Rf Engineer Quality Control

NESTOR VARGAS

RF Engineer

Degree: Bachelor of Science in Electronic and Communications Engineering, in UANL

LinkedIn URL: https://www.linkedin.com/in/nestor-vargas-3a450710b/

Monterrey NL

Mobile: +1-925-***-****

*******@*****.***

WORK EXPERIENCE:

Satellite Gateway RF Engineer Sept 2024 – Oct 2025

AST Space Mobile Midland TX

Oversee the day-to-day activities of a company or organization to ensure the efficient and effective functioning of its processes and systems.

Support hardware RF sustaining and development engineering projects. This includes tasks such as managing production and supply chains, ensuring quality control, tracking performance metrics, analyzing and improving processes, and managing resources, with the goal of increasing efficiency, reducing costs, and improving customer satisfaction.

Development of tests for satellite 4G/5G broadband network, validating speeds and connectivity.

Provide Integration support of antennas equipment and troubleshooting.

Design for Testing activities and link-budget. Contribute with lab testing and characterization using VNAs, spectrum analyzers, signal generators, oscilloscope, multimeter, and other RF test equipment.

Coverage and Beam Analysis.

Nokia MantaRay solutions support and 4G/5G validation of Nokia BBU.

Collecting Logs, Analysis and reporting. QXDM, XCAL.

Give support collecting logs for IQ analysis ( USRP Logging Application V.3.5, Keysight tools).

Collaboration and support on Create system-level simulations of NTN, Multi-beam phased arrays using (Keysight PathWave)

Giving support characterization using RF components of such as RF amplifiers, filters, splitters, etc.

RF Performance Optimization, parameter audits, coverage validation, link-budgets, and adjustments recommendations.

Support 4G/5G network trials and proof-of-concepts

Analyze, and troubleshoot technical issues, working closely with vendors and internal teams for resolution.

Lab support flashing and testing new HW/SW using Spectrum Analyzer and Signal Generators.

Contribute to the continuous improvement NTN 4G/5G testing, deployment, integration, and operational processes.

RF Engineer Oct 2020 – March 2024

SNAP Project with Samsung Networks with Verizon. Plano – TX

4G/5G SNAP Project from Nokia to Samsung ensuring End to End Deployment and KPIs performance on Target of Verizon Wireless.

KPIs Data Analytics performance KPI’s tuning for Technologies 4G/5G NR, NSA and SA (Carriers 700MHz, 850MHz, 1900 MHz, AWS-1, AWS-3) RAN, C-RAN and ORAN.

4G/5G VoLTE, CBRS, DSS, mmWave, and C-BAND, 5G NSA and SA. PRE and Post launch KPI’s network performance monitoring, optimization analysis, reporting and send recommendations to improve them (Accessibility, Retainability, Throughput and Traffic monitoring and reporting).

RF Optimization for Macro, In-Building, SmallCells and DAS deployment and post-launch

performance, LTE network KPIs and key parameters

Mobility and Hand-Over parameters optimization

Antenna design validation and review, RF circuits, and system-level RF performance optimization.

Perform event analysis, providing recommendation and address accessibility, retainability and HO success rate issues (performing analysis on A5, intrasesrxh, treshxlow, threshxhigh, qrxlevmin, plmn0, A3, cell individual offset).

Parameters changes recommendation according of the golden standard and Trials

Load balancing analysis, mobility parameters analysis and optimization

VoLTE KPIs; RTP GAP, SIP DC and VoLTE IA analysis and optimization

Investigated VoLTE call drops under good RF conditions, specifically drops and RTP gaps

Post launch No-Harm Optimization and audits for 4G / 5G sites.

5G Networks Monitoring KPIs, CBand, DSS, Clean NR and mmWave.

Mobile devices Logs Analysis & debugging UE issues. Analysis of 4G & 5G Wireless Protocols

Experience in RTP Gap, VoLTE IA, SIP DC, ENDC Drop, Throughput, Traffic volume, etc. analysis across multiple streams.

Analysis of 4G& 5G air Interface and Call Processing and reviewing UE signaling connection in NSA and SA scenarios.

National RF Engineering support with RF Design and performance optimization analysis

ORAN CIQ validation, Support and Troubleshooting, nationwide Radio Access Network (RAN)

Parameter verification and green table alignment, RAN networks (gNB, eNB), RAN features (carrier aggregation, MIMO, SA/NSA, VoLTE/VoNR).

ENDC Drops analysis and troubleshooting to improve performance on 5G NSA and SA.

