Uplink Scheduling with Candidate Grants for Unlicensed Spectrum
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Solution Overview
Problem
Current uplink scheduling in unlicensed spectrums for wireless communication systems, such as LTE and NR, is inefficient due to the lack of effective channel availability determination, leading to wasted transmission opportunities and increased delay when scheduled channels are unavailable, while available non-scheduled channels cannot be used for transmission.
Innovation Solution
Implementing a method at both base stations and terminal devices to generate and select multiple candidate uplink grants with different frequency resources, incorporating a multi-grant selection scheme based on payload size, channel power, radio quality, transmit power, and buffered data, to optimize channel utilization and scheduling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single uplink grant is allocated to a terminal device, then the scheduling procedure is simple, but the channel utilization is low when the scheduled channel is unavailable
Solution Approach 1:
The patent segments the uplink grant allocation into multiple candidate grants (first candidate, second candidate, etc.), each corresponding to different frequency resources. The terminal device performs LBT separately for each candidate and selects one for transmission. This segmentation allows the system to try multiple channels independently, improving channel utilization without requiring complex joint scheduling across all channels simultaneously.
Solution Approach 2:
The base station performs preliminary actions by allocating multiple candidate uplink grants in advance, before the terminal device performs LBT and actual transmission. Each candidate grant is pre-configured with frequency resources, allowing the terminal device to quickly select from available options without requiring complex real-time scheduling decisions, thus improving responsiveness while maintaining manageable complexity.
2Reliability
If the terminal device performs LBT on the scheduled channel, then it can determine channel availability, but transmission delay increases when the channel is unavailable
Solution Approach 1:
The terminal device performs LBT on multiple candidate frequency resources in advance, before actual data transmission is needed. By having multiple pre-evaluated candidates ready, the system can quickly switch to an alternative candidate if the primary channel becomes unavailable, significantly reducing transmission delay while maintaining reliable channel availability determination through the preliminary LBT actions.
Solution Approach 2:
The patent prepares multiple candidate uplink grants with different frequency resources as a cushion against channel unavailability. When the first candidate's channel is found unavailable through LBT, the terminal device already has alternative candidates ready, providing a buffer that prevents transmission delay without requiring complex real-time channel switching decisions.
3Productivity
If multiple candidate uplink grants with different frequency resources are allocated, then channel utilization improves, but the scheduling overhead increases
Solution Approach 1:
The patent applies local quality by allocating different frequency resources to different candidate grants based on local channel conditions and requirements. Each candidate grant is tailored with specific frequency resources suitable for particular transmission scenarios, allowing the system to optimize channel utilization for each candidate independently while keeping the overall scheduling information manageable through localized rather than global optimization.
Data Source
AI summary
Embodiments of the present disclosure provide a method, apparatus and computer program product for uplink scheduling. A method implemented at a base station comprises generating a plurality of candidate uplink grants with different frequency resources in an unlicensed spectrum scheduled for uplink transmission of a terminal device and transmitting the plurality of candidate uplink grants to the terminal device. With embodiments of the disclosure, the efficiency of the uplink scheduling can be improved.