Multicast DRX Feedback Timing for Reliable 5G NR Reception
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Solution Overview
Problem
Existing wireless communications systems, particularly 4G and 5G systems, struggle to provide suitable discontinuous reception (DRX) operations for multicast communications, leading to inadequate support for high reliability and low latency multicast services.
Innovation Solution
Configuring communication devices with device-specific and group-specific feedback mechanisms, including hybrid automatic repeat request (HARQ) feedback, to optimize DRX operations for multicast communications in 5G systems, utilizing multicast-specific timers such as the multicast feedback timer and retransmission timer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If discontinuous reception (DRX) operations are implemented for multicast communications in existing wireless systems, then power consumption is reduced and device autonomy is improved, but the system fails to provide suitable DRX operations for high reliability and low latency multicast services
Solution Approach 1:
The patent segments the feedback mechanism into device-specific feedback and group-specific feedback modes. Device-specific feedback allows individual UEs to provide HARQ acknowledgments for reliable delivery, while group-specific feedback enables collective feedback for power-efficient operation. This segmentation resolves the contradiction by allowing the system to switch between reliability-focused and power-saving modes based on service requirements.
Solution Approach 2:
The patent introduces dynamic configuration of feedback modes through RRC signaling, allowing the network to adaptively switch between device-specific and group-specific feedback modes. The gNB can dynamically adjust DRX parameters and feedback requirements based on current service demands, resolving the contradiction between power efficiency and service reliability by making the system adaptable to different operational scenarios.
2Reliability
If feedback mechanisms are added to support high reliability multicast services, then service reliability improves, but device complexity and processing overhead increase
Solution Approach 1:
The patent extracts the feedback requirement from the universal DRX operation and makes it configurable. Instead of always requiring complex device-specific feedback, the system can extract feedback requirements based on service type, using group-specific feedback for less critical services and device-specific feedback only when high reliability is needed. This reduces overall device complexity while maintaining reliability where necessary.
Solution Approach 2:
The patent creates a universal feedback framework that can operate in multiple modes (device-specific and group-specific). The same DRX infrastructure supports both high-reliability unicast-like multicast and power-efficient broadcast-like multicast services. This multi-functionality reduces the need for separate complex mechanisms for different service types.
3Reliability
If device-specific feedback is implemented for every multicast transmission, then high reliability is achieved, but spectral efficiency and system capacity deteriorate
Solution Approach 1:
The patent merges multiple feedback approaches into a unified configurable framework. By combining device-specific and group-specific feedback modes, the system can achieve high reliability when needed while maintaining spectral efficiency through selective use of feedback mechanisms. The gNB merges feedback from multiple UEs at the group level when appropriate, reducing uplink overhead while maintaining service quality.
4Loss of time
If DRX cycles are shortened to reduce latency for multicast services, then low latency is achieved, but power consumption increases and device autonomy decreases
Solution Approach 1:
The patent applies different DRX configurations to different multicast services based on their specific requirements. Critical low-latency services receive shorter DRX cycles with device-specific feedback for immediate acknowledgment, while non-critical services use longer DRX cycles with group-specific feedback for power efficiency. This local optimization resolves the contradiction by tailoring DRX parameters to service quality requirements rather than applying a uniform configuration.
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AI summary
Methods, systems, and devices for wireless communications are described. A communication device, such as a user equipment (UE) may receive, in an active duration of a multicast discontinuous reception (DRX) cycle, downlink control information indicating resources of a downlink data channel for a multicast message for a plurality of UE. The UE may monitor the indicated resources for the multicast message, as well as transmit, based on the monitoring the indicated resources, a feedback message corresponding to the multicast message. The UE may initiate a multicast feedback timer based on the monitoring the indicated resources for the multicast message, the multicast feedback timer indicating a time for monitoring for a retransmission of the multicast message. The multicast feedback timer may be different than a unicast feedback timer associated with unicast messages for the UE. In some examples, the UE may initiate a multicast retransmission timer following the multicast feedback timer. The multicast retransmission timer may be different than a unicast retransmission timer associated with the unicast messages.