Handling Preempted Reference Signals in Wireless UEs

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Solution Overview

Problem

Wireless communication systems face performance issues due to the loss of reference signals when higher priority transmissions preempt resources allocated to them, leading to system instability and reduced performance.

Innovation Solution

Implementing a reference signal preemption response scheme that allows user equipment (UE) and base stations to identify and respond to preempted reference signals by adjusting channel measurement, decoding, and tracking procedures based on the number and type of preempted resources.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If resources are allocated to reference signals for channel measurement and tracking, then system performance and reliability are improved, but when higher priority transmissions preempt these resources, the reference signals are lost leading to degraded performance

Engineering Contradiction:

Improvesystem performanceVSAvoidresource utilization

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The system dynamically adjusts reference signal processing based on preemption detection. When preemption is detected via DCI indicators, the UE adapts its behavior by skipping channel measurements, freezing tracking, or adjusting demodulation approaches. This dynamic response allows the system to maintain reliability under varying resource allocation conditions while prioritizing high-priority transmissions.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system implements feedback mechanisms where the base station sends preemption indication information to the UE through DCI messages. The UE uses this feedback to determine whether reference signal resources were preempted and adjusts its processing accordingly. This closed-loop feedback enables the system to respond to resource preemption events and maintain performance despite dynamic resource reallocation.

Inventive Principle:

Principle #23Feedback

2Reliability

If reference signal resources are preempted for priority transmissions, then high priority communication reliability is improved, but channel measurement and tracking accuracy deteriorate

Engineering Contradiction:

Improvepriority transmission reliabilityVSAvoidchannel measurement accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The system segments reference signal processing into multiple independent components: channel measurement, phase tracking, frequency tracking, and demodulation. When preemption is detected, the UE can selectively adjust or freeze specific segments rather than halting all processing. For example, the UE may freeze phase tracking while continuing frequency tracking, or skip channel measurements while maintaining other functions. This segmented approach allows priority transmissions to proceed reliably while preserving measurement precision where possible.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system changes processing parameters based on preemption detection. When preemption indicators are received, the UE modifies its behavior by adjusting tracking parameters, changing measurement configurations, or altering demodulation approaches. These parameter changes enable the system to adapt to the degraded reference signal conditions caused by preemption while maintaining acceptable performance for both priority and non-priority communications.

Inventive Principle:

Principle #35Parameter changes

3Duration of action of stationary object

If the UE continues to perform channel measurements on preempted reference signals, then measurement continuity is maintained, but system performance degrades due to processing corrupted data

Engineering Contradiction:

Improvemeasurement continuityVSAvoidperformance

Core Design Contradiction:

Duration of action of stationary objectVSReliability

Solution Approach 1:

The system extracts and removes corrupted reference signal measurements from processing when preemption is detected. Instead of continuing to process potentially corrupted data, the UE identifies preempted reference signal resources through preemption indication information and excludes them from channel measurements. This extraction approach maintains measurement continuity by using available non-preempted references while preventing performance degradation from corrupted data processing.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The system prepares for potential preemption events by having fallback mechanisms in place. When preemption is detected, the UE can switch to alternative processing modes such as using previously stored channel estimates, freezing tracking parameters, or adjusting measurement configurations. These pre-prepared cushioning measures ensure measurement continuity while protecting against performance degradation from processing corrupted reference signals.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentUS10779328B2Reference signal and preempted resources collision handling

Publication Date: 2020.09.15 QUALCOMM INC

AI summary

Methods, systems, and devices for wireless communications are described. A user equipment (UE) may identify a reference signal preemption scheme associated with one or more reference signal resources being preempted for priority transmissions during a time period. The UE may determine that resources of one or more reference signals have been preempted during the time period and in accordance with the reference signal preemption scheme. The UE may implement a reference signal preemption response scheme that is selected based at least in part on the resources of the one or more reference signals being preempted.