4G/5G VoLTE, CBRS, DSS, LAA (License Assisted Access), mmWave, and C-BAND, PRE and Post launch Key KPI’s wireless network performance monitoring, optimization analysis, and reporting to the client (Accessibility, Retainability, Throughput and traffic monitoring and reporting). 5G NR NSA and SA.

RF Design, RFDS, CQ, CIQ, and RF Scripts following and verifications using FUZE ConQuest.

Atoll tool extraction for CQ creation.

Daily KPI and weekly status reporting to market managers

Proposes solutions and route causes for network performance deviations.

USM parameters change, configurations and status validations.

Checking alarms, RSSI, VSWR, Lock and Unlock cells.

PSMD Data extraction and analysis. RTT tool, TrueCall, xLP, VSON and IRISVIEW

Reviewing designs with system performance Engineers, working with Fuze project per site, and node, with specific information that can be given from Verizon.

Reviewing the existing site configuration to determine what modification is before and after migration and send recommendations and performance status.

CBRS migration, SAS registration, health check and alarms following.

CBRS Performance monitoring.

DSS PRE and Post-launch Performance monitoring. sub-3GHz and sub-6GHz bands.

4G/5G Parameters and Anchoring audits.

4G/5G Macro, In-Buiding, Small Cells Solutions, mmV, and DAS Pre and Post migration and integration heath check and KPIs performance assurance.

Performance Optimization for optimal site/cluster performance (antenna selection, tilts, neighborlist, etc).

Design RFDS, CQ and CIQ validation and re-creation Macro, DAS, and SmallCells or in-building coverage.

Give Validation support with Design documentation (RFDS, CQ) for parameter and RF changes requested by the CTX Market RF Design team.

5G carrier's health check, Anchoring and Desing validation, 5G protocol checks and call flows.

Call trace analysis 3GPP to detect Core issue and backhaul.

Collecting and analyzing cell and UE traces for 5G NR and 4G LTE analysis.

RFI testing and interference verification using Spectrum analyzer, Network Analyzer, and signal generators. Keysight equipment.

RF and microwave test and measurement applications.

RF development testing for IoTs.

ATOLL dump extraction and analysis to make KPI performance recommendations.

QGIS tables creation for the team for sector carriersreference and optimization.

RF Engineer August 2018 - May 2020

VoLTE Optimization Project with T-Mobile-Sprint, DFW and East TX Markets.

PRE and Post VoLTE launch Optimization of cluster for Ericsson equipment in Sprint Network

Implementing approved change request in OSS Ericsson (ENM), Samsung (USM) and Nokia( NetAct)

RF shaping and parameters changes per cluster analysis to improve SINR

Cluster optimization and performance analysis

Network KPI optimization and analysis and extensive experience with network tools like NG1,

True Call

In-Building and SmallCells sites health check and monitoring for LTE TDD band 41

Ericsson Parameters and Frequencies relations audit perform on Ericsson ENM.

Expertise in analyzing traces and call flows using logs and the Rad COM ACE tool

Troubleshooting for VoLTE Accessibility, SIP Session Setup Failures and RRC Connection

Drops Analysis

KPI Monitoring and Trending, Identification and troubleshooting Top Offenders, accessibility,

mobility & retainability aspects of LTE

Troubleshooting and call flow analysis for VoLTE Retain ability, SIP Session Failures with the

different cause codes

Coverage analysis Optimization and change proposal provided

Traffic analysis and load balancing optimization

Muting issues analysis and parameters change proposal provided

Quality check and analysis reports with recommendations (KPIs, legends, event plots, XDB

creation)

SIP events analysis on Windcatcher and layer 3 messages for 4G and 5G.

Voice drops and Voice access fails analysis trough Windcatcher, IRIS and Wireshark

Analysis of all Fails, Drops, poor SINR, low MOS areas on UEs and Scanner data analysis 3G/4Gand 5G air-interface protocols (L1/L2/L3).

Provide LTE VoLTE analysis using various other tools -IRIS view, True call and Windcatcher

LTE Statistics -Sprint Tools PRTS, Checking alarms with Patrol for Ericsson eNBs.

Analyze system logs, performance issue, Windcatcher, IRIS and TrueCall.

LTE and VoLTE responsible network optimization to achieve the desired network KPI Accessibility, retainability, Hand Over and events Troubleshooting.

Analysis & Troubleshooting of Drive Test in LTE/VoLTE using Windcatcher NEMO and, IRIS, Wireshark, TEMS Investigation and QXDM.

