(Senior) Modem Integration Engineer

Job Summary

Sasken Finland Oy serves domestic and global customers in design and development of hardware and software products and provides services for industries such as Telecommunication, Industrials and Defence, and Satcom. Sasken Finland has a strong track record of successfully delivering R&D product programs with high-end expertise in wireless and embedded system technologies.

More about Sasken here: https://www.sasken.fi/

We are now looking for a (Senior) Modem Integration Engineer to join our Tampere-based software team.

The Role

As a Modem Integration Engineer, you will own the integration of the physical layer (L1) with the upper-layer modem stack (L2/L3) across our multi-processor 5G NTN User terminal architecture. You will work at the most critical technical boundary of the product — where PHY meets MAC, where third-party IP meets our system software, and where 3GPP procedures meet real satellite behaviour Your work will directly determine whether the terminal acquires, tracks and holds a satellite link, sustains multi-gigabit throughput and remains stable in the field.

Your primary technical focus will be the MAC–PHY interface built on FAPI/nFAPI and you will own everything that happens across that boundary — message flows, slot timing, buffer ownership, cache coherency and the vendor-specific behaviours that always emerge in real integrations.

The hardest bugs in this kind of system rarely live inside one processor, and we expect you to enjoy the detective work of tracking them across the boundaries between them.

Beyond the day-to-day integration work, you will contribute directly to the software development, architecture, interface control documents, integration plans, verification plans and technical risk assessments that guide the program. flows, and you will work closely with customers, satellite operators and IP vendors in technical reviews, integration workshops and issue-resolution sessions.  Based on your experience you might be mentoring more junior team members to grow in technical aspects.

Key responsibilities

• Integrate L1 (PHY) and L2/L3 (MAC, RLC, PDCP, RRC, NAS) software on multi-processor 5G NTN user terminal.
• Own the MAC–PHY interface based on FAPI/nFAPI over PCIe and shared memory, including message flows, timing, buffer ownership and cache coherency.
• Debug end-to-end failures across processors and drive resolution with internal teams and third-party vendors.
• Contribute to the software architecture, interface control documents, integration plans, verification plans and technical risk assessments.
• Support system-level integration with the antenna control unit, host controller and RF subsystem, including satellite acquisition, tracking and handover flows.
• Work directly with customers, satellite operators and IP vendors in technical reviews, integration workshops and issue-resolution sessions.
• Mentor junior engineers on FAPI, MAC–PHY integration, real-time debugging and cross-processor system behaviour based on your experience.

Required Competencies

Technical skills

• Hands-on experience integrating 5G or LTE modem software integration, ideally at the MAC–PHY boundary.
• Solid working knowledge of PHY concepts (OFDM, channel coding, MIMO, synchronization) at the level needed to integrate and debug.
• Practical experience with FAPI / nFAPI or an equivalent MAC–PHY interface.
• Strong C/C++ and embedded experience, with real-time software design skills and CD/CI proficient.
• Comfortable work in multiprocessor environment with cross-processor debugging skills using logs, traces, diagnostics etc.
• Strong problem-solving skills, capable of isolating and reporting issues across PHY, MAC, transport, RF and antenna.
• Expertise on working on ARM and/or RISC processor and with modern OS (embedded Linux, Zephyr, FreeRTOS)
• Excellent collaboration and communication skills, able to work effectively across disciplines, teams, cultures and organizations.

Nice-to-have

• Understanding of 3GPP NR NTN REL-18 / 19 Physical layer(L1) processing and/or familiarity with 5G higher-layer (L2/L3 protocols and procedures. (MAC/RLC/PDCP/RRC/NAS)
• Experience with RTOS environments (Zephyr, FreeRTOS) on host or auxiliary processors.
• Experience with antenna control.
• Familiarity with NTN over LEO/GEO/MEO constellations.

What We Offer

• A Senior technical role at the heart of exciting 5G NTN activities.
• Real ownership of a critical, high-visibility part of the product.
• A close-knit, low hierarchy engineering team working with leading global customers.
• Deep involvement in system design decisions, not just implementation.
• Access to leading vendors, IP partners and satellite operators.

Education and Experience Required

B.Sc. or M.Sc. in relevant field (Embedded Systems, Electronics, Software Engineering, etc.)

Minimum:

2+ years experience (Engineer)

5+ years experience (Senior Engineer)

Additional Information

For further information please contact Tomi Nummela via email tomi.nummela@sasken.com.

Our recruitment process follows Sasken Finland Oy procedures, and all applications and inquiries are handled with strict confidentiality. The selected candidate will be required to pass a medical examination, including a drug test.

Please note that Sasken Finland does not provide relocation support and this opportunity is not for remote only work.