IAB Bearer Mapping Using DSCP and Flow Labels for Multi-Hop QoS
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Solution Overview
Problem
Existing IAB networks face challenges in efficiently mapping user equipment bearers to backhaul RLC channels, particularly in multi-hop scenarios, with unclear signaling aspects for bearer mapping configurations.
Innovation Solution
The proposed solution involves the central unit control plane (CU-CP) of a donor base station transmitting mapping information to distribute unit (DU) and IAB nodes to map field values to backhaul RLC channels, using differentiated services code point (DSCP) and IPv6 Flow Label values for both downlink and uplink packets, enabling flexible 1:1 or N:1 bearer mappings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If wireless backhaul links are deployed to connect small cells to the operator's network, then deployment cost and practicality are improved, but QoS handling and bearer mapping complexity increase
Solution Approach 1:
The patent introduces a BAP layer as an intermediary between the IP layer and RLC layer to handle bearer mapping and routing functions. This intermediary layer simplifies the complexity by providing a standardized interface and protocol for QoS handling and bearer mapping between IAB nodes and the donor node, rather than implementing complex mapping logic directly in the RLC layer or higher layers.
Solution Approach 2:
The patent segments the bearer mapping functionality into distinct components: the BAP layer for routing and mapping decisions, the RLC layer for channel-specific operations, and the IP layer for end-to-end connectivity. This segmentation allows each layer to be optimized independently and reduces overall system complexity by distributing functions across multiple layers.
2Adaptability or versatility
If multi-hop deployments are supported in IAB networks, then network coverage and flexibility are improved, but routing and bearer mapping complexity increase
Solution Approach 1:
The BAP layer acts as a mediator that handles multi-hop routing and bearer mapping through standardized protocols. It provides routing identifiers and mapping rules that enable IAB nodes to forward traffic through multiple hops without requiring complex end-to-end path computation at each node, thereby supporting network flexibility while controlling complexity.
Solution Approach 2:
The patent implements preliminary configuration of bearer mappings and routing rules at the BAP layer before data transmission occurs. This preliminary action allows multi-hop routes to be pre-established with defined mapping relationships, enabling IAB nodes to simply follow pre-configured paths rather than dynamically computing complex routing decisions in real-time.
3Ease of operation
If standardized bearer mapping functionalities are implemented, then configuration simplicity is improved, but flexibility in handling different QoS requirements may be reduced
Solution Approach 1:
The BAP layer implements universal bearer mapping functionalities that can handle multiple QoS requirements through a standardized interface. The same BAP layer structure and protocols can accommodate different QoS classes, traffic types, and service requirements by configuring appropriate mapping rules and routing identifiers, thereby providing both configuration simplicity and QoS flexibility through multi-functionality.
Data Source
AI summary
In an example, a method performed by central unit control plane, CU-CP, of a base station for providing Integrated Access and Backhaul, IAB, bearer mapping information is disclosed. The base station is configured as a donor base station for one or more IAB nodes. The method comprises transmitting, to a distributed unit DU of the base station which is configured as a donor DU for one or more IAB nodes, mapping information to map one or more field values to one or more backhaul radio link control BH RLC channels between the DU and a first IAB node on a downlink path.