IAB Slot Formats for Flexible DL-UL Spatial Multiplexing
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Solution Overview
Problem
Existing wireless communication technologies in integrated access and backhaul networks face limitations in supporting space division multiplexing due to restrictive downlink-uplink (DL-UL) slot format configurations, particularly the DL-F-UL pattern, which hinders efficient resource allocation and utilization in IAB nodes.
Innovation Solution
Implementing semi-static and dynamic slot format configurations that allow for flexible DL-UL patterns, such as UL-F-DL, and dynamic slot format indication (SFI) to match resource directions at both the IAB mobile termination (MT) and distributed unit (DU), enabling support for spatial multiplexing through enhanced resource allocation schemes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If DL-F-UL slot format configuration is used in IAB nodes, then resource allocation follows standard patterns, but space division multiplexing support is limited
Solution Approach 1:
The patent introduces dynamic slot format indication (SFI) that allows the slot format to be changed dynamically through DCI signaling. This enables the IAB node to adapt between different DL-UL patterns (DL-F-UL, UL-F-DL, etc.) based on spatial multiplexing requirements, resolving the contradiction by making the configuration flexible rather than fixed.
Solution Approach 2:
The patent changes the slot format parameters (DL-UL pattern, flexible symbol positions) to support both DL-F-UL and UL-F-DL configurations. By allowing parameter changes in the slot format structure, the system can enable space division multiplexing while maintaining manageable configuration complexity through standardized parameter sets.
2Productivity
If flexible DL-UL patterns are implemented, then resource utilization improves, but configuration and signaling complexity increases
Solution Approach 1:
The patent uses RRC signaling to pre-configure multiple slot format patterns (including DL-F-UL and UL-F-DL) before actual transmission. This preliminary configuration allows the system to have flexible resource allocation capabilities ready, while the actual dynamic selection is simplified through SFI indication, thus improving resource utilization without proportionally increasing configuration complexity.
Solution Approach 2:
The patent creates a universal slot format configuration framework that can support multiple DL-UL patterns (DL-F-UL, UL-F-DL, and variations) through a unified SFI mechanism. This multi-functional approach allows single configuration structures to serve multiple resource allocation needs, improving productivity while controlling complexity through reuse of common configuration elements.
3Adaptability or versatility
If slot formats are configured to match resource directions at IAB MT and DU, then spatial multiplexing is enabled, but signaling overhead increases
Solution Approach 1:
The patent introduces SFI as an intermediary mechanism that carries slot format indication information efficiently. The SFI provides a compact representation of the slot format configuration, allowing the IAB node to understand the resource direction alignment between MT and DU without requiring extensive explicit signaling, thus enabling spatial multiplexing while controlling signaling overhead.
Solution Approach 2:
The patent uses RRC signaling to pre-define and store multiple slot format patterns in both the IAB MT and DU. This copying of configuration patterns to both sides beforehand allows them to independently understand the resource direction alignment, reducing the need for continuous explicit signaling and thereby reducing signaling overhead while maintaining adaptability.
Data Source
AI summary
Resource allocation is provided for an integrated access and backhaul (IAB) network, such as a distributed unit (DU) of an IAB. Methods and systems for allocating resources include allocating a first cell-specific pattern of downlink-flexible-uplink (DL-F-UL) availability for one or more slots, allocating a second cell-specific pattern of DL-F-UL availability for the one or more slots. The IAB DU can signal one or more of the first and second cell-specific patterns to an other IAB DU. At least one of the first cell-specific pattern and the second cell-specific pattern defines a slot format different from a DL-F-UL format. Slot format configuration (e.g., semi-static or dynamic SFI) are provided to support space division multiplexing/spatial multiplexing (SDM).