Uplink Timing Offset Selection for Non-Terrestrial Networks
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Solution Overview
Problem
Wireless communication systems face challenges in managing uplink transmission timing due to large propagation time delays when communicating with Non-Terrestrial Networks (NTNs), leading to conflicts and ambiguities when scheduling offset updates are received, particularly for acknowledgments (ACK/NACK) and other uplink transmissions.
Innovation Solution
The system determines a selected scheduling offset value to use for uplink transmissions by considering the activation time of scheduling offset updates relative to the scheduled transmission time, allowing for accurate alignment of uplink and downlink time slots based on the old or updated Koffset values, ensuring timely and correct transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a scheduling offset update is received between downlink reception and uplink transmission, then the propagation time delay compensation can be updated, but ambiguity arises about whether to use the old or updated Koffset value for the uplink transmission
Solution Approach 1:
The patent applies preliminary action by determining the activation time of the scheduling offset update in advance and comparing it with the downlink reception time and uplink transmission time. This allows the system to pre-establish clear rules for selecting between old and updated Koffset values based on timing relationships, eliminating ambiguity before the uplink transmission occurs. The activation time determination is performed proactively rather than reactively at transmission moment.
Solution Approach 2:
The patent implements dynamics by making the Koffset value dynamic based on the timing relationship between activation time, downlink reception time, and uplink transmission time. The system transitions from a static Koffset value to a dynamically selected value (old or updated) depending on whether the activation time falls within specific time windows relative to the downlink and uplink timings, allowing adaptive timing alignment.
2Productivity
If the activation time of a scheduling offset update falls between the downlink reception time and uplink transmission time, then the updated Koffset can be applied, but this creates timing conflicts and transmission errors
Solution Approach 1:
The patent determines the activation time of the scheduling offset update in advance and compares it with the downlink reception time and uplink transmission time to proactively identify potential timing conflicts. By performing this timing relationship analysis before uplink transmission, the system can pre-determine which Koffset value to use, preventing transmission errors caused by ambiguous timing scenarios.
Solution Approach 2:
The patent implements feedback by using the activation time information to determine whether to apply the old or updated Koffset value. The system receives feedback about the activation time from the network and uses this feedback to adjust the timing selection, ensuring that the correct Koffset is applied based on the actual timing relationship between downlink reception, activation, and uplink transmission.
3Adaptability or versatility
If multiple K1 values are used for different uplink time slots, then scheduling flexibility is improved, but the complexity of managing timing offsets increases when Koffset updates occur
Solution Approach 1:
The patent applies preliminary action by determining the activation time of Koffset updates in advance and comparing it with the scheduled uplink transmission time. This allows the system to pre-determine whether to use old or updated Koffset values for each uplink transmission, simplifying the management of multiple K1 values by providing a clear selection criterion based on timing relationships rather than complex dynamic adjustments.
Solution Approach 2:
The patent implements dynamics by making the Koffset selection dynamic based on the relationship between activation time and uplink transmission time. The system adapts the Koffset value (old or updated) dynamically for each uplink transmission based on whether the activation time falls before or after the uplink transmission time, maintaining scheduling flexibility while providing clear management rules.
Data Source
AI summary
Systems and techniques are provided for wireless communications. For example, an apparatus (e.g., a user equipment (UE)) may receive a downlink transmission in a first downlink time slot and receiving an update to a scheduling offset associated with a propagation time delay of communications between the apparatus and a network entity. The update indicates an updated scheduling offset. The apparatus may determine a selected scheduling offset as one of the scheduling offset or the updated scheduling offset. The apparatus may transmit, using a second uplink time slot, an uplink transmission associated with the downlink transmission. The second uplink time slot may be determined based on a first uplink time slot and the selected scheduling offset.