Overview: We are looking for an experienced Network Engineering Specialist (4G ESN / Mobile RAN Performance SME) to shape mobile RAN strategy and optimize critical, high-availability networks. Operating in the 4G Emergency Services Network (ESN) domain, you will lead end-to-end performance analysis, troubleshoot complex protocol traces, and drive network fixes across enterprise mobile infrastructure. Key Responsibilities: E2E Performance & Root Cause Analysis: Conduct deep-dive analysis using UE logs, drive tests, and Wireshark traces (L1-L7) to resolve underperforming KPIs and defects in ESN PTT over SRTP. Protocol & Network Optimization: Analyze eNodeB, Core Network, and OTT traces to resolve LTE, SIP signaling, and SRTP/DTLS performance issues. Vendor & Fix Delivery: Collaborate with delivery teams and external suppliers (Nokia/Ericsson) to propose, agree, and implement fixes. Data Storytelling: Translate complex technical network data into clear insights for technical and business stakeholders.Requirements: Technical Expertise: Deep knowledge of 4G RAN macro networks, Public Safety over LTE/5G+, Nokia/Ericsson RAN, and 3GPP standards. Tools Proficiency: Hands-on experience with Accuver, TEMS/Nemo, Actix, Wireshark, and protocol analysis (SIP, PTT, SRTP, DTLS). Telecom Background: Proven track record as a performance SME in high-availability mobile networks working with 3rd-party suppliers.Randstad Technologies is acting as an Employment Business in relation to this vacancy