IAB Donor Packet Forwarding Across Donors After Backhaul Failure
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Solution Overview
Problem
In a cellular communication system with Integrated Access and Backhaul (IAB) nodes, failures in the backhaul link between an IAB node and the donor gNB lead to transmission issues, as the IAB node cannot decipher packets intended for the original donor gNB when rerouting occurs, and existing solutions do not effectively address this problem.
Innovation Solution
Implementing inter-donor re-routing mechanisms that allow IAB nodes to forward packets to a different donor gNB, enabling data forwarding and deciphering through a configured path between donors, and utilizing existing BAP addresses and routing configurations to establish re-routable paths without changing the routing configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If IAB nodes use traditional rerouting mechanisms when backhaul link fails, then the IAB node can forward packets to alternative paths, but the IAB node cannot decipher packets intended for the original donor gNB causing transmission failure
Solution Approach 1:
The patent introduces a donor gNB as an intermediary node that receives packets from the IAB node, decipheres them using the original donor gNB's PDCP key, and forwards them to the core network. This mediator resolves the contradiction by enabling packet transmission without requiring the IAB node to possess the deciphering capability of the original donor gNB.
Solution Approach 2:
The patent segments the packet transmission function into two separate roles: the IAB node handles packet forwarding, while the donor gNB handles packet deciphering. This functional segmentation allows the IAB node to maintain simple forwarding operations while the donor gNB performs the complex deciphering task using the appropriate security keys.
2Adaptability or versatility
If the system configures multiple donor gNBs for IAB nodes, then re-routable paths are established, but the system complexity and configuration overhead increase
Solution Approach 1:
The patent makes the donor gNB a multi-functional node that serves both as a primary donor for its own IAB nodes and as a intermediary for deciphering packets from other donors' IAB nodes. This universal function reduces the need for separate dedicated intermediary nodes and simplifies the overall system architecture.
Solution Approach 2:
The patent establishes pre-configured routing paths between donor gNBs before backhaul link failures occur. When a failure is detected, the IAB node can immediately switch to the pre-configured alternative path without requiring complex real-time routing calculations, thereby reducing operational complexity.
3Ease of manufacture
If existing BAP addresses and routing configurations are used for inter-donor rerouting, then configuration changes are minimized, but packet routing between different donors may fail without proper forwarding paths
Solution Approach 1:
The patent implements a feedback mechanism where the donor gNB receives packets from IAB nodes, attempts to decipher them, and if successful, forwards them to the core network. This feedback loop ensures that packets are properly routed and processed, maintaining reliability while using existing BAP addresses and routing configurations.
Data Source
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AI summary
In a first aspect, a communication control method is used in a cellular communication system. The communication control method includes transmitting, by a first relay node subordinate to a first donor base station, a first packet to a second donor base station different from the first donor base station. The communication control method includes forwarding, by the second donor base station, the first packet to the first donor base station by using a path for data forwarding, and transmitting, by the first donor base station, the first packet to a network.