Mobile Core Network Engineer Jobs (NOW HIRING)

Position: Core Network Engineer (5G)

Location: Richardson, Texas

Reporting to: Director of Engineering

Role:

The Core Network Engineer (5G) works within the Engineering department and is responsible for the design, deployment, operation, and optimization of Limitless Mobile?s 5G core network platforms.

The role is focused on hands-on engineering execution, supporting both internal network operations and contracted wholesale customer deployments across U.S. and international environments. Innovation is delivered through practical improvements in automation, reliability, observability, and deployment efficiency rather than strategic product ownership.

Tasks/Responsibilities:

• Core Network Design, Deployment and Management
  • Design, deploy, operate, and maintain 5G Core Network (5GC) components including AMF, SMF, UPF, NRF, PCF, AUSF, and UDM across both SA and NSA deployments.
  • Deploy, manage and operate 5G core environments in high-availability and geo-redundant configurations, ensuring resilience, scalability, and service continuity.
  • Support inter-PLMN connectivity including roaming, SEPP, and secure interconnect architectures.
  • Support mediation requirements for billing / charging and performance statistics on 5G core platform.
  • Perform end-to-end call-flow debugging and protocol-level troubleshooting across N1, N2, N3, N4, N6, N10, N11, and N12 interfaces.
  • Implement and support network slicing, policy control, and service function chaining.
  • Ensure compliance with relevant 3GPP specifications, security requirements, and interface protocols (e.g. HTTP/2, PFCP, SCTP).
  • Collaborate with RAN and infrastructure teams to support lab test-cells, and limited production radio deployments where required.
  • Integrate, harden, and operate both vendor-supplied and open-source 5G core solutions (e.g. Open5GS, free5GC, Magma) in test, pre-production, and production environments.
  • Contribute fixes, enhancements, and operational tooling where appropriate to support production stability and maintainability.
  • Use automation to reduce mean time to repair (MTTR), improve deployment repeatability, and increase operational visibility.
  • Develop and maintain custom scripts and tooling (e.g. Python, Bash, Go) to automate deployment, configuration, testing, monitoring, and fault analysis.

• Pre-Sales
  • Provide technical input and peer review to pre-sales and solution architecture activities, validating feasibility, integration complexity, and operational impact.
  • Contribute implementation-level considerations and constraints to High-Level Design (HLD) documentation produced by Solution Architects.

• Projects
  • Execute assigned technical workstreams within contracted wholesale customer projects, including deployment, integration, testing, and handover to operations.
  • Work under the direction of the Director of Engineering and in coordination with Solution Architects and Project Manager to deliver agreed technical outcomes.

• Operations
  • Provide Tier-3 technical support to the Network Operations Centre (NOC) for live network incidents affecting wholesale and internal services.
  • Participate in escalation and support on-call rotations as required.
  • Conduct root-cause analysis, document findings, and implement corrective and preventative actions.

• Skills Development
  • Continuously develop technical expertise across core network functions, infrastructure platforms, and emerging 3GPP features relevant to Limitless Mobile?s network roadmap.

Measurement:

• Performance will be assessed based on a combination of delivery effectiveness, operational stability, incident resolution time, change success rate, and successful deployment of wholesale customer solutions.

Desired Expertise & Experience:

• Bachelor?s or Master?s degree in computer science or engineering.
• Minimum of 5-8 years working in the telecommunications industry designing, integrating and managing mobile core network propositions for e.g. a Network Equipment Provider or carrier / Mobile Network Operator (MNO).
• Deep understanding of 5G Core architecture (SA/NSA), 3GPP specs, and control/user plane functions.
• Experience with open source 5G cores like Open5GS, free5GC, or Magma.
• Experience with Mongo database for opensource 5G solutions is a plus.
• Programming in at least one of the C++, Python, Golang, Bash, or equivalent languages.
• Familiarity with containerization (Docker, Kubernetes), Git, and CI/CD tools.
• Hands-on experience with Wireshark, PCAP analysis, and log-level debugging.

• Minimum of five years of systems integration, management and/or technical support of 4G / LTE and 5G mobile core network components.
• In-depth knowledge of mobile voice and data core network architecture (including MNO and MVNO / MVNE infrastructure architecture) as well as network topology, including ability to describe the key elements of a mobile network and understand how the components function and interact as well as how mobile calls are made and received and how mobile data sessions work both in VoLTE and VoNR environments.
• Understanding of Packet Switched network elements, interfaces and messaging for 4G / LTE networks, including IMS architectures and PCRF.
• Understanding of Voice SIP / RTP, ISUP and voice convergence technologies, including IMS (including VoLTE and VoWiFi).
• Understanding of RADIUS and Diameter for both signaling and charging scenarios.
• Experience of capacity management and dimensioning of mobile core elements.
• Familiarity with LI (Lawful Intercept), E911 and CALEA requirements.
• Familiarity with IMS and VoNR architecture.
• Demonstrated experience implementing and operationalizing technically robust mobile core network solutions aligned with customer, regulatory, and operational requirements.

Desired Personality:

• Entrepreneurial and proactive and accountable self-starter, comfortable with taking ownership of complex technical problems and hunger to make a difference as well as strong performance and results orientation.
• Ability to thrive in a fast-paced start-up environment, managing multiple projects and deadlines in parallel with ability to recognise and adjust priorities as required.
• Detail-oriented, methodical, and well organised yet able to demonstrate a high degree of flexibility and adaptability.
• Able to operate calmly and methodically in live-network and incident-driven environments.
• Ability to work effectively both independently as well as in a team.
• Effective communicator with strong documentation discipline and the ability to collaborate across engineering and operations teams.
• Positive and constructive personality, including willingness to go beyond the call-of-duty to ensure successful and on-time delivery of the projects.

Residence Requirement:

• Candidate must have authorization to work in the US.