Uplink Transmission Timing in Shared Spectrum
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Solution Overview
Problem
Existing wireless communication systems face challenges in managing the timeline for ultra-reliable low-latency communication (URLLC) operations in shared spectra, particularly due to the need to validate next-generation NodeB (gNB) channel occupancy assumptions for uplink transmissions.
Innovation Solution
The proposed solution involves methods and systems that manage the timeline for URLLC operations by determining when to generate and transmit a transport block for a medium access control (MAC) protocol data unit via a physical uplink shared channel (PUSCH) transmission. This includes detecting downlink transmission bursts and determining the length of these bursts to segment actual repetitions accordingly, and configuring retransmission timers to manage hybrid automatic repeat request processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a communication device transmits uplink data in a shared spectrum without validating gNB channel occupancy assumption, then transmission latency is reduced, but transmission reliability deteriorates due to potential channel conflicts
Solution Approach 1:
The communication device performs preliminary validation by detecting downlink transmission bursts from the gNB within the fixed frame period to confirm channel occupancy assumption before transmitting uplink data. This advance verification ensures channel availability while maintaining efficient transmission timing.
Solution Approach 2:
The device monitors downlink transmission bursts as feedback indicators from the gNB to validate whether the channel is occupied. This feedback mechanism allows the device to make informed transmission decisions based on actual gNB channel usage, balancing reliability and latency.
2Reliability
If the communication device validates gNB channel occupancy by detecting downlink transmission bursts, then transmission reliability is improved, but transmission latency increases due to additional detection time
Solution Approach 1:
The gNB configures the fixed frame period and downlink transmission burst timing in advance, allowing the communication device to perform validation at predetermined intervals without ad-hoc delays. The validation process is integrated into the existing frame structure, minimizing additional latency.
3Productivity
If the communication device segments PUSCH repetitions around gNB idle periods, then channel access efficiency is improved, but transmission complexity increases
Solution Approach 1:
The physical uplink shared channel repetitions are segmented into multiple parts, with gaps inserted at gNB idle periods. This segmentation allows the device to transmit data during gNB active periods while avoiding channel conflicts, improving overall channel access efficiency despite the added segmentation logic.
Solution Approach 2:
The transmission schedule is dynamically adjusted based on gNB idle period detection. The device flexibly segments and reschedules PUSCH repetitions according to actual gNB channel usage patterns, optimizing channel access while managing complexity through adaptive rather than static scheduling.
Data Source
AI summary
Various aspects relate to a device that receives a configured uplink grant from a base station for semi-persistent uplink transmissions, receives a configuration for a retransmission timer, receives a configuration of a next-generation NodeB (gNB) fixed frame period (FFP) for semi-static channel access in a shared spectrum, detects a downlink transmission burst within gNB-FFP, and obtains a medium access control protocol data unit for a configured uplink transmission that includes a first physical uplink shared channel (PUSCH) transmission. A communications manager establishes that a hybrid automatic repeat request process associated with the first PUSCH transmission is pending so as to preclude performance of the first PUSCH transmission in response to determinations that the first PUSCH transmission is associated with a gNB channel occupancy time (COT), there is a time gap between the downlink transmission burst within the gNB-COT, and the first PUSCH transmission is smaller than a time gap threshold.