Graduate Engineer, Network Solutions

Skylo; Espoo; Hybrid; EUR 45,000 - 60,000; Full time

Benefits offered by this job

Competitive compensation

Healthcare and life insurance

Learning & development budget

Phone & Internet allowance

Job summary

Skylo is seeking a graduate engineer for its Protocol Stack team in Espoo, Finland. You will implement 5G NR upper-layer and core interfaces (PDCP, eGTP, XnAP, NGAP) and work end-to-end with satellites and mobile operator cores.

You will learn NTN adaptations and contribute to NGAP/N2 procedures, with mentorship and real traffic in a disaggregated vRAN setup. This role supports on-site 3 days/week as part of a hybrid work model.

Qualifications

• Bachelor's or higher in a relevant field.
• Strong C++ programming and memory management skills.
• Familiar with Linux and Git workflows.

Responsibilities

• Write and maintain C++ code for 5G NR upper-layer and core interfaces (PDCP, eGTP, XnAP, NGAP).
• Learn NTN-specific PDCP adaptations and provide robust, scalable implementations.
• Support N3 user plane tunnelling and GTP-U path management.
• Contribute to NGAP/N2 procedures and end-to-end interface validation.
• Build tests, harnesses, and automation; participate in code reviews and docs.

Skills

C++ programming

Linux

Git version control

Networking fundamentals

3GPP awareness

Education

Bachelor's, Master's, or PhD in Electrical Engineering/Computer Science or related field

Tools

Wireshark

tcpdump

GDB

Job description

Sound Like You? What You Bring

The world still has coverage blind spots. You could help eliminate them at Skylo. Skylo has pioneered a standards-based approach to satellite connectivity. We connect smartphones and IoT devices directly to satellites. No special hardware, no entirely new networks. Just billions of existing devices, suddenly reachable anywhere on Earth. We're not building toward this future. We're already in it. Our direct-to-device service is live on millions of activated devices across five continents, covering more than 72 million square kilometers, in partnership with leading satellite operators, mobile network operators, Tier-1 chipset makers, and OEMs worldwide. And we're just getting started. At the heart of it all is Skylo's commercial NTN vRAN: a 3GPP standards-based, cloud-native platform that seamlessly bridges terrestrial and satellite networks. It's the infrastructure that makes true anywhere, anytime connectivity possible. When you join Skylo, you'll work at the intersection of three markets reshaping how the world stays connected: mass-market consumer devices, automotive, and industrial IoT. Enabling people outdoors and critical workflows in the world's most remote places.

This role is based in Espoo, Finland, one of Skylo's core engineering hubs and fastest-growing sites. You'll work onsite three days a week as part of a team that’s scaling quickly.

How You Will Impact Skylo

Skylo is looking for a graduate engineer to join our Protocol Stack team, working on 5G NR-NTN upper-layer and core interface protocols. You’ll learn to build, integrate, and validate the PDCP, eGTP, Xn, and NGAP (N2/N3) software that connects Skylo’s NTN vRAN to mobile operator core networks — working alongside our Core Network, MNO integration, and systems teams.

You’ll be mentored by senior engineers, but the work is real: what you build carries live traffic between our satellite network and our MNO partners’ cores.

