Autonomous Uplink Control Channel Configuration for Unlicensed Spectrum
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently coordinating and configuring control channels for autonomous uplink transmissions, particularly in unscheduled scenarios and unlicensed radio frequency spectrum bands.
Innovation Solution
The implementation of various autonomous uplink control channel configurations, including frequency and time division multiplexing of control information with data, use of narrow bandwidth portions, and specific waveform and payload configurations such as ePUCCH and sPUCCH, to support unscheduled uplink transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If autonomous uplink transmissions are implemented in unlicensed spectrum bands, then uplink transmission efficiency is improved, but coordination and control channel configuration becomes more complex
Solution Approach 1:
The control channel is segmented into multiple formats (e.g., compact control channel format, extended control channel format) with different payload sizes and structures. This segmentation allows the system to handle different autonomous uplink scenarios with appropriate control information levels, reducing overall configuration complexity while maintaining high transmission efficiency.
Solution Approach 2:
The control channel configuration is made dynamic through configurable parameters such as control channel bandwidth, resource allocation patterns, and multiplexing schemes. The base station can dynamically adjust these parameters based on traffic conditions, spectrum availability, and interference levels, enabling efficient autonomous uplink transmissions without fixed complex configurations.
2Productivity
If control information is multiplexed with data in frequency division manner, then spectral efficiency is improved, but control information detection difficulty increases
Solution Approach 1:
Different quality levels are applied to control information and data regions within the frequency-division multiplexed structure. Control information is allocated in protected resource elements with higher reliability requirements, while data regions use standard modulation and coding. This local quality differentiation maintains spectral efficiency while ensuring control information detection reliability.
Solution Approach 2:
Reference signals and demodulation pilots are introduced as intermediary elements that facilitate the detection of control information multiplexed with data. These intermediary signals provide channel estimation and synchronization information that helps the receiver separately decode control information from the multiplexed signal, reducing detection difficulty while maintaining spectral efficiency.
3Productivity
If narrow bandwidth portions are used for control channels, then spectrum utilization is improved, but control information capacity is reduced
Solution Approach 1:
Control information is transmitted periodically in narrow bandwidth control resource sets, with different periodicities for different types of control information. Critical control information uses shorter periods while less critical information uses longer periods. This periodic transmission in narrow bands achieves good spectrum utilization while maintaining adequate control information capacity through time-domain distribution.
Solution Approach 2:
The system transitions from relying solely on frequency bandwidth for control information capacity to utilizing time-domain dimensions as well. By spreading control information across multiple time instances and using code division multiplexing within narrow bandwidth resources, the system achieves adequate control information capacity while maintaining narrow bandwidth for good spectrum utilization.
Data Source
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AI summary
Methods, systems, and devices for wireless communication are described. Various autonomous uplink control channel configurations may be used for unscheduled uplink transmissions. For example, a user equipment (UE) may initiate an unscheduled uplink transmission and may identify an autonomous uplink control channel configuration for the uplink transmission. The UE may transmit control information and data during an initial transmission time interval of a transmission opportunity according to the control channel configuration, where the control channel configuration control may include a number of different waveforms and payload configurations. For example, an autonomous uplink control channel configuration may include control information frequency division multiplexed or time division multiplexed with data and transmitted in one or more frequency interlaces. In some cases, the control channel configuration may include a symbol period for a clear-to-send signal, and one or more symbol periods used a guard period before the data transmission.