Wireless Handover During Connection Resume
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Solution Overview
Problem
Current wireless communication systems face latency issues when a user equipment (UE) attempts to resume an RRC connection, particularly when the target node is overloaded, as they can only send an RRCReject or RRCRelease message, leading to increased latency and potential repeated rejections.
Innovation Solution
The system allows for direct handover to a second cell upon receiving an RRCReconfiguration or RRCResume message, enabling the target node to perform handover to a different cell without waiting for the UE to complete the resume procedure, by retrieving the UE context and preparing a reconfiguration message for the new cell.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the target node sends an RRCReject or RRCRelease message when overloaded, then the UE connection resumption procedure is completed, but the latency is increased and repeated rejections may occur
Solution Approach 1:
The target node performs preliminary actions by retrieving the UE context and preparing a handover command to a second cell before the UE completes the resume procedure. This proactive approach prevents the UE from attempting to resume connection to an overloaded node, thereby avoiding repeated rejections and reducing overall latency.
Solution Approach 2:
The patent introduces a second cell as an intermediary solution. When the target node is overloaded, it acts as a mediator by redirecting the UE to another cell that has available resources. This intermediary approach allows the connection resumption to succeed while avoiding the latency and repeated rejections associated with direct rejection messages.
2Reliability
If the UE waits for the resume procedure to complete before handover, then the procedure is completed successfully, but the latency increases due to waiting
Solution Approach 1:
The handover command is prepared and sent to the UE in advance, before the UE completes the resume procedure. This preliminary action eliminates the waiting time that would otherwise occur if the handover were initiated only after resume completion, while still ensuring reliable procedure completion through proper sequencing of operations.
3Loss of time
If the target node retrieves UE context and prepares handover command, then immediate handover to a less congested cell is enabled, but the device complexity increases
Solution Approach 1:
The target node utilizes already-available UE context information that was previously stored when the UE entered the inactive state. This self-service approach allows the node to quickly prepare a handover command without requiring complex real-time context retrieval or establishment procedures, thereby reducing latency while maintaining manageable device complexity.
Data Source
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AI summary
A method in a wireless device for resuming a connection of the wireless device is provided. The method comprises: sending, to a first network node, a request to resume a connection with the first network node; in response to sending the request, receiving a response comprising an indication to hand over to a second network node; and performing the handover with the second network node. A method in a first network node for resuming a connection is also provided. The method comprises: receiving, from a wireless device, a request to resume a connection with the first network node; sending a handover request to a second network node in response to receiving the resume request; in response to receiving an acknowledgement for the handover request, from the second network node, sending a response to the wireless device for indicating a handover of the wireless device to the second network node.