5G Network Performance Engineer

Randstad Technologies Recruitment; Greater London; Hybrid; GBP 90,000 - 120,000; Full time

Job summary

Randstad Technologies Recruitment is seeking a 4G/5G RAN Performance & Optimisation Expert (ESN) in London on a hybrid site. The contract runs for six months with a potential extension.

You will drive ESN performance, define SLAs/KPIs, and coordinate optimisation trials across Nokia and Ericsson RAN. You will analyse drive tests, logs and CN protocol data, troubleshoot SRTP/DTLS issues, and work with SMEs and third-party suppliers to deliver fit-for-purpose RAN designs for ESN, ensuring high

Qualifications

• Extensive experience in 4G/5G ESN performance and optimisation.
• Strong understanding of SA/NSA, VoNR and network slicing concepts.
• Proven ability to translate complex data into clear business cases.

Responsibilities

• Lead 4G/5G ESN performance management and define SLAs/KPIs.
• Drive feature and parameter optimisation trials across Nokia and Ericsson RAN.
• Perform root cause analysis using drive tests, logs and protocol data.
• Troubleshoot interworking and end-to-end network performance issues.
• Collaborate with SMEs and vendors to deliver fit-for-purpose RAN designs.

Skills

RAN performance

Nokia RAN

Ericsson RAN

SLA KPIs

Drive tests

CN protocol

SRTP/DTLS

Test tools

Tools

Nemo

TEMs

Accuver

Actix

Job description

Job Title: 4G/5G RAN Performance & Optimisation Expert (ESN)

Duration: 06 months with possibility of extension

Location: London-Hybrid

Why This Role Matters

Join us and play a critical role in maintaining our position as a leading UK mobile network and driving our vision to be a global top-ten network. In this role, you will directly impact our current and future network efficiency, shaping the Mobile RAN strategy and ensuring a flawless subscriber experience-particularly for the highly critical Emergency Services Network (ESN).

What You'll Be Doing

• Performance Leadership: Drive 4G/5G ESN performance management, define SLAs/KPIs, and build action plans for continuous performance uplift.


• RAN Optimisation: Lead feature and parameter optimisation trials across Nokia and Ericsson RAN, assessing network impacts and quantifying gains.


• Deep-Dive Analysis: Conduct root cause analysis of performance degradation using drive test logs, Wireshark, OSS data, and CN protocol analysis (OSI L1-L7).


• Technical Troubleshooting: Investigate and resolve systematic issues in 5G SA/NSA interworking, ESN PTT (Push to Talk) over SRTP, and overall End-to-End network performance.


• Cross-Functional Collaboration: Work closely with key SMEs, stakeholders, and 3rd-party IT/Network suppliers to deliver "fit for purpose" RAN designs.

What You'll Bring

• Expertise in Mobile Networks: Extensive experience as a Performance SME in high-availability 4G/5G/5G+ networks, with expert understanding of SA, NSA, VoNR, and Slicing architectures.


• Vendor Knowledge: Deep, hands-on experience with Nokia and Ericsson RAN counters, KPIs, and parameters.


• Protocol & Tool Proficiency: Strong knowledge of LTE/SIP signalling, SRTP/DTLS troubleshooting, and familiarity with test/post-processing tools (Nemo, TEMs, Accuver, Actix).


• Analytical Storytelling: The ability to convert highly technical data into compelling, simple-to-understand cases for change for both technical and business audiences.


• Forward-Thinking Vision: A proactive approach to network design, keeping ahead of telecom market developments and 3GPP/ETSI specifications to build the networks of the future.