Per-Subband PMI Reporting for Subband Full-Duplex CSI
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Solution Overview
Problem
Current subband full-duplex (SBFD) communication systems lack effective techniques for determining precoding matrix indicators (PMI) for each downlink subband, leading to reduced data rates and signaling capability due to non-contiguous downlink shared channels with wideband precoding.
Innovation Solution
The implementation of wideband channel state information (CSI) reporting for SBFD communications, which includes channel quality indicator (CQI) and PMI reporting, allows user equipment (UE) to report CSI for entire bandwidths of respective downlink subbands, enabling per-downlink subband PMI reporting and improving signaling throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If wideband precoding is used for non-contiguous downlink shared channels, then device complexity is reduced, but manufacturing precision of PMI determination deteriorates
Solution Approach 1:
The patent divides the bandwidth into multiple downlink subbands and introduces a first indication information field that specifies different precoding matrix indicator (PMI) values for each subband. This segmentation allows the system to maintain wideband precoding structure while achieving subband-level precoding precision, resolving the contradiction between device complexity and PMI determination precision.
2Loss of information
If per-subband PMI reporting is implemented, then signaling capability is improved, but loss of information is reduced
Solution Approach 1:
The patent introduces a new dimension for CSI reporting by adding a first indication information field that operates at the subband level within the existing wideband CSI framework. This dimensional addition enables per-subband PMI reporting without fundamentally restructuring the entire reporting system, thus improving information accuracy while limiting complexity increase.
3Productivity
If subband full-duplex communications are used, then productivity is improved, but reliability deteriorates due to interference
Solution Approach 1:
The patent applies local quality by enabling independent precoding optimization for each downlink subband through subband-specific PMI indication. This allows the system to adapt precoding parameters locally to counteract subband-specific interference characteristics in full-duplex operation, thereby maintaining communication quality while preserving the high spectral efficiency of full-duplex communications.
Data Source
AI summary
Methods, systems, and devices for wireless communication are described. A user equipment (UE) may receive a control message indicating a channel state information (CSI) reporting configuration for a subband full-duplex (SBFD) slot. The CSI reporting configuration may indicate that the UE is to report CSI for entire bandwidths of respective downlink subbands of the SBFD slot. That is, the CSI reporting configuration may configure the UE for per-downlink subband CSI reporting. The UE may receive CSI reference signals via the downlink subbands, and measure CSI for the reference signals. The UE may transmit, according to the CSI reporting configuration, a CSI report indicating the CSI for the downlink subbands. In some examples, the CSI may include some combination of channel quality indicators (CQIs) and precoding matrix indicators (PMIs).