Uplink Grant Discarding via Zero Buffer Status Report

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Solution Overview

Problem

In wireless communication systems, particularly in LTE, there is a need to efficiently manage uplink grants after the last transmission to avoid unnecessary power consumption and resource waste, especially when buffer status reporting indicates zero data availability.

Innovation Solution

User Equipment (UE) ignores or discards uplink grants received after transmitting a buffer status report with zero buffer size, preventing additional transmissions and optimizing resource usage by considering the last transmission as successful.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the UE processes and transmits uplink grants received after the last uplink transmission, then the uplink communication reliability is improved, but the power consumption and resource waste increase

Engineering Contradiction:
Improveuplink communication reliabilityVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The UE performs preliminary action by transmitting a Buffer Status Report (BSR) with zero buffer size after the last uplink transmission, indicating to the eNodeB that no further transmissions are needed. This preliminary notification prevents the eNodeB from allocating additional uplink grants, thereby avoiding unnecessary power consumption and resource usage while maintaining communication reliability.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If the UE processes and transmits uplink grants received after the last uplink transmission, then the uplink communication reliability is improved, but the resource waste increases

Engineering Contradiction:
Improveuplink communication reliabilityVSAvoidresource waste
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The UE sends a BSR with zero buffer size as a preliminary action to inform the eNodeB that the buffer is empty and no further uplink transmissions are required. This prevents the eNodeB from allocating additional uplink resources, thereby eliminating resource waste while ensuring that necessary communications are completed reliably.

Inventive Principle:
Principle #10Preliminary action

3Use of energy by moving object

If the UE ignores uplink grants received after the last uplink transmission, then the power consumption is reduced, but the communication protocol compliance may be affected

Engineering Contradiction:
Improvepower consumptionVSAvoidprotocol compliance
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The UE uses feedback mechanism by transmitting a BSR with zero buffer size to the eNodeB, providing explicit information about the buffer status. This feedback allows the eNodeB to understand that no further uplink grants should be allocated, enabling the UE to ignore subsequent grants without violating protocol compliance, thus reducing power consumption while maintaining reliability.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3409060B1Method for processing an uplink grant after the last uplink transmission in wireless communication system and a device therefor
Publication Date: 2021.07.07 LG ELECTRONICS INC
  • EP3409060B1 patent drawingFigure 1~2A
  • EP3409060B1 patent drawingFigure 2B
  • EP3409060B1 patent drawingFigure 3(a)~4

AI summary

The present invention relates to a wireless communication system. More specifically, the present invention relates to a method and a device for processing an uplink grant after the last uplink transmission in wireless communication system, the method comprising: transmitting uplink data with a buffer status reporting (BSR); receiving uplink grant after the BSR is transmitted; and discarding the received uplink grant if the received uplink grant is for new transmission and a buffer size of the BSR is set to zero.