SIM Management, 5G Core Engineer

E-Space•Arlington, TX

4d•Onsite

About The Position

The SIM Management 5G Core Engineer will analyze, design, implement, and verify the configuration and integration of subscriber data management nodes (UDR / UDM), networks, and systems across our 5G infrastructure. Your scope of work includes introduction, upgrade, expansion, functionality, and capacity scenarios on modern cloud-native UDM and UDR deployments. You will be a key contributor to the convergence of subscriber databases as platform evolves — and your work will directly shape the reliability and scalability of the networks our partners depend on.

Requirements

At least 10 years of experience in core network engineering with a focus on subscriber data management in 5G Core networks.
Deep operational knowledge of HSS/HLR or UDR/UDM platforms.
Hands-on experience with configuration and troubleshooting.
Practical experience with 5G UDM and UDR, including cloud-native deployments (containerized/Kubernetes-based NFs) and HTTP/2 SBI interfaces (N8, Nudm_SubscriberDataManagement, Nudr_DataRepository).
Solid understanding of subscriber profile structures: 5GS subscription.
Experience with IMSI/MSISDN range management, number portability (NP/MNP) integration, and SIM/eSIM provisioning workflows.
Working knowledge of 5G SA (AMF/SMF/UDM/UDR/AUSF/UDSF) core architectures and their subscriber data flows.
Familiarity with 3GPP standards governing subscriber data: TS 29.503/29.504 (UDM/UDR SBI), TS 23.502 (5G procedures).
Comfortable with Linux/Unix-based systems — able to navigate shells, interpret logs, manage processes, and perform basic system administration on telecom NF hosts.
Hands-on with Wireshark, tcpdump, and vendor-specific trace tools for deep analysis of MAP, Diameter, and HTTP/2 subscriber signaling.
Experience with high-availability configurations for subscriber databases: active/standby, geo-redundancy, and database replication/synchronization.
Familiarity with cloud-native telecom platforms (Kubernetes) and Helm-based NF lifecycle management.
Bachelor's or Master's degree in Telecommunications, Computer Science, or equivalent; post-graduate studies are a plus.
10+ years of core telecommunications network experience, with a minimum of 5 years hands-on with HLR, HSS, UDR, or UDM platforms.

Nice To Haves

Experience with 3GPP NTN core adaptations (Rel-17/18): satellite access node (SAN) architecture, timer and window parameter adaptation for high-latency links, or UPF placement in non-terrestrial topologies.
Background in MVNO core architecture: roaming interfaces (N32/SEPP, Diameter S6a/S9), multi-PLMN federation, MVNO interconnect, or eSIM/SM-DP+ integration.
Familiarity with 3GPP SA2/CT4 specifications or direct standards contribution experience.
Experience with NEF or network exposure APIs and B2B API gateway architecture.
Background in SIM provisioning platforms, subscription management, or UDM/HSS data modelling.
Experience in a startup or fast-paced R&D environment where architectural decisions move at product speed.

Responsibilities

Manage and operate UDR, and UDM nodes across 5G core domain, ensuring high availability and data integrity for subscriber profiles.
Design and maintain subscriber provisioning workflows, including IMSI/MSISDN management, service profiles, and roaming configurations.
Implement and verify HTTP/2-based (N8, Nudm) interfaces connecting subscriber data nodes to AMF and other core elements.
Use and build dashboards to monitor subscriber node KPIs, quickly surface abnormal conditions, and identify patterns before they become outages.
Own incident management for the subscriber data domain: follow communications procedures for internal escalation and external vendor coordination, ensuring SLAs are met.
Perform maintenance, security audits, patching, and emergency response for UDM/UDR platforms.
Undertake fault handling and corrective actions at node, service, and infrastructure level, including protocol trace analysis (Wireshark/tcpdump) on HTTP/2 signaling.
Lead and contribute to project activities: E2E introduction of new subscriber management nodes, capacity expansions, software upgrades, and feature activations.
Support onboarding by configuring subscriber data repositories, IMSI ranges, and roaming agreements in UDM/UDR systems.
Collaborate with teams to resolve cross-domain subscriber authentication and registration issues.