Aperiodic SRS Transmission Timing in LTE Wireless Systems

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Solution Overview

Problem

Current wireless communication systems, such as LTE, face challenges in efficiently transmitting aperiodic sounding reference signals from user equipment to base stations, particularly in terms of timing and resource allocation, which affects channel quality reporting and data transmission efficiency.

Innovation Solution

A method and apparatus for transmitting an aperiodic sounding reference signal (SRS) in a wireless communication system, where the user equipment receives downlink control information, decodes instructions within the DCI format for downlink transmission, and transmits the aperiodic SRS according to the instructions, potentially delaying the transmission by 4 or more subframes, using resources allocated for periodic SRS transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If aperiodic SRS transmission is triggered by UL scheduling assignment, then resource allocation flexibility is improved, but timing synchronization and transmission efficiency deteriorate

Engineering Contradiction:
Improveresource allocation flexibilityVSAvoidtransmission timing delay
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The base station pre-allocates uplink resources and provides advance notification to the UE about future SRS transmission opportunities. This allows the UE to prepare transmission timing in advance, reducing actual transmission delay while maintaining resource allocation flexibility through dynamic triggering based on downlink scheduling conditions.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements dynamic switching between periodic and aperiodic SRS transmission modes. The transmission timing and resource allocation are adjusted dynamically based on downlink scheduling status, allowing the system to optimize between flexibility and timing efficiency depending on current network conditions.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If aperiodic SRS uses separate resource allocation, then transmission flexibility is improved, but resource utilization efficiency deteriorates

Engineering Contradiction:
Improvetransmission flexibilityVSAvoidresource utilization efficiency
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The same uplink resources are configured to serve both periodic SRS transmission and aperiodic SRS transmission. The base station dynamically triggers aperiodic SRS using downlink scheduling assignments, allowing single resources to fulfill multiple transmission purposes and improving overall resource utilization while maintaining transmission flexibility.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the resource allocation mechanisms for periodic and aperiodic SRS into a unified framework. By using downlink scheduling assignments to trigger aperiodic transmissions on pre-configured resources, the system combines the resource efficiency of periodic allocation with the flexibility of dynamic triggering.

Inventive Principle:
Principle #5Merging (Combining)

3Stability of the object's composition

If SRS transmission timing is delayed by 4 or more subframes, then resource coordination is improved, but channel quality reporting timeliness deteriorates

Engineering Contradiction:
Improveresource coordination stabilityVSAvoidchannel quality reporting timeliness
Core Design Contradiction:
Stability of the object's compositionVSLoss of time

Solution Approach 1:

The base station provides advance notification through downlink scheduling assignments about upcoming SRS transmission opportunities. This preliminary action allows the UE to synchronize transmission timing in advance, maintaining resource coordination stability while minimizing actual transmission delays and improving channel quality reporting timeliness.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2482591B1Method for transmitting a sounding reference signal in a wireless communication system, and apparatus for same
Publication Date: 2018.08.15 LG ELECTRONICS INC
  • EP2482591B1 patent drawingFigure 1
  • EP2482591B1 patent drawingFigure 2
  • EP2482591B1 patent drawingFigure 3

AI summary

The present invention relates to a method in which user equipment transmits a non-periodic sounding reference signal in a wireless communication system. In detail, the method comprises: a step of receiving a downlink control channel from a base station; a step of decoding a downlink control information (DCI) format contained in the downlink control channel; a step of checking a non-periodic sounding reference signal transmission instruction in the DCI format; and a step of transmitting a non-periodic sounding reference signal to the base station in accordance with the transmission instruction. Preferably, if the downlink control channel is received via an nth subframe, the non-periodic sounding reference signal is transmitted via an (n+k)th subframe (where k≤4).