SRS Switching Capability Reporting for TDD Component Carrier Selection

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Solution Overview

Problem

Current wireless communication systems face challenges in efficiently supporting SRS switching capabilities, particularly in TDD systems, where UE cannot transmit SRS on DL-only component carriers due to limitations in TX chain coverage, leading to unclear chain selection between UE and eNB, resulting in potential configuration conflicts.

Innovation Solution

The UE reports its SRS switching capability to the eNB, which includes a list of secondary cells for SRS transmission, allowing the eNB to configure SRS transmission for each DL-only SCell based on the UE's RF implementation and timing differences, enabling optimal TX chain selection and minimizing interruption time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If UE transmits SRS on DL-only component carriers, then DL beamforming performance is improved, but TX chain coverage limitations prevent reliable transmission

Engineering Contradiction:
ImproveSRS transmission reliabilityVSAvoidSRS transmission flexibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamic SRS carrier switching where the UE can switch between different component carriers based on eNB configuration and channel conditions. The UE dynamically selects which carrier to transmit SRS on, allowing adaptation to TDD system constraints while maintaining transmission reliability when switching is permitted.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the operational parameters of SRS transmission by introducing carrier switching capability. The eNB configures specific carriers for SRS transmission, and the UE adjusts its transmission parameters based on the configured carrier list, enabling reliable SRS transmission on DL-only carriers when switching is enabled.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If eNB configures SRS transmission on multiple carriers, then beamforming performance improves, but configuration complexity increases

Engineering Contradiction:
Improvebeamforming performanceVSAvoidconfiguration complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the SRS configuration by providing a list of specific component carriers where SRS transmission is permitted. Instead of a blanket configuration, the eNB specifies individual carriers in a list, allowing selective SRS transmission on DL-only carriers while maintaining clear configuration management.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements a feedback mechanism where the eNB requests SRS switching capability information from the UE, and the UE reports its capability. Based on this feedback, the eNB configures appropriate carriers for SRS transmission, optimizing beamforming performance while managing configuration complexity through informed decision-making.

Inventive Principle:
Principle #23Feedback

3Adaptability or versatility

If UE switches TX chain between carriers, then SRS transmission on DL-only carriers is enabled, but interruption time increases

Engineering Contradiction:
ImproveSRS transmission capabilityVSAvoidinterruption time
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by having the eNB pre-configure the list of component carriers where SRS transmission is permitted before actual SRS transmission occurs. The UE is provided with advance knowledge of which carriers to use, allowing it to prepare TX chain switching in advance and minimize interruption time during actual transmission.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3456074B1Techniques for reporting SRS switching capability of a user equipment
Publication Date: 2022.02.23 NOKIA TECHNOLOGIES OY
  • EP3456074B1 patent drawingFigure 1
  • EP3456074B1 patent drawingFigure 2A~2B
  • EP3456074B1 patent drawingFigure 3~4

AI summary

Methods, apparatuses, and computer software for UE reported sounding reference signal (SRS) switching capability are provided. A method may include receiving a request, from a base station, for a sounding reference signal (SRS) switching capability of a user equipment, wherein the request comprises a list of possible cells to be used by the user equipment for SRS transmission; determining, at the user equipment, the SRS switching capability of the user equipment based on the list of possible cells; and transmitting, from the user equipment to the base station, an indication of the SRS switching capability of the user equipment.