Core Engineer (5G/LTE)

TL;DR

Core Engineer (5G/LTE): Troubleshooting and optimizing live mobile core infrastructure for global roaming and MVNO operations with an accent on 3GPP standards and GTP flow design. Focus on integrating network elements, managing session lifecycle, and resolving complex signaling issues across 4G and 5G-SA architectures.

Location: Bucharest, Romania

Company

Global data MVNO providing enterprise-grade connectivity and IoT services across 200+ countries and 600+ mobile carriers' networks.

What you will do

• Troubleshoot real network issues across 3G, 4G, and 5G Standalone (SA) infrastructure.
• Lead integrations and projects on a live production network end-to-end.
• Manage GTP-C/GTP-U, CUPS, Diameter, and Radius signaling flows and routing.
• Configure and troubleshoot PGW, PCRF, and GTP Proxy elements.
• Design and scale network elements within a live environment.
• Perform 24x7 on-call duties to resolve network incidents.

Requirements

• At least 3 years of practical experience as a core network engineer.
• Deep understanding of MNO/MVNO architecture and end-to-end GTP flow design.
• Expertise in 3GPP standards (2G/3G/4G/5G) and 5G-SA architecture (AMF, SMF, UPF, NRF, PCF).
• Experience with GRX routing, IPX interconnect, and roaming procedures (IR.21).
• Proficiency with APIs and basic scripting, such as Python.
• Ability to work under pressure during live network incidents.

Culture & Benefits

• International environment with highly professional specialists.
• Rapid professional development opportunities within an innovative and growing company.
• Meal vouchers.
• Challenging workplace with an emphasis on technical ownership and independence.