Target gNB Secondary Role for Seamless NR Handover
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Solution Overview
Problem
Current wireless communication systems face challenges in efficiently managing handovers in cellular networks, particularly for devices at the cell edge, where performance degradation occurs, and there is a need for improved methods to enhance capacity and performance through techniques like new radio (NR) communication and split bearers.
Innovation Solution
The implementation of a method where a target gNB receives a message for handover from a source gNB, operating as a master gNB before the handover, and transitions to a secondary gNB, then to a master gNB after the handover, facilitating seamless data packet relay and RRC reconfiguration for User Equipment (UE) through split bearers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional handover method is used where the target gNB directly becomes the master gNB, then the handover process is simplified, but service interruption occurs and communication continuity is broken
Solution Approach 1:
The target gNB is configured as a secondary gNB before the handover is completed. This preliminary configuration allows the target gNB to prepare data forwarding paths and establish connectivity with the UE in advance, ensuring that data transmission can continue without interruption during the handover transition.
Solution Approach 2:
The source gNB acts as an intermediary by forwarding data packets to the target gNB (which operates as secondary gNB) during the handover process. This intermediary role ensures continuous data flow from the core network through the source gNB to the target gNB and finally to the UE, maintaining communication continuity without service interruption.
2Productivity
If the target gNB operates only as master gNB after handover, then the handover procedure is straightforward, but data packet forwarding from the source gNB cannot be maintained
Solution Approach 1:
The target gNB is pre-configured as a secondary gNB before the handover is finalized, establishing data forwarding paths in advance. This allows the target gNB to immediately begin receiving and forwarding data packets from the source gNB without waiting for the handover to complete, eliminating data loss and reducing transition time.
Solution Approach 2:
By maintaining the target gNB as a secondary gNB during the handover transition, the system ensures continuous data packet forwarding from the source gNB through the target gNB to the UE. This continuous action prevents any interruption in data transmission, maintaining productivity throughout the handover process.
3Reliability
If multi-connectivity with split bearers is implemented, then service interruption is reduced, but the signaling overhead and configuration complexity increase
Solution Approach 1:
The data transmission path is segmented into multiple bearers: a master bearer from the source gNB and a secondary bearer from the target gNB (operating as secondary gNB). This segmentation allows data to flow through multiple paths simultaneously, ensuring service continuity while distributing the signaling load across different bearer types (MCG and SCG bearers).
Solution Approach 2:
The target gNB serves multiple functions during the handover process: it acts as a secondary gNB for data forwarding, receives data packets from the source gNB, and maintains connectivity with the UE. This multi-functionality reduces the need for separate mechanisms for each function, thereby reducing overall signaling overhead despite the complexity of multi-connectivity.
Data Source
AI summary
Embodiments of a generation Node-B (gNB), User Equipment (UE) and methods for communication are generally described herein. A source gNB may operate as a master gNB (MgNB) before a handover. A target gNB may operate as a secondary gNB (SgNB) before the handover. The target gNB may operate as the MgNB after the handover. The target gNB may, as part of operation as the SgNB, transmit a first data packet received from the source gNB for relay to the UE. The target gNB may, as part of operation as the MgNB, transmit, a second data packet received from a serving gateway (SGW) for relay to the UE.