Support VoLTE Pre and Post Launch Clusters in DFW and East TX Market

Features for resource adaptive configuration to increase Accessibility and network

performance

Baseline audit consistency check in whole Network and recommendations for further

improvements. Implementation of Technical Support Notes

Parameters adjustment and extraction of CDMA using CACP tool

LTE Call flow and Call Processing test

5G gNB validation and KPIs monitoring

Analyze post-processing, 4G/5G LTE Call Processing

Trouble shoot problems and collect logs with available tools like XCal and Windcatcher

3GPP 4G/5G Access Stratum protocols (L3) for call and log analysis

Trial Proposal for thresholds changes and testing of Features like Handovers, Inter-RAT

Handovers, Intra Frequency Handovers, Cell Reselection, Carrier Aggregation, Data

Throughput

Provide Optimization and Fine-Tune services and analysis

Contributing and Resolving customer service issues, assisting in implementing solutions, and collecting drive test data in support of performance evaluations.

Colleting logs using Nemo Outdoor (Keysight) for drive test on benchmarking and network QoS/QoE analysis.

RAN Design Engineer November 2017 - June 2018

Nokia to AT&T, Naperville IL. - Berean Group International Inc. for

LTE RAN Design Former ALU, Nokia Equipment SWAP for AT&T New York market

Scripting and Site Configuration Files (SCF) files creation for Nokia sites using BTS Site

Manager Nokia tool

Nokia performance monitoring and reporting to manager and team

Nokia Parameters and Frequencies audit and validation

Air interface LTE parameters configuration management

Change parameters for SCF files and executing and ensuring that the sites are alarms free

Validation and checking issues on WPS and BTS Site Manager. Nokia NPO Eagle Tool

AirScale cMRO RFM swap and Carrier Growth

SCF File re-configurations on BTSSM

Create Commissioning File, Cell Resources, MIMO Mode: 4x2 4x4, HW Selection

Perform pre-commission, Commissioning scripting SCF files

LTE-eNodeB Carrier Add-3C CMRO/AirScale AWS3 B66

3GPP 4G/5G Access Stratum protocols (L1/L2/L3)

Python scripting

Site RF survey, Drive test

Antenna theory and propagation analysis for LTE optimization coverage purpose

Commissioning, Integration, and cell site acceptance of Nokia LTE cell Sites

Nokia RAN performance optimization, NetAct.

RF Engineer July 2016 - July 2017

TSG (Technical Support Group) Project for AT&T Norther California,

San Francisco Bay area CA USA with Yupana LLC.

Ericsson Parameters Audits and Alignment to AT&T Baseline and Gold configuration

Project Coordination for RAN LTE and 5G Troubleshooting

Performance Monitoring and Troubleshooting LTE alarms for AWS, and PCS bands

Provide support for E911 validation including locking cells and checking internal systems and

external alarms for accurate results

Perform and follow up to VOLTE PSAP call test, testing and submission of TVW

LTE RFDS creation, RFDS modification and creation of CQ. Atoll and Visio tools

RF Design Prepare ATOLL database for RFDS creation, Autoforms. Monte Carlo review.

Use Atoll features for coverage and cell planning including ACP to perform analysis.

Create site design RFDS and complete plumbing diagrams. Utilize propagation tools and

other RF related equipment such as MapInfo, Google Earth, ATOLL

Modify RFDS to prepare for promotion to C&E including plumbing diagrams

Prepare RNDCIQ for all the tabs – eNB Info, Eutran parameters, PCI, clusters, EUTRAN neighbor relations, Co-sites, LTE-UMTS Frequency relations, LTE to LTE frequency relations, Inter-Frequency relations.

Troubleshoot and Support for field technicians in VSWR and RSSI alarms

Support to Field team getting plots before and after PIM testing

Verification of parameter configurations using Ericsson OSS AMOS, ENM

Radio network parameter change impact analysis (cell status, alarm & crash impact)

Declare neighbor IRAT, UTRAN, EUTRAN

Analyze traces and exception for worst cell troubleshooting (cell tracing analysis)

Perform KPI monitoring (daily monitoring radio performance and RAN parameter)

Provide consultation and support to customers on technical matters related to LTE RAN

Products

Multilayer and Multiband Performance for AWS, WCS, PCS and 700

DFT activities and ensuring HW to improve testability. IEE1076 test bench marking and waveform analysis.

Waveform Analysis to review simulation outputs.

Support to Field team in PIM testing getting VSWR and RSSI plots before and after PIM test

Perform, test, suggest, Audit Features on RFDS and RNDCIQ for Northern California Project

VOLTE PSAP and TVW test following and reporting

Standardization of parameters on Ericsson OSS a scheduled Parameter Inconsistency Check

according to the Network requirements

Getting and Monitoring KPIS in Ericsson OSS with Get RSSI, VSWR and alarms; make

electrical tilts changes, getting traffic on real time in Ericsson OSS for RAN support

troubleshooting purposes

PIM test reviewing using Quantum

Logs collections using Keysight Nemo tools for post processing and getting RSRP, RSRQ and SINR plots.

