DCI-Controlled Grant-Free Uplink Access in Unlicensed Spectrum
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently providing various services, such as eMBB, mMTC, and URLLC, over unlicensed spectra due to the need for efficient channel access procedures and handling of grant-free uplink transmissions.
Innovation Solution
A method and apparatus for transmitting and receiving downlink control information (DCI) in a wireless communication system, including receiving uplink configuration information, identifying activation of grant-free uplink transmission, and transmitting an uplink signal based on this information, with channel access procedures adapted for unlicensed spectra.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If grant-free uplink transmission is implemented to improve service efficiency, then channel access complexity increases
Solution Approach 1:
The base station pre-configures uplink resources and transmission parameters through RRC signaling before actual data transmission. This preliminary configuration includes resource allocation, modulation and coding schemes, and other transmission parameters, allowing the terminal to perform grant-free transmission without real-time scheduling requests, thus improving efficiency while managing complexity through advance preparation
Solution Approach 2:
Downlink control information (DCI) transmitted via PDCCH serves as an intermediary mechanism to activate or deactivate grant-free uplink transmission. This intermediary allows the base station to dynamically control terminal behavior without requiring full scheduling procedures, balancing the need for efficient grant-free transmission with the need for base station control
2Adaptability or versatility
If multiple services (eMBB, mMTC, URLLC) are provided over unlicensed spectra, then spectrum utilization improves, but interference management becomes more difficult
Solution Approach 1:
Different services (eMBB, mMTC, URLLC) are allocated different uplink transmission configurations and resources tailored to their specific requirements. Each service type receives customized parameters such as modulation schemes, coding rates, and resource allocations, allowing simultaneous operation with differentiated quality requirements while managing interference through service-specific optimization
Solution Approach 2:
The system dynamically adapts transmission parameters and resource allocations based on service type and channel conditions. The base station can flexibly adjust grant-free transmission configurations, activation states, and resource assignments in response to varying traffic demands and interference levels, enabling reliable multi-service operation over unlicensed spectra
3Stability of the object's composition
If DCI format 0_0 is used for uplink scheduling, then compatibility with fallback procedures is improved, but control information capacity is reduced
Solution Approach 1:
DCI format 0_0 is designed to serve multiple purposes: it functions as both a fallback scheduling mechanism for basic uplink transmissions and as an activation/deactivation command for grant-free transmission. By encoding multiple control functions within a compact format, the system achieves broad compatibility while maintaining sufficient control capability through efficient use of available bits
Data Source
AI summary
A method and an apparatus for transmitting and receiving downlink control information in a wireless communication system are provided. The method of the terminal includes receiving uplink configuration information from a base station, receiving, from the base station, downlink control information (DCI) including information related to activation of grant-free uplink transmission, identifying the information related to the activation of the grant-free uplink transmission, based on the uplink configuration information, and transmitting an uplink signal to the base station, based on a result of the identifying.