TRS Frequency Shifting for SBFD Uplink Overlap

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Solution Overview

Problem

In wireless communications systems employing subband full duplex (SBFD) operation, user equipment (UE) and network entities face challenges in receiving tracking reference signals (TRS) due to overlaps with uplink subbands or guard bands, leading to incomplete or unavailable TRS reception.

Innovation Solution

The UE and network entity manage TRS overlaps by dropping, puncturing, or shifting the frequency position of TRS within downlink subbands to ensure complete reception, using frequency hopping schemes for both half duplex and SBFD slots.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If TRS is scheduled in SBFD slot with uplink subband, then frequency resource utilization is improved, but TRS reception reliability deteriorates due to overlap with uplink or guard band

Engineering Contradiction:

Improvefrequency resource utilizationVSAvoidTRS reception reliability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent segments the TRS into multiple parts and schedules them across different frequency resources. When overlap with uplink subband or guard band is detected, the TRS is divided such that at least one part can be received in downlink subband, ensuring partial or complete TRS reception while maintaining frequency resource utilization in SBFD operation

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic TRS scheduling where the network entity adjusts TRS frequency position, monitoring behavior, or transmission parameters based on detected overlaps with uplink subband or guard band. This dynamic adaptation allows the system to maintain reliable TRS reception while flexibly utilizing frequency resources in SBFD slots

Inventive Principle:

Principle #15Dynamics

2Reliability

If TRS monitoring is adjusted to avoid overlap with uplink subband, then TRS reception completeness is improved, but time resource efficiency deteriorates

Engineering Contradiction:

ImproveTRS reception completenessVSAvoidtime resource efficiency

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent employs preliminary detection of overlap between scheduled TRS and uplink subband or guard band. Based on this preliminary detection, the system proactively adjusts TRS monitoring or transmission parameters before the actual TRS reception, preventing incomplete reception and avoiding the need for retransmission or additional monitoring time

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent changes TRS monitoring parameters such as monitoring occasion, frequency position, or monitoring duration based on detected overlaps. These parameter adjustments allow the system to maintain complete TRS reception while minimizing the time penalty by optimizing which parameters are changed and by how much

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS20250373390A1Tracking reference signals in full duplex operation

Publication Date: 2025.12.04 QUALCOMM INC

AI summary

Methods, systems, and devices for wireless communications are described. Techniques described herein relate to schemes for managing an overlap of at least part of a tracking reference signal (TRS) with an uplink subband or a guard band in a subband full duplex (SBFD) slot or symbol. In some examples, if a user equipment (UE) and/or a network entity determines that at least a portion of a TRS is scheduled for reception in an uplink subband or a guard band of an SBFD slot or symbol, the UE and/or the network entity may: drop the TRS, puncture the portion of the TRS that overlaps with the uplink subband or the guard band; or may shift the frequency position of the TRS such that the TRS is scheduled within the downlink subband(s) of the SBFD slot or symbol.