Principal Engineer – Core

Skylo; Bengaluru; On-site; INR 5,500,000 - 9,000,000; Full time

Benefits offered by this job

Stock option equity program

Comprehensive health coverage

Wellness & education reimbursement

Generous time off and international st

Job summary

Skylo is seeking a Principal Engineer – Core to lead the architecture and performance of Skylo’s cloud-native 5G core, IMS voice, and SMS services, integrated with NTN RAN. This role drives capacity planning, KPI frameworks, and cross‑functional collaboration with vendors and operations.

You’ll mentor the Network Design & Planning team and shape the core network strategy across consumer, automotive, and IoT use cases for Skylo’s first commercial direct-to-device satellite network.

Qualifications

• 15+ years of experience in mobile core network engineering or architecture.
• Deep hands-on experience with 5G Core (SA) and EPC, SBA/SBI, and 3GPP core specs.
• Hands-on IMS architecture and end-to-end call flows for SMS, VoLTE, VoNR.
• Strong knowledge of NAS, NGAP/S1AP, GTP, PFCP, Diameter, SIP, HTTP/2.
• Proven capability in traffic forecasting, capacity planning, and dimensioning.
• Experience defining KPI frameworks and performance thresholds.
• Experience managing core network vendors and design reviews.
• Excellent roaming/interconnect understanding.
• Cloud-native network functions experience and cloud tech proficiency.
• Experience with NTN/Rel-17+ NTN is a plus and strong documentation skills.

Responsibilities

• Own end-to-end architecture and design of Skylo’s 5G core and interworking with EPC.
• Lead technical design reviews with core network vendors and drive roadmaps.
• Design IMS-based voice and messaging services for satellite-connected devices.
• Define core integration with NTN vRAN and roaming requirements.
• Lead capacity planning and resource forecasting across cloud and on‑prem.
• Develop KPI frameworks and drive performance analysis for registration, session, voice and SMS.
• Design roaming architectures with MNO partners and interconnects.
• Collaborate with Regulatory, Security and Operations on compliance and security.
• Create technical specifications and engineering docs for core elements.
• Mentor engineers and provide technical leadership across the team.

Skills

5G Core expertise

EPC SBA/SBI knowledge

IMS architecture

Cloud-native networks

KPI frameworks & performance

Core network capacity planning

Vendor management

Roaming architectures

VNode/VoLTE/VoNR knowledge

Leadership & mentoring

Tools

Kubernetes

Docker

AWS

GCP

Job description

The world still has coverage blind spots. You could help eliminate them at Skylo.

Skylo has pioneered a standards-based approach to satellite connectivity. We connect smartphones and IoT devices directly to satellites. No special hardware, no entirely new networks. Just billions of existing devices, suddenly reachable anywhere on Earth. We're not building toward this future. We're already in it.

Our direct-to-device service is live on millions of activated devices across five continents, covering more than 72 million square kilometers, in partnership with leading satellite operators, mobile network operators, Tier-1 chipset makers, and OEMs worldwide. And we're just getting started.

At the heart of it all is Skylo's commercial NTN vRAN: a 3GPP standards-based, cloud-native platform that seamlessly bridges terrestrial and satellite networks. It's the infrastructure that makes true anywhere, anytime connectivity possible.

When you join Skylo, you'll work at the intersection of three markets reshaping how the world stays connected: mass-market consumer devices, automotive, and industrial IoT. Enabling people outdoors and critical workflows in the world's most remote places.

This is a rare chance to work on technology that matters, at a company that's already proving it works

This role is located in Bangalore, India where we are onsite 3 days a week in office.

Summary Of How You Will Impact Skylo

Skylo is hiring a Principal Engineer – Core to help fulfill Skylo’s mission of making satellite connectivity available to all. As a key member of the Network Design & Planning team, this individual will be the technical authority for Skylo’s core network and service layer, owning the architecture, design, capacity planning, and performance of our cloud-native 5G core, IMS voice and SMS services, and their integration with Skylo’s NTN RAN. Your work will ensure our core network is reliable, scalable, and high-performance as we support millions of devices across consumer, automotive, and IoT use cases on the world’s first commercial direct-to-device satellite network.

