Uplink Cancellation Indication for Wireless Resource Management
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Solution Overview
Problem
Current wireless communication systems face challenges in efficiently handling transmission cancellations at the physical (PHY) and media access control (MAC) layers due to overlapping transmissions, particularly in scenarios where higher priority communications need to preempt lower priority ones, leading to inefficiencies and increased latency.
Innovation Solution
The implementation of uplink cancellation indications (ULCI) allows user equipment (UE) to receive cancellations for existing transmissions, enabling the UE to drop portions of scheduled communications and reconfigure transmission parameters for subsequent transmissions without altering previous MAC and PHY layer procedures, thus optimizing resource allocation and reducing latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If uplink cancellation indication (ULCI) is implemented to preempt lower priority transmissions, then resource utilization and latency are improved, but system complexity and difficulty of managing overlapping transmissions increase
Solution Approach 1:
The base station sends ULCI indications to UEs in advance before the lower priority transmission occurs, allowing the UE to preemptively cancel the transmission. This preliminary action prevents resource conflicts before they happen, improving resource utilization while maintaining manageable system complexity through clear advance notification.
Solution Approach 2:
The transmission cancellation mechanism is segmented into distinct components: ULCI indication generation at the base station, ULCI reception and processing at the UE, and the actual transmission cancellation action. This segmentation allows each component to be optimized independently, improving overall system efficiency without proportionally increasing complexity.
2Loss of time
If ULCI is used to cancel scheduled transmissions for higher priority communications, then latency is reduced, but the reliability of MAC and PHY layer procedures may be compromised
Solution Approach 1:
The ULCI mechanism applies preliminary anti-action by canceling the lower priority transmission before it can interfere with the higher priority communication. This prevents the harmful effect (interference/latency) from occurring in the first place, reducing latency while maintaining reliability through proactive rather than reactive cancellation.
Solution Approach 2:
The ULCI serves as an intermediary signal between the base station's scheduling decisions and the UE's transmission actions. This intermediary mechanism ensures that cancellation decisions are communicated reliably and processed systematically, maintaining procedure reliability while achieving low latency through efficient intermediation.
3Productivity
If the UE drops portions of scheduled communications based on ULCI, then resource allocation efficiency is improved, but the complexity of managing power control and intra-UE multiplexing increases
Solution Approach 1:
When a ULCI is received, the UE applies partial action by canceling only the specific transmission indicated in the ULCI while maintaining other scheduled transmissions. This selective cancellation improves resource allocation efficiency without requiring complete reconfiguration of all UE transmissions, thereby limiting the increase in power control complexity to only the affected transmission.
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. The method, system, or devices for wireless communications may implement receiving a grant for a first transmission scheduled for a first set of resources, the first transmission associated with a first transmission parameter; receiving an indication to cancel the first transmission; dropping the first transmission based on receiving the indication; determining a second transmission parameter for a second transmission based on the first transmission parameter and irrespective of dropping the first transmission; and performing or receiving the second transmission according to the second transmission parameter. Alternatively, a device may receive an indication to cancel the second transmission; drop the second transmission based on receiving the indication; and refraining from rescheduling the first transmission on the first set of resources based on receiving the indication and irrespective of dropping the second transmission.