IAB Terminal System Information Updates with Migration Change Indications
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Solution Overview
Problem
In integrated access and backhaul (IAB) networks, user equipment (UE) devices experience issues with autonomous system information (SI) acquisition during inter-donor migration, leading to potential errors and disruptions due to unannounced changes in the new radio cell global identifier (NCGI) without proper notification.
Innovation Solution
Implementing a system where network devices broadcast or transmit system information change indications before the UE's autonomous acquisition period expires, using dedicated signaling for devices unable to receive broadcast information, and adjusting periods for timely SI updates during migration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the network device changes SI (NCGI) during inter-donor migration without notification, then the migration can proceed, but the UE device may acquire outdated SI and treat it as an error case
Solution Approach 1:
The network device broadcasts an SI change indication before the actual SI change occurs during inter-donor migration. This preliminary notification allows the UE device to prepare for the upcoming SI update, preventing the UE from acquiring outdated SI and treating it as an error case, thus maintaining reliability while enabling migration
Solution Approach 2:
An SI change indication message serves as an intermediary between the network device's internal SI change and the UE device's SI acquisition process. This intermediary notification mechanism bridges the gap between network-side migration operations and terminal-side SI management, ensuring synchronized updates
2Reliability
If the UE device autonomously acquires SI after a fixed period, then the device can maintain updated information, but unannounced network changes cause the UE to acquire outdated SI
Solution Approach 1:
The network device provides feedback to the UE device through SI change indications, informing the UE when SI will change during inter-donor migration. This feedback mechanism allows the UE to adjust its SI acquisition timing accordingly, preventing the acquisition of outdated SI while maintaining the ability to update autonomously when appropriate
3Reliability
If the network broadcasts SI change indication before autonomous acquisition expires, then timely SI updates are ensured, but additional signaling overhead is introduced
Solution Approach 1:
The network device broadcasts SI change indications selectively - only when SI changes are planned during inter-donor migration events. This partial action approach avoids continuous or excessive signaling, introducing overhead only when necessary to maintain SI update timing reliability
Data Source
AI summary
An apparatus may include at least one processor and at least one memory. The at least one memory may include computer program code, and the at least one memory and the computer program code may be configured to, with the at least one processor, cause the apparatus as a terminal device in an integrated access and backhaul network to perform receiving, a system information change indication from a network device associated with an integrated access and backhaul node in the integrated access and backhaul network or system information via a dedicated signaling from another network device associated with a donor in the integrated access and backhaul network, before an expiry of a period after which the terminal device autonomously acquires the system information from the another network device, and restarting the period in a case of receiving the system information change indication or the system information via the dedicated signaling.