Senior Engineer, 3GPP Core Network, IRIS2

PROGRAMME description

IRIS² is the new European Union secure satellite communications constellation. This project is the European Union's answer to the pressing challenges of tomorrow to provide secure connectivity services and enhanced communication capacities to the EU and its Member States as well as to governmental users, private companies and European citizens while ensuring high-speed internet broadband to cope with connectivity dead zones.

SES – together with other consortium partners and core members – was selected by European Commission to build and to operate the IRIS² multi-orbit satellite constellation.

The IRIS² team enters the next project phase and there is a strong need for support for all the activities around service provisioning and products that the system can offer in the future.

Role description summary

Work requirements

The (Senior) Engineer 5G Core Network (User Plane) is responsible for defining, implementing, integrating, and validating system concepts for 3GPP-based user plane architectures, with a strong focus on 5G Core data path functions, packet processing, QoS enforcement, traffic steering, and N3/N6/N9/N4 related integration. The role includes contributing to user plane architecture, OSS supervision and orchestration functions, resource management interfaces, and performance monitoring across terrestrial and non-terrestrial (NTN) environments.

General work requirements

• Define and specify 5G Core user plane requirements for terrestrial and non-terrestrial networks, including UPF behavior, N3/N6/N9 interfaces, N4/PFCP control, QoS flows, PDU session data path handling, traffic steering, and packet forwarding behavior.
• Define user plane resource management functions for multi-orbit satellite systems, including gateway selection, feeder-link capacity usage, ISL/backhaul constraints, breakout location, routing policy, and QoS-aware capacity allocation.
• Design and specify OSS orchestration and management flows for user plane resources in a multi-orbit satellite system, including configuration, monitoring, performance management, and service assurance of user plane functions.
• Define and manage the implementation and testing of 5G-NTN user plane procedures, including PDU session establishment from a data path perspective, UPF selection, QoS enforcement, traffic breakout, mobility anchoring, and service continuity over satellite links.
• Provide system architecture input on user plane resource orchestration, service provisioning, data path interworking, and traffic handling between NTN access, terrestrial 5G Core networks, gateways, and external data networks.

Qualifications Background and Experience

Qualification Basis

• Master’s degree in engineering or science, preferably in Telecommunications Engineering.
• Experience in the telecom industry required; for Senior Engineer, 10+ years of relevant industry experience is required.
• Expert knowledge of 3GPP 5G Core standards, especially user plane architecture, UPF, N3/N6/N9 interfaces, N4/PFCP, QoS framework, PDU sessions, traffic steering, packet forwarding, GTP-U, IP routing, and service continuity mechanisms.
• Proven experience implementing or integrating 3GPP Core Network subsystems, with emphasis on user plane functions, packet processing, QoS, routing, performance, scalability, and service assurance.

Essential experience

• Hands-on experience with the development, integration, and testing of 3GPP 5G Core user plane systems, especially UPF, N3/N6/N9 data path integration, N4/PFCP behavior, and end-to-end traffic validation.
• Strong knowledge of 5G Core user plane functions and concepts: UPF, SMF-UPF interaction over N4, PDU Session Anchor, ULCL, branching point, traffic steering, QoS flows, 5QI, ARP, GBR/non-GBR handling, and charging/usage reporting support from a user plane perspective.
• Experience with network resource orchestration and user plane handling for 5G network slicing, including slice-specific UPF selection, QoS isolation, traffic breakout, and capacity management.
• Software implementation or integration experience in telecom user plane contexts, including packet processing frameworks, data path acceleration, routing, tunneling, GTP-U, PFCP, Linux networking, cloud-native deployment, and observability.
• Basic familiarity with 5G-NTN user plane aspects, including latency, jitter, Doppler and link variability impacts on data path performance, QoS adaptation, mobility, and satellite gateway/feeder-link constraints.

Highly desirable experience (several of the following):

• Experience with satellite communications user plane integration, including gateway interworking, backhaul constraints, traffic routing, QoS management, and NTN data path optimization.
• Knowledge of 5G-NTN enhancements and their user plane implications, including Rel-17 and beyond, NR-NTN, service continuity, mobility, QoS, and satellite access constraints.
• Experience with user plane testing, troubleshooting, and simulation tools, including traffic generators, protocol analyzers, packet capture tools, GTP-U/PFCP analysis, performance testing, and tools such as Spirent, Keysight, Wireshark, iPerf, TRex, or similar.
• Experience with end-to-end 5G user plane call flows and data path validation, including PDU session establishment, N3/N6/N9 forwarding, QoS enforcement, UPF selection, mobility impact on user plane continuity, and NTN traffic breakout scenarios.

Proven work attitude:

Other key requirements / comments

• The candidate must be eligible for a “SECRET” security clearance, in accordance with the national regulations as well as EU/ESA/NATO equivalents
• Willing to work 60% onsite from office
• Travel as required for project realization purposes
• Management of technology development, work with cross discipline teams (software experts, satellite and telecom experts, sales, business experts, etc.)
• Research and Development project management experience
• Communication skills, ability to explain complex concepts to non-technical stakeholders
• Excellent written and verbal communication skills
• Commitment to deadlines and willingness to meet tight development schedules
• Fluent in English, other languages are an upside