Hang Li

**** *** ****** **. • Allen, TX *****

214-***-**** (home) • 214-***-**** (cell) • acqdxv@r.postjobfree.com

Summary:

** **** ******** ******** ********** in developing/innovating/architecting/optimizing/servicing for mobile broadband system/networks

• Deep understanding of wireless technologies: LTE, LTE-A, UMTS, WiMax, WiFi, Microwave PtP, PtMP.

• Solid backgrounds and working experiences in antenna line products, RF propagation, signal processing algorithm/architecture, radio architecture, smart antenna, 4G/5G MIMO, cellular 4G RAN architecture/equipment/dimensioning.

• Strong analytic skills in various wireless system/network analysis based on theoretical reasoning, simulation tools (Matlab, C/C drive test and network OAM statistics.

• Extensive field trials, lab hand-on and commercial network diagnostic experience in identifying system issues and initiating optimization schemes with R&D

Seek opportunity in wireless 3G/4G/5G system/network design, development and/or optimization.

Experience:

11/2013 to present: Sr. Staff System Engineer, 4G RAN Development, Network Division, Samsung Electronics America, Richardson, TX

Provided subject matter expertise to TD-LTE 8T8R system deployment with highest competence in the market through leveraging antenna/remote radio/BBU architecture, Beam-Forming/MIMO technology, RF propagation, interference characterization, 3GPP standards and regulations, ensuring network performance with technical guidance, advising and HW/SW/FW diagnosis, tool development and data analysis:

(1) Developed MOPs and internal technical documents; guided Tier-2 team in network issue resolution, lead cross team activities of identifying, troubleshooting and resolving various remote radio head defects (LNA, TXLO, Mixer/VGA, etc); lead cross team activities of identifying and resolving various network interference issues.

(2) Interacted with customers regularly to identify their needs, consulted with R&D or supplier if necessary, worked out solution to meet customer needs in a timely manner.

(3) Initiated and developed automatic tools for time/frequency interference signature capture and analysis, enabling network wise interference identification, classification and eventual driving customer needed resolution; Developed tools to verify and optimize Broadcast beam to meet specifications for all selected antenna suppliers.

(4) Evaluated radio link budget to specify valid RF jumper length range, BF calibration power range and necessary attenuation to meet deployment requirements; Evaluated propagation link budget and identified power loss due to broadcast beam-forming weight, initiated antenna supplier to provide optimized broadcast beam to reduce power loss.

(5) Worked out customer driven enhanced solutions for Beam-forming related operations (ToF detection, Broadcast beam auto-configuration, Beam-forming calibration enhancement, Beam-forming operation under RF path failure).

(6) Advised customers of performance vs use cases under different LTE transmission modes and proper scheduler parameter settings: specified simulation requirements, created simulation results and explanations.

(7) Reviewed antenna/radio solutions to meet new customer requirements, reviewed RFP and supplier product (backhaul, antenna, etc)

(8) Analyzed field trial drive test data and commercial network OAM data to resolve various field issues;

7/2012 to 9/2013: Principal System Engineer, Exalt Communications, Richardson, TX

Architected Exalt next generation high capacity microwave/millimeter-wave radio and small cell backhaul system: RF aspects modeling/simulation and analysis, optimal air interface design, key propagation consideration, transceiver algorithms and protocol developments and experimental RF verifications:

1)Architected baseband and RF aspects of high QAM (>=2048) and high spectrum efficiency (with XPIC, LOS MIMO and full duplexing TX/RX) microwave radio, specified architecture of cost efficient microwave transceiver to achieve high performance under propagation and various RF distortions (nonlinearity, phase noise, TX/RX quadrature error, IQ differential delay);

2)Designed small cell backhaul system to meet capacity, link budget, QoS and cost requirements: air interface design through analysis and simulation, link budget with rain, NLOS and power, hub capacity dimensioning;

3)Developed complete XPIC and LOS-MIMO microwave radio link model to accurately analyze end-to-end impacts of propagation channel, various RF distortions, various tracking loops and receiver complexity on the performance;

4)Created a portfolio of cost aware receiver algorithms (blind equalizers in acquisition and tracking modes, carrier tracking loops, etc) and verified with real radio link to mitigate RF impairments and meet high QAM link specifications: phase noise, differential phase noise, TX/RX quadrature error, differential IQ delay, interaction between AGC and demodulation.

4/2009 to 6/2012: Member of Architecture Department, ZTE Corporation, Richardson, TX

System architected key features for LTE TDD/FDD system’s competitiveness; designed LTE PHY/MAC platform architecture and created algorithms to better 3GPP specs and competitors; key reviewing participant of advanced LTE PHY/MAC features, designed and oversaw initial lab and field trial verification of key functions; initiated and specified requirements of system performance monitoring tool; technical lead field trials in a highly dynamic and multi-vendor environment with top tier operators.

