4G/5G Stack-L3- Principal Systems Architect / Delivery Lead

Job Title: Principal Systems Architect / Delivery Lead – 4G/5G Stack-L3

Experience Level: 12+ Years

Location: Bangalore, India

Position Type: Full-Time

Job Overview

We are seeking a highly accomplished Principal Systems Architect and Delivery Lead specializing in 4G/5G Stack-L3 engineering. In this role, you will spearhead the design, development, optimization, and end-to-end delivery of Layer 3 control-plane software across our wireless portfolio.

You will manage large-scale product development, software sustenance, and customer support programs across multiple eNodeB and gNodeB deployment variants, including vRAN, O-RAN, and custom hardware architectures. By mentoring high-performance L3 teams and collaborating with senior internal and external stakeholders, you will ensure delivery excellence for mission-critical network features.

Roles & Responsibilities

• Control-Plane Feature Engineering: Design and implement RRC, S1AP, X2AP, NGAP, F1AP, E1AP, XnAP, and higher-layer control-plane features for LTE and 5G NR networks.
• Technical Mentorship: Review technical architectures and mentor high-performance L3 teams to resolve complex defects and engineering bottlenecks.
• Defect Resolution & Analysis: Lead investigations to close system-level defects, including attach/registration failures, handover drops, security-mode failures, RRC resume issues, paging misses, Xn/F1/E1 mis-synchronization, and vendor-specific interoperability challenges.
• Cross-Functional Collaboration: Partner closely with verification, OAM, and core-network teams to establish rigorous call-flow validation, stress scenarios, interoperability campaigns, and negative/failure-recovery tests.
• Program Delivery Leadership: Drive large-scale 4G/5G L3 product development, software sustenance, and field support programs across global deployments.
• Stakeholder Engagement: Act as a key technical liaison, interfacing effectively with senior levels of internal management and external customer stakeholders.

• LTE/E-UTRAN (4G): In-depth knowledge of physical layer and services description (TS 36.300, TS 36.302), RRC protocol specification (TS 36.331), architecture frameworks (TS 36.401), S1 interfaces (TS 36.410 to TS 36.414), and X2 interfaces (TS 36.420 to TS 36.425).
• 5G NR / NG-RAN: Advanced knowledge of NR Stage-2 descriptions (TS 38.300), RRC protocol specifications (TS 38.331), architecture layout (TS 38.401), NG interfaces (TS 38.410 to TS 38.415), Xn interfaces (TS 38.420 to TS 38.425), E1 interfaces (TS 38.460 to TS 38.463), and F1 interfaces (TS 38.470 to TS 38.474).
• Layer 3 Signaling & Procedures: Extensive expertise in control-plane workflows including attach/registration, handovers, re-establishment, carrier aggregation (CA), EN-DC/NR-DC, mobility control, measurement configuration, bearer/session signaling, security activation, dual connectivity, idle/connected transitions, RLF handling, cell reselection, paging, and core-triggered session coordination.
• Core Network Interaction: Solid understanding of how gNodeB/eNodeB RRC procedures interact with AMF, MME, SMF, SGW-C, and PGW-C core elements.
• Software Engineering & Cloud-Native Platforms
• Programming & Systems Design: Strong hands-on engineering using C, C++, and Python. Expert knowledge of state machine design, memory pooling, error handling, and robust multi-vendor interoperability engineering.
• Linux Kernel & OS Internals: Deep familiarity with Linux execution environments, including processes, threads, multithreading paradigms, and Inter-Process Communication (IPC).
• L3 Data Path Performance: Advanced expertise in GTPU protocols alongside DPDK and VPP data-path frameworks.
• Cloud & Virtualized Infrastructure: Practical knowledge of containerized systems including Kubernetes, Pod topologies, and Docker. Experience in Linux performance tuning for virtualized DU/CU setups, x86/ARM server deployments, FPGA/SoC-based acceleration, SmartNIC/DPU-assisted data paths, hugepages, and SR-IOV.
• Network Testing, Log Analysis & Diagnosis
• Field & Lab Issue Resolution: Proven ability to analyze network traces (RRC, NGAP, S1AP, F1AP, E1AP), manage timer/state transitions, verify ASN.1 handling, maintain backward/forward compatibility across releases, and replicate field anomalies in lab environments.
• Specialized Telemetry Tools: Mastery in analyzing system logs and utilizing specialized tools such as Wireshark (packet capture/decode workflows), QCAT (UE log analysis), and KPI dashboards.
• Network Testing Equipment: Technical experience configuring and executing test routines on industry-standard platforms including Viavi, IxLoad Wireless, IxNetwork, Spirent Landslide, and associated timing logs.

• Bachelors or Masters degree in Telecommunications, Computer Science, Electronics Engineering, or a matching technical domain.
• Minimum of 12 years of core hands-on experience in L3 software development.
• Proven track record in a strategic leadership or program management role driving the delivery of complex 4G/5G L3 wireless solutions.

Skills: architecture,interfaces,ts,4g,software,wireless,c,design,rrc