RF Engineer May 2015 - May 2016

SpiderCloud Wireless, Mexico City.

RF engineer in Small Cells Deployment Project (SpiderCloud Wireless) with Telcel and

America Movil

IBwave RF Designs and RF Optimization and KPIs improvements reporting of day to day

Operations activities & Metrics

Optimization, Pre and Post Launch for Indoor Small Cells Project (SpiderCloud Wireless)

Hand-Over and mobility Optimization

Monitoring and analysis of post launch critical KPIs Retainability, Accessibility and

Throughput, LTE and 3G

Analysis of KPIs, Site survey (QXDM) and IBwave Design for enterprise projects, protocol

analyzers, XCAL/QXDM tool, Wireshark

RF Design reviewing and analysis using IBwave and Ranplan to send coverage change recommendations support site survey.

Adjusted, 3G and LTE networks to improve performance to Radio Nodes and Services Node

RF Engineer Nov 2014 - May 2015

Telcel – ONE RAN Project – Mexico City

Optimization of LTE and WCDMA pre and post launch based on Statistics monitoring

Design and Optimization of LTE and WCDMA RAN Network and DT activities. MAPINFO and

ATOLL for Designs

Provide to the team updated RFDS

Capable of analyzing Layer 3 Messages and understand traces results

Worst cells analysis and recommendations

Parameters and Features Audit and Optimization

Experience with Moshell Ericsson OSS platform and its application

Audit Baseline Implementation on 3G Sites

Sites troubleshooting (Alarms understanding, consistency check, traces)

Parameters Change implementation on Moshell Ericsson OSS.

Analyzed statistical reports to detect any deviations in key performance indicators

Adjusted GSM, 3G and LTE networks to improve performance

Monitor and trend network statistics, troubleshoot issue sites and resolve capacity issues

Project for LTE and WCDMA KPI ‘s improvement in urban and rural areas.

Optimization, Adjusted and Performed Troubleshooting on the 3G and LTE networks, RF

performance, (CDMA & PCS).

Performance PMR’s in Pre and Post SWAP ONE RAN Project

Creation Mapinfo and Atoll plots for predictions and reports

C&I Engineer Jul 2013 - May 2014

3s Network in Irvine CA US

Adjusted 3G and LTE networks to improve performance

Design and Optimization, Adjusted and Performed on the 3G and LTE networks

Revised quality parameters prior to commercial used. Radio Network Quality of Service

Parameters, Transport Network Quality of Service Parameters

Work with RF Integration and technical support teams to resolve any hardware/technical

issues and implement changes on NodeB/ eNodeB RBS6000 series.

Perform RF optimization/performance activities according to project plan and in project

manager’s guidance

Troubleshooting 2G and 3G Nodes

Experience generating RF engineering related progress reports for Managers.

Radio Frequency, optimization and KPI’s Analyst February 2009 - January 2013

TELCEL. Radiomovil DIPSA S.A. de C.V. Monterrey NL Mexico.

Provide inputs for to create Design on the new projects

DAS Design Coverage optimization at through Walk test Analyzed with Atoll and Keysight Nemo tools for logs collecting

Check the coverages are already cording to the design for special clusters

Responsible gathering field measurements and reconciling them with technical and

commercial requirements.

Perform analysis of network KPI’s, troubleshoot issues, and be involved hands-on with day-

to-day performance management / optimization functions

Generated periodic reports for tracing and system optimization, adding obtained results to

determine appropriate actions.

Ensured functionality delivered during project implementation did not deviate from the

design document RFDS for indoor DAS and Macro sites (ASSET tool)

Analyzed statistical reports to detect any deviations in key performance indices

PROFESSIONAL DEVELOPMENT:

5G Training “TDD MASSIVE MIMO KEY TECHNOLOGIES AND OPTIMIZATION”

5G/4G KPIs and Optimization

CISCO CCNA 4 Modules -In process of certification

AT&T ask yourself

OSHA10

SOFTWARE:

Windows, Office, Remedy, JIRA, SMART, MAPINFO PROFESSIONAL, VSON, Diversity Cell, Arieso Software OMT, Element Manager, HyperTerminal, Moshell, Ericsson ENM, NQDI (4G and 5G optimizer), Actix, NEMO Outdoor, Nemo Handy, Nemo Analyze, QXDM,

TEMS investigation, Windcatcher, XCAL, XCAP, IBWAVE, ATOLL, PowerShell Scripting, BTS Site Manager, NetAct, AT&T Quantum, Python, TrueCall, QGIS, FUZE, RTT.

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