Uplink Control Information Transmission in NR-U Carrier Sensing
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Solution Overview
Problem
In NR-based radio communication utilizing unlicensed bands, channel sensing failures can lead to suppressed uplink control information transmission, resulting in unnecessary resource consumption and reduced system resource utilization due to data retransmissions.
Innovation Solution
A communication device and method that perform carrier sensing with a base station to control radio signal transmission via designated carriers, ensuring uplink control information is transmitted or acquired appropriately, even when initial transmission is suppressed, by utilizing designated carriers and managing HARQ bits and channel resources effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If channel sensing (LBT) is performed before transmission in unlicensed bands, then coexistence with other radio systems is improved, but information transmission may be suppressed depending on LBT results
Solution Approach 1:
The base station performs channel sensing and determines channel availability in advance before scheduling uplink control information transmission. This preliminary action allows the base station to proactively identify unavailable channels and notify terminal devices, preventing transmission attempts that would fail due to LBT failures, thus resolving the contradiction between maintaining coexistence protocols and ensuring transmission reliability
2Reliability
If uplink control information transmission is suppressed due to LBT failure, then channel availability is respected, but radio communication resources are consumed unnecessarily due to data retransmission
Solution Approach 1:
The base station monitors channel sensing results and provides feedback information to terminal devices indicating which channels are available or unavailable for uplink control information transmission. This feedback mechanism enables terminal devices to adjust their transmission decisions based on actual channel conditions, preventing unnecessary retransmissions and optimizing resource utilization while maintaining compliance with channel availability requirements
Solution Approach 2:
The base station determines channel availability in advance and notifies terminal devices before transmission attempts. This preliminary notification allows terminal devices to skip transmission on unavailable channels, preventing the waste of radio resources on doomed retransmissions while still respecting channel availability constraints
3Measurement precision
If carrier sensing is performed together with base station, then channel availability determination is improved, but system complexity increases
Solution Approach 1:
The patent extracts the channel sensing and availability determination function from the terminal device and centralizes it at the base station. The base station performs carrier sensing independently and provides availability information to terminal devices, simplifying terminal device complexity while maintaining or improving channel availability determination accuracy through centralized coordination
Data Source
AI summary
Provided is a communication device that includes a communication unit that performs radio communication, and a control unit that performs carrier sensing together with a base station and that performs control so that a radio signal is transmitted via a carrier which is designated by the base station based on results of the carrier sensing. The control unit further performs control so that information relating to transmission of uplink control information in a case where the transmission of the uplink control information via the carrier is suppressed is acquired from the base station.