Descrição da Vaga

CORE COMPUTER SCIENCE ENGINEER (HYBRID PORTUGAL)

Portuguese company hires for remote position

📍 Location: Lisbon

💼 Work Model: Hybrid 2x week - Business Hours (with availability for out-of-hours support when required)

🗣️ Language Requirements: Spanish and English – Mandatory

🕓 Seniority: Mid-level (3+ years)

🏭 Sector: Telecommunications

💲Rate Between €1700 - 2000 RV (gross value)

⚠️ Instructions: Please send your CV in English and make sure to include all skills and experience that match the requirements of the opportunity. This will significantly increase your chances of success

About the Opportunity

As a Core CS & IMS Network Engineer, you will work with Mobile Core Network platforms responsible for voice services, signalling, interconnection, and subscriber management.

You will provide technical support for Core CS and IMS environments, investigate complex incidents, participate in upgrades and network changes, and contribute to the implementation and acceptance of new functionalities.

You will collaborate with Operations, Engineering teams, and technology vendors to maintain service quality and support the continuous evolution of the mobile network.

Key Responsibilities

• Support and maintain Core CS and IMS platforms.
• Ensure the availability, stability, capacity, and performance of critical network services.
• Monitor and support voice, signalling, interconnection, and subscriber management services.
• Perform advanced troubleshooting and Root Cause Analysis.
• Investigate complex technical incidents and recurring network issues.
• Analyse SS7, SIGTRAN, Diameter, and SIP signalling flows.
• Support software upgrades, patches, network changes, and maintenance activities.
• Participate in planned interventions and service validation activities.
• Support the implementation, integration, validation, and acceptance of new platforms and functionalities.
• Validate network configuration and service behaviour following changes or upgrades.
• Coordinate technical activities with Operations, vendors, and engineering teams.
• Escalate complex issues and follow them through to resolution.
• Develop and maintain technical documentation, procedures, and engineering guidelines.
• Contribute to network evolution and optimisation initiatives.
• Identify opportunities to improve network resilience, performance, and operational efficiency.
• Support continuous improvement and knowledge-sharing activities.

Core Network Platforms

The role requires experience with several of the following subscriber management and Core Network platforms:

• HLR – Home Location Register
• HSS and HSS-FE – Home Subscriber Server
• CUDB – Centralised User Database
• UDM – Unified Data Management
• UDR – Unified Data Repository
• AuC – Authentication Centre
• EIR – Equipment Identity Register
• DNS – Domain Name System

IMS and Voice Core Platforms

Relevant experience may include:

• CSCF – Call Session Control Function
• MTAS – Multimedia Telephony Application Server
• MGW – Media Gateway
• MGC – Media Gateway Controller
• MRF – Media Resource Function
• Media Server

Signalling and Interconnection Technologies

Candidates should have practical knowledge of several of the following:

• SS7
• SIGTRAN
• Diameter
• SIP
• SBC
• STP

Mandatory Requirements

• Degree in Telecommunications Engineering, Networking, Computer Science, or a related field.
• At least 3 years of experience in Mobile Core Network engineering, support, or operations.
• Hands-on experience supporting Core CS or IMS environments.
• Knowledge of voice, signalling, interconnection, or subscriber management services.
• Experience with relevant Core Network platforms such as HLR, HSS, CUDB, UDM, UDR, AuC, EIR, or DNS.
• Knowledge of IMS and Voice Core components such as CSCF, MTAS, MGW, MGC, MRF, or Media Server.
• Practical knowledge of telecommunications signalling protocols such as SS7, SIGTRAN, Diameter, or SIP.
• Experience troubleshooting complex Mobile Core Network incidents.
• Ability to perform technical analysis and identify the root cause of service issues.
• Experience with Ericsson and/or Huawei Core Network platforms.
• Strong analytical, troubleshooting, and problem-solving skills.
• Ability to collaborate with Operations, Engineering teams, and vendors.
• Professional communication skills in both Spanish and English.
• Ability to work effectively in a remote and international environment.

