Test Engineer T-Mobile

ANDY (KYUNG ILL) YOON

703-***-**** • ********@*****.*** • 25916 Stinger Dr, Chantilly VA 20152

Andy, a self-motivated wireless RAN engineer with a strong sense of ownership and accountability to provide high-quality products, has more than 20 years of solid experience in the wireless telecom industry. Possess knowledge and experience in various integration testing, troubleshooting, KPI analysis, and deployment rollout throughout the product lifecycle.

KNOWLEDGE

Telecom protocol and standard

o5G/4G TDD/FDD

oORAN

oGSM/CDMA/WiMAX

oTCP/IP protocol with Linux OS-based servers

ENGINEERING EXPERIENCE

RAN (Radio Access Network) products

oSamsung CDMA/LTE/5G RAN and EMS

oEricsson GSM/LTE/5G RAN and EMS

O-RAN products

Flex RAN (L1: intel, L2/L3: Radisys) + Foxconn RRU

Skilled testing tools

XCAL/XCAP, QXDM/QCAT – air interface packet analysis

Iperf, Wireshark – IP packet generating and analysis.

VIAVI TM 500 – air interface emulating

ARTS (Automatic Regression Testing Solution) and VIAVI TM 500

RF Spectrum analyzer – RF signal generating and analysis.

JIRA – test plan/execution management

Programming languages

C++, Python (Not super proficient for coding, but skillful for scripts for log capturing and test automation)

WORK EXPERIENCE

09/2022 – Present RAN Engineer IV @Ericsson, Reston, VA

I have been working to perform tests of LTE and 5G SA/NSA in the T-Mobile lab for the Ericsson CI/CD (Continuous Integration Continuous Delivery) project to validate software quality with regression and new feature cases (voice and data traffic, handover, link budget). In addition, I work for 4G/5G KPI monitoring, optimization, and troubleshooting issues from T-Mobile’s field sites by analyzing logs.

12/2021 – 02/2023 5G RAN Engineer @Deepsig, Arlington, VA

The company Deepsig has been developing 5G software based on AI (Artificial Intelligence) and ML (Machine Learning). As the company proceeds development with focusing on UL quality enhancement based upon O-RAN structure (Intel Layer 1 + Radisys Layer 2/3 + Foxconn RRU), my role was to design 5G O-RAN network for the lab, operate end-to-end the overall systems, and troubleshoot to find improvement 5G PHY layer software under end-to-end 5G core to Physical layer. I measured and reported DL/UL throughput performance with details of RF factors like BLER, number of layers, etc.

In addition, I also have experienced VIAVI TM 500 simulators during the IOT test, where Deepsig was considering how to increase multi-UE capabilities for downlink and uplink on the physical layer. The subject was how to interoperate ORAN functionalities and TM500 functionalities, including physical and logical connections.

01/2019 – 11/2021 Principal Engineer @Accuver, Reston, VA

Accuver is a company that has been providing LTE/5G testing tools like XCAL/XCAP in the telecom area, and I was to end-to-end support the customer T-Mobile to operate an automation testing tool in the lab for regression testing.

My job was to design and operate the automation testing tool in T-Mobile’s lab, to verify the eNB/gNB vendor’s software, and troubleshoot issues. For example, T-Mobile engineers requested me to operate the automatic tool when new 4G/5G eNB/gNB software loaded, I built up test cases (voice/data traffic performance, handover, link budget), scripts in the automation system regarding the customer required as well as operated the tool, found test results with analysis report including major KPI’s. Also, I was communicating with HQ engineers in South Korea to come up with software bugs and requirements from customers.

02/2001–12/2018 Principal Engineer, Director @Samsung Electronics, Korea

1.Wireless Telecommunication Principal Engineer (02/2016 – 12/2018)

Working as an LTE project leader, I was managing maintenance projects for both JIO in India and Sprint PCS in the U.S. major service provider, with the following activities.

Monitor KPI trends in commercial sites (Coverage, Capacity, Availability, and other issue events on service issues). When faced with issues, I analyzed logs and coworking to build patches and applied them at commercial sites.

Project leader of Massive MIMO field trial for JIO in Mumbai, India, 2017. I selected candidates out of commercial sites, replaced old RRH with M-MIMO unit, and prepared pre/post KPI trend.

Build up feature roadmaps (high-level feature design) regarding customer requirements.

Project Coordination of wireless telecom products based upon R&D process (Controls of delivery schedule, costs, headcounts for commercial project)

Lab testing to validate L1(RF), L2(DSP/MAC) and L3(Call processing) configuration/parameters.

2.Deployment and Maintenance Senior Manager (03/2013 – 01/2016)

I was working as a Senior manager to support deployment and maintenance services of the Sprint NV (Network Vision) project, which was to replace 2G/3G RAN with LTE RAN DU/RRH. I was dispatched to Samsung's local branch, VA, and was working with project managers and engineers on the following activities. My report went to the executive level of headquarters in Korea.

Monitor forecast and actuals of deployment steps, and analysis of issues

Make a MOP (Method of Procedure) and train field engineers to achieve site acceptance

Professional service proposal based on performance analysis in the customer's commercial network.

Analyzing headcount for engineering service and reporting to executives.

Risk management for vendor program, internal headcount, and supply-chain /logistics

Material planning and logistics based on deployment schedule and procurement.

3.S/W quality assurance Senior Test Engineer (03/2001 – 02/2013)

As a software assurance engineer for CDMA, WiMAX, and TDD-LTE RAN systems, I was responsible for testing, functioning, and qualifying of RAN S/W Package in the Lab and delivering it to the customer. Also, troubleshooting issues in commercial sites with the following activities

Test Plan/Case build, environment setup, testing/troubleshooting, and reporting the result.

Discussion of feature description and priority regarding customer demand

Testing, troubleshooting, and bug fixing for new features and regression in the internal LAB

Single/Multi data call testing with simulators (MOS, E500, and other simulators) and DM tool

Technical support for the customer’s validation test in the customer’s LAB with business trips

Support for S/W package application into the commercial network with pre-checking, applying, and post-audit.

Lab testing to validate L1(RF), L2(DSP/MAC) and L3(Call processing) configuration/parameters

The history of past customers is below.

CDMA 1X and EVDO systems with SK Telecom (No.1 provider in South Korea) 2001 ~ 2005

M-WiMAX system with KT (No.2 provider in South Korea) 2005 ~ 2006

M-WiMAX system with Sprint PCS/CLEARWIRE in the US 2006 ~ 2012

FDD/TD-LTE system with Sprint PCS/CLEARWIRE in the US 2010 ~ 2013

EDUCATION

Korea University, BS in electrical engineering – 2001 Seoul, South Korea

CERTIFICATION

PMP (Project Management Professional) by PMI

Number: 1935908

Credential holder since: 14 Jun 2016

Credential valid through: 13 Jun 2022

OTHERS

BILINGUAL – ENGLISH (moderate proficient) and KOREAN (native)

MILITARY SERVICE in the Korean Army – 1995 ~ 1997 (26 months)

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