Avoiding Packet Fragmentation in Mobile Handovers
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Solution Overview
Problem
In LTE wireless communication systems, packet fragmentation during handovers to non-3GPP networks like Wi-Fi often results in call drops due to unsupported IP fragmentation, leading to poor user experience.
Innovation Solution
A method involving determining MTU configurations for both 3GPP and non-3GPP network interfaces, calculating tunnel overhead, and selecting appropriate transport protocols like TCP or UDP to avoid packet fragmentation by considering the path MTU and additional overhead, ensuring packets are transmitted as single units or fragmented appropriately based on network capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If packets are transmitted over non-3GPP access during handover, then network connectivity is maintained, but packet fragmentation occurs causing call drops
Solution Approach 1:
The system performs preliminary determination of MTU configurations for both 3GPP and non-3GPP network interfaces before transmission. By calculating the tunnel overhead size and selecting appropriate transport protocols in advance based on these configurations, the system prevents packet fragmentation from occurring in the first place, thereby maintaining call continuity while avoiding packet loss
Solution Approach 2:
The system dynamically adjusts transmission parameters by determining MTU configurations for different network interfaces and calculating tunnel overhead. Based on these parameter determinations, the system selects appropriate transport protocols (TCP or UDP) to optimize packet transmission, changing the transmission mode to adapt to different network conditions and avoid fragmentation issues
2Adaptability or versatility
If UE fragments packets for non-3GPP transmission, then packet size adapts to network constraints, but network elements drop fragmented packets due to lack of support
Solution Approach 1:
Instead of fragmenting packets at the UE side to adapt to non-3GPP network constraints, the system inverts the approach by determining MTU configurations and calculating tunnel overhead to select transport protocols that prevent fragmentation from occurring. This reverse approach maintains packet integrity while still adapting to network constraints through proper protocol selection
Solution Approach 2:
The system introduces an intermediary calculation step that determines tunnel overhead size between network interfaces. This intermediary parameter allows the system to select appropriate transport protocols that act as mediators between the UE's transmission capabilities and the non-3GPP network's constraints, ensuring packets are transmitted without fragmentation
Data Source
AI summary
Various solutions for avoiding packet fragmentation with respect to user equipment and network apparatus in mobile communications are described. An apparatus may determine a first maximum transmission unit (MTU) configuration of a session via a first network interface. The apparatus may determine a second MTU configuration of the session via a second network interface. The apparatus may determine a tunnel overhead size between the second network interface and the first network interface. The apparatus may select a transport protocol to generate a packet according to the second MTU configuration and the tunnel overhead size. The apparatus may transmit the packet via the second network interface.