LAA Frame Structure Signaling for LBT-Based Uplink Timing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing frame structures in LTE systems applied to Licensed-Assisted Access (LAA) systems face issues such as resource waste and transmission delays due to uncertainty in unlicensed spectrum availability, lacking a method to indicate the frame structure between communicating parties for efficient DL and/or UL transmission.
Innovation Solution
A method and apparatus for indicating a frame structure over an unlicensed spectrum by signaling information to a terminal device, specifying the start position of uplink transmission after Listen Before Talk (LBT) is performed, ensuring efficient resource utilization and collision avoidance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing frame structure in LTE systems is directly applied to LAA systems, then licensed spectrum communication is maintained, but unlicensed spectrum resource waste and transmission delays occur due to uncertainty in resource availability
Solution Approach 1:
The patent applies dynamics by making the frame structure flexible and adaptable to unlicensed spectrum conditions. The base station dynamically determines whether to perform LBT and adjusts the frame structure accordingly - using traditional LTE frame structure when LBT is not performed, and using a modified frame structure with LBT indication when LBT is performed. This dynamic adaptation resolves the contradiction between maintaining communication reliability and reducing transmission delays.
Solution Approach 2:
The patent changes the frame structure parameters based on LBT performance. When LBT is performed, the frame structure includes an LBT indication field and adjusts the timing of uplink transmissions. This parameter change allows the system to adapt to unlicensed spectrum availability, reducing transmission delays while maintaining reliability through proper signaling.
2Reliability
If Listen Before Talk (LBT) is performed before uplink transmission on unlicensed spectrum, then collision avoidance is achieved, but resource availability uncertainty causes frame structure indication problems
Solution Approach 1:
The patent introduces an LBT indication field as an intermediary element in the frame structure. This indicator serves as a mediator between the base station's LBT performance and the terminal device's transmission timing. When LBT is performed, the base station sets the LBT indication to notify the terminal device to wait for the next uplink opportunity, thereby simplifying the frame structure indication while maintaining collision avoidance.
Solution Approach 2:
The patent segments the frame structure into distinct parts: traditional LTE frame structure elements and a new LBT indication field. This segmentation allows the system to maintain compatibility with existing LTE protocols while adding the necessary LBT signaling mechanism, reducing overall complexity by keeping the changes localized rather than restructuring the entire frame.
3Adaptability or versatility
If uplink transmission starts position is not clearly indicated, then flexibility in resource allocation is maintained, but resource waste occurs due to uncertainty in transmission timing
Solution Approach 1:
The patent implements feedback through the LBT indication field, which provides clear information to the terminal device about when uplink transmission should start. This feedback mechanism eliminates uncertainty in transmission timing, allowing the terminal device to accurately allocate resources without wasting them, while the base station maintains flexibility by dynamically controlling the LBT indication based on actual spectrum conditions.
Data Source
Figure 1
Figure 2(A)~2(C)
Figure 3(A)~3(C)
AI summary
Embodiments of the present disclosure provide a method of performing transmission between a base station and a terminal device according to a frame structure over an unlicensed spectrum in a wireless network that supports communications over both a licensed spectrum and the unlicensed spectrum. The method comprises signaling information indicating the frame structure and performing transmission between the base station and the terminal device on an unlicensed carrier in the unlicensed spectrum according to the frame structure. There is also provided the corresponding apparatus.