Objective Speech Quality Estimates for Project 25/Voice over Long Term Evolution (P25/VoLTE) Interconnections

In an extended P25/VoLTE public safety communication system voice signals will pass through both Multi-Band Excitation (MBE) and Adaptive Multi-Rate (AMR) speech coders. Thus it is important to quantify the speech quality that can be expected for MBE, AMR, and combinations of these speech coders. We used the Perceptual Evaluation of Speech Quality (PESQ) algorithm to provide initial assessments of speech quality for these coders alone and in combinations.

Funding for this work was provided by the Office for Interoperability and Compatibility (OIC). The work was conducted at the Public Safety Communications Research (PSCR) program’s Boulder, Colorado, laboratories under the supervision of J. R. Bratcher. Certain commercial equipment and materials are identified in this report to specify adequately the technical aspects of the reported results. In no case does such identification imply recommendation or endorsement by National Telecommunications and Information Administration (NTIA), National Institute of Standards and Technology (NIST) or DHS, nor does it imply that the material or equipment identified is the best available for this purpose.