Receiver Selective HARQ Feedback for Point-to-Multipoint QoS
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Solution Overview
Problem
In communication systems, the probability of erroneous reception increases with the number of receivers in broadcast communication using hybrid automatic repeat request (HARQ), leading to increased retransmissions and reduced system efficiency, as current methods do not effectively manage feedback based on quality of service (QoS) thresholds.
Innovation Solution
Implementing quality of service thresholds at the receiver to determine whether to send ACK, NACK, or no feedback for erroneously received transport blocks, configuring the medium access control (MAC) layer to align with QoS parameters such as packet loss rate and delay budget, and provisioning user equipment (UE) with QoS information to optimize HARQ feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If HARQ feedback is applied to broadcast communication with multiple receivers, then error correction capability is improved, but the probability of NACK increases in proportion to the number of receivers, leading to increased retransmissions and reduced system efficiency
Solution Approach 1:
The patent changes the feedback mechanism parameter by introducing QoS thresholds that modify the binary ACK/NACK decision into a multi-level feedback system. Receivers compare their reception quality against QoS thresholds to determine whether to request retransmission, thereby changing the feedback parameter from simple error detection to quality-driven selective acknowledgment.
Solution Approach 2:
The patent makes the feedback behavior dynamic by allowing receivers to adaptively decide whether to send ACK, NACK, or no feedback based on real-time reception quality relative to QoS thresholds. This dynamic decision-making process optimizes system efficiency by reducing unnecessary retransmissions while maintaining reliable delivery for critical data.
2Reliability
If more robust channel coding is used to reduce the probability of NACKs, then reception reliability is improved, but spectral efficiency decreases
Solution Approach 1:
The patent applies partial action by having receivers selectively request retransmissions only when QoS thresholds are not met, rather than requesting retransmission for every erroneous packet. This partial feedback approach reduces the number of retransmissions needed, allowing the system to use less robust coding while maintaining reliability, thereby improving spectral efficiency.
3Adaptability or versatility
If the transmitter uses the same channel coding schemes as unicast transmission, then coding flexibility is maintained, but the probability of erroneous reception increases with the number of receivers
Solution Approach 1:
The patent introduces quality-of-service-driven feedback mechanisms where receivers provide selective ACK/NACK feedback based on QoS threshold comparisons. This feedback loop allows the transmitter to maintain coding flexibility while receiving information about actual reception quality, enabling adaptive retransmission decisions that compensate for the increased error probability in broadcast scenarios.
Data Source
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AI summary
Various communication systems, such as radio access networks, may benefit from various error correction techniques. For example, certain communication systems may benefit from quality of service driven receiver selective hybrid automatic repeat request for point-to-multipoint communication. A method can include identifying, at a receiver, at least one quality of service threshold. The method can also include identifying, at the receiver, at least one quality of service. The method can further include determining, at the receiver, whether or what kind of feedback is to be used for an erroneously received transport block based on the identified at least one quality of service threshold and the identified at least one quality of service. The method can additionally include communicating, by the receiver, with a transmitter of the erroneously received transport block based on the determination.