PDCCH Transmission in UE-Initiated COT With Subband Sharing
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Solution Overview
Problem
Existing technologies face challenges in efficiently managing PDCCH transmission during UE-initiated Channel Occupancy Time (COT) in unlicensed spectrum, particularly in shared DL slots, due to issues with channel access and resource allocation for both uplink and downlink communications.
Innovation Solution
A method for configuring subbands for uplink data transmission, performing successful channel access procedures, and transmitting uplink control information with indicators to facilitate PDCCH monitoring within the COT, including configuring control resource sets for downlink control channel transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If UE performs channel access procedure on each subband to obtain COT, then uplink data transmission is enabled, but downlink control channel monitoring becomes complex in shared slots
Solution Approach 1:
The patent segments the frequency band into multiple subbands and divides the COT into different time periods (first period for UE uplink transmission, second period for gNB downlink transmission). This segmentation allows independent channel access procedures per subband while managing PDCCH monitoring complexity through time-division in shared slots.
Solution Approach 2:
The patent dynamically configures the COT sharing arrangement where the UE indicates in UCI whether the gNB should transmit PDCCH in shared slots. This dynamic adaptation allows the system to switch between UE-only transmission mode and shared mode based on real-time needs, simplifying PDCCH detection when not required.
2Productivity
If UE transmits uplink data in COT obtained by successful channel access on first set of subbands, then data transmission is enabled, but PDCCH transmission in shared slots becomes unreliable
Solution Approach 1:
The patent applies preliminary action by having the UE perform channel access procedure and obtain COT before the actual uplink data transmission. The UE also preliminarily indicates in UCI whether PDCCH should be transmitted in shared slots, allowing the gNB to prepare accordingly and ensure reliable PDCCH delivery when needed.
Solution Approach 2:
The patent uses feedback mechanisms where the UE includes an indicator in UCI to inform the gNB about the COT status and PDCCH transmission needs. This feedback loop ensures that the gNB adjusts its transmission strategy to maintain reliability, especially in shared slots where both UE and gNB have access rights.
3Ease of operation
If gNB transmits PDCCH in shared slots within UE-initiated COT, then downlink control communication is enabled, but channel access fairness with other wireless systems is compromised
Solution Approach 1:
The patent implements periodic action through the structured COT sharing mechanism where time periods are alternated between UE uplink transmission and gNB downlink transmission. This periodic structure ensures that gNB maintains its channel access rights for PDCCH transmission while respecting the UE's initially obtained COT, thereby preserving fairness with other wireless systems in the unlicensed spectrum.
Solution Approach 2:
The patent changes parameters dynamically, particularly the COT duration and sharing configuration, based on the specific transmission needs. The UE can indicate whether PDCCH should be transmitted in shared slots, allowing flexible adjustment of transmission parameters to balance downlink communication needs with coexistence requirements.
4Reliability
If UE monitors PDCCH in shared slots without configured search space, then downlink control information can be received, but detection complexity increases
Solution Approach 1:
The patent applies universality by configuring the search space to be valid across multiple slots, including shared slots within UE-initiated COT. This multi-functional search space configuration allows the UE to monitor PDCCH in both dedicated UE slots and shared slots without requiring separate configurations, thereby reducing overall device complexity while maintaining reliable downlink control information reception.
Data Source
AI summary
Methods, a remote unit and a base unit are disclosed. According to one embodiment, a method at a remote nit, comprising: receiving, from a base unit, a first signaling for configuring a plurality of subbands for transmitting uplink data; performing a first channel access procedure on each of the plurality of subbands and obtaining a channel occupancy time (COT) on a first set of subbands, wherein the first set of subbands comprises one or more subbands of the plurality of subbands with the first channel access procedures being successful; and transmitting, to the base unit, the uplink data on the first set of subbands within the COT; and transmitting, to the base unit, uplink control information (UCI) associated to the uplink data, wherein the UCI includes a first indicator indicating the first set of subbands.