Modem System Test Engineer - Wireless Technologies and Ecosystems |

Summary Join the Wireless Technologies and Eco-Systems (WTE) team and drive wireless innovations that impact millions of users worldwide! We design, validate, and integrate cutting-edge wireless technologies that enrich everyday experiences across our entire product ecosystem.

We are seeking a passionate, detail-oriented Modem Systems Test Engineer with a focus on Wireless Coexistence (COEX). In this role, you will be at the forefront of validating multi-radio platforms ensuring seamless concurrent operation between cellular technologies (LTE, 5G NR FR1/FR2) and adjacent radios such as Wi-Fi, Bluetooth, Ultra-Wideband (UWB), and GNSS. If you thrive in a fast-paced environment solving complex cross-radio interference, desense, and protocol arbitration challenges, we would love to hear from you.

Description In this role, you will be responsible for end-to-end system testing, performance characterization, and failure triage of advanced cellular baseband and multi-radio coexistence features. You will bridge baseband protocol software, RF hardware, and connectivity systems to guarantee robust real-world performance under hostile interference conditions.

You will rely on deep trace analysis, lab simulation, RF instrumentation, and automation to uncover edge-case performance degradation, desense mechanisms, and protocol timing collisions. Working cross-functionally with system architecture, firmware, protocol development, RF design, and carrier engineering, you will drive test coverage, root-cause complex issues, and influence system-level mitigation designs.

Responsibilities

Coexistence Test Design & Execution: Define, develop, and execute comprehensive test plans targeting in-device coexistence (IDC), inter-radio arbitration, multi-SIM / multi-active scenarios, and concurrent multi-band operation (LTE/5G NR with Wi-Fi, Bluetooth, UWB, and GNSS).

RF & Protocol Root-Cause Analysis: Analyze baseband protocol traces (PHY, MAC, RLC, PDCP, RRC), air-interface captures, and RF measurements to root-cause desense, throughput degradation, scheduling conflicts, dropped calls, and handover anomalies.

Mitigation & Feature Validation: Evaluate and validate dynamic coexistence mechanisms, including power back-off, time-division multiplexing (TDM) / frequency-division multiplexing (FDM) filtering, antenna switching/sharing, and adaptive link management.

Intelligent Test Automation: Develop robust, scalable test automation scripts and post-processing analytics pipelines in Python to automate test execution, KPI aggregation (BLER, throughput, latency), and anomaly detection.

Testbed & Environment Integration: Set up, calibrate, and maintain sophisticated lab testbeds incorporating cellular network emulators (call boxes), RF matrix switches, combiners, spectrum analyzers, and wireless channel emulators.

Cross-Functional Collaboration: Partner closely with baseband firmware, connectivity software, RF systems engineering, and hardware teams to reproduce lab/field defects, validate fixes, and verify 3GPP and internal performance specifications.

Minimum Qualifications Education: Bachelor’s or Master’s degree in Electrical Engineering, Computer Engineering, Telecommunications, or a related field.

Cellular Protocol Stack Expertise: Deep technical understanding of 3GPP LTE and 5G NR (Rel-15/16+) across Layer 1 (PHY), Layer 2 (MAC/RLC/PDCP), and Layer 3 (RRC/NAS).

Coexistence & RF Fundamentals: Strong grasp of RF transceiver architectures, in-device coexistence (IDC), antenna isolation, harmonics, intermodulation distortion (IMD), receiver desense, and multi-radio interference mitigation techniques.

Hands-on Validation Experience: Proven track record of system test, integration, or validation using commercial wireless network emulators (e.g., Keysight, Rohde & Schwarz, Anritsu) and RF instrumentation (spectrum analyzers, signal generators, power meters).

Automation & Scripting: Strong proficiency in Python for test automation, instrument control (SCPI/VISA), and automated parsing/analysis of large log datasets.

Analytical Problem Solving: Demonstrated capability to triage and root-cause multi-layer failures across hardware, firmware, and protocol interactions.

Preferred Qualifications Prior experience testing Dual-SIM / Dual-Active (DSDS/DSDA) or complex Cellular scenarios with simultaneous connectivity radios. Working knowledge of 3GPP in-device coexistence specifications (e.g., Rel-11+ IDC mechanisms, autonomous denial, auxiliary information reporting). Experience with non-cellular wireless standards (Wi-Fi 6/6E/7 - 802.11ax/be, Bluetooth 5.x, UWB, NFC, GNSS). Familiarity with data analysis and visualization libraries (Pandas, NumPy, Plotly/Matplotlib) for large-scale test KPI dashboards. Contributions to 3GPP standardization (RAN4, RAN5) or carrier certification testing for coexistence and performance. Proficiency in diagnosing complex system-level issues through lab/field experimentation, analytics, and log analysis. Excellent analytical & critical thinking skills, Excellent communication & interpersonal skills.

Pay & Benefits At Apple, base pay is one part of our total compensation package and is determined within a range. This provides the opportunity to progress as you grow and develop within a role. The base pay range for this role is between $150,400 and $277,600, and your base pay will depend on your skills, qualifications, experience, and location.

Apple employees also have the opportunity to become an Apple shareholder through participation in Apple’s discretionary employee stock programs. Apple employees are eligible for discretionary restricted stock unit awards, and can purchase Apple stock at a discount if voluntarily participating in Apple’s Employee Stock Purchase Plan. You’ll also receive benefits including: Comprehensive medical and dental coverage, retirement benefits, a range of discounted products and free services, and for formal education related to advancing your career at Apple, reimbursement for certain educational expenses - including tuition. Additionally, this role might be eligible for discretionary bonuses or commission payments as well as relocation. Learn more about Apple Benefits

Note: Apple benefit, compensation and employee stock programs are subject to eligibility requirements and other terms of the applicable plan or program.

EEO Statement Apple is an equal opportunity employer that is committed to inclusion and diversity. We seek to promote equal opportunity for all applicants without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, disability, Veteran status, or other legally protected characteristics. Learn more about your EEO rights as an applicant

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Application Deadline Apple accepts applications to this posting on an ongoing basis.