Configurable Codebook for CSI Feedback Overhead Reduction
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Solution Overview
Problem
The existing LTE systems face challenges in efficiently managing the high overhead associated with advanced channel state information (CSI) feedback, particularly in multi-beam precoding scenarios, which can lead to increased signaling burden and inefficiencies.
Innovation Solution
A method and apparatus for configuring a configurable codebook to adjust uplink signaling overhead by selectively including dual-polarized beams with received power above a threshold, allowing for optimized CSI feedback, thereby reducing unnecessary reporting and enhancing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If advanced CSI feedback with multi-beam precoding is used, then channel state information accuracy is improved, but signaling overhead increases
Solution Approach 1:
The patent extracts only the necessary beam information (beam index and beam power) from the complete multi-beam precoding CSI feedback, reporting only beams with power above a threshold. This selective extraction reduces the amount of feedback information while preserving the most significant channel characteristics, thereby reducing signaling overhead while maintaining accuracy.
Solution Approach 2:
The patent introduces a power threshold parameter to filter beam reports dynamically. By changing the reporting criterion from reporting all beams to reporting only beams exceeding a power threshold, the system adapts the feedback quantity based on channel conditions, reducing overhead when few beams are significant while maintaining accuracy when many beams are needed.
2Loss of information
If all beams are reported in CSI feedback, then completeness of channel information is improved, but feedback overhead increases
Solution Approach 1:
The patent applies different reporting quality to different beams based on their power levels. Strong beams (above threshold) are reported with full information (index and power), while weaker beams are not reported. This local differentiation ensures that the most important channel information is captured while avoiding unnecessary reporting of insignificant beams, reducing overall feedback overhead.
Solution Approach 2:
Instead of reporting all beams (excessive action), the patent reports only the necessary subset of beams that exceed the power threshold (partial action). This partial reporting strategy provides sufficient channel information for accurate precoding while significantly reducing feedback overhead by excluding beams that contribute minimally to the channel characteristics.
3Productivity
If configurable codebook with threshold filtering is implemented, then feedback efficiency is improved, but system complexity increases
Solution Approach 1:
The patent implements a dynamic filtering mechanism where the codebook reporting behavior adapts based on beam power levels relative to a threshold. The system dynamically determines which beams to report based on current channel conditions, making the feedback process adaptive and efficient. This dynamic approach improves feedback efficiency while keeping the complexity manageable through a simple threshold-based decision rule.
Data Source
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AI summary
Network nodes, wireless devices and methods of reducing signaling overhead are provided. In one embodiment, a method includes transmitting to the wireless device at least one power threshold parameter to be used by the wireless device to determine a number of beams to be included in a multi-beam precoder codebook and transmitting to the wireless device a signal to interference plus noise ratio (SINR) to be used by the wireless device to determine to use one of a single beam precoder and a multiple beam precoder.