Conditional PSCell Addition Cancellation for Handover Resource Control
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Solution Overview
Problem
The existing conditional handover (CHO) and conditional PSCell addition (CPA) procedures in cellular communications networks face challenges in managing resource allocation and cancellation efficiently, particularly in scenarios where radio conditions are poor, leading to potential failures and suboptimal resource utilization.
Innovation Solution
The introduction of a mechanism for the secondary node to cancel already prepared conditional PSCell additions (CPA) through messages like S-NODE RELEASE REQUIRED or CHO CANCEL, triggered by overload, resource need, or timer expiration, ensuring efficient resource management and reducing the risk of handover failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conditional PSCell addition is prepared in advance to improve handover robustness, then handover reliability is improved, but network resource overhead increases
Solution Approach 1:
The patent implements conditional PSCell addition where the target SCG configuration is prepared and provided to the UE in advance, before the actual handover execution. This allows the UE to have the configuration ready when handover conditions are met, improving handover reliability by avoiding configuration delays during poor radio conditions.
Solution Approach 2:
The patent introduces dynamic cancellation mechanisms where the network can cancel prepared conditional PSCell addition configurations based on changing conditions (overload, resource availability, timer expiration). This allows the system to adapt resource allocation dynamically, releasing reserved resources when they are no longer needed, thus reducing network resource overhead while maintaining reliability when conditions warrant preparation.
2Reliability
If multiple candidate PSCells are prepared for conditional addition, then handover options and robustness are improved, but resource allocation complexity increases
Solution Approach 1:
The patent segments the conditional PSCell addition process by allowing multiple candidate PSCells to be prepared independently with separate configurations. Each candidate can be individually managed, evaluated, and cancelled, which simplifies the overall management complexity compared to treating multiple candidates as a single complex entity.
Solution Approach 2:
The patent uses timer-based mechanisms and configurable parameters to automatically manage the lifecycle of conditional PSCell additions. By changing parameters such as timer values and cancellation conditions, the system can dynamically adjust resource allocation without increasing operational complexity, as the management follows standardized procedural rules.
3Loss of time
If conditional PSCell addition configuration is provided early to improve handover execution timing, then interruption time is reduced, but risk of configuration waste increases
Solution Approach 1:
The patent provides the target SCG configuration to the UE in advance as part of the conditional PSCell addition setup, before the actual handover is triggered. This preliminary provision of configuration eliminates delays that would occur if configuration had to be prepared and transmitted after handover conditions were met, thereby reducing interruption time during handover execution.
Solution Approach 2:
The patent implements cancellation mechanisms that allow the network to discard prepared conditional PSCell addition configurations when they are no longer needed (due to overload, resource unavailability, or expiration of preparation time). This prevents waste of configuration resources by removing outdated or unnecessary configurations, while still allowing valid configurations to be used when needed.
Data Source
AI summary
Systems and methods are disclosed herein for cancellation of Conditional Primary Secondary Cell (PSCell) Addition (CPA) in a cellular communications network. In one embodiment, a method performed by a secondary node comprises receiving a request from a master node for a conditional secondary node addition, the request comprising information that indicates a request for CPA for one or more PSCells. The method further comprises transmitting, to the master node, a response to the request that confirms that a User Equipment (UE) may be accepted for CPA for the one or more PSCells unless a canceling indication is later received and sending, to the master node, a message that indicates that the CPA is cancelled for at least one of the one or more PSCells. In this manner, the secondary node to cancel an already prepared CPA.