Relay Node Backhaul Control During RRC-Inactive Transitions
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Solution Overview
Problem
Relay nodes in mobile communication systems face challenges in maintaining communication relay when transitioning from an RRC connected state to an RRC inactive state, leading to potential failures in radio backhaul links and inability to properly perform relay functions.
Innovation Solution
The relay node maintains a Backhaul Adaptation Protocol (BAP) entity during the transition to an RRC inactive state and performs RRC re-establishment processes to re-establish the radio backhaul link, using cell information from lower nodes to identify and exclude non-selected cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the relay node transitions from RRC connected state to RRC inactive state, then power consumption is reduced and battery life is extended, but the BAP entity is released and communication relay function is lost
Solution Approach 1:
The patent segments the RRC state management and BAP entity management into independent control modules. The RRC state can transition between connected and inactive states while the BAP entity lifecycle is independently controlled, allowing the BAP entity to be maintained even when RRC connection is released, thus preserving relay functionality while enabling power savings through RRC state transition.
Solution Approach 2:
The patent introduces dynamic control mechanisms where the BAP entity's release behavior is made configurable based on RRC state transitions. Through parameters like releaseBapEntityUponRRCConnectionRelease and conditional release based on upper node notifications, the system dynamically adjusts BAP entity lifecycle to balance power consumption and relay functionality requirements.
2Device complexity
If the BAP entity is released when transitioning to RRC inactive state, then system resources are freed, but radio backhaul link fails and relay communication is interrupted
Solution Approach 1:
The patent applies local quality by allowing different BAP entity release behaviors for different relay nodes based on their specific configurations and network conditions. Each relay node can be configured with specific parameters (releaseBapEntityUponRRCConnectionRelease, uponUpperNodeNotification, uponLowerNodeNotification) to determine whether to maintain or release BAP entities, enabling fine-grained control over resource usage versus reliability trade-offs.
3Stability of the object's composition
If the relay node maintains BAP entity during RRC inactive state, then communication relay continuity is improved, but memory usage and processing overhead increase
Solution Approach 1:
The patent implements partial action by conditionally maintaining BAP entities only when necessary for relay functionality. Through configurable parameters and conditional logic (checking upper node notifications, lower node notifications, and configuration settings), the system maintains BAP entities partially (only when needed) rather than universally, thus balancing relay continuity with resource conservation.
Data Source
AI summary
A communication control method including establishing, by a relay node, a radio backhaul link for relaying communication between user equipment and a donor base station, for a cell managed by an upper node, and performing, by the relay node, an RRC re-establishment process in order to re-establish the radio backhaul link in response to detecting a failure related to the upper node. Performing the RRC re-establishment includes identifying a non-selected cell by use of cell information acquired from a lower node of the donor base station or the relay node, and performing an exclusion process for excluding the non-selected cell from targets for which the radio backhaul link is to be re-established.