User Device Timing Gap Feedback for Carrier Aggregation
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Solution Overview
Problem
In dual connectivity (DC) type carrier aggregation, the lack of synchronization between system frame numbers, subframe numbers, and transmission timings across different base stations leads to inefficiencies in discontinuous reception (DRX) control and measurement gap management, resulting in increased energy consumption and wasteful radio resource allocation.
Innovation Solution
A user apparatus measures the timing gap between radio signals from multiple base stations and transmits this information to the base stations, allowing for coordinated DRX control and measurement gap scheduling, thereby aligning on-duration periods and preventing unnecessary resource allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If dual connectivity is implemented to achieve high throughput by using CCs under different base stations, then data rate is improved, but synchronization between system frame numbers and transmission timings deteriorates
Solution Approach 1:
The user apparatus measures the timing gap between radio signals from different base stations and feeds back this timing gap information to the base stations. This feedback enables the base stations to adjust their transmission timings to achieve synchronized subframe boundaries while maintaining dual connectivity for high data rates.
2Adaptability or versatility
If independent DRX control is performed for each base station, then adaptability is improved, but energy consumption increases due to non-aligned on-duration periods
Solution Approach 1:
The patent merges the independent DRX control operations of multiple base stations by aligning their on-duration periods based on the measured timing gap. This allows the user apparatus to enter sleep mode more effectively during overlapping off-duration periods, reducing energy consumption while maintaining the adaptability of independent DRX control.
3Measurement precision
If measurement gap is set for frequency switching, then measurement accuracy is improved, but radio resource allocation efficiency deteriorates due to unsynchronized subframe gaps
Solution Approach 1:
The user apparatus performs preliminary measurement of the timing gap between base stations before conducting radio quality measurements. This preliminary action allows the base stations to pre-coordinate measurement gap scheduling, ensuring that both bases station's measurement gaps are synchronized, thus preventing wasteful radio resource allocation while maintaining measurement accuracy.
Data Source
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Figure 3A~3B
Figure 4
AI summary
A user apparatus communicating with a first base station and a second base station in a communication system which supports carrier aggregation is provided. The user apparatus includes a measurement unit configured to measure a timing gap between a reception timing of a first radio signal received from the first base station and a reception timing of a second radio signal received from the second base station; and a transmission unit configured to transmit the information indicating the timing gap measured by the measurement unit to the first base station or the second base station.