Nice-to-Have Qualifications

• Experience with both Ericsson and Huawei Core Network platforms.
• Knowledge of SBC and STP platforms.
• Experience supporting software upgrades and planned network changes.
• Participation in the integration and acceptance of new Core Network functionalities.
• Experience analysing signalling traces and end-to-end call flows.
• Knowledge of Mobile Core Network performance and service monitoring.
• Experience creating technical procedures and engineering documentation.
• Background in network optimisation, capacity management, or continuous improvement.
• Experience working in multi-vendor telecommunications environments.
• Knowledge of 4G/EPC, VoLTE, VoWiFi, or 5G Core technologies.

The Ideal Candidate

The ideal candidate is a Mobile Core Network Engineer with practical experience supporting Core CS, IMS, voice, signalling, and subscriber management platforms.

You are comfortable investigating complex incidents, analysing signalling flows, performing Root Cause Analysis, and coordinating technical resolutions with internal teams and technology vendors.

You combine hands-on technical knowledge with a structured and proactive approach. You can support daily operations while also contributing to upgrades, integrations, platform acceptance, technical documentation, and network improvement initiatives.

Experience with Ericsson or Huawei platforms and the ability to communicate confidently in Spanish and English are essential for this position.

Questions for Candidates

Before applying, please confirm:

1. Do you have at least 3 years of experience in Mobile Core Network engineering, support, or operations?
2. Do you have hands-on experience with Core CS, IMS, or Voice Core platforms?
3. Which subscriber management platforms have you supported: HLR, HSS, HSS-FE, CUDB, UDM, UDR, AuC, EIR, or DNS?
4. Which IMS or Voice Core components have you worked with: CSCF, MTAS, MGW, MGC, MRF, or Media Server?
5. Which signalling protocols do you use in your daily work: SS7, SIGTRAN, Diameter, or SIP?
6. Do you have practical experience with SBC or STP platforms?
7. Have you worked with Ericsson Core Network platforms?
8. Have you worked with Huawei Core Network platforms?
9. Do you have experience analysing signalling traces and end-to-end voice call flows?
10. Have you performed advanced troubleshooting and Root Cause Analysis for complex network incidents?
11. Have you supported software upgrades, network changes, or maintenance activities?
12. Have you participated in the implementation, integration, validation, or acceptance of new Core Network functionalities?
13. Do you have professional working proficiency in Spanish?
14. Do you have professional working proficiency in English?
15. Are you available to work fully remotely?
16. Are you comfortable working under a B2B/RV contract within the proposed monthly rate?

CV Instructions

Please submit your CV in English and clearly describe your experience with Mobile Core Networks, Core CS, IMS, voice services, subscriber management, signalling protocols, and Ericsson or Huawei platforms.

For each relevant professional experience, include the network platforms, technologies, protocols, vendors, and technical activities you handled. Please highlight your involvement in troubleshooting, Root Cause Analysis, upgrades, integrations, acceptance, and network optimisation.

CV Keywords

Mobile Core Network, Core CS, Circuit-Switched Core, IMS, Voice Core, Core Network Engineer, Telecommunications Engineer, Mobile Network Engineering, Core Network Operations, Core Network Support, HLR, HSS, HSS-FE, CUDB, UDM, UDR, AuC, EIR, DNS, Subscriber Management, Subscriber Database, CSCF, P-CSCF, I-CSCF, S-CSCF, MTAS, MGW, MGC, MRF, Media Server, SS7, SIGTRAN, Diameter, SIP, SBC, Session Border Controller, STP, Signalling Transfer Point, Voice Services, Mobile Signalling, Interconnection, Ericsson, Huawei, Ericsson Core Network, Huawei Core Network, Network Troubleshooting, Root Cause Analysis, RCA, Signalling Analysis, Signalling Traces, Call Flow Analysis, Incident Management, L2 Support, L3 Support, Software Upgrades, Network Changes, Network Maintenance, Platform Integration, Functional Validation, Technical Validation, Solution Acceptance, Network Performance, Service Availability, Network Stability, Network Optimisation, Technical Documentation, Engineering Guidelines, Vendor Coordination, Telecommunications, VoLTE, VoWiFi, EPC, 5G Core

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