RRC Uplink Cancellation Policy Using Multi-Channel Slot Format Indications
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Solution Overview
Problem
Conventional techniques for determining the configuration of symbols for RRC configured uplink signals in wireless communications systems are deficient, leading to potential interference due to incomplete processing of slot format indications (SFIs), especially when UEs are unable to finish processing SFIs before transmitting uplink signals.
Innovation Solution
A UE determines the configuration of slots based on detected and undetected SFIs in multiple control channels, using a cancellation policy to transmit or cancel uplink signals accordingly, and employs SFIs with overlapping ranges to eliminate no-cancellation periods, thereby preventing interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the UE determines slot configuration based on detected SFIs only, then the processing is simple and fast, but the configuration determination is incomplete leading to potential interference
Solution Approach 1:
The UE performs preliminary processing of detected SFIs before the uplink transmission deadline, maintaining a list of detected slot format indications. This preliminary action allows the UE to have configuration information ready in advance, reducing last-minute processing time while ensuring more accurate and reliable configuration determination through complete SFI processing.
2Reliability
If the UE waits to process all SFIs before transmission, then the configuration determination is complete and accurate, but the transmission timing is delayed
Solution Approach 1:
The UE applies a cancellation policy that proactively prevents interference by checking the determined slot configuration against the scheduled uplink transmission. If the configuration indicates the slot is not suitable for uplink transmission, the UE cancels the transmission before it occurs. This preliminary anti-action ensures configuration accuracy is maintained while avoiding timing delays, as the cancellation decision is made based on pre-processed SFI information.
3Loss of information
If the SFI processing is performed late, then the information is more up-to-date, but the UE cannot cancel transmissions in time avoiding interference
Solution Approach 1:
The UE maintains a list of detected SFIs and processes them preliminarily before the uplink transmission deadline. This preliminary processing ensures that the most recent SFI information is incorporated into the configuration determination while still having sufficient time to make cancellation decisions. The UE determines the slot configuration based on this processed information and applies the cancellation policy to prevent interference, thus achieving both information completeness and timely interference avoidance.
4Speed
If the UE transmits RRC configured uplink signals without determining slot configuration, then the transmission is timely, but interference occurs due to incorrect transmission in downlink or flexible symbols
Solution Approach 1:
The UE determines the slot configuration based on detected SFIs and applies a cancellation policy as a preliminary anti-action measure. Before transmitting RRC configured uplink signals, the UE checks whether the determined slot configuration permits uplink transmission. If the configuration indicates downlink or flexible symbols, the UE cancels the transmission to prevent interference. This approach maintains timely transmission when appropriate while preventing harmful interference when the slot is not suitable for uplink.
Data Source
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AI summary
Methods, systems, and devices for wireless communication are described. The examples described herein provide a procedure at a user equipment (UE) for determining whether to transmit radio resource control (RRC) configured uplink signals to a base station based on detected slot format indications (SFIs) and/or undetected SFIs in multiple control channels. In particular, a UE may identify multiple control channels configured to include SFIs from a base station, and, as described herein, the UE may determine whether to transmit RRC configured uplink signals in a set of symbols based on a configuration of the set of symbols (e.g., uplink, downlink, or flexible) determined based on detected SFIs and/or undetected SFIs in the multiple control channels. The UE may be able to determine whether to transmit RRC configured uplink signals in a set of symbols based on any combination of detected SFIs and undetected SFIs.