Uplink Control Information Transmission in LAA Cells
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Solution Overview
Problem
In LTE systems operating in unlicensed bands, the direct application of existing wireless communication schemes can result in inappropriate communication due to interference control issues, particularly when listening-based interference control functions are used, leading to unpredictable transmission timing for uplink signals.
Innovation Solution
The user terminal employs a method to transmit uplink control information using a different UL channel than the PUSCH in an LAA SCell, regardless of the listening result, and uses a UL channel guaranteed in transmission, allowing independent control of uplink control information transmission, even when listening is successful before PUSCH transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If listening-based interference control function is applied in unlicensed bands, then coexistence with LTE, Wi-Fi, and other systems is improved, but transmission timing of uplink signals becomes unpredictable and communication reliability deteriorates
Solution Approach 1:
The patent segments the uplink transmission into two independent parts: uplink control information (UCI) and uplink data (PUSCH). UCI transmission on PUCCH is decoupled from listening results, while PUSCH transmission remains subject to listening control. This segmentation allows different reliability requirements to be met for control and data transmissions separately.
Solution Approach 2:
The patent introduces a licensed band cell as an intermediary carrier for UCI transmission. By transmitting UCI on the licensed band PUCCH rather than the unlicensed band PUSCH, the system ensures reliable control information delivery independent of unlicensed band listening outcomes, while still enabling LAA functionality.
2Ease of operation
If existing wireless communication schemes are directly applied in listening-based cells, then implementation simplicity is maintained, but communication appropriateness and reliability deteriorate
Solution Approach 1:
The patent implements dynamic transmission control where the uplink carrier selection adapts based on listening results. When listening succeeds, both PUCCH and PUSCH transmit; when listening fails, only PUCCH transmits. This dynamic approach maintains simplicity while ensuring communication appropriateness.
Solution Approach 2:
The patent applies different transmission rules to different parts of the uplink transmission: UCI on PUCCH follows one rule (transmit regardless of listening), while data on PUSCH follows another rule (transmit only if listening succeeds). This local differentiation ensures each component meets its specific requirements.
Data Source
Figure 1A~1B
Figure 2
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AI summary
This invention aims to achieve appropriate communication in a communication system which uses a cell defined to apply listening. This invention provides a user terminal which performs communication using cells including an LAA cell which applies listening before UL transmission, the terminal including a transmission unit which transmits uplink control information and uplink data, and a control unit which controls transmission of the uplink control information and the uplink data, wherein the control unit performs control to transmit the uplink control information using an uplink channel other than an uplink shared channel of the LAA cell.