Shortened Frame Sounding for Low-Overhead MIMO CSI Feedback
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Solution Overview
Problem
Current wireless communication systems face challenges with outdated channel state information (CSI) feedback due to high overhead-to-data ratios and limited channel reciprocity, leading to inefficient data transmission and increased resource element usage for retransmissions, particularly in advanced MIMO systems with many antenna ports.
Innovation Solution
Implementing a transceiver that can partially blank transmission time intervals to embed reference signals, allowing for faster CSI feedback and reducing the need for redundant data transmission, while utilizing channel reciprocity in frequency division duplex systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of antenna ports is increased to improve MIMO system capacity, then the system can support more data streams and higher throughput, but the overhead-to-data ratio worsens due to increased resource elements needed for feedback symbols
Solution Approach 1:
The patent segments the feedback transmission by dividing the bandwidth into multiple subbands and assigning different feedback timing configurations to different subbands. This allows the system to handle the increased feedback requirements from multiple antenna ports through distributed, rather than centralized, feedback mechanisms, thereby managing overhead more efficiently.
Solution Approach 2:
The patent introduces dynamic feedback timing configurations where the feedback timing can vary across different subbands and different feedback instances. This dynamic approach allows the system to adapt the feedback schedule to current channel conditions and traffic requirements, optimizing the balance between feedback accuracy and overhead for high antenna port configurations.
2Device complexity
If channel feedback is limited to available reverse link time slots to maintain system simplicity, then the feedback mechanism remains straightforward to implement, but the CSI becomes outdated when channel changes occur between feedback and transmission
Solution Approach 1:
The patent enables the UE to perform channel measurements and prepare feedback information in advance during downlink subframes, storing the measured channel state information. This preliminary action allows the feedback to be transmitted in the next available uplink slot with minimal delay, ensuring the CSI remains valid even when channel conditions change rapidly.
Solution Approach 2:
The patent implements periodic feedback opportunities through configured uplink slots dedicated for CSI feedback transmission. By establishing regular feedback intervals and allowing multiple feedback instances within a period, the system ensures that updated CSI is provided frequently enough to maintain reliability while keeping the feedback mechanism structured and manageable.
3Ease of operation
If the UE stores feedback information and waits for uplink slots to transmit CSI feedback, then the feedback can be transmitted through the available reverse link, but the feedback delay increases causing outdated CSI at the transmitter
Solution Approach 1:
The patent merges multiple feedback transmissions into a single uplink slot when possible, allowing the UE to aggregate channel state information from multiple downlink subframes and transmit them together. This combining approach reduces the total number of feedback transmissions and minimizes the time delay while maintaining comprehensive CSI coverage.
Solution Approach 2:
The patent ensures continuous channel measurement and feedback preparation by the UE, with no idle periods between measurements. The UE continuously monitors downlink channels and maintains an updated buffer of channel state information, ready for immediate transmission when uplink feedback opportunities arise, thereby minimizing feedback delay while maintaining operational simplicity.
Data Source
AI summary
Embodiments provide a transceiver, wherein the transceiver is configured to transmit or receive data in at least one transmission time interval on certain allocated resource elements of a wireless communication system, wherein the transceiver is configured to at least partially blank a transmission time interval for a data block to be transmitted or received by the transmitter, wherein the transceiver is configured (a) to signal to another transceiver a transmission grant in a blanked part of the at least partially blanked transmission time interval or (b) to at least partially blank the transmission time interval based on a blanking pattern received from another transceiver.