In our world things change by the millisecond
We build the technology that creates amazing moments and better connects our customers. Ready to play your part? Join us and Be Phenomenal. Working towards the same shared goal of better connectivity, our tech teams enjoy a high degree of freedom. We love hearing ideas and seeing them come to life. With great resources, you’ll get to be part of a team at the foundations of the transformation of our business. Who knows what the next innovation will be? That’s what makes a career at Three so exciting.

Since we set foot in Ireland, we’ve done things differently
Investing in infrastructure, we built a network that now connects 2.2 million customers nationwide, carrying more data than all alternative telecommunications providers combined. We take the script and rip it up, we’re a big-hearted energetic bunch, striving for a better connected life. We encourage our employees to face their weaknesses, to really open themselves up to new tasks and projects in a super-charged and rich learning environment. We want you to become the best version of yourself.

Join us as a Test Engineer (Networks) (Fixed Term Contract)

This position resides in the Three Ireland Networks Test Team- a team which is accountable for ensuring the delivery of all Mobile Core Network (MCN) testing (Voice, Messaging & Data Services, RAN, IP, Service Control and VAS). The primary focus of this role is managing the Test Lab RAN environment, ensuring stability and availability to support testing across the MCN.

As a Network Test Engineer, you will work alongside a team of experienced engineers tasked with the continued evolution of the Three Ireland mobile network. Collaboration with multi-disciplinary experts across network design, solutions & operations with the goal of delivering first class customer experience on voice, data & messaging services.

The Network Test Engineer position reports to the Networks Test Manager and offers the successful candidate a fantastic opportunity to learn and develop rapidly within a fast paced, dynamic environment, with exposure to a full end-to-end mobile network.

The suitable candidate will have a strong background in mobile RAN networks combined with a good understanding of testing frameworks and principles.

As a Test Engineer you will be hands-on across a wide range of Network equipment and technology, contributing to a wide array of solution introductions and existing mobile network validations:
Manage and drive all RAN related testing.Design, execute, and maintain test plans for Radio Access Network (RAN) features across 2G/3G/4G/LTE and 5G NR mobile networks.
Perform functional, regression, interoperability, and performance testing on RAN nodes such as gNodeB/eNodeB/BTS, DU, CU, RNC, BSC and associated interfaces.
Validate mobility procedures including handovers, cell reselection, carrier aggregation, SRVCC and VoLTE scenarios.
Analyse network logs, protocol traces, and KPIs using tools such as Wireshark, TEMS, QXDM, or vendor-specific tracing platforms.
Conduct lab testing to verify radio coverage, throughput, latency, and network stability under varying traffic and mobility conditions.
Troubleshoot and isolate issues related to RF performance, signalling failures, call drops, attach failures, and data session interruptions.
Collaborate with RAN design, core network, transport, and operations teams to reproduce, debug, and resolve network defects.
Automate test execution and reporting using scripting languages such as Python, Bash, or automation frameworks integrated with CI/CD pipelines.
Prepare detailed test reports, defect documentation, and validation summaries for customer acceptance and release sign-off activities.
Ensure compliance with 3GPP standards, operator requirements, and vendor specifications during feature validation and network integration activities.

The skills we're looking for

The successful candidate should be competent in all aspects of networking and security, across both physical and virtualised platforms, with a high level of RAN and IP troubleshooting ability and previous testing experience.
They must be motivated and driven, with a proven ability to work in both a team environment and autonomously.
Educated to degree level in an Engineering / Telecommunications discipline, or equivalent experience
Hands-on experience with physical RAN lab setup and integration, including cabling, rack installation, power connections, antenna/RF path configuration, test UE setup, and coordination of lab infrastructure for end-to-end network testing.
Strong knowledge of RAN architecture, protocols, and procedures based on 3GPP standards.
Experience with RAN testing tools and log analysis platforms such as TEMS, Wireshark, Nemo, or vendor-specific OSS tools.
Understanding of RF concepts including propagation, interference, handovers, carrier aggregation, MIMO, and beamforming.
Hands-on experience troubleshooting network issues related to call setup failures, dropped calls, mobility, and data performance.
Familiarity with interfaces and signalling protocols including S1, X2, NG, SCTP, GTP, and RRC.
Ability to develop and maintain test automation scripts using Python, Bash, or similar scripting languages.
Experience working in lab and field test environments with telecom equipment from vendors such as Ericsson, Nokia,
Huawei, or Samsung.
Strong analytical, problem-solving, communication, and documentation skills with the ability to work in cross-functional engineering teams.

Nice to Have:

Knowledge of Mobile Core and RAN Network architectures
Linux System Admin experience
Project and Design lifecycle understanding

Benefits of Working at Three

Flexible working with our new Hybrid model, our employees will enjoy more flexibility working from home and our office locations (3 days per week office based). Please see job description for the office location of this role.
Competitive salary, annual performance bonus & pension contribution
25 days holidays plus 2.5 company days
Annual Leave buy or sell (buy or sell up to 5 days AL each year)
Healthcare Insurance through our flexible benefits programme
Life assurance, phone & laptop, subsidized canteen
Access to learning & development tools such as Coursera
Free on-site parking

There’s a lot more to us than meets the eye.

You may think you know us, but we’re full of surprises. Intrigued? Join us and Be Phenomenal.
Apply now at: https://www.three.ie/careers #Jobs

At Three, we are committed to equity, diversity and inclusion. As Ireland’s largest mobile telecommunications provider, we provide a better connected life for our diverse customer base, and want our teams to reflect this. We welcome and celebrate all identities and strive to create a culture of belonging where employees can thrive as their authentic selves. If you do not ‘tick every box’ in this job description, you likely have other valuable skills that would make you a great fit for one of our teams. If you feel this role is for you, then please apply! #Jobs

If you require reasonable adjustments for your interview, please let us know when scheduling your interview, or alternatively, please email aoife.omeara@three.ie Apply now at Three, a Phenomenal career awaits!

Network Test Engineer IP

Benefits

Job Description