Nokia · 10.5.3.1
Aspects of downlink-based CSI acquisition ·
RAN1#124bis · Source verification
the AI's delta
strengthened
vs RAN1#124
Nokia hardened their framework-level framing from establishing 5G Rel-20 as baseline to comprehensive restructuring of the 6GR DL CSI acquisition framework with a mandate to address identified shortcomings—moving from baseline-reuse language to explicit restructuring language. They expanded their CSI-RS port target from 128 APs to 256 antenna ports and added concrete design mechanisms: new CDM group sizes, block-pattern and comb-pattern based configurations, and flexible density adaptation in both frequency and spatial domains (previously only frequency domain densities 1/16 and 1/32 were mentioned). Their position on decoupling measurement triggering from reporting is new at this meeting. The CPU framework proposal shifted from open-ended studying flexible CPU framework where processing units scale with the CSI processing window to a specific proposal to simplify the legacy CPU occupation model by evolving the CSI processing framework.' On AI/ML, they dropped their prior observation comparing one-sided vs two-sided JSCM performance and instead added new concrete constraints (constrained QAM modulation symbols for JSCM) and presented initial single-sided JSCM simulation results. The codebook position hardened from proposes unified codebook design that delivers accurate PMI to advocates for a single specified codebook design for PMI compression.'
AI-synthesized from contributions · all text is paraphrased
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Contributions at RAN1#124bis · 1 doc
On downlink-based CSI acquisition in 6GR
Position extracted by AI
Nokia proposes a comprehensive restructuring of the 6GR DL CSI acquisition framework, using the 5G NR framework as a baseline but mandating studies to address its identified shortcomings. The company proposes studying CSI-RS designs supporting up to 256 antenna ports through new CDM group sizes, block-pattern and comb-pattern based configurations, and flexible density adaptation in frequency and spatial domains. It questions the necessity of periodic CSI reporting and proposes studying PUSCH-only CSI reporting to simplify UCI handling, and supports decoupling CSI measurement triggering from reporting to alleviate PUSCH scheduling restrictions. Nokia proposes adopting UE-initiated/event-based CSI reporting, proposing studies on use cases where reporting occurs only upon an associated event or the UE selects a reporting configuration, and presents technical arguments for simplifying the legacy CPU occupation model by evolving the CSI processing framework. It advocates for a single specified codebook design for PMI compression and proposes studying AI/ML-based CSI compression under practical constraints, including constrained QAM modulation symbols for JSCM, while presenting initial simulation results on single-sided JSCM performance.
Summary
This Nokia Tdoc discusses the evolution of the downlink CSI acquisition framework for 6GR, presenting 40 proposals and 29 observations aimed at enhancing flexibility, scalability, and energy efficiency. Key themes include CSI-RS design for large antenna arrays (up to 256 ports), a streamlined CSI framework addressing energy savings and large bandwidths, support for AI/ML-based CSI prediction and compression, and a simplified signaling and processing framework.
Prior contributions at RAN1#124 · 1 doc · Feb 09, 2026
On downlink-based CSI acquisition in 6GR
Position extracted by AI
Nokia proposes establishing 5G Rel-20 CSI-RS design up to 128 APs as the baseline for 6GR CSI acquisition and strives for reusing existing 5G CSI-RS design principles for new 6GR antenna array configurations, including studying new frequency domain densities of 1/16 and 1/32. The company presents a technical case for a unified codebook design that delivers accurate PMI representation across the full range of feedback overhead for both SU-MIMO and MU-MIMO operations, while studying codebook adaptation aspects for different sub-array patterns. Nokia questions the necessity of periodic CSI reporting given semi-persistent reporting flexibility, proposes studying the feasibility of PUSCH-only CSI reporting to simplify UCI handling, and advocates for studying UE-initiated/event-based CSI reporting as a new type. In the AI/ML domain, Nokia observes that JSCC/JSCM primarily improves low-SNR performance by mitigating the cliff effect and that one-sided JSCM performs close to two-sided, while proposing to study generalization, scalability, and fine-tuning for CSI prediction under Rel-18-defined cases.
Summary
This Nokia Tdoc (R1-2600039) presents 34 proposals and 23 observations on DL-based CSI acquisition for 6GR. It covers CSI-RS design for large arrays (>128 ports), energy savings, AI/ML-based CSI compression and prediction, unified codebook design, and reporting mechanism simplifications, all aimed at enhancing 6GR over the 5G NR baseline.
How this was derived
The AI extracted the "position extracted" field above directly from each Tdoc during summarization.
For the delta summary at the top, the AI compared Nokia's consolidated stance at RAN1#124bis
against their stance at RAN1#124 and classified the change as
strengthened.
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