COT Initiator Determination for Unlicensed Spectrum PUSCH
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Solution Overview
Problem
In wireless networks operating in unlicensed spectrum, determining the channel occupancy initiator for physical uplink shared channel (PUSCH) transmissions is challenging, especially in frame-based equipment mode, where clear channel assessment is performed before transmission, and there is a need to differentiate between UE-initiated and gNB-initiated channel occupancy times to avoid collisions and optimize resource allocation.
Innovation Solution
A method and apparatus that determine the channel occupancy time (COT) initiator for each PUSCH transmission, allowing the transceiver to transmit without overlapping with idle periods of the determined COTs, by using scheduling downlink control information (DCI) to identify and manage COT initiators for each PUSCH transmission, enabling efficient resource allocation and collision avoidance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If clear channel assessment (LBT) is performed before transmission in unlicensed spectrum, then channel access reliability is improved, but transmission delay increases due to the additional sensing period
Solution Approach 1:
The system performs clear channel assessment (LBT) in advance during idle periods before actual data transmission begins. This preliminary channel sensing ensures the channel is free before committing to transmission, improving reliability while minimizing impact on data transmission timing.
Solution Approach 2:
The channel access mechanism dynamically adjusts transmission timing based on LBT outcomes. When the channel is sensed as idle, transmission can begin immediately; when busy, transmission is deferred. This dynamic adaptation optimizes both reliability and timing efficiency in unlicensed spectrum.
2Device complexity
If multiple PUSCH transmissions are scheduled without distinguishing COT initiators, then resource allocation simplicity is improved, but collision probability increases
Solution Approach 1:
The system segments multiple PUSCH transmissions by identifying and marking the COT initiator for each transmission. This segmentation allows the network to distinguish between UE-initiated and gNB-initiated transmissions, enabling collision avoidance mechanisms while maintaining manageable resource allocation through structured identification.
Solution Approach 2:
The COT initiator identification provides feedback information to both the UE and gNB about which entity initiated each COT. This feedback enables both parties to make informed decisions about subsequent transmissions, reducing collision probability while keeping resource allocation rules clear and implementable.
3Productivity
If PUSCH transmissions overlap with idle periods of COT, then resource utilization efficiency is improved, but protocol compliance deteriorates
Solution Approach 1:
The system applies different rules to different portions of PUSCH transmissions based on their relationship with COT idle periods. Transmissions that would overlap with idle periods are identified and adjusted locally, while other portions can proceed normally. This selective application maintains protocol compliance without unnecessarily reducing overall resource utilization efficiency.
Data Source
AI summary
Apparatuses, methods, and systems are disclosed for channel occupancy initiator determination for transmissions in unlicensed spectrum. An apparatus (700) includes a transceiver (725) that receives a scheduling downlink control information (“DCI”) for scheduling a set of physical uplink shared channel (“PUSCH”) transmissions, the set of PUSCH transmissions comprising at least two PUSCH transmissions. The apparatus (700) includes a processor (705) that determines a channel occupancy time (“COT”) initiator for each PUSCH transmission of the set of PUSCH transmissions and determines a set of COTs associated with the set of PUSCH transmissions based on the determined COT initiator for each PUSCH transmission of the set of PUSCH transmissions. The transceiver (725) transmits the set of PUSCH transmissions without transmitting a set of symbols of the set of PUSCH transmissions that overlap with idle periods of the determined set of COTs.