Non-Contiguous CSI Reference Resources for Full-Duplex Reporting
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Solution Overview
Problem
In full-duplex communication modes, the assumptions regarding the CSI reference resource do not hold due to non-contiguous downlink frequency resources, leading to a need for adapting CSI-RS resource configuration, particularly in sub-band full-duplex (SBFD) mode, where a portion of the bandwidth is not available for downlink.
Innovation Solution
The CSI reference resource definition is adapted for full-duplex communication by explicitly defining disjoint frequency domain resource allocations using bitmaps or start and length indicators, and incorporating ZP CSI-RS resources to rate-match around uplink sub-bands, ensuring accurate CSI reporting in SBFD slots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the CSI reference resource is defined using contiguous downlink frequency resources, then the measurement and reporting process is simplified, but it cannot accurately represent the channel conditions in full-duplex modes with non-contiguous resource allocations
Solution Approach 1:
The CSI reference resource is segmented into multiple parts corresponding to different frequency sub-bands. Each sub-band has its own reference signal resources, allowing the system to handle non-contiguous frequency allocations by treating each segment separately while maintaining overall measurement accuracy for full-duplex modes
Solution Approach 2:
The patent changes the parameters of the CSI reference resource definition to accommodate full-duplex operation. Specifically, it modifies the frequency domain resource allocation parameters to allow non-contiguous allocations, and adjusts the association between CSI reports and reference resources to reflect the actual resource partitioning in full-duplex modes
2Productivity
If the bandwidth of the CSI reference resource is configured to match the entire system bandwidth, then resource utilization is maximized, but it includes frequency regions allocated for uplink transmissions which are not available for downlink CSI measurements
Solution Approach 1:
The patent extracts and removes the uplink frequency regions from the CSI reference resource configuration. By identifying and excluding the frequency sub-bands allocated for uplink transmissions, the system ensures that CSI measurements are performed only on valid downlink resources, maintaining measurement reliability while still utilizing the maximum available downlink bandwidth
Solution Approach 2:
The CSI reference resource configuration is made dynamic to adapt to different duplex modes. The system can switch between contiguous and non-contiguous resource allocations depending on whether half-duplex or full-duplex mode is active, allowing optimal resource utilization in each operating scenario
3Device complexity
If zero-power CSI reference signal resources are not allocated, then the resource allocation is simplified, but it prevents accurate rate-matching around uplink sub-bands in full-duplex modes
Solution Approach 1:
The patent introduces zero-power CSI reference signal resources as intermediary elements that occupy the uplink frequency regions without transmitting actual reference signals. These ZP CSI-RS resources serve as placeholders that enable accurate rate-matching by informing the UE which resource elements should be excluded from CSI measurements, thereby maintaining measurement precision without requiring complex dynamic resource allocation
Data Source
AI summary
Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive, from a network node, a configuration for a channel state information (CSI) report associated with one or more CSI reference signal (CSI-RS) resources. The UE may determine a duplex mode associated with the CSI report. The UE may obtain one or more measurements of a CSI reference resource of the one or more CSI-RS resources based at least in part on the duplex mode associated with the CSI report. The UE may transmit, to the network node, the CSI report based at least in part on the one or more measurements of the CSI reference resource. Numerous other aspects are described.