Access Node Handover Using Shared ARQ/HARQ Process
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current wireless communication systems experience service interruptions and increased latency during handovers due to the limitations of control plane procedures, particularly in dense access networks, which are exacerbated by the need for complex hardware and spectral resources in soft handovers and the inherent service interruption in hard handovers.
Innovation Solution
A wireless communication system that employs a shared ARQ/HARQ process between source and target access network nodes, allowing seamless handovers without service interruptions by maintaining data connections and synchronizing the ARQ/HARQ protocol state, enabling proactive handover planning based on accurate channel predictions and minimizing the need for additional hardware and spectral resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If hard handover procedures are used to enable independent operation of access nodes, then device complexity is reduced, but service interruption and latency increase during handover
Solution Approach 1:
The target access node performs preliminary actions by preparing the data connection and synchronizing the ARQ/HARQ process before the handover occurs. This includes pre-configuring the data connection and synchronizing the ARQ process state, so that when the handover happens, the service interruption is minimized or eliminated.
2Reliability
If soft handover procedures are used to maintain service continuity during handover, then reliability is improved, but device complexity and resource requirements increase
Solution Approach 1:
The invention extracts the essential function of maintaining service continuity from the complex soft handover procedure. By taking out only the critical ARQ/HARQ synchronization mechanism and applying it in a simplified manner during handover, the patent achieves service continuity without the full complexity of traditional soft handover procedures.
3Ease of operation
If control plane procedures are used during handover to manage connection switching, then handover control is improved, but latency and service interruption increase
Solution Approach 1:
The ARQ/HARQ process acts as an intermediary mechanism that maintains data connection continuity during handover. By using the ARQ process as a mediator between the source and target access nodes, the patent enables smooth transition without requiring complex control plane procedures, thereby reducing handover latency.
4Measurement precision
If RACH channel access is required during handover to assess timing advance, then timing synchronization is improved, but handover delay increases
Solution Approach 1:
The target access node performs preliminary timing synchronization and ARQ process synchronization before the handover occurs. This preliminary action eliminates the need for the UE to wait for RACH opportunities during handover, as the timing advance and ARQ state are already synchronized in advance.
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The invention relates to an access network node for a wireless communication system. The access network node is configured to act as a source access network node or as a target access network node, and comprises a transceiver configured to receive a handover instruction from a control device, the handover instruction comprising a handover time instance for a user device, a processor configured to serve the user device by maintaining a data connection with the user device until the handover time instance, and share an Automatic Repeat Request/Hybrid Automatic Repeat Request, ARQ/HARQ, process with a target access network node for the user device; or serve the user device by maintaining a data connection with the user device after the handover time instance, and share a ARQ/HARQ process with a source access network node for the user device.