Multicast HARQ-ACK Feedback Control via DCI Indication
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Solution Overview
Problem
Current communication systems face challenges in efficiently transmitting and receiving multicast physical downlink shared channels (PDSCH) and multicast hybrid automatic repeat request (HARQ) feedback, particularly in 5G networks with higher frequency bands, where prioritization and feedback mechanisms are complex and inefficient.
Innovation Solution
The method involves a terminal receiving RRC messages and DCI from a base station to generate and transmit HARQ codebooks, including HARQ-ACK bits for both multicast and unicast PDSCHs, even when HARQ-ACK feedback is disabled, allowing for prioritization and efficient transmission based on scheduling information and resource allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If HARQ-ACK feedback is disabled for multicast PDSCH to reduce feedback overhead, then feedback complexity is reduced, but reliable transmission confirmation is lost
Solution Approach 1:
The patent extracts the HARQ-ACK feedback requirement specifically for multicast PDSCH by introducing a separate indication field in DCI. This allows the system to selectively enable or disable HARQ-ACK feedback for multicast transmissions independently from unicast transmissions, reducing overall feedback complexity while maintaining reliability where needed through separate control mechanisms.
2Reliability
If separate HARQ codebooks are generated for multicast and unicast PDSCH to ensure reliable delivery, then transmission reliability is improved, but processing complexity increases
Solution Approach 1:
The patent segments the HARQ codebook into separate multicast and unicast portions, with distinct generation rules for each. Multicast HARQ-ACK bits are generated based on specific DCI indications while unicast HARQ-ACK bits follow traditional generation rules. This segmentation allows reliable delivery for both types while managing processing complexity through standardized separate procedures.
Solution Approach 2:
The patent creates a universal HARQ codebook structure that can accommodate both multicast and unicast PDSCH feedback requirements. The same codebook transmission mechanism handles both types of feedback, with the base station interpreting the combined HARQ-ACK bits according to the specific DCI indications received, reducing the need for separate processing paths.
3Reliability
If HARQ-ACK bits are generated for all multicast PDSCH to ensure acknowledgment, then transmission reliability is improved, but feedback overhead increases
Solution Approach 1:
The patent introduces dynamic control of HARQ-ACK feedback for multicast PDSCH through DCI indications. The base station can dynamically enable or disable HARQ-ACK feedback on a per-multicast-PDSCH basis using fields in the DCI, allowing the system to adapt feedback overhead to actual transmission reliability requirements rather than always generating acknowledgments.
Solution Approach 2:
The patent changes the parameter of feedback generation from a fixed rule to a dynamically controllable parameter. By using DCI fields to indicate whether HARQ-ACK feedback should be generated for each multicast PDSCH, the system can adjust the feedback overhead parameter based on traffic conditions, channel quality, and reliability requirements, reducing overhead when full acknowledgment is not necessary.
Data Source
AI summary
A method and a device for supporting multicast transmission are disclosed. A terminal operating method comprises the steps of: receiving, from a base station, an RRC message indicating the activation of HARQ-ACK feedback; receiving, from the base station, a first DCI including information indicating deactivation of the HARQ-ACK feedback; receiving, from the base station, a first multicast PDSCH on the basis of first scheduling information included in the first DCI; generating a first HARQ-ACK bit for the first multicast PDSCH even if the first DCI indicates deactivation of the HARQ-ACK feedback; generating a HARQ codebook including the first HARQ-ACK bit; and transmitting, to the base station, the HARQ codebook through an uplink channel.