SPS HARQ-ACK Feedback Timing Within Maximum Delay Windows
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Solution Overview
Problem
In wireless communication systems, particularly in ultra-reliable low-latency communications, the timely transmission of HARQ-ACK feedback for semi-persistent scheduling (SPS) is challenging due to difficulties in identifying available uplink resources within the expected response window, leading to ineffective acknowledgement and potential communication service unavailability.
Innovation Solution
A method and apparatus for managing HARQ-ACK feedback in user equipment (UE) by determining a maximum allowed feedback time delay and identifying available physical channel occasions for transmission within this delay, allowing the feedback message to be transmitted only if it can be sent within this time, otherwise it is skipped.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the feedback message is transmitted using semi-persistent scheduling to reduce control channel overhead, then resource efficiency is improved, but the ability to timely identify available uplink resources within the expected response window deteriorates
Solution Approach 1:
The system pre-configures multiple candidate feedback time points and corresponding physical channel occasions in advance through semi-persistent scheduling. When a feedback message needs to be transmitted, the UE can directly use the pre-configured information to identify suitable transmission opportunities without real-time resource allocation overhead, thus resolving the contradiction between reducing control channel overhead and maintaining timely feedback transmission.
2Productivity
If the feedback message transmission is delayed to wait for an available physical channel occasion, then resource utilization is improved, but the feedback effectiveness deteriorates when the delay exceeds the maximum allowed feedback time delay
Solution Approach 1:
The system pre-configures multiple candidate feedback time points with their corresponding physical channel occasions in advance. When determining where to transmit feedback, the UE checks these pre-configured options against the maximum allowed feedback time delay requirement, selecting the earliest suitable occasion that meets the timing constraint. This ensures both efficient resource utilization and guaranteed feedback effectiveness.
Solution Approach 2:
The system dynamically selects from multiple pre-configured feedback time points based on current conditions. The UE evaluates which pre-configured physical channel occasions are available and suitable for transmission within the maximum allowed feedback time delay, adapting the selection to real-time channel conditions and resource availability while maintaining reliability.
3Loss of energy
If the feedback message is not transmitted when no suitable physical channel occasion is available within the maximum allowed feedback time delay, then resource wastage is avoided, but communication service availability may deteriorate
Solution Approach 1:
By pre-configuring multiple candidate feedback time points and their corresponding physical channel occasions, the system ensures that there is always a predetermined suitable transmission opportunity available within the maximum allowed feedback time delay. This eliminates the need to transmit feedback outside the allowed window, avoiding resource wastage while guaranteeing communication service availability.
Data Source
AI summary
A method and apparatus are provided, in which information of a feedback time for transmitting a feedback message from the user equipment for a physical shared channel message is received. A maximum allowed feedback time delay associated with the feedback message for the physical shared channel message is determined. A physical channel occasion available to be used by the user equipment for transmitting the feedback message is identified. The feedback message is transmitted when the identified available physical channel occasion, which is available to be used for the feedback message, allows for the feedback message to be transmitted within the maximum allowed feedback time delay, otherwise the feedback message is not transmitted, when the identified available physical channel occasion does not allow for the feedback message to be transmitted within the maximum allowed feedback time delay.