Voice Quality Evaluation in a Mobile Cellular Network: In Situ Mean Opinion Score Measurements.

Area of Science:

• Telecommunications Engineering
• Network Performance Analysis
• Mobile Communication Systems

Background:

• Mobile cellular networks are evolving, with a shift from circuit-switched (CS) to packet-switched (PS) domains.
• Voice over Long-Term Evolution (VoLTE) and over-the-top (OTT) services like WhatsApp are increasingly used for voice communication.
• Understanding voice quality across different network domains is crucial for user experience and network optimization.

Purpose of the Study:

• To evaluate and compare the voice call quality in a mobile cellular network across different scenarios.
• To measure and analyze user experience for mobile-to-mobile calls using circuit-switched (CS) GSM, Voice over LTE (VoLTE), and WhatsApp (OTT) services.
• To provide context-specific insights into network performance for local improvements and decision-making.

Main Methods:

• Conducted drive tests in Bucharest, Romania, collecting logs using specialized measurement terminals.
• Evaluated three scenarios: CS calls on GSM, VoLTE calls on 4G PS domain, and WhatsApp calls on 4G PS domain.
• Assessed voice quality using the Mean Opinion Score (MOS) to compare performance across CS and PS domains.

Main Results:

• In-situ measurements provided detailed performance data for each voice service scenario.
• User experience and voice quality (MOS) were compared between circuit-switched (CS) and packet-switched (PS) domains.
• Specific insights into network performance were gathered within the Bucharest, Romania context.

Conclusions:

• The study provides valuable, location-specific data on voice call quality in modern mobile networks.
• Findings can inform network operators, policymakers, and investors for targeted improvements.
• Comparative analysis highlights the performance differences between traditional and modern voice communication methods over mobile networks.