DMRS Sharing Across UEs Using Buffered Channel Estimation

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Solution Overview

Problem

Existing wireless communications systems face challenges in efficiently sharing demodulation reference signals (DMRSs) across user equipments (UEs), leading to unnecessary signaling overhead and processing latency, particularly in scenarios with narrow bands and complex environments.

Innovation Solution

Implementing additional layer 1 (L1) control signaling, such as downlink control information (DCI), to enable a UE to buffer and reuse DMRSs from a PDSCH communication scheduled for another UE, reducing the need for DMRS transmission in subsequent communications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If DMRS are transmitted for every PDSCH communication, then channel estimation accuracy is maintained, but signaling overhead increases

Engineering Contradiction:

Improvechannel estimation accuracyVSAvoidsignaling overhead

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The system performs preliminary channel estimation using DMRS from a first PDSCH communication scheduled for another UE. The channel estimation results are buffered and reused for subsequent PDSCH communications scheduled for the apparatus, avoiding the need to transmit new DMRS for every PDSCH and thereby reducing signaling overhead while maintaining estimation accuracy

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The apparatus copies and reuses channel estimation information obtained from DMRS in a first PDSCH communication intended for another UE. This copied estimation data is applied to decode subsequent PDSCH communications, eliminating the need for redundant DMRS transmissions and reducing overall signaling overhead

Inventive Principle:

Principle #26Copying

2Reliability

If DMRS are transmitted for every PDSCH communication, then demodulation reliability is ensured, but processing latency increases

Engineering Contradiction:

Improvedemodulation reliabilityVSAvoidprocessing latency

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

Channel estimation is performed in advance using DMRS from a first PDSCH communication scheduled for another UE. The estimation results are buffered and readily available when subsequent PDSCH communications arrive, eliminating the need for real-time DMRS processing and reducing demodulation latency while maintaining reliability

Inventive Principle:

Principle #10Preliminary action

3Quantity of substance

If DMRS information is buffered and reused across UEs, then signaling overhead is reduced, but system complexity increases

Engineering Contradiction:

Improvesignaling overheadVSAvoidsystem complexity

Core Design Contradiction:

Quantity of substanceVSDevice complexity

Solution Approach 1:

The system introduces an intermediary buffering mechanism that stores channel estimation results from DMRS transmissions. This buffer acts as a mediator between the first PDSCH communication (scheduled for another UE) and subsequent PDSCH communications, enabling DMRS information sharing without requiring complex real-time coordination between UEs

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The buffered channel estimation results serve multiple functions: they are used for decoding subsequent PDSCH communications scheduled for the apparatus, and the same mechanism can be applied to multiple different PDSCH communications. This universal reuse of estimation data reduces overhead without proportionally increasing complexity

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS20250317929A1DEMODULATION REFERENCE SIGNAL (DMRS) SHARING ACROSS USER EQUIPMENTS (UEs)

Publication Date: 2025.10.09 QUALCOMM INC

AI summary

Certain aspects of the present disclosure provide techniques for sharing demodulation reference signals (DMRSs) across user equipments (UEs). A method generally includes receiving an indication to buffer first information associated with one or more first DMRSs that are scheduled in a first physical downlink shared channel (PDSCH) for a first UE, receiving, in the first PDSCH, the one or more first DMRSs; buffering the first information associated with the one or more first DMRSs; receiving a second PDSCH scheduled for the apparatus, and performing channel estimation to decode the second PDSCH based on one or more of: the first information; or one or more second DMRSs received in the second PDSCH.