1)Technical lead the whole process of LTE FDD/TDD PHY uplink interference mitigation (IRC) feature from concept, design, simulation, review, performance verification and optimization;

2)Technical lead FDD-LTE Adaptive DL MIMO and UL AMC development, from algorithm, simulation, lab and field verification.

3)Designed multi-sector multi-UE uplink joint receiver algorithm to mitigate intra-site interference;

4)Technical lead TDD LTE 200 + UE/Cell project, specified lab configuration with monitoring tools at both UE and eNB, analyzed KPI, PHY/MAC/RRC signaling trace and initiated performance optimization of corresponding layers.

5)Designed dual layer beam-forming, super cell architecture design, TDD/FDD LTE deployment in high speed train;

6)Technical lead in the following LTE network trials, technical interface with customers, proposed optimizations with R&D;

a)2.3GHz TDD-LTE field trial with India Bharti AirTel in Delhi;

b)2.6GHz TDD-LTE key technology test with China Mobile in Beijing;

c)DD band FDD-LTE field trial with Vodafone in Germany;

d)2.6GHz TDD-LTE field trial with Deutsche Telekom in Prague;

e)First ZTE 2.6GHz LTE FDD-LTE field demo with CSL in Hong Kong with 2.6 GHz;

f)DD band (800MHz) FDD-LTE field demo with Vodafone D2 in Germany;

8/2007 to 3/2009: Director of Systems Department at Beijing Xinwei Telecom Technology, Beijing, China

Key contributor to the McWiLL technology, later become the first Chinese Broadband Wireless Access standard in 2009 and ITU broadband wireless access standard in 2010. Responsible for system design, specifications, optimization, standardization and evolution of McWiLL technology which has also been granted key technological invention award by Chinese Ministry of Information Industry in 2008.

1)Optimized voice and video transmission and interference mitigation;

2)Optimized commercially deployed McWiLL enterprise networks.

3)Lead standardizing McWiLL technology to become the first national standard of broadband wireless communication in Chinese Communications Standards Association (CCSA); The technology has become ITU standard for Broadband Wireless Access later of 2009;

4)Major contributor and developer of McWiLL air interface evolution towards a multi-media trunked radio system;

5)Designed and developed of McWiLL air interface evolution for higher spectrum efficiency and performance;

6)Lead comparative study of WiMAX, HSPA, UMB and LTE technologies.

12/2004 to 7/2007: Director of System Department at Arrowping Networks Inc, Beijing, China

Key technology contributor of the company, in charge of system and algorithm design. Lead system group to perform PHY/MAC protocol/algorithm design, simulation, development, verification, optimization and field test; all of the following innovations have been incorporated into the commercial McWiLL systems:

1)Co-designed McWiLL air interface protocol, a CS-OFDMA based wireless broadband access system providing high speed data and high efficiency voice services;

2)Designed a highly efficient smart antenna based space-frequency joint detection algorithm to combat both fading and interference;

3)Designed a smart antenna based transmit diversity scheme;

4)Designed a voice retransmission scheme;

5)Designed a complete radio resource management algorithm;

6)Designed a link adaptation (transmission mode, power and rate control) algorithm;

7)Designed interference management scheme to mitigate inter-cell interference;

9/2001 to 11/2004: Senior System Engineer, System Group at Navini Networks, Richardson, TX

Key system member of Navini Networks responsible for specifying advanced technology used for smart antenna based wireless broadband systems. My work involved PHY/MAC algorithm design, simulation, development, lab/field verification and optimization; all of the following contributions have been incorporated into the commercial MC-SCDMA system

1)Designed smart antenna based space-time joint detection algorithm in MC-SCDMA system to combat inter-cell, MAI and ISI interference, worked with DSP engineer to implement and performance verification;

2)Designed active code detection algorithm to assist MAC channel assignment scheme in MC-SCDMA system;

3)Designed a novel power control algorithm to handle fast fading and interference in wireless network environment;

4)Designed and co-implemented bandwidth request algorithm to optimize TCP throughput;

5)Designed and co-implemented TCP Proxy based scheme to speed up TCP data rate under wireless link.

Educations:

6/1997 - 12/1998: Master of Science, Electrical Engineering, University of Texas at Austin, TX

9/1990 - 2/1993: Master of Science, Electrical Engineering, University of Electronic Science and Technology, China

Patents or patent applications:

20+ Patents issued in the US and China.granted or USA

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