Senior Engineer, 5G NR/LTE Protocol
Job Description
As Senior Engineer for 5G NR/LTE Protocol at CloudlyIO, you will implement and debug NR and LTE protocol features and bug fixes in the OAI UE and gNB stacks, with primary focus on MAC, RLC, PDCP, and RRC, and with the PHY-layer context needed to understand the constraints those layers operate under. You will work directly from 3GPP specifications, locate the exact sections relevant to each task, and deliver robust, reviewable patches in C/C++ on Linux.
Your debugging work is evidence-based and systematic: log to hypothesis, reproduce, fix, validate, and back every root cause analysis with PCAP evidence. You will strengthen regression coverage as you go, leaving the codebase more testable than you found it.
CloudlyNet is our RAN optimization platform for telecom operators and enterprise networks. It uses a Bayesian Digital Twin with real UE data to deliver energy savings, load balancing, mobility robustness, and coverage and capacity optimization across 4G and 5G deployments.
CloudlyIO is building deep internal expertise in the OpenAirInterface (OAI) open-source protocol stack across both UE and gNB. This role sits at the implementation core of that effort. You will work closely with the Protocol Lead to take well-scoped feature tasks from specification through implementation, debugging, and validated delivery.
Your debugging work is evidence-based and systematic: log to hypothesis, reproduce, fix, validate, and back every root cause analysis with PCAP evidence. You will strengthen regression coverage as you go, leaving the codebase more testable than you found it.
CloudlyNet is our RAN optimization platform for telecom operators and enterprise networks. It uses a Bayesian Digital Twin with real UE data to deliver energy savings, load balancing, mobility robustness, and coverage and capacity optimization across 4G and 5G deployments.
CloudlyIO is building deep internal expertise in the OpenAirInterface (OAI) open-source protocol stack across both UE and gNB. This role sits at the implementation core of that effort. You will work closely with the Protocol Lead to take well-scoped feature tasks from specification through implementation, debugging, and validated delivery.
Job Requirement
- Implement protocol features and bug fixes across the OAI UE and gNB stacks, working primarily in the MAC, RLC, PDCP, and RRC layers in C/C++ on Linux
- Navigate 3GPP specification documents (38-series for NR, 36-series for LTE) independently to locate the relevant sections for each implementation task, without requiring the specification to be pre-digested for you
- Debug state machine mismatches, timer and retransmission failures, PDCP security anomalies, and RRC procedure issues with structured rigor: log analysis, hypothesis formation, reproduction, fix, and validation
- Produce crisp root cause analyses backed by PCAP evidence and clear log-to-fix narratives that are useful to the Protocol Lead, the integration team, and future engineers reading the commit history
- Write clean, well-structured patches that pass code review without requiring significant rework
- Add unit-level checks where feasible and contribute to strengthening the regression test suite as part of every feature delivery
- Collaborate closely with the Protocol Lead on design decisions that span multiple protocol layers, bringing implementation-level insights back into architecture discussions
YOU MAY BE A GOOD FIT IF YOU HAVE
- Strong NR and LTE L2 and L3 fundamentals across MAC, RLC, PDCP, and RRC, including timer behavior, state machines, HARQ procedures, and security mode procedures
- Comfort working directly with 3GPP specification documents (38-series and 36-series) as day-to-day working references, not occasional references
- Solid C/C++ development skills in a Linux environment, including debugger proficiency (gdb), log analysis, and basic performance tooling
- Strong Git workflow discipline: clean commits, clear commit messages, and readiness to engage in substantive code review
- Proficiency with Wireshark and tcpdump for protocol trace analysis and day-to-day validation work
- A systematic, evidence-first debugging approach: you document your reasoning and your fix is not done until the PCAP confirms it
PREFERRED QUALIFICATIONS
- Direct experience with the OpenAirInterface (OAI) codebase or the srsRAN Project on either the UE or gNB side
- ASN.1 knowledge in a practical protocol context, including encoding and decoding RRC messages
- Understanding of PHY-facing constraints including HARQ timing, scheduling interactions, and numerology effects on L2 behavior
- Familiarity with Wireshark dissectors relevant to 5G NR protocols and how to extend them for custom debugging
- Experience with E2E testbed validation using open-source core stacks such as Magma, Open5GS, or free5GC
- Bachelor's or Master's degree in Telecommunications Engineering, Electrical Engineering, Computer Science, or a related field
COMPENSATION & BENEFITS
- Salary: Competitive base, negotiable based on experience
- Performance-based commission structure: your earnings scale directly with your results
- Two annual festive bonuses, each equivalent to half a month's salary
- Two-day weekends, 10 days casual leave, 10 days sick leave, and 14 public holidays per CloudlyIO's global holiday calendar for Bangladesh
- Fully subsidized lunch and evening snacks, plus tea and coffee throughout the day
- Direct collaboration with US clients and teams, with real exposure to global enterprise AI deals from day one