Full Duplex COT Sharing in Unlicensed Spectrum
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Solution Overview
Problem
Current wireless communication systems in unlicensed spectrum, particularly for 5G NR, face limitations in full duplex operation due to time-division duplexing, which restricts simultaneous uplink and downlink transmissions, leading to inefficiencies in spectral usage and increased latency.
Innovation Solution
Implementing procedures for full duplex operation in unlicensed spectrum by allowing simultaneous uplink and downlink transmissions through the use of Channel Occupancy Time (COT) sharing information, where UEs and gNBs can transmit and receive data concurrently by adjusting transmission durations and offsets, enabling gNBs to initiate downlink transmissions without sensing the medium during uplink receptions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If time-division duplexing is used to avoid interference in unlicensed spectrum, then interference between uplink and downlink transmissions is reduced, but simultaneous uplink and downlink transmission opportunities are limited and spectral efficiency deteriorates
Solution Approach 1:
The patent segments the channel occupancy time into multiple portions, allowing different UEs to have simultaneous uplink and downlink transmissions in different time segments. The gNB divides the COT into first and second portions, where first UEs transmit uplink in the first portion while second UEs receive downlink in the second portion, enabling parallel communications that improve spectral efficiency while maintaining interference avoidance through temporal segmentation.
2Reliability
If time-division duplexing is implemented to prevent UL and DL interference, then network reliability is improved, but transmission latency increases due to sequential access
Solution Approach 1:
The patent enables continuous useful action by allowing overlapping uplink and downlink transmissions within the same channel occupancy time. Instead of sequential TDD switching, the gNB maintains continuous transmission opportunities by scheduling uplink for some UEs and downlink for other UEs simultaneously in different time portions of the COT, eliminating idle switching periods and reducing transmission latency while preventing interference through coordinated scheduling.
3Productivity
If a UE initiates a COT for uplink transmission, then the UE can transmit without sensing the medium, but the gNB cannot simultaneously perform downlink transmissions without performing clear channel assessment
Solution Approach 1:
The patent applies local quality by granting different transmission rights to different UEs within the same COT. The gNB identifies a first UE that initiated the COT and grants it uplink transmission rights without sensing, while simultaneously identifying second UEs and granting them downlink transmission rights. This localized differentiation allows the gNB to enable full-duplex operation where specific UEs can transmit and receive simultaneously without requiring all UEs to perform clear channel assessment, thus maintaining both uplink efficiency and downlink versatility.
Data Source
AI summary
Apparatuses, methods, and systems are disclosed for full duplex operation in unlicensed spectrum. One method includes receives UCI containing first COT sharing information and second COT sharing information. The first COT sharing information includes a first duration and a first offset from the end of a slot where the UCI is detected. The second COT sharing information includes a second duration different than the first duration. The method includes transmitting a first set of DL transmissions to a first set of UEs for the duration of the first duration and transmitting a second set of DL transmissions to a second set of UEs for the duration of the second duration, where the first set of DL transmissions occurs after the first offset and where the first UE belongs to the first set of UEs.