Multi-TRP Coherent Joint Transmission With Layer-Based CSI Mapping
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Solution Overview
Problem
Coherent joint transmissions (CJTs) across multiple transmission-reception points (TRPs) in wireless communications systems lead to increased complexity in channel state information (CSI) reporting, particularly in multi-TRP scenarios, due to differing channel conditions and spatial multiplexing layers.
Innovation Solution
Grouping TRPs into defined sets for coherent joint transmissions based on supported quantities of spatial multiplexing layers, allowing for separate CSI reporting and phase-coherent joint transmissions within these sets, either determined by the network or the user equipment (UE).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If coherent joint transmissions are implemented across multiple TRPs, then transmission reliability and coverage are improved, but CSI reporting complexity increases
Solution Approach 1:
The patent segments the set of multiple TRPs into first set(s) and second set(s) based on supported quantities of spatial multiplexing layers. This segmentation allows the UE to report CSI separately for each set rather than treating all TRPs uniformly, thereby reducing CSI reporting complexity while maintaining the benefits of multi-TRP coherent joint transmissions for improved reliability.
2Loss of information
If multiple TRPs are grouped into sets with different spatial multiplexing layers, then CSI reporting overhead is reduced, but system configuration complexity increases
Solution Approach 1:
The patent introduces a parameter-based grouping approach where TRPs are classified into sets based on their supported quantities of spatial multiplexing layers. This parameter change from individual TRP handling to set-based handling with different spatial multiplexing capabilities enables reduced CSI reporting overhead while managing configuration complexity through standardized grouping criteria.
3Loss of information
If TRP sets are defined for coherent joint transmissions, then feedback overhead is reduced, but network coordination requirements increase
Solution Approach 1:
The patent segments TRPs into distinct sets that can be independently configured and reported. This segmentation allows the network to coordinate feedback mechanisms more efficiently by handling each set separately, reducing overall feedback overhead while introducing structured coordination requirements for network configuration and management.
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. A user equipment (UE) may receive control signaling indicating multiple transmission-reception points (TRPs), and may perform measurements for reference signals received from the multiple TRPs within a set of measurement resources. The UE may transmit a channel state information (CSI) report including a first CSI part and a second CSI part, where at least one of the first CSI part or the second CSI part indicates a first mapping between a first set of TRPs and a first set of spatial multiplexing layers, and a second mapping between a second set of TRPs and a second set of spatial multiplexing layers. The UE may then receive a phase-coherent joint transmission of a downlink message from the first set of TRPs in accordance with the first mapping, or from the second set of TRPs in accordance with the second mapping.