CSI Feedback Segmentation for Wireless Antenna Systems
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Solution Overview
Problem
Conventional methods for acquiring accurate and timely channel state information (CSI) in wireless communication networks, particularly in multi-antenna systems using frequency division duplexing (FDD), face challenges due to increasing CSI acquisition overhead with the number of antennas, leading to insufficient resources for reliable and timely CSI transmission.
Innovation Solution
A CSI exchange scheme that involves remapping, selecting, and quantizing channel data elements to reduce the amount of information needed for feedback, using a multi-stage process including invertible mappings, piecewise function approximation, and variable-bit-width quantization to efficiently convey CSI from receivers to transmitters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If direct CSI signaling is used from users to transmitter, then CSI reliability is improved, but CSI acquisition overhead increases linearly with the number of antennas
Solution Approach 1:
The patent segments the CSI feedback process into multiple stages: first transmitting a reduced set of channel data elements, then progressively transmitting additional elements in subsequent feedback opportunities. This segmentation allows the system to achieve reliable CSI acquisition by distributing the feedback burden over time, rather than requiring all CSI elements to be transmitted simultaneously, thus reducing the instantaneous overhead while maintaining reliability.
Solution Approach 2:
The patent applies preliminary action by having the receiver transmit a subset of channel data elements first, before the full CSI is available or before all processing is complete. This preliminary feedback allows the transmitter to begin utilizing partial CSI information while the receiver continues processing to generate the complete CSI set, which is then transmitted in subsequent feedback opportunities.
2Measurement precision
If training sequence length is increased to improve CSI accuracy, then measurement precision is improved, but time available to serve users decreases
Solution Approach 1:
The patent applies partial action by transmitting only a subset of channel data elements in the initial feedback message rather than waiting to transmit all elements. This allows the feedback process to be completed within the available time budget, while the transmitter can still utilize the partial CSI information provided by the reduced set of elements, achieving a balance between accuracy and timing constraints.
3Reliability
If full channel data elements are transmitted, then CSI reliability is improved, but feedback message size increases
Solution Approach 1:
The patent segments the channel data elements into multiple transmission groups, where the first feedback message contains a selected subset of elements and subsequent messages contain the remaining elements. This segmentation reduces the size of each individual feedback message, making them more manageable for transmission while ensuring that the complete CSI information is eventually delivered through the sequence of segmented messages.
4Measurement precision
If CSI feedback is performed frequently to maintain accuracy, then measurement precision is improved, but system resources are consumed
Solution Approach 1:
The patent applies partial action by transmitting only a subset of channel data elements in each feedback opportunity rather than transmitting the complete CSI set every time. This reduces the resource consumption per feedback transmission while still providing the transmitter with useful partial CSI information, allowing for more frequent or efficient feedback cycles without proportionally increasing resource usage.
Data Source
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AI summary
The invention relates to a communication device (101) comprising: a communication interface (103) configured to transmit a pilot signal via a communication channel (120) to a further communication device (131) and to receive a plurality of data elements representing channel state information (CSI) from the further communication device (131), wherein the plurality of data elements are a subset of a set of data elements representing the full channel state information (CSI) being available at the further communication device (131); and a processing unit (105) configured to generate the full channel state information (CSI) on the basis of the plurality of data elements by applying a fitting scheme to the plurality of data elements received from the further communication device (131).