LAA SCell Control Signaling for Unlicensed Band Communication
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Solution Overview
Problem
In next-generation mobile communication systems, unlicensed band cells with pre-transmission listening exhibit different communication performance compared to licensed band cells, making it challenging to achieve synchronization, measure channel state information, or perform communication processes such as rate matching adequately when control information from licensed band cells is directly applied to unlicensed band cells.
Innovation Solution
A user terminal equipped with a receiving section for common control information via a downlink control channel in LAA SCell and a control section to manage communication processes based on this information, allowing for adequate communication in unlicensed bands by signaling specific control information such as CRS, CSI-RS/IM, DRS, and burst information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If control information from licensed band cells is directly applied to unlicensed band cells, then the signaling structure is simple and easy to implement, but synchronization, CSI measurement, and communication processes cannot be performed adequately
Solution Approach 1:
The patent applies different control information signaling methods to different cell types (licensed vs. unlicensed bands). Specifically, for unlicensed band cells (LAA SCell), the patent introduces enhanced control information including LAA-specific fields for subframe configuration, LBT status indication, and burst duration control, while licensed band cells use traditional control information. This local differentiation enables adequate communication processes in unlicensed bands while maintaining simplicity in licensed bands.
Solution Approach 2:
The patent changes the parameters of control information by adding LAA-specific fields to the downlink control channel signaling. These parameters include subframe configuration information, LBT status indication, and burst duration control, which are specific to unlicensed band operations. By modifying the control information parameters rather than creating an entirely new system, the patent achieves reliable communication in unlicensed bands while maintaining compatibility with existing licensed band infrastructure.
2Adaptability or versatility
If unlicensed band cells use pre-transmission listening, then spectrum utilization is expanded and communication flexibility is improved, but communication performance differs from licensed bands making direct application of licensed band control difficult
Solution Approach 1:
The patent makes the downlink control channel universal by enabling it to carry both traditional licensed band control information and enhanced LAA-specific control information. The control channel can dynamically adapt its content based on the cell type (licensed or unlicensed), allowing a single channel structure to serve multiple purposes. This multi-functionality expands spectrum utilization flexibility while managing control information complexity through a unified approach.
Solution Approach 2:
The patent performs preliminary configuration of control information parameters before actual communication begins. By pre-configuring LAA-specific fields such as subframe configuration and burst duration in the control information, the system prepares the necessary parameters in advance, enabling flexible spectrum utilization while avoiding the complexity of dynamic parameter negotiation during communication.
3Measurement precision
If LAA SCell uses enhanced control information signaling, then communication processes like synchronization and CSI measurement can be performed adequately, but the control information structure becomes more complex
Solution Approach 1:
The patent segments the control information into different types: common control information applicable to all cells and cell-specific control information specific to LAA SCell. By segmenting rather than monolithic treatment, the patent can apply enhanced signaling only where needed (in LAA SCell) while maintaining simpler structures in licensed bands, thereby achieving accurate CSI measurement without unnecessarily increasing overhead everywhere.
Solution Approach 2:
The patent introduces an intermediary layer in the control information structure that bridges licensed band control mechanisms and LAA-specific requirements. This intermediary layer processes and adapts control information for LAA SCell, enabling accurate measurement and communication while isolating the complexity from the base control mechanism, thus preventing unnecessary overhead propagation to licensed band operations.
Data Source
AI summary
The present invention is designed to carry out communication adequately in cells (for example, unlicensed bands) where listening is executed prior to transmission. According to one aspect of the present invention, a user terminal has a receiving section that receives common control information, via a downlink control channel, in an LAA SCell (License-Assisted Access Secondary Cell), and a control section that controls a communication process in the LAA SCell based on the common control information.