How You Will Contribute

• Own the end-to-end architecture and design of Skylo’s 5G core (5GC) and its interworking with EPC, including AMF, SMF, UPF, AUSF/UDM/UDR, PCF, NRF, NSSF and NEF functions.
• Act as the lead technical counterpart to our core network vendors, driving roadmap and feature requirements, design reviews, and release acceptance.
• Design and evolve IMS-based voice and messaging services (VoLTE/VoNR, SMS over NAS, SMS over IP, SMSC and IP-SM-GW interworking) for satellite-connected devices.
• Define how the core integrates with Skylo’s NTN vRAN, including NTN-specific requirements such as extended timers, long round-trip delay, mobility, tracking area design, and satellite/terrestrial roaming.
• Lead core network capacity planning and dimensioning, including traffic forecasting, subscriber growth modelling, and resource planning across cloud and on-prem deployments.
• Define core network KPI frameworks, baselines, and thresholds, and drive performance analysis and optimisation of registration, session, voice, and SMS success rates.
• Design roaming and interconnect architectures with MNO partners (S6a/S8, N32/SEPP, Diameter and HTTP/2 signalling, DEA/DRA, SMS interworking).
• Partner with Regulatory, Security, and Operations teams to ensure the core supports Lawful Intercept, emergency services, and network security requirements.
• Create technical specifications, high- and low-level designs, and engineering documentation for core network elements.
• Conduct proof-of-solutions and lab validation to assess new features, vendors, and architecture options.
• Drive continuous improvement loops with Operations & Implementation teams, including root cause analysis of core network incidents.
• Mentor engineers and provide technical leadership across the Network Design & Planning team.

What We Look For

• 15+ years of experience in mobile core network engineering, design, or architecture, preferably acquired within a mobile network operator or a core network vendor.
• Deep hands‑on experience with 5G Core (SA) and EPC, including the service‑based architecture (SBA/SBI) and 3GPP core specifications (e.g. TS 23.501, 23.502, 23.401).
• Hands‑on experience with IMS architecture (P/I/S‑CSCF, TAS, HSS) and end‑to‑end call flows for SMS delivery, VoLTE, and VoNR.
• Strong understanding of NAS, NGAP/S1AP, GTP, PFCP, Diameter, SIP, and HTTP/2 protocols.
• Proven ability to perform core network traffic forecasting, capacity planning, and dimensioning.
• Demonstrated expertise in defining KPI frameworks, baselines, and thresholds, and in driving performance optimisation.
• Experience managing core network vendors, including leading technical design reviews and acceptance testing.
• Excellent understanding of inbound and outbound roaming architectures and interconnect.
• Hands‑on experience with cloud‑native network functions and cloud technologies such as Kubernetes, Docker, and public cloud (AWS, GCP).
• Experience with Non‑Terrestrial Networks (NTN) and 3GPP Rel-17+ NTN is highly preferred.
• Familiarity with Lawful Intercept, emergency services, and core network security is a plus.
• Excellent written and verbal communication skills for creating detailed technical documentation and presenting solutions to internal and partner audiences.
• Previous experience mentoring engineers or leading technical teams.

What We Offer

With employees working across three continents, Skylo is proud to be an equal opportunity employer dedicated to building an inclusive and diverse workforce. Our worldwide and inclusive culture encourages a flexible approach to work, and we also offer an attractive range benefits such as:

• Competitive compensation packages including a stock option based equity program
• Comprehensive occupational health coverage
• Monthly allowances for wellness and education reimbursement
• A generous time off policy, holidays, and the opportunity to temporarily work abroad
• Once in a lifetime opportunity to be a part of developing and running world’s first commercial, live direct-to-device satellite network and service
• Access to world-class team and talent across tech domains: software, hardware, chipsets, telecom, satellite and network virtualization
• Open, transparent, inclusive culture that blends multi-national characteristics
  

EEO Statement

Skylo is an equal‑opportunity employer and we celebrate diversity. We do not discriminate on the basis of race, religion, color, ancestry, national origin, caste, sex, sexual orientation, parent or caregiver status, political affiliation, gender, gender identity or expression, age, disability, medical condition, pregnancy, genetic makeup, marital status, or military service consistent with applicable federal, state, and local laws.

We are also committed to providing reasonable accommodations for qualified individuals with disabilities and disabled veterans in our job application procedures. Please let us know if you need assistance or accommodation due to a disability.