Graduate Engineer, Network Solutions

Skylo Technologies, Inc.; Espoo; Hybrid; EUR 42,000 - 56,000; Full time

Benefits offered by this job

Competitive compensation

Healthcare

Wellness & lunch benefits

Phone & Internet allowance

Learning budget

Job summary

Skylo has built a global satellite connectivity platform and is expanding its core NTN vRAN team in Espoo, Finland. This graduate role focuses on 5G NR-NTN upper-layer and core interface protocols, bridging Skylo’s NTN with operator cores.

You’ll learn by doing: implement PDCP, eGTP, XnAP, and NGAP in C++, contribute to tests, and collaborate with Core Network and MNO teams while reading 3GPP specs.

Qualifications

• Strong programming ability in C++ and memory management.
• Bachelor's, Master's, or PhD in Electrical Engineering, Wireless Communications, CS, or related field.
• Networking fundamentals: the protocol stack model, IP, UDP/TCP, tunnelling.
• Familiarity with 5G or LTE architecture.
• Comfortable working in Linux and with version control (Git).
• Curiosity and persistence when debugging via packet captures.
• Willingness to read 3GPP specifications and translate to software.
• Clear communication and eagerness to learn from engineers.

Responsibilities

• Write and maintain C++ code across 5G NR upper-layer protocols and core interface components.
• Contribute to NTN-specific PDCP adaptations and handling extended sequence spaces.
• Support eGTP-U tunnelling work for the N3 user plane and QoS mappings.
• Contribute to Xn interface procedures (XnAP) and NG-RAN configuration.
• Contribute to NGAP procedures over N2 including UE messaging and handover.
• Build test cases, simulation harnesses, and automation for validation.
• Support Core Network and MNO integration teams in NGAP validation.
• Validate Xn/N2/N3 interfaces end-to-end across disaggregated vRAN.
• Debug interface-layer issues using Wireshark, tcpdump, and logs.
• Learn 3GPP Rel-17/18 NR-NTN specs and translate into software requirements.
• Participate in code reviews and architecture discussions.
• Use AI coding assistants across the development lifecycle.

Skills

C++

Networking basics

Linux

Git

3GPP knowledge

Debugging

Education

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

Tools

Wireshark

tcpdump

srsRAN

Job description

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'll 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.

With employees working across three continents, Skylo is proud to be an equal opportunity employer dedicated to building an inclusive and diverse workforce. Our worldwide and inclusive culture encourages a flexible approach to work, and we also offer an attractive range benefits such as:

• 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.