LAA Uplink Scheduling via Downlink Control Information
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Solution Overview
Problem
In Licensed-Assisted Access (LAA) LTE systems, the existing methods for uplink subframe scheduling result in heavy signaling overheads due to the need for multiple uplink scheduling indication information transmissions, which can burden the communication between base stations and terminals.
Innovation Solution
The proposed method reduces signaling overheads by using downlink control information to schedule multiple uplink subframes on unlicensed carriers, allowing terminals to send uplink data based on uplink scheduling indication information, and optionally using licensed carriers for cross-carrier scheduling to manage uplink subframes efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple uplink scheduling indication information transmissions are used to schedule uplink subframes, then scheduling flexibility and reliability are improved, but signaling overhead increases
Solution Approach 1:
The patent combines multiple uplink scheduling indication informations into a single transmission by using a bitmap field in the downlink control information. Each bit in the bitmap corresponds to a specific uplink subframe, allowing the base station to indicate multiple uplink subframes simultaneously. This merging approach maintains scheduling reliability while significantly reducing signaling overhead compared to transmitting separate scheduling indications for each uplink subframe.
Solution Approach 2:
The downlink control information is designed to serve multiple functions simultaneously: it provides both downlink scheduling information and uplink scheduling indication information. The bitmap field within the downlink control information can indicate multiple uplink subframes, making the signaling mechanism universal and multi-functional, thereby reducing the need for separate dedicated uplink scheduling transmissions.
2Ease of operation
If self-scheduling mode is used on unlicensed carrier, then scheduling simplicity is improved, but inability to meet scheduling requirements occurs when uplink subframes exceed downlink subframes
Solution Approach 1:
The patent segments the scheduling function by introducing cross-carrier scheduling capability. When the number of uplink subframes exceeds downlink subframes on the unlicensed carrier, the system divides the scheduling task between the unlicensed carrier (for downlink and some uplink) and the licensed carrier (for remaining uplink subframes). This segmentation allows the system to maintain scheduling simplicity on the unlicensed carrier while achieving the adaptability needed to handle varying traffic demands through licensed carrier assistance.
Data Source
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AI summary
Embodiments of the present invention provide a radio communications method, a base station, and a terminal. In the embodiments of the present invention, the base station sends downlink control information to the terminal, where the downlink control information includes uplink scheduling indication information, and the uplink scheduling indication information is used to instruct the terminal to send uplink data in a plurality of uplink subframes on at least one unlicensed carrier, so that the terminal sends uplink data in a plurality of uplink subframes on one or more corresponding unlicensed carriers based on the uplink scheduling indication information, thereby implementing scheduling, by using uplink scheduling indication information in one piece of downlink control information, of a plurality of uplink subframes to perform uplink transmission. This increases a data volume in data transmission while effectively reducing scheduling signaling overheads.