HARQ-ACK Timeout Control for HARQ-Less Feedback Scheduling
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Solution Overview
Problem
Existing wireless communication systems face inefficiencies in managing HARQ-less feedback scenarios, particularly in dynamic and semi-persistent scheduling, where UEs determine acknowledgement or negative acknowledgement transmissions based on predetermined conditions, including timeout periods, to optimize resource allocation and reduce feedback latency.
Innovation Solution
A method and apparatus for configuring hybrid automatic repeat request acknowledgement (HARQ-ACK) timeouts to activate HARQ-less feedback operations, allowing UEs to transmit ACK/NACK feedback based on network-configured conditions, such as timeout periods, to improve scheduling efficiency and reduce latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If HARQ-ACK feedback is transmitted for every PDSCH reception, then reliability of data transmission is improved, but feedback latency and scheduling overhead increase
Solution Approach 1:
The patent implements dynamic HARQ-ACK feedback by introducing a timeout mechanism where the UE determines whether to transmit feedback based on whether the PDSCH reception occurred within a configured timeout period before a scheduled feedback transmission time. This dynamic approach allows the system to adaptively switch between HARQ-ACK feedback and HARQ-less operation based on timing conditions, resolving the contradiction between reliable feedback transmission and reduced latency.
Solution Approach 2:
The patent changes the feedback transmission parameter by introducing a timeout threshold that dynamically controls whether HARQ-ACK feedback is transmitted. When the time difference between PDSCH reception and scheduled feedback transmission exceeds the timeout, the UE transitions to HARQ-less operation (not transmitting feedback). This parameter-based control mechanism allows the system to balance reliability and latency by adjusting feedback behavior based on timing parameters.
2Loss of time
If HARQ-less feedback operation is implemented to reduce latency, then feedback latency is reduced, but scheduling complexity and resource allocation difficulty increase
Solution Approach 1:
The patent uses feedback from the network entity to the UE regarding the configured timeout value and feedback transmission conditions. The network entity provides downlink control information that configures the timeout parameter, and the UE follows this configuration to determine its feedback behavior. This feedback mechanism simplifies scheduling complexity by having the network entity centrally manage the timeout configuration rather than requiring complex distributed scheduling decisions.
Solution Approach 2:
The UE autonomously determines whether to transmit HARQ-ACK feedback based on the configured timeout parameter and its own timing measurements. The UE self-evaluates whether the PDSCH reception time falls within the timeout period before the scheduled feedback transmission and makes the decision independently without requiring complex network scheduling coordination for each individual feedback instance.
3Productivity
If timeout-based HARQ-less feedback is configured to optimize resource allocation, then resource allocation efficiency is improved, but device complexity for determining feedback conditions increases
Solution Approach 1:
The network entity pre-configures the timeout value and feedback transmission conditions to the UE before the UE needs to make feedback decisions. By providing this configuration in advance through downlink control information, the UE can simply compare its timing measurements against the pre-provided timeout threshold without performing complex real-time analysis, thus improving resource allocation efficiency while keeping device complexity manageable.
Data Source
AI summary
Aspects relate to feedback such as HARQ-ACK/NACK feedback in wireless communication systems. A predetermined condition, such as a timeout condition, is configured for a user equipment (UE) to determine whether a HARQ-less feedback should be implemented in the UE. In a particular aspect, the predetermined condition may be a timeout period or some other condition where a UE will cancel or discard feedback if the UE is unable to respond within the timeout period or meet the condition imposed. Various conditions may be imposed and are communicated through either radio resource control (RRC) signaling or downlink control information (DCI) parameters, or a combination thereof.