Principal Software Engineer – 5G Core Networks

2026-09-17

United States of America

US-CA-SAN JOSE-826 ~ 200 Holger Way ~ BLDG 826

Onsite

The ability to obtain and maintain a U.S. government issued security clearance is required.​ U.S. citizenship is required, as only U.S. citizens are eligible for a security clearance

• Typically requires a degree in Science, Technology, Engineering or Mathematics (STEM) and a minimum of 8 years of prior relevant experience

• Aggregate of 5 years software development experience in one or more of the following areas:

• Developing 3GPP network functions, network interfaces, and/or service-based interfaces, such as:

• User Plane Function (UPF), Access and Mobility Management Function (AMF), and/or Session Management Function (SMF),

• N4 and/or N11 network interfaces, and/or

• Namf, Nsmf, and/or Nupf services.

• Developing protocols such as NAS, PFCP, GTP-U, and/or HTTP/2.

• Reverse engineering telecommunications protocols.

• Troubleshooting distributed systems and control-plane signaling paths.

• Using 5G core network control-plane probes.

• Developing service-based microservices with REST-like APIs.

• Demonstrated expertise developing Linux-based software systems utilizing modern C++, Python, or equivalent environments to architect, implement, and validate complex telecommunications processing solutions.

• Ability to obtain and maintain a U.S. government issued Top Secret SCI (TS/SCI) security clearance with polygraph after start.

• U.S. citizenship is required, as only U.S. citizens are eligible for a security clearance.

• Existing U.S. government issued TS/SCI security clearance with polygraph or current SSBI.

• Knowledge of AMF, SMF, UPF, UDM, PCF, AUSF, NRF behavior, interactions, and call flows.

• Experience developing 5G core network control-plane probes for monitoring network traffic, extracting signaling and user-plane information, decoding 3GPP protocols, and/or traffic replay.

• Experience with observability frameworks (OpenTelemetry, Prometheus, Grafana)

• Familiarity with 4G EPC (MME, SGW, PGW, HSS).

• Familiarity with network virtualization and/or containerization technologies (KVM, VMware, OpenStack, AWS, Kubernetes, Helm, Docker).

• Experience developing with Go or Rust.

TS/SCI with Polygraph

Active and existing security clearance required after day 1

Raytheon Company Managed by Collins Aerospace

At RTX, the world's largest aerospace and defense company, 185,000 great minds are united by purpose and inspired to make a difference solving the world’s most complex problems. With our three market leading businesses, world-class operations and investments in research and development, we offer capabilities and opportunity no one else can. Together, we push the boundaries of known science and find new ways to connect and protect our world.

Collins Aerospace is a leader in technologically advanced, intelligent solutions that help redefine the aerospace and defense industry. With a comprehensive portfolio and deep technical expertise, we help customers meet the demands of the global market. Join us and help shape the future of aerospace and defense.

Applied Signal Technology (AST) is seeking a Principal Software Engineer with specialization in protocol development within 5G Core Networks who strives for excellence and has a passion to be part of a team that strengthens our nation and improves the security of our world. 

AST provides trusted strategic and tactical SIGINT solutions that secure the interests of the U.S. and its partners. AST’s work in areas such as high-capacity broadband communications, signal processing and analysis, tactical SIGINT, and wireless communications continually challenge our extraordinary engineers to resolve problems and make the world a safer place.  AST’s work environment is passionate, highly collaborative and provides engineers with the freedom to strengthen and expand their skills, explore new and creative ideas, and work closely with our nation’s finest service members all while embracing integrity, innovation, and work-life balance.

This is an ONSITE position at the San Jose, CA location. To learn more about AST, please click the link below.

Applied Signal Technology: WHO WE ARE

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  Apply your 5G Core Network software development experience to advance our next generation mobile telecommunication processing solutions by:

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  Collaborating with technical leaders to further product visions and roadmaps and developing innovative software solutions,

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  Collaborating with customers to elicit requirements and CONOPS, and

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  Performing technical research, developing technical documentation, presentations, and/or leading concept demonstrations.

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  Travel up to 15% travel time to other AST sites and customer sites to support customers meetings and/or demonstrations, system deployments.

Click on this link to read the Policy and Terms