UL Channel Access Reservation for URLLC Cancellation in Unlicensed Bands
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently managing uplink cancellations and channel access in unlicensed bands, particularly when prioritizing Ultra-Reliable Low-Latency Communication (URLLC) devices over enhanced mobile broadband (e.gMBB) devices, which are often operating in unlicensed frequency bands with potential interference.
Innovation Solution
Implementing techniques for inter-user device uplink cancellation and channel access in unlicensed bands by transmitting unlicensed frequency transmission capability information, receiving and scheduling uplink transmission times, and performing listen-before-talk to ensure efficient use of unlicensed frequency bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If uplink cancellation is implemented to prioritize URLLC devices over eMBB devices in unlicensed bands, then latency for URLLC is reduced, but channel access complexity and interference management difficulty increase
Solution Approach 1:
The system performs preliminary channel sensing and reservation actions before the actual uplink transmission. The gNB schedules cancellation in advance and UEs perform listen-before-talk procedures beforehand, allowing the channel to be reserved and ready for URLLC transmission without waiting until the last moment, thus reducing latency while managing complexity through advance preparation
Solution Approach 2:
The channel access process is segmented into distinct phases: channel sensing, reservation transmission, cancellation indication, and actual data transmission. This segmentation allows each phase to be optimized independently - sensing can be quick, reservation can be brief, and cancellation can be immediate - thereby reducing overall latency while making the complex process more manageable through structured division
2Object-affected harmful factors
If listen-before-talk is performed in unlicensed bands to avoid interference, then interference avoidance is improved, but channel access time and latency increase
Solution Approach 1:
The listen-before-talk procedure is performed as a preliminary action before actual data transmission. The system senses the channel and makes a quick determination about availability, then immediately proceeds with transmission if clear or with cancellation if not. This preliminary sensing approach ensures interference avoidance while minimizing the time spent on channel access by not delaying the actual transmission
Solution Approach 2:
When the channel is sensed as available, the system rushes through the channel access process by immediately transmitting without prolonged waiting or additional verification steps. The cancellation mechanism allows the system to skip ahead to the next available channel slot quickly, reducing the overall channel access time while maintaining interference avoidance through the initial listen-before-talk check
Data Source
AI summary
A technique for wireless communications in a wireless system including: transmitting, from a second user device, unlicensed frequency transmission capability information, receiving an uplink transmission time for the second user device based on the unlicensed frequency transmission capability, receiving, at the second user device, a request to transmit a reservation transmission in an unlicensed frequency band based on a cancellation time capability of a first user device and the uplink transmission time, transmitting, by the second user device, the reservation transmission in the unlicensed frequency band, and transmitting, by the second user device, a higher priority uplink transmission in the unlicensed frequency band.