VoLTE Roaming Call Admission via Handover Probability Assessment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Users of 3GPP2 networks, which do not support Single Radio-Voice Call Continuity (SRVCC), face limitations in utilizing VoLTE services due to incompatibility with SRVCC technology, leading to restricted use of packet-switched voice technologies during roaming scenarios.
Innovation Solution
A method where a cellular network determines whether a roaming User Equipment (UE) is associated with a non-SRVCC carrier and assesses the probability of handover from a packet-switched network to a circuit-switched network, selectively accepting or rejecting VoLTE calls based on this probability, and providing signaling to trigger a fallback to circuit-switched networks when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If VoLTE service is provided to roaming UEs from non-SRVCC carriers, then utilization of packet-switched voice technology is improved, but call reliability deteriorates due to inability to handover to circuit-switched network
Solution Approach 1:
The system performs preliminary assessment of PS coverage probability before establishing VoLTE calls. The network evaluates coverage conditions in advance and makes proactive decisions about call setup or fallback, preventing call drops before they occur rather than reacting after failures happen.
Solution Approach 2:
The system introduces an intermediate evaluation mechanism that assesses PS coverage probability and acts as a mediator between the desire to use VoLTE and the need for call reliability. This intermediary layer enables informed decision-making about whether to allow VoLTE calls based on real-time coverage conditions.
2Adaptability or versatility
If VoLTE calls are accepted in areas with limited packet-switched coverage, then service availability is improved, but call drop probability increases
Solution Approach 1:
The system evaluates PS coverage probability in advance before allowing VoLTE call setup. By performing this preliminary assessment, the network can identify areas where VoLTE calls are likely to succeed and areas where they would fail, making proactive decisions about call admission or fallback.
Solution Approach 2:
The system uses feedback about PS coverage conditions to dynamically control VoLTE call admission. Coverage probability information feeds back into the call setup decision process, allowing the network to adapt call acceptance policies based on real-time radio conditions and coverage availability.
3Reliability
If fallback to circuit-switched network is implemented for non-SRVCC UEs, then call reliability is improved, but service quality deteriorates due to loss of simultaneous voice and data capability
Solution Approach 1:
The system applies different service qualities locally based on coverage conditions and UE characteristics. In areas with reliable PS coverage, full VoLTE functionality including simultaneous voice and data is provided. In areas with poor PS coverage, fallback to CS is applied. This localized quality adjustment optimizes both reliability and service capability where appropriate.
Solution Approach 2:
The system applies fallback to CS only partially - specifically for UEs from non-SRVCC carriers in areas with low PS coverage probability. Rather than universally applying fallback or never applying it, the system selectively applies CS fallback only where and when needed, preserving VoLTE benefits elsewhere while ensuring reliability where necessary.
Data Source
AI summary
Some embodiments relate to a cellular network which better utilizes packet-switched (PS) voice technologies, such as VoLTE, for roaming user equipment (UE) devices. When a roaming UE associated with a home cellular carrier that does not support PS to CS handover (SRVCC) desires to make a VoLTE call, the cellular network may determine probability of such a handover during the the call. The cellular network may selectively accept or reject the packet-switched wireless voice call based on the handover probability. If the probability of handover is high, the cellular network may reject the packet-switched wireless voice and trigger the UE to fall back to a circuit-switched network and re-originate the wireless voice call on the circuit-switched network. In the case of a mobile terminated call, the cellular network may provide signaling to the UE to perform a fallback to a circuit-switched network in order to receive the mobile terminated call.