Semi-Persistent MBS Scheduling to Cut NR Downlink Signaling
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Solution Overview
Problem
The existing method for multicast/broadcast services in new radio (NR) results in a waste of air interface resources due to the need for the base station to send separate downlink control information to each user equipment for scheduling the same physical downlink shared channel, leading to inefficient resource utilization.
Innovation Solution
A semi-persistent scheduling method where terminal devices receive semi-persistent configuration information, including identifiers and PDSCH-related information, and activate this configuration upon receiving activation information, allowing for efficient multicast/broadcast data transmission without the need for repeated signaling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate DCI is sent to each UE for scheduling the same PDSCH resource, then each UE can receive MBS data individually with dedicated control information, but air interface resources are wasted due to redundant signaling
Solution Approach 1:
The patent merges the control information for multiple UEs into a single group DCI message. Instead of sending separate DCI to each UE, the base station sends one group DCI that schedules PDSCH resources for multiple UEs simultaneously. This combining approach reduces redundant signaling and saves air interface resources while maintaining individual UE data reception capability through unique PUCCH resources assigned to each UE.
Solution Approach 2:
The group DCI is designed to serve multiple UEs universally. A single DCI message with group identifier can schedule PDSCH resources that are accessible by multiple UEs in the group. Each UE distinguishes its own data through unique PUCCH resources for feedback, allowing one control message to perform the function of multiple individual DCI messages.
2Reliability
If separate DCI is sent to each UE, then individual PUCCH resources can be allocated for HARQ feedback, but the complexity of control signaling increases
Solution Approach 1:
The patent segments the control signaling into two parts: a shared group DCI for common PDSCH scheduling information, and individual PUCCH resources for UE-specific HARQ feedback. This segmentation allows the control signaling complexity to be reduced at the downlink (single group DCI instead of multiple individual DCI) while maintaining uplink feedback capability through dedicated PUCCH resources for each UE.
3Reliability
If semi-persistent configuration information is sent repeatedly, then UEs can maintain accurate scheduling information, but air interface resources are consumed
Solution Approach 1:
The patent applies preliminary action by configuring semi-persistent scheduling information in advance for multiple UEs. The base station pre-allocates PDSCH resources and associated PUCCH resources for HARQ feedback before actual data transmission. This preliminary configuration reduces the need for repeated control signaling during data transmission, as UEs can autonomously use the pre-configured resources according to the activation indication, thereby saving air interface resources while maintaining scheduling accuracy.
Data Source
AI summary
The present application provides a semi-persistent scheduling method for a multicast/broadcast service, an apparatus and a storage medium. A network device configures semi-persistent configuration information for terminal devices in advance, and the semi- persistent configuration information includes a first identifier for scrambling activation information and related information of a PDSCH for sending a multicast/broadcast service. Every time multicast/broadcast service data transmission is required, the network device sends the activation information to terminal devices according to the first identifier to indicate activating the semi-persistent configuration information, and then sends the PDSCH to the terminal devices by multicast/broadcast according to the semi-persistent configuration information, to realize that multicast/broadcast service data is transmitted from the network device to N terminal devices by multicast/broadcast.