Job Description: About Organization Core Network Operations Department is responsible for the operation of Rakuten Mobile’s fully virtualized network. We manage critical infrastructure, including IMS (IP Multimedia Subsystem), RCS (Rich Communication Services), EPC (Evolved Packet Core), International Roaming, IoT, and Emergency Services. Our mission is to ensure the continuity, reliability, and availability of these services through advanced automation and AI-driven operational frameworks. The team consists of 50+ highly skilled Technical SMEs, Operations Engineers, Project Managers, and Problem Managers working within a VNF/CNF-based fully virtualized core network environment. 5G SA Expansion: With the launch of 5G SA services, we are initiating 5GC operations and require specialized talent to lead this transition. Strengthening Capabilities: As core technology becomes increasingly complex and we migrate toward cloud-native architectures, we need to reinforce our team to ensure uninterrupted and reliable service delivery using AI and automation. Workload Management: Due to our expanding customer base and the adoption of cutting-edge technologies, we are seeking additional resources to manage the increasing operational demands. Job Duties Provide L2/L3 level troubleshooting support for 5GC E2E operations. Resolve technical issues related to core and cloud infrastructure, including vendor-specific product support. Manage and resolve complex customer issues escalated from the monitoring support team. Perform in-depth audits and implement improvement plans. Conduct regular technical analysis to ensure service optimization and quality. Collaborate with internal teams, partners, and vendors to resolve technical issues and implement corrective actions. Conduct configuration testing and verification to ensure compliance with regulatory and service requirements. Analyze service/operational KPIs, generate reports, and contribute to process and procedure improvements. Document and maintain detailed records of support activities, including resolutions and troubleshooting steps. Execute configuration changes and manage communication across different domains. Build and maintain a knowledge database to enhance daily operational efficiency. Identify and fix incidents within the agreed Service Level Agreement (SLA). Participate in an on-call shift rotation, including occasional night and weekend support for urgent issues or scheduled maintenance. Work Location: Tokyo Office-based. Minimum Qualifications 10+ years of experience in mobile core network operations or planning. Hands-on experience with 5GC products. Hands-on experience with multi-vendor Packet Core products. Hands-on experience with container-based infrastructure (Kubernetes). Strong knowledge of automation and AI frameworks. Preferred Qualifications Deep understanding of mobile network protocols (Diameter, GTP, SIP, RTP, IP-based protocols). Strong technical knowledge of E2E Virtual Core network architecture (IMS, EPC, RCS, CNF) and CNF-based mobile networks. Experience with monitoring tools, performance analysis, and 5G Core/Cloud deployment. Proficiency in industry-standard tools for analyzing KPIs and metrics. Working experience with OpenStack or Kubernetes. Expertise in Method of Procedure (MOP) preparation and validation. Experience leading Incident Bridges and preparing reports for senior management. Strong analytical, problem-solving, and interpersonal communication skills. Relevant technical certifications. Languages: English (Overall - 3 - Advanced) Looking for members to join our mobile phone business “They cannot succeed if they step into the field at this late date” Some people say Rakuten is reckless in trying to enter the mobile communications business. However, innovation is realized if we succeed when something seems impossible. At Rakuten, we think the world changes when we achieve such changes. Because our history has always been a series of innovations since our establishment. Launching a communication carrier is an opportunity that we have once in our lives. Crack open the current communication industry. Blow new wind into life. Why not create innovation with us? Why not do something big? Job Opening: Regular Employee Company Name Rakuten Mobile, Inc. Qualifications [Required] TOEIC score of 600 or equivalent English proficiency/skills. Rakuten Group Englishnization Rakuten Mobile, Inc. aims for all employees to achieve a TOEIC score of 800 or higher, in line with Rakuten Group, Inc.'s Englishnization policy. As a first step, a TOEIC score of 600 (or equivalent English proficiency) is required for mid-career hires. Job Responsibilities [Upon initial hiring] Varies depending on the position. The scope of work changes may include assignments to other duties determined by the company based on directives, etc. (If a transfer is ordered in accordance with the secondment regulations, the duties will be those of the seconded company.) Contract Period No fixed term Probationary Period Yes (3 months) The probationary period may be extended at the company's discretion. Employment conditions will not change during the probationary period. Work Location [Upon initial hiring] Headquarters (Rakuten Crimson House, 1-14-1 Tamagawa, Setagaya-ku, Tokyo), and other business sites. The scope of work location changes may include reassignments