VoLTE and ViLTE Testing: Ensuring Quality Voice and Video Services

Back to Blog

Core Areas of VoLTE & ViLTE Testing

1. Functional Testing

Functional testing validates that basic and advanced calling features operate correctly across the network.

• Session Initiation Protocol (SIP) Signaling: Verifies that SIP registration, call establishment, call holding, and termination flows function flawlessly over the IMS core.

• Supplementary Services: Validates secondary features like call waiting, multi-party conference calls, call forwarding, and Caller ID presentation.

• Emergency Calling (E911): Ensures emergency calls are given highest priority, bypass regular network congestion, and accurately transmit location data.

2. Media Quality Assessment

Unlike data transfers, real-time media is highly sensitive to network fluctuations. Testing evaluates user-perceived audio and video clarity.

• Voice Quality Testing (VQT): Uses automated ITU standard algorithms like POLQA (Perceptual Objective Listening Quality Assessment) to grade the audio experience. It measures the ⁠Mean Opinion Score (MOS) across narrowband and wideband codecs like AMR-WB and EVS.

• Video Quality Testing: Evaluates sharpness, pixelation, frame rates, and Lip-Sync synchronization between the video and audio streams using the H.264 video codec standard.

3. Network Performance & QoS Integration

Voice and video require specialized radio treatment to maintain stability over standard web traffic.

• QoS Class Identifiers (QCI): Verifies that the network accurately maps VoLTE traffic to QCI 1 (Guaranteed Bit Rate for voice) and ViLTE traffic to QCI 2 or QCI 7 (for video media and signaling).

• Robustness to Impairments: Subjects the media stream to simulated network stress, checking how the codecs gracefully handle packet loss, high latency, and jitter.

4. Mobility & Handover Testing

Mobile users frequently move between cell towers and different network technologies, requiring smooth connection state handovers.

• SRVCC (Single Radio Voice Call Continuity): Tests the seamless fallback of a VoLTE or ViLTE call to legacy 2G or 3G circuit-switched networks when a user exits 4G coverage, ensuring the call does not drop.

• VoWiFi (Voice over Wi-Fi) Interworking: Validates handover continuity when moving a live call from an LTE macro cell to a home Wi-Fi network through the Evolved Packet Data Gateway (ePDG).

5. Device Interoperability and Conformance

• Multi-Vendor Interoperability: Tests the communication between different device chipsets and varying IMS network vendor infrastructures to guarantee cross-compatibility.

• Conformance Testing: Confirms that hardware manufacturers adhere to strict universal standards defined by the 3GPP, GSMA, and regulatory groups like GCF or PTCRB.

• Battery Consumption Analysis: Measures the current draw of real-time video encoders to ensure the device balances power use without generating excessive thermal overhead.