Reporting Data Transmission Drops in Unlicensed Spectrum Carrier Aggregation
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Solution Overview
Problem
In wireless communication systems, particularly in carrier aggregation with at least one SCell operating in an unlicensed spectrum, there is a challenge in reporting data transmission drops due to unavailability of unlicensed spectrum, which is not addressed by existing technologies.
Innovation Solution
A method where User Equipment (UE) informs the eNodeB of data transmission drops on an unlicensed cell through L1/L2 signals, indicating that the data transmission is not possible due to the cell being occupied by other transmitters, rather than due to power limitations, allowing the network to manage resources effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If UE performs data transmission on unlicensed SCell, then network throughput is improved, but transmission reliability deteriorates when spectrum is occupied by other transmitters
Solution Approach 1:
The patent implements a feedback mechanism where the UE reports data transmission drop information to the eNodeB through L1/L2 signals. When the UE detects that data transmission is dropped on an unlicensed SCell (not due to power limitation), it sends a report containing the cell index and drop indicator to the eNodeB, enabling the network to respond to transmission failures and improve reliability while maintaining throughput on available channels.
2Productivity
If eNodeB allocates uplink grant for unlicensed SCell, then resource utilization is improved, but resource waste occurs when transmission is dropped due to spectrum unavailability
Solution Approach 1:
The eNodeB uses feedback from UE transmission drop reports to adjust future resource allocation decisions. When the eNodeB receives a report indicating transmission drop on a specific SCell, it can avoid allocating uplink grants for that cell in subsequent scheduling decisions, thereby preventing resource waste while maintaining high utilization on reliable channels.
Solution Approach 2:
The system dynamically adjusts resource allocation based on real-time channel conditions and transmission success/failure reports. The eNodeB transitions from static grant allocation to dynamic allocation that considers current spectrum availability and transmission reliability, optimizing resource utilization by allocating grants only to cells with successful transmission history.
3Loss of information
If UE reports all transmission drops, then network awareness is improved, but signaling overhead increases
Solution Approach 1:
The patent extracts and reports only the essential information needed for network decision-making: the SCell index where transmission drop occurred and a binary drop indicator. By selecting only critical data elements rather than reporting all transmission details, the system achieves adequate network awareness while minimizing signaling overhead.
Solution Approach 2:
The system implements partial reporting by notifying the eNodeB only when transmission drops occur on unlicensed SCells, rather than reporting all transmission activities. This selective partial reporting provides sufficient network awareness for resource management while significantly reducing signaling overhead compared to comprehensive reporting.
Data Source
Figure 1~2A
Figure 2B
Figure 3(a)~4
AI summary
TThe present invention relates to a wireless communication system. More specifically, the present invention relates to a method and a device for transmitting a power status reporting in a carrier aggregation with at least one SCell operating in an unlicensed spectrum, the method comprising: receiving an uplink grant to transmit data on a cell from an eNB; determining drop of the data transmission on the uplink grant; generating information including an indicator indicating that the data transmission is dropped; and transmitting the information to the eNB.