What You’ll Do

• Write and maintain C++ code across our 5G NR upper-layer and core interface protocols — PDCP, eGTP-U/C, XnAP, and NGAP — starting with well-scoped modules and growing into larger components
• Learn and contribute to NTN-specific PDCP adaptations: extended sequence number space, reordering timer adjustments for long propagation delay, lossless handover support, and PDCP status reporting
• Support eGTP-U tunnelling work for the N3 user plane: GTP-U path management, echo/error indication handling, end-marker procedures, and QoS flow-to-DRB mapping
• Contribute to Xn interface procedures (XnAP): Xn Setup, UE context retrieval, handover preparation, and NG-RAN node configuration update
• Contribute to NGAP procedures over N2: Initial UE Message, UE Context Setup/Modification/Release, paging, and handover signalling
• Build test cases, simulation harnesses, and automation to validate interface behaviour against 3GPP specifications
• Support Core Network and MNO integration teams in validating NGAP procedures against commercial and lab AMF implementations
• Help validate Xn/N2/N3 interfaces end-to-end across gNB-CU-CP, gNB-CU-UP, and core network elements in a disaggregated vRAN architecture
• Debug and root-cause interface-layer issues using packet capture and protocol analysis tools — Wireshark, tcpdump, custom dissectors, GDB, and log analysis. This is where you build the instincts that define strong protocol engineers.
• Learn to read 3GPP Rel-17/18 NR-NTN specifications (TS 38.413, TS 38.423, TS 29.281, TS 38.323) and translate them into software requirements, with guidance from systems engineers
• Participate in code reviews, architecture discussions, and technical documentation
• Use AI coding assistants (Claude, Cursor, Codex) across the development lifecycle — from spec interpretation and boilerplate generation to test automation and code review — and help shape how the team works with them

Sound Like You? What You Bring

Essential

• Strong programming ability in C++ — you’ve written non-trivial C++ (university projects, internships, open source, or personal work) and understand memory management, pointers/references, and the standard library. This is our top priority.
• Bachelor's, Master's, or PhD in Electrical Engineering, Wireless Communications, Telecommunications, Computer Science, or a closely related field
• Working knowledge of networking and communications fundamentals: the protocol stack model, IP, UDP/TCP, tunnelling, and packet-based signalling
• Familiarity with 5G or LTE architecture from coursework, projects, or research — RAN vs. core, control plane vs. user plane, and what a handover involves
• Comfortable working in Linux and with version control (Git)
• Curiosity and persistence when debugging: you enjoy chasing a problem through a packet capture until you understand the root cause
• Willingness to work from specifications — much of this role is reading a 3GPP document and turning it into correct code
• Clear communication and a genuine appetite to learn from experienced engineers

Nice to Have

• Internship, thesis, or research experience in telecom protocol development, core networks, or open-source RAN/core projects (srsRAN, OpenAirInterface, Open5GS, free5GC)
• Exposure to PDCP concepts: ciphering, integrity protection, header compression (ROHC), sequence number management
• Exposure to GTP tunnelling, or to 5G core interfaces (N2/N3) and the AMF/UPF roles
• Any experience with ASN.1, protocol message encoding/decoding, or state machine design
• Hands‑on packet analysis with Wireshark or tcpdump
• Python for test automation and analysis
• Any experience with multi‑threaded software
• Interest in satellite communications and NTN

Prior professional experience is a plus. We hire graduates for their fundamentals and their trajectory, and we invest in the rest.

What We Offer

This is a once-in-a-lifetime opportunity to help build and run the world’s first commercial, live direct-to-device satellite network. You’ll work alongside a world-class team spanning software, hardware, chipsets, telecom, satellite, and network virtualization, some of the most sought-after expertise in the industry. And you’ll do it inside a culture that’s open, transparent, and inclusive, shaped by the best of Silicon Valley, Nordic, and South Asian ways of working.

Benefits

• Competitive compensation packages
• Occupational Healthcare and Health and Life Insurance
• E-passi including, wellness, culture, lunch and commuting benefit
• Phone & Internet allowance
• Individual learning & development budget for further personal and professional development

EEO Statement Skylo is an equal-opportunity employer and we celebrate diversity. We do not discriminate on the basis of race, religion, color, ancestry, national origin, caste, sex, sexual orientation, parent or caregiver status, political affiliation, gender, gender identity or expression, age, disability, medical condition, pregnancy, genetic makeup, marital status, or military service consistent with applicable federal, state, and local laws.

We are also committed to providing reasonable accommodations for qualified individuals with disabilities and disabled veterans in our job application procedures. Please let us know if you need assistance or accommodation due to a disability.