Downlink Packet Replication for Seamless Handover
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Solution Overview
Problem
Existing handover procedures in 4G 3GPP networks face challenges in maintaining connection integrity during UE movement between Access Points, leading to potential packet loss and poor user experience due to the lack of efficient packet replication mechanisms, especially when X2 interfaces are not available.
Innovation Solution
The implementation of downlink packet replication techniques using Routing Locators (RLOCs) and Map Server (MS) registration messages to replicate packets on a fabric node or source Access Point, ensuring delivery to both source and target Access Points, and utilizing packet encapsulation for seamless handover support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional handover procedures (S1AP or X2) are used in 4G networks, then connection maintenance during UE movement is achieved, but packet loss occurs and user experience deteriorates due to lack of efficient packet replication mechanisms
Solution Approach 1:
The patent applies preliminary action by establishing packet replication before the actual handover occurs. The network node replicates downlink packets in advance and stores them in a buffer, so that when handover is needed, the packets are already prepared and can be immediately delivered to the target cell, preventing packet loss during the transition.
Solution Approach 2:
The patent implements copying by creating duplicate copies of downlink packets at the network node. Instead of relying on a single packet transmission path, the system copies packets and distributes them through multiple paths (to both source and target cells), ensuring that packets are not lost when the UE moves between cells.
2Loss of information
If packet replication is implemented to minimize packet loss, then data delivery continuity is improved, but network complexity increases due to additional replication and buffering mechanisms
Solution Approach 1:
The patent applies universality by designing the packet replication mechanism to serve multiple functions: it replicates packets for handover support, buffers packets for quality of service, and manages packet distribution across multiple cells. This multi-functionality reduces the need for separate dedicated systems, thereby limiting the increase in network complexity.
Solution Approach 2:
The patent uses an intermediary approach by introducing a network node (acting as a mediator between the core network and radio access network) that handles packet replication and buffering. This intermediary structure centralizes the complex replication logic in a dedicated component, simplifying the overall network architecture compared to distributed replication approaches.
3Loss of information
If downlink packets are replicated and buffered to ensure continuous delivery, then user experience during handover is improved, but energy consumption increases due to additional packet processing and buffering operations
Solution Approach 1:
The patent applies partial action by replicating packets selectively rather than all packets. The system identifies handover scenarios and applies replication only to packets that need to be forwarded during handover, avoiding unnecessary replication for normal traffic. This selective approach reduces energy consumption while maintaining data delivery continuity when needed.
Data Source
AI summary
Techniques are provided for downlink packet replication to support handovers. In one example, downlink packet replication occurs on a fabric node in an S1AP handover scenario. In another example, downlink packet replication occurs on a source Access Point (AP) using a target AP as a secondary AP in an S1AP handover scenario. In yet another example, downlink packet replication occurs on a source AP using packet encapsulation in an S1AP handover scenario. In still another example, downlink packet replication occurs on a source AP in an X2 handover scenario. Similar techniques are provided for any suitable telecommunications/cellular technology.