correspond to a second portion of the wireless transmission. The BS modifies at least one of the precoders based on the channel state reports. Other aspects, embodiments, and features are also claimed and described.