Slot Format Indication for 5G NR IAB Resource Flexibility
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Solution Overview
Problem
In 3GPP 5G NR multi-hop Integrated Access and Backhaul (IAB) systems, the existing slot format indication mechanisms lose flexibility and cause resource collisions between access and backhaul links due to a half-duplex constraint, and the starting position of Downlink Control Information (DCI) 2_0 being limited to slot boundaries, which impacts resource utilization efficiency.
Innovation Solution
A method and apparatus for indicating slot format information by receiving Radio Resource Control (RRC) signaling to determine the time domain starting position of a slot format, allowing for dynamic indication of resource usage between backhaul and access links, and introducing a new state to differentiate access link resources, enabling more flexible resource allocation and efficient multiplexing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the legacy slot format indication mechanism is reused for IAB systems, then backward compatibility is maintained, but flexibility is lost and resource collisions occur between access and backhaul links
Solution Approach 1:
The slot format indication is segmented into two parts: a new state 'A' is introduced specifically for access link resources, while the legacy states (D, F, U) are retained for backhaul link resources. This segmentation allows the system to differentiate between access and backhaul link requirements, providing flexibility for IAB systems while maintaining backward compatibility with legacy systems that only recognize the original three states.
Solution Approach 2:
The system dynamically selects between legacy and enhanced slot format indication mechanisms based on the specific IAB scenario requirements. When flexibility is needed, the new state 'A' is activated; when backward compatibility is sufficient, the legacy mechanism is used. This dynamic adaptation resolves the contradiction between flexibility and system complexity.
2Productivity
If DCI 2_0 starting position is limited to slot boundary, then legacy compatibility is maintained, but resource utilization efficiency is impacted
Solution Approach 1:
The DCI 2_0 indication mechanism is extended from the traditional slot boundary dimension to the symbol-level dimension. By allowing DCI 2_0 to start at any symbol position within a slot rather than being constrained to slot boundaries, the system gains finer-grained control over resource allocation, thereby improving resource utilization efficiency without fundamentally changing the underlying indication mechanism.
Solution Approach 2:
The starting position parameter of DCI 2 0 is changed from a fixed slot boundary value to a flexible symbol-level value. This parameter change enables more precise resource allocation and improves resource utilization efficiency while maintaining compatibility with the existing DCI structure and processing logic.
Data Source
AI summary
A method and apparatus for indicating slot format information is disclosed. The method comprising: t receiving a RRC (radio resource control) signaling indicating a time domain starting position of a slot format information and determining the time domain starting position based on the RRC signaling.