5G NR Multicast Feedback HARQ ACK Transmission via PUCCH
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Solution Overview
Problem
The next-generation 5G NR wireless communication system lacks support for reliable feedback mechanisms for multicast or broadcast services, which is crucial for enhancing user experience and system efficiency, particularly in scenarios like public safety and mission-critical applications where reliability and dynamic resource allocation are essential.
Innovation Solution
The method involves a user equipment (UE) receiving radio resource control messages from a base station to provide Hybrid Automatic Repeat Request (HARQ) acknowledgments for physical downlink shared channel receptions, determining physical uplink control channel resources, and transmitting feedback information, while the base station schedules retransmissions using appropriate Radio Network Temporary Identifiers (RNTIs) to ensure reliable feedback transmission for multicast or broadcast services.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If feedback mechanism is added to 5G NR MBS, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent implements a feedback mechanism where UEs transmit HARQ ACK/NACK information on PUCCH resources to indicate successful reception or failure of MBS data, enabling the network to schedule retransmissions only when needed, thus improving reliability while managing complexity through structured feedback protocols
Solution Approach 2:
The patent segments the feedback process into distinct components: separate PUCCH resources for ACK/NACK transmission, dedicated RNTI types (G-RNTI for group feedback, C-RNTI for individual feedback), and differentiated DCI formats for scheduling, which organizes complexity into manageable segments
2Reliability
If HARQ feedback transmission is enabled, then reliability is improved, but loss of time increases
Solution Approach 1:
The patent configures PUCCH resources and HARQ timing parameters in advance through RRC signaling, so that when feedback is needed, the UE can immediately transmit on pre-configured resources without delay, reducing feedback time while maintaining reliability
Solution Approach 2:
The patent implements periodic HARQ feedback cycles where UEs transmit ACK/NACK at scheduled intervals, allowing the network to prepare for subsequent transmissions in advance and reducing overall time loss through rhythmic, predictable feedback patterns
3Productivity
If dynamic resource allocation is implemented, then system efficiency is improved, but device complexity increases
Solution Approach 1:
The patent enables dynamic resource allocation by allowing the network to adjust PDSCH scheduling based on real-time HARQ feedback, switching between group-based (G-RNTI) and UE-specific (C-RNTI) transmission modes, and adapting resource allocation to actual reception conditions, thereby improving efficiency while managing complexity through flexible but structured control
Data Source
AI summary
A method of performing a feedback transmission for a multicast or broadcast service (MBS) for a user equipment (UE) is provided. The method includes receiving, from a base station (BS), a RRC message enabling the UE to provide HARQ ACK information for a PDSCH reception corresponding to the MBS; receiving, from the BS, a first DCI format that schedules a first PDSCH for receiving MBS data, the first DCI format being a DCI format with CRC scrambled by a G-RNTI; determining a PUCCH resource according to the first DCI format; transmitting, to the BS, first HARQ ACK information corresponding to the first PDSCH on the PUCCH resource; and receiving, from the BS, a second PDSCH providing a retransmission of the MBS data, the second PDSCH being scheduled by a second DCI format using the G-RNTI or a C-RNTI.