Packet-to-Circuit Handover for VoIP Call Setup Reliability
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Solution Overview
Problem
In cellular communication networks, especially in packet-switched systems like LTE, there is a high likelihood of call setup failures due to resource unavailability, leading to dropped calls when the originating device fails to set up communication resources, resulting in abort messages instead of handovers to alternative networks.
Innovation Solution
Implementing a Packet Switch to Circuit Switch handover technique, such as Single Radio Voice Call Continuity (SRVCC) or Enhanced Single Radio Voice Call Continuity (eSRVCC), which transfers the voice call from a failed packet-switched network to a circuit-switched 3G network, preventing call abortions and maintaining the call session.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If packet-switched network resources are allocated for VOIP call setup, then call setup speed is improved, but call reliability deteriorates due to resource unavailability and failed setup
Solution Approach 1:
The patent applies preliminary action by pre-establishing circuit-switched fallback paths and resource allocations before VOIP call setup fails. When packet-switched resources become unavailable, the system has already prepared alternative circuit-switched resources, allowing immediate handover without waiting for failure detection and resource re-allocation, thus maintaining both speed and reliability
Solution Approach 2:
The patent implements beforehand cushioning by maintaining standby circuit-switched network resources and handover capabilities in advance. This cushioning mechanism ensures that when packet-switched resources fail, there is already a prepared fallback path, preventing call setup failure and maintaining reliability while keeping the transition rapid
2Reliability
If handover to circuit-switched network is implemented, then call reliability is improved, but network complexity increases
Solution Approach 1:
The patent applies universality by designing the network system to perform multiple functions through integrated architecture. The same network infrastructure supports both packet-switched VOIP calls and circuit-switched fallback calls, with unified resource management and control mechanisms. This multi-functionality reduces the need for separate dedicated systems, thereby limiting the increase in overall network complexity while maintaining high reliability through handover capability
3Adaptability or versatility
If packet-switched network is used exclusively, then network modernization is achieved, but service continuity deteriorates when resources are unavailable
Solution Approach 1:
The patent applies dynamics by creating a flexible, adaptive network architecture that can dynamically switch between packet-switched and circuit-switched modes. The system monitors resource availability and automatically adjusts the active communication path, allowing the network to be modernized with packet-switched infrastructure while maintaining service continuity through dynamic fallback to circuit-switched networks when needed
Data Source
AI summary
When initiating a Voice-over-IP (VoIP) communication session between an originating device (MO) and a terminating device (MT) on a packet-switched network, network components associated with the MO may encounter a failure when preparing resources for the session, such as a failure to establish a dedicated bearer with the MO. This might typically cause the system to abort the session. Instead, the network components are configured to detect the failure and to initiate a handover to a circuit-switched communication network so that the session may be conducted through the circuit-switched communication network. The failure may be detected by a component of a Long-Term Evolution (LTE) Radio Access Network (RAN) of the network, by a Mobility Management Entity (MME) of the network, or by some other network component. Single Radio Voice Call Continuity (SRVCC) procedures may be used to implement the handover.