4G/5G RAN Layer 3 (RRC/PDCP) Protocol Developer (C++)

Project overview

Contract role for a 4G/5G RAN Layer-3 protocol engineer to design, implement, debug and sustain LTE/NR control-plane features (RRC and related interfaces such as S1AP/X2AP/NGAP/F1AP/E1AP/XnAP). The role needs strong 3GPP spec understanding, hands-on C++ (plus C/Python), Linux multithreading/IPC, and deep knowledge of L3 procedures (attach/registration, handover, re-establishment, paging, dual connectivity, security). Candidates should be comfortable with trace/log analysis (Wireshark/PCAP, KPI dashboards, UE/network traces) and interoperability/field issue reproduction.

Locations: Bengaluru (Manyata) or Delhi NCR.

Responsibilities

• 4G/5G Layer 3 Procedures Knowledge: attach, handover, re-establishment, carrier aggregation (CA), EN-DC/NR-DC
• Knowledge of control-plane interfaces and procedures including S1AP/X2AP for LTE and NGAP/F1AP/E1AP/XnAP for 5G architectures, along with understanding of how RRC procedures interact with AMF/MME, SMF/SGW-C/PGW-C
• Programming: C/C++/ Python Programming Language, memory pooling, Programming & Debugging state machine design, error handling, traceability, and robust interoperability engineering across different UE/chipset/core/network-vendor combinations, ASN.1/protocol decode workflows
• L3 data path expertise
• GTPU, DPDK & VPP expertise
• Understanding of Linux Environment, Inter-Process Communication (IPC), Processes, Threads, and Multithreading
• Knowledge of containerization (Kubernetes, Pods, and Docker)
• Experience in field issue analysis using RRC/NGAP/S1AP/F1AP/E1AP traces, Wireshark decodes, KPI dashboards, and log-correlation from RAN and core, and in translating issues into reproducible lab scenarios
• Knowledge of call-flow, ASN.1 handling, timer/state management, error recovery, and backward/forward compatibility across releases
• Log Analysis: Proficiency in analyzing system logs to diagnose issues.
• Specialized Tools: Expertise in using tools like QCAT (UE logs) Viavi (network testing and measurement equipment) plus IxLoad Wireless, IxNetwork, Spirent Landslide, Wireshark for testing/debugging
• Expertise on FPGA/SoC-based acceleration, SmartNIC/DPU-assisted data paths, DPDK/hugepages/SR-IOV, Linux performance tuning for virtualized DU/CU implementations, x86/ARM servers deployment, diagnosis of KPI loss using traces, PCAPs, timing logs, etc
• Additional years of driving delivery of 4G/5G L3 programs

Requirements

• 4G/5G RAN (LTE/E-UTRAN, NR/NG-RAN) Layer 3 protocol knowledge
• RRC protocol expertise
• PDCP knowledge (Layer 3 stack as mentioned)
• 3GPP specifications understanding and ability to implement per spec
• C++ programming (plus C as applicable)
• LTE/5G control-plane interfaces and procedures (S1AP, X2AP, NGAP, F1AP, E1AP, XnAP)
• L3 procedures: attach/registration, handover, re-establishment, paging, idle/connected transitions, RLF handling, cell reselection, carrier aggregation, EN-DC/NR-DC
• Linux environment fundamentals (processes/threads, IPC, multithreading)
• Debugging/state machine design, timers/state management, error handling and recovery
• Trace/log analysis using protocol traces and Wireshark/decodes; field issue analysis and lab reproduction
• ASN.1/protocol decode workflows and call-flow understanding

Project details

• Start: flexible
• Remote: onsite
• Location: India, IN