Cellular Audio Telephony Certification Engineer

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What We're Looking For

We are seeking an experienced Cellular Audio Telephony Certification Engineer to lead audio quality validation and certification activities for mobile/cellular devices. The ideal candidate will bring deep expertise in acoustic testing methodologies, hands-on proficiency with HEAD Acoustics measurement systems, and demonstrated experience using Rohde & Schwarz (R&S) network simulators for LTE/VoLTE call testing. This role is critical to ensuring devices meet carrier acceptance criteria, 3GPP specifications, and global regulatory standards
 

Key Responsibilities:

Audio Certification & Compliance Testing

• Plan, execute, and analyze end-to-end audio telephony tests for cellular devices across LTE, VoLTE, VoNR (5G), VoWiFi, and legacy 2G/3G voice technologies
• Perform acoustic measurements including SLR, RLR, STMR, sidetone, echo loss (TCLw), send/receive frequency response, jitter buffer management, and speech quality (POLQA/P.863)
• Execute certification test campaigns aligned with 3GPP TS 26.131/26.132, GCF, PTCRB, GSMA TS.27, and carrier-specific requirements (e.g., Verizon, AT&T, T-Mobile, Vodafone, NTT DOCOMO)
• Validate devices in handset, handsfree, headset, and speakerphone modes per applicable use cases

Test System Operation & Development

• Configure and operate HEAD Acoustics ACQUA software with hardware such as HMS II.3, labCORE, HEC 03.1, HAE-BT, and artificial ears/mouths for acoustic testing
• Set up and drive Rohde & Schwarz CMW500 / CMX500 / CMW-KM network simulators to emulate LTE/VoLTE/VoNR call scenarios, IMS registration, and codec negotiation (AMR-NB, AMR-WB, EVS)
• Develop automated test scripts and sequences in ACQUA and integrate with R&S CMW for repeatable regression testing
• Maintain calibration integrity of acoustic chambers, artificial heads, and reference equipment

Analysis, Debug & Reporting

• Perform root cause analysis on audio impairments (clipping, distortion, packet loss artifacts, echo, latency, DTX/CNG issues)
• Collaborate with firmware, DSP, and RF teams to debug codec, AEC, noise suppression, and beamforming implementations
• Generate certification-ready test reports, waivers, and compliance matrices for submission to carriers and certification bodies
• Support field trials and IOT (interoperability testing) with live networks

Cross-Functional Leadership

• Serve as the audio SME during design reviews, test plan development, and lab readiness assessments
• Mentor junior engineers on acoustic measurement fundamentals and cellular voice architecture
• Interface directly with certification labs, carriers, and equipment vendors