QoS and Hop-Aware Adaptation Layer for Multi-Hop IAB
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Solution Overview
Problem
In 5G wireless communication networks, the configuration of backhaul bearers in integrated access backhaul (IAB) networks for relay nodes is challenging due to the need for quality of service (QoS) guarantees and efficient hop-by-hop forwarding, especially with the CU/DU split architecture, where RLC and MAC/PHY protocols are separated from RRC/PDCP protocols.
Innovation Solution
The adaptation layer is placed above the RLC in IAB nodes, allowing reuse of NR lower layers and enabling QoS-based service quality guarantees by mapping end-user bearers to backhaul bearers considering QoS classes and hop depth, with separate bearers for high-priority and low-priority traffic, and modifying time-to-live values for packet delay requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the adaptation layer is placed above the RLC in IAB nodes, then QoS-based service quality guarantees are enabled and NR lower layers can be reused, but the complexity of bearer mapping configuration increases
Solution Approach 1:
The patent segments the bearer mapping configuration by introducing separate mapping rules for different QoS classes. The adaptation layer divides the complex mapping task into manageable segments: high-priority bearers are mapped to specific backhaul bearers with guaranteed resources, while low-priority bearers use remaining capacity. This segmentation reduces overall configuration complexity by handling different QoS requirements independently.
Solution Approach 2:
The patent applies local quality by configuring different mapping strategies for different parts of the bearer hierarchy. High-priority bearers receive dedicated mapping with strict QoS guarantees, while low-priority bearers use best-effort mapping. This localized differentiation allows the system to provide QoS guarantees where needed without complicating the entire mapping configuration.
2Productivity
If separate backhaul bearers are configured for high-priority and low-priority traffic, then QoS management efficiency is improved, but the number of bearers and system complexity increases
Solution Approach 1:
The patent merges multiple end-user bearers onto shared backhaul bearers where appropriate. Instead of creating one-to-one mappings for all bearers, the adaptation layer consolidates multiple low-priority bearers onto shared backhaul resources, while only high-priority bearers receive dedicated mappings. This merging reduces the total number of backhaul bearers needed while maintaining QoS efficiency.
Solution Approach 2:
The patent makes backhaul bearers universal by enabling them to serve multiple functions: dedicated bearers for high-priority traffic and shared bearers for low-priority traffic. The same backhaul bearer infrastructure supports both guaranteed service and best-effort service, reducing the need for completely separate bearer sets and lowering overall system complexity.
3Reliability
If the adaptation layer considers both QoS classes and hop depth for bearer mapping, then fairness among bearers is improved, but the complexity of mapping rules increases
Solution Approach 1:
The patent changes the mapping parameters from simple QoS-class-based rules to composite rules that incorporate both QoS class and hop depth. The adaptation layer uses the hop count as an additional parameter to determine bearer selection, ensuring that bearers with more hops receive appropriate resource allocation. This parameter expansion improves fairness while keeping the rule structure manageable through systematic evaluation criteria.
4Loss of time
If time-to-live values are modified for packet delay requirements, then packet delay control is improved, but the complexity of adaptation layer processing increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and setting appropriate time-to-live (TTL) values in the adaptation layer before packets traverse the multi-hop network. Based on the packet's QoS class and the number of hops to destination, the adaptation layer pre-configures the TTL to ensure packets are forwarded with appropriate delay constraints. This preliminary setting simplifies subsequent processing at each hop, as intermediate nodes only need to decrement and check the pre-set TTL value.
Data Source
AI summary
A node maps end-user bearers to backhaul bearers in an adaptation layer. The node maps a plurality of end-user bearers to backhaul bearers in consideration of QoS classes for the end-user bearers and a distance from the node to a destination relay node for each of the plurality of end-user bearers, such that at least one of the backhaul bearers carries end-user bearers with different QoS classes and different distances to the destination relay node. The distance from the node to the destination relay node for at least one of the end-user bearers may be considered in terms of a number of remaining hops from the node to the destination relay node and/or in terms of an estimated end-to-end delay from the node to the destination relay node.