NR Uu Broadcast and Groupcast Scheduling With DCI Search Space Control
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Solution Overview
Problem
Existing NR Uu interface scheduling mechanisms are inadequate for efficient broadcast and groupcast transmissions, particularly in scenarios requiring higher reliability and lower latency, such as V2X communication and public safety, due to the lack of defined BWP, CORESET, and search space configurations for these services.
Innovation Solution
Introduce group-based, UE-specific, and sub-group-based scheduling schemes, including group common DCI, dedicated DCIs, and semi-persistent scheduling for NR MBS, with enhancements like G-RNTI, G-SPS-RNTI, and specific configurations for BWP, CORESET, and search space to support broadcast and groupcast transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional unicast scheduling mechanisms are used for broadcast and groupcast services, then the system can maintain simple scheduling procedures, but transmission efficiency and scheduling flexibility deteriorate for multi-UE scenarios
Solution Approach 1:
The DCI format 1_1 is enhanced to serve multiple purposes: it can schedule both unicast PDSCH transmissions and broadcast/groupcast PDSCH transmissions. The same DCI structure is used, but with flexible interpretation of certain fields depending on the RNTI type (C-RNTI for unicast, G-RNTI for groupcast, SI-RNTI for broadcast) and the castType indicator, allowing a single scheduling mechanism to handle diverse service types efficiently
Solution Approach 2:
The scheduling mechanism is segmented by introducing a castType indicator field that divides the scheduling space into unicast and broadcast/groupcast segments. This allows the system to apply different scheduling rules and resource allocation methods appropriate for each service type while using a unified DCI format, improving transmission efficiency without sacrificing procedural simplicity
2Adaptability or versatility
If dynamic scheduling is used for broadcast and groupcast, then scheduling flexibility is improved, but latency increases due to continuous monitoring requirements
Solution Approach 1:
The system implements dynamic scheduling where the DCI format 1_1 can be dynamically adjusted to indicate broadcast or groupcast transmissions through the castType indicator. This allows the scheduler to adapt resource allocation, modulation and coding schemes, and other parameters in real-time based on channel conditions and service requirements, providing flexibility while managing latency through efficient resource utilization
Solution Approach 2:
The system supports both dynamic and periodic scheduling approaches. For broadcast and groupcast services, periodic scheduling can be implemented where UEs monitor PDSCH at predetermined intervals rather than continuously, reducing latency while maintaining scheduling flexibility through the enhanced DCI format that can indicate periodic transmission patterns
3Reliability
If blind decoding is performed across the entire spectrum, then scheduling detection reliability is improved, but power consumption increases
Solution Approach 1:
The system applies local quality by configuring UEs with specific search space sets and CORESETs where broadcast and groupcast DCIs are located. Instead of blind decoding the entire spectrum, UEs focus their decoding efforts on these locally defined regions, maintaining detection reliability through targeted monitoring while significantly reducing power consumption by avoiding unnecessary full-spectrum scanning
Data Source
AI summary
Methods, systems, and apparatuses may assist scheduling for broadcast and groupcast on new radio Uu interface. In an example, there may be broadcast and groupcast transmission scheduling mechanism with: group based scheduling, UE specific based scheduling, or sub-group based scheduling. In another example, there may be a serving cell configuration for broadcast and groupcast transmission with dedicated cell for broadcast and groupcast, or broadcast and groupcast cell which is shared with the cell for unicast. In another example, there may be downlink control related configuration for broadcast and groupcast transmission with details of the BWP configuration, the CORESET configuration, or the search space configuration.