UE DMRS Bundling Indication for Phase-Coherent Uplink Estimation

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Solution Overview

Problem

Base stations struggle to unambiguously determine whether user equipment (UE) can maintain phase coherence for demodulation reference signal (DMRS) bundling across uplink transmissions, leading to communication errors and inaccurate channel estimation.

Innovation Solution

UEs indicate their ability to maintain phase coherence for DMRS bundling by transmitting an appropriate DMRS sequence or port, allowing base stations to perform accurate joint channel estimation and control DMRS bundling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If base stations signal DMRS bundling requests to UEs, then channel estimation accuracy is improved, but communication errors increase due to inability to unambiguously determine UE phase coherence capability

Engineering Contradiction:

Improvechannel estimation accuracyVSAvoidcommunication error rate

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent implements a feedback mechanism where UEs report their phase coherence capability status to base stations. This feedback loop allows base stations to receive explicit information about whether UEs can maintain phase coherence for DMRS bundling, resolving the ambiguity that previously caused communication errors while preserving channel estimation accuracy benefits

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent applies preliminary action by having UEs pre-indicate their phase coherence capability before DMRS bundling operations commence. This advance notification allows base stations to properly configure and interpret DMRS bundling requests without encountering determination errors during actual communication operations

Inventive Principle:

Principle #10Preliminary action

2Productivity

If base stations perform joint channel estimation across multiple slots, then spectral efficiency is improved, but system complexity increases due to phase coherence determination challenges

Engineering Contradiction:

Improvespectral efficiencyVSAvoidbase station processing complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The feedback mechanism provides base stations with clear UE capability information, eliminating the need for complex algorithms to infer phase coherence status. This reduces base station processing complexity while maintaining the ability to perform joint channel estimation for improved spectral efficiency

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent changes the parameter state by introducing explicit capability indication from UEs. This transforms the determination process from a complex inference problem to a simple parameter check, reducing system complexity while enabling joint channel estimation operations

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12556432B2Indicating whether demodulation reference signal bundling is applied by a user equipment

Publication Date: 2026.02.17 QUALCOMM INC

AI summary

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive a request to apply demodulation reference signal (DMRS) bundling to uplink transmissions. The UE may transmit multiple uplink transmissions. The UE may transmit an indication of whether the UE is able to comply with the request based at least in part on whether the UE is able to maintain phase coherence across the multiple uplink transmissions. Numerous other aspects are provided.