or transfers to locations nationwide and overseas. If remote work is partially permitted, the work location will be the remote work location approved by the company. The work location at the time of hiring will be communicated in the job description for each position and the offer letter. As a measure against passive smoking, smoking is prohibited on the premises of Rakuten Crimson House (however, this may vary depending on the business site). Working Hours Standard working hours: 9:00 AM - 5:30 PM On days when Rakuten Group morning meetings are held, the prescribed working hours will be 8:00 AM - 4:30 PM. Prescribed working hours are 7.5 hours, with a 1-hour break. A flextime system is partially applied. Core time: 11:00 AM - 3:00 PM (8:00 AM - 12:00 PM on morning meeting days) Some positions may differ from the above; details will be specified in the offer letter (e.g., application of discretionary labor system). Overtime work or work on holidays may be instructed. Holidays/Leave/Absence Complete two-day weekend system (Saturday and Sunday) and national holidays Summer vacation, New Year's holiday, annual paid leave, menstrual leave, special leave (condolence, volunteer, etc.) Maternity leave, childcare leave, family care leave Some positions may differ from the above; details will be specified in the offer letter. Salary Monthly salary: JPY300,000 ~ (Breakdown: Base salary JPY 227,848 + fixed overtime pay for 40 hours JPY 72,152) The above is the minimum salary offered for mid-career hires. Overtime work exceeding 40 hours per month will be paid separately as overtime allowance. Some positions may differ from the above; details will be specified in the offer letter (e.g., application of discretionary labor system). Commuting allowance will be provided (conditions and maximum amount apply). Salary Increase Yes Reviewed in January and July based on company performance and individual evaluation. Bonus Yes Paid in June and December based on company performance and individual evaluation. Stock Option Plan Yes Retirement Allowance Yes Insurance Employees' Pension Insurance, Health Insurance, Workers' Accident Compensation Insurance, Employment Insurance, etc. Benefits Cafeteria (breakfast, lunch, dinner generally free) Employee Stock Ownership Plan English learning support, etc. Job Opening: Fixed-term Employee Company Name Rakuten Mobile, Inc. Qualifications Varies depending on the recruiting position. Job Responsibilities [Upon initial hiring] Varies depending on the recruiting position. The scope of work changes may include assignments to other duties determined by the company based on directives, etc. (If a transfer is ordered in accordance with the secondment regulations, the duties will be those of the seconded company.) Contract Period Fixed term Maximum contract renewal period: Yes (The total contract period is 5 years, starting from the initial employment contract date.) Probationary Period None Work Location [Upon initial hiring] Headquarters (Rakuten Crimson House, 1-14-1 Tamagawa, Setagaya-ku, Tokyo), and other business sites. The scope of work location changes may include reassignments or transfers to locations nationwide and overseas. If remote work is partially permitted, the work location will be the remote work location approved by the company. The work location at the time of hiring will be communicated in the job description for each position and the offer letter. As a measure against passive smoking, smoking is prohibited on the premises of Rakuten Crimson House (however, this may vary depending on the business site). Working Hours Standard working hours: 9:00 AM - 5:30 PM On days when Rakuten Group morning meetings are held, the prescribed working hours will be 8:00 AM - 4:30 PM. Prescribed working hours are 7.5 hours, with a 1-hour break. A flextime system is partially applied. Core time: 11:00 AM - 3:00 PM (8:00 AM - 12:00 PM on morning meeting days) Some positions may differ from the above; details will be specified in the offer letter (e.g., application of discretionary labor system). Overtime work or work on holidays may be instructed. Holidays/Leave/Absence Complete two-day weekend system (Saturday and Sunday) and national holidays Summer vacation, New Year's holiday, annual paid leave, menstrual leave, special leave (condolence, volunteer, etc.) Maternity leave, childcare leave, family care leave Some positions may differ from the above; details will be specified in the offer letter. Salary Determined individually based on experience, etc. Commuting allowance will be provided (conditions and maximum amount apply). Salary Increase Yes Upon contract renewal, a salary revision may be proposed based on the most recent evaluation. Bonus May be paid taking into account company performance, general economic conditions, and work performance/abilities. Stock Option Plan None Retirement Allowance None Insurance Employees' Pension Insurance, Health Insurance, Workers' Accident Compensation Insurance, Employment Insurance, etc. Benefits Cafeteria (breakfast, lunch, dinner generally free) Employee Stock Ownership Plan English learning support, etc.

Senior Engineer - 5G Cloud (RMI Core Network Operations Dep).

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Senior Engineer - 5G Core (RMI Core Network Operations Dep)

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