Uplink Timing Control for Multi-Carrier Stability
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Solution Overview
Problem
In the LTE-A system, ensuring stable operation of user terminals when transmitting uplink signals at different transmission timings with multiple component carriers is challenging, particularly due to the risk of simultaneous transmission between uplink channels that can disrupt operation and prevent signal transmission.
Innovation Solution
A radio communication system and method where the radio base station provides transmission timing information for each component carrier, and the user terminal determines whether to avoid simultaneous transmission based on this information, especially when using contiguous component carriers to prevent overlap and ensure stable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple component carriers with different transmission timings are used in uplink, then spectral efficiency and data rates are improved, but simultaneous transmission of uplink signals occurs causing operational disruptions
Solution Approach 1:
The invention applies preliminary action by having the radio base station pre-indicate transmission timing information for each component carrier before actual transmission occurs. The user terminal uses this advance information to determine whether simultaneous transmission will occur and takes preventive measures (dropping or delaying transmission) before the conflict happens, thus maintaining stable operation while allowing flexible use of multiple component carriers.
2Productivity
If different transmission timing information is indicated for multiple component carriers, then frequency-domain scheduling effect is improved, but simultaneous transmission cannot be avoided without additional control mechanisms
Solution Approach 1:
The invention implements feedback by having the radio base station monitor and determine whether simultaneous transmission occurs based on the transmission timing information it indicated. The base station provides feedback control by adjusting transmission timing indications for different component carriers to avoid simultaneous transmission, thus managing the complexity centrally at the base station rather than requiring complex terminal-side coordination.
3Reliability
If simultaneous transmission of uplink signals is prevented, then stable operation is ensured, but transmission resources cannot be fully utilized
Solution Approach 1:
The invention applies dynamics by making the transmission timing flexible and adaptive. The user terminal dynamically adjusts transmission timing based on indicated information about simultaneous transmission conditions. When simultaneous transmission is detected, the terminal dynamically drops or delays transmission of certain uplink signals, allowing the system to maintain stable operation while still utilizing transmission resources effectively in non-conflicting scenarios.
Data Source
AI summary
To ensure stable operation of a user terminal even in the case where the user terminal is instructed to transmit uplink signals at different transmission timings with a plurality of component carriers, in a radio communication system provided with a radio base station apparatus that indicates transmission timings of uplink signals for each component carrier, and a user terminal that transmits an uplink signal at a transmission timing set based on transmission timing information indicated from the radio base station apparatus and the like, it is a feature that the radio base station apparatus indicates different transmission timing information in a plurality of component carriers, and that the user terminal avoids simultaneous transmission of uplink signals in the case of performing communications using a plurality of contiguous component carriers.