Downlink and Uplink Partial Subframe Scheduling After LBT in Shared Spectrum
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In wireless communication systems using shared radio frequency spectrum, the timing of access to the spectrum is uncertain due to contention-based access procedures, leading to inefficiencies in scheduling and transmission, particularly in partial subframes, which increases complexity and reduces network performance.
Innovation Solution
Implementing partial subframe durations with predefined starting points for transmissions and using uniform puncturing of resource elements to reduce processing complexity at the base station, allowing for flexible and efficient scheduling even after successful LBT procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple starting and ending positions in a subframe for UL are implemented, then scheduling flexibility is improved, but device complexity increases
Solution Approach 1:
The subframe is segmented into multiple possible starting positions (e.g., symbol 0, symbol 3, symbol 6) and ending positions, allowing the UL transmission to occupy different portions of the subframe. This segmentation enables flexible scheduling while maintaining a standardized subframe structure, reducing the complexity of handling completely variable subframe lengths.
Solution Approach 2:
The UL subframe configuration is made dynamic by allowing the starting and ending positions to be adjusted based on LBT outcomes and scheduling requirements. The system can dynamically select from predefined starting positions and configure corresponding ending positions, providing adaptability without requiring complete reconfiguration of the subframe structure.
2Productivity
If partial subframes are used for transmissions after LBT, then network efficiency is improved, but processing complexity at base station increases
Solution Approach 1:
The base station performs preliminary actions by pre-configuring multiple starting positions and their corresponding ending positions before actual transmissions occur. This preparation allows the base station to quickly select and execute the appropriate partial subframe configuration after LBT success, improving network efficiency while managing processing complexity through advance planning.
Solution Approach 2:
The system changes parameters by adjusting the starting position and duration of partial subframes based on LBT outcomes and traffic requirements. By modifying these parameters within a predefined framework, the base station achieves flexible scheduling and improved network efficiency without requiring complex real-time processing for completely new configurations.
3Device complexity
If uniform puncturing of resource elements is implemented, then processing complexity is reduced, but transmission flexibility is limited
Solution Approach 1:
Uniform puncturing segments the resource elements in a systematic pattern, removing specific REs at regular intervals. This segmentation approach simplifies the processing complexity by providing a predictable, repeatable pattern while still allowing the remaining REs to be flexibly allocated across different starting positions and subframe configurations.
Solution Approach 2:
The puncturing pattern applies homogeneous treatment to resource elements by using a uniform, consistent pattern across different subframes and configurations. This homogeneity reduces processing complexity through standardized operations while the overall system maintains flexibility through the combination of uniform puncturing with variable starting positions and subframe durations.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Configuration of downlink and uplink partial subframes in shared radio frequency (RF) spectrum is discussed. The various described aspects provide for different configurations for start and end transmissions from base stations and user equipments (UEs) when transmitting over partial subframes. With downlink initial partial subframes, a uniform puncturing may be used to reduce the number of resource elements (REs) available for downlink transmission without causing the base station to re-precode any of the data. Additional aspect for downlink partial subframe transmission allows for downlink control channels to identify multiple start points within the subframe at short downlink shared channel locations. On the uplink aspect, UEs may be informed with configurations for both full and partial subframe transmissions. The UE will select which configuration to use based on whether it will transmit on full or partial subframes. Additionally, a UE have scheduled or semi-scheduled modes for partial subframe transmissions.