A Comparative Study of Voice Quality and Coverage for Voice over Long Term Evolution Calls Using Different Codec Mode-sets

• Main Authors: Jaideep Abichandani, Jeffrey Baenke, Michael S. Irizarry, Narothum Saxena, Purva Vyas, Sanjay Prasad, Shruti Mada, Yohannes Z. Tafesse
• Format: Article
• Language: English
• Published: IEEE 2017-01-01
• Series: IEEE Access
• Subjects: Handover; Internet telephony; packet loss; speech codecs; VoLTE; wireless networks
• Online Access: https://ieeexplore.ieee.org/document/7932849/
• ISSN: 2169-3536

In this paper, we examine the impact of four voice over long term evolution adaptive multi-rate wideband codec mode-sets on coverage at pedestrian and vehicular speeds. Industry-standardized mean opinion scores were used as a metric for voice quality. Controlled laboratory experiments simulating pedestrian speeds indicated that there was an improvement in voice quality when mode-set eight was employed. At vehicular speeds, mode-set eight outperformed the other mode-sets for path losses less than 130 dB; however, all four mode-sets experienced a significant decline in voice quality when the path loss was greater than 130 dB. Based on the current implementations, there are no significant benefits to lowering the mode-sets or deploying dynamic codec rate adaptation.