Mobile Voice Core Engineer

This is a senior engineering opportunity within a Mobile & IP function responsible for delivering high availability across CS, EPC and IMS environments. The successful candidate will act as a subject matter expert for voice and IMS services, ensuring operational resilience and service optimisation!

• Operating and maintaining IMS, CS and EPC components in line with KPIs and SLAs.
• Performing configuration, upgrades and patching of mobile core network elements.
• Monitoring and optimising capacity and performance metrics.
• Troubleshooting complex signalling protocols including Diameter, SIP, SS7 and HTTPS.
• Managing IMS platforms and SIP‑based services for mobile and fixed voice.
• Supporting Cloud Voice, FTTH voice and Microsoft Teams Operator Connect services.
• Supporting roaming services and ensuring IREG compliance.
• Managing SIP carrier interconnect deployments and troubleshooting.
• Supporting value‑added voice services and voicemail platforms.
• Contributing to core network expansion, capacity planning and vendor evaluations.
• Supporting security compliance and incident response within the domain.
• Participating in an on‑call rota and maintaining regulatory compliance.

The ideal candidate will have strong experience across 2G, 4G and 5G mobile core environments, with hands‑on expertise in IMS components and mobile core nodes. A solid understanding of SIP, Diameter, SS7 and GTP protocols is essential, alongside knowledge of IP networking and telecoms virtualised environments. Strong communication skills, structured problem‑solving ability and a proactive approach to learning new technologies are key.

Candidates must be comfortable working collaboratively across technical teams and external partners.

For a full job description or further information on this role please call 711188 , or email

If you wish to apply for this role, please submit your CV via the Apply Now button below.