Cross-Slot DMRS Combining for Single-DMRS Downlink Demodulation
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Solution Overview
Problem
Existing wireless communication technologies face challenges in efficiently combining demodulation reference signals (DMRS) across slots or subslots, leading to performance degradation due to channel variations and mobility issues, particularly in LTE and NR networks.
Innovation Solution
Implementing methods and apparatuses that allow for cross-slot DMRS combining by configuring a single DMRS in a slot or subslot to be combined with a DMRS in a subsequent adjacent slot or subslot, with signaling indicating whether DMRS combining is supported, and adjusting channel estimation and processing timelines accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If DMRS combining is performed across slots to improve demodulation performance, then channel estimation accuracy is improved, but processing complexity and timing requirements increase
Solution Approach 1:
The patent segments the DMRS combining process into distinct phases: receiving signaling indicating DMRS configuration, identifying the single DMRS in the current slot, and combining it with DMRS in the subsequent slot. This segmentation allows the UE to handle the complex combining operation in manageable steps, reducing processing complexity while maintaining accuracy.
Solution Approach 2:
The base station performs preliminary action by sending signaling in advance that indicates the DMRS configuration and whether combining is supported. This allows the UE to prepare the appropriate processing approach before actually receiving and combining the DMRS signals, reducing real-time processing complexity.
2Quantity of substance
If a single DMRS is configured per slot to reduce overhead, then resource efficiency is improved, but demodulation performance degrades due to channel variations
Solution Approach 1:
The patent merges the single DMRS from the current slot with the DMRS from the subsequent slot to create a combined channel estimate. This combining approach maintains the low overhead benefit of single-DMRS configuration while improving demodulation performance by utilizing channel information from both slots, effectively mitigating channel variations.
Solution Approach 2:
The patent extends the useful action of DMRS by allowing it to serve dual purposes: as a standalone reference signal in its own slot and as part of a combined reference signal when merged with the subsequent slot's DMRS. This continuity maximizes the utility of each DMRS transmission, improving performance without increasing overhead.
3Productivity
If DMRS combining across slots is implemented to support higher data rates, then throughput is improved, but the processing timeline becomes more constrained
Solution Approach 1:
The patent introduces dynamic adaptability by allowing the UE to process DMRS combining based on received signaling that indicates whether combining is supported and how the timeline should be adjusted. This dynamic approach allows the system to optimize between throughput and processing time constraints on a per-scheduling-instance basis, rather than being fixed to a single timeline requirement.
Solution Approach 2:
The patent changes the processing timeline parameter dynamically based on the DMRS combining configuration. When combining is indicated, the processing timeline is extended to accommodate the additional slot required for DMRS reception and combining. This parameter adjustment allows higher throughput to be achieved when conditions permit, while maintaining flexibility to adapt to different timing constraints.
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. A user equipment may receive signaling that indicates one of a plurality of demodulation reference signal (DMRS) configurations for demodulating a downlink data channel in a slot or subslot. The UE may receive the signaling from a network entity, such as a base station, and the network entity may select the indicated DMRS configuration. The plurality of DMRS configurations may indicate whether DMRS combining is supported across the slot or subslot and a subsequent adjacent slot or subslot, and the plurality of DMRS configurations may include a configuration that is capable of indicating to the UE that a single DMRS is configured in the slot or subslot and is to be combined with a DMRS in a subsequent adjacent slot or subslot to demodulate the downlink data channel.