5G Core System Engineering Lead in Santa Clara, California at E-Space
Job Description
We are hiring a 5G Core System Engineering Lead to own end-to-end system design and interface definition for E-Space's satellite 5G Core network. This architecture-level role defines interfaces and information flows across the core service chain, resolves satellite-specific trade-offs, and drives architectural decisions to closure across software, platform, and back-end engineering teams.
Your missionEnd-to-end architecture. Own the 5G Core system architecture across AMF, SMF, UPF, UDM, PCF, AUSF, CHF, and NEF. Decompose system requirements across the full service chain. Produce and maintain architecture decision records (ADRs), system decomposition documents, and interface specifications as the engineering source of truth.
Interface definition. Define and own interfaces and information flows at every core domain boundary, including interfaces between network functions, Nx reference points, UPF-to-data-network anchoring, and back-end integrations for charging, billing, and SIM provisioning. Make responsibilities and dependencies explicit.
System trade-offs. Drive trade-off analyses across competing constraints, including latency-aware timer and retransmission parameter tuning and complexity versus flexibility in policy and charging architecture. Document the evidence, decision, accountable owners, and next steps, and drive decisions to closure.
Satellite constraints. Analyze how satellite-imposed constraints propagate into core design decisions. Resolve architecture trade-offs for session continuity across dynamic links, SIM management, OSS/BSS, charging and policy, and subscription management for a globally mobile user base.
Call-flow design. Lead call-flow design for key 5G Core procedures in the satellite context. Ensure interfaces, information flows, and protocol behavior are consistent with the system architecture.
Back-end integration. Define requirements and interface contracts for CDR generation and the CHF interface, SIM provisioning and the UDM data model, and BSS/OSS integration points. Resolve dependencies across software, platform, and back-end engineering teams and verify that agreed contracts are implemented.
Build-versus-buy decisions. Evaluate core network functions and platform components through structured trade studies. Quantify criteria for performance, standards conformance, operational complexity, and cost, and drive recommendations to a decision.
System acceptance. Define system-level acceptance criteria and benchmarks for session setup latency, registration success rate, charging accuracy, and failover recovery time. Coordinate with the integration lab team so test coverage matches the architecture scope, and follow through on gaps until results are verified.
Standards alignment. Maintain alignment with 3GPP Release 17 and 18 core specifications across SA2, SA5, and CT4. Identify where standard assumptions diverge from satellite operational constraints, communicate the impact early, and drive resolution.
- Strong command of 3GPP 5G Core architecture, including NAS protocols, SBI service interfaces, N-reference points, and session, policy, and charging management across AMF, SMF, UPF, UDM, PCF, AUSF, and CHF.
Demonstrated experience authoring interface specifications, system requirements documents, and trade study reports in a multi-team engineering environment.
Understanding of how network-layer constraints propagate into core protocol behavior, and how to address them through parameter tuning or architectural adaptation.
Experience with charging and policy architecture.
Proven ability to drive architecture decisions to closure across software, platform, and back-end engineering teams.
Strong written communication, with the ability to produce precise interface specifications and trade-off analyses that stand on their own.
Experience with 3GPP NTN core adaptations in Releases 17 and 18, including 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, including roaming interfaces such as N32/SEPP and 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.
This is a full time, exempt position, based out of our Santa Clara, CA or Arlingtion, TX locations. The target base pay for this position in Santa Clara, California is $180,000 - $220,000 annually. The total compensation package will be determined by various factors such as your relevant job-related knowledge, skills, and experience and location.
We are redefining how satellites are designed, manufactured and used—so we’re looking for candidates with passion, deep knowledge and direct experience on LEO satellite component development, design and in-orbit activities. If that’s your experience – then we’ll be immediately wow-ed.
E-Space is not currently able to provide employment sponsorship for candidates who do not hold work authorization for the location of this role.
$180,000 - $220,000 a year
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