Christine (Ying) Li

 

 

                                                               

SUMMARY

 

About 20 years excellent experience of software design, integration & verification, trouble shooting and technical support on Femtocell, wireless and PSTN. With deep understanding in CDMA, SIP/IMS and SS7 protocols, strong skills in VxWorks, UNIX and signaling simulators. Works well either independently or as a team player.

 

PROFESSIONAL SKILLS

 

l        Femtocell: SIP based IOS, access control, auto configuration

l        Wireless Network: CDMA 1xRTT/EVDO, IS-41, UMTS and LTE.

l        Signaling Tools: Wireshark, QXDM, MGTS, INET, Turbo7

l        Signaling: SIP, IMS, SIGTRAN, SS7 and its ITU/ANSI/CH7 standards

l        Protocols: RADIUS, PPP, TCP/IP, VOIP, ISDN, Q.931

l        Operating Systems: VxWorks, Linux, UNIX, Windows

l        Languages:  C/C++, Tcl, Expect, Java, Perl, SQL

l        Ericsson Open Platform: Cello and TSP

l        Good team work, communication and planning skills.

l        Excellent trouble shooting skill, self-motivated and a quick learner.

 

PROFESSIONAL BACKGROUND

 

Aug. 2005 - Present: UbeeAirWalk / AirWalk Communications, Richardson, TX

 

Sr. Software Engineer, in charge of 1X MCC(Main Call Control) module, EVDO DSS(DO Session Control) module in CDMA IPBS product and interface with core network, include high level design, unit design, implementation and test of new features, support system test, debug customer field issues.

 

·         Upgraded Macro IPBS A1 interface from IOS 4.1 to IOS 5.0

·         Upgraded Pico IPBS A1 interface from SCCP Lite to SUA over SCTP, developed SUA protocol from scratch, and successfully integrated with ZTE MSC

·         Design and developed signaling plane of  IPSC (IP Signaling Concentrator), by which hundreds of IPBS can connect to same MSC through SUA/SCTP interface, to resolve SPC (Signaling Point Code) limit issue on MSC

·         Design and developed EVDO A12 interface with AAA, including RADIUS, CHAP, LCP and PPP protocol

·         Integrated and maintain eFemto BS SIA (SIP Adaptor, converting IOS interface to SIP interface) module, support and debug customer site SIP/IMS related issue

·         Review and designed TCS-eFemto interface for Sprint LTE CSFB (Circuit Switched Fallback) feature, and implemented on eFemto.

 

 

Dec. 2000 – Aug. 2005: Ericsson Canada Inc., Canada

 

System Test Engineer, C-RAN System I&V, Nov. 2002 – Aug. 2005

·      System integration and verification of CDMA RAN Network, IS2000 protocol and A Interface, for both CDMA 1X and EVDO

·      Analyze feature documents and requirement, design test scenarios, write test specification

·      Establish test environment, execute test cases and find problems

·      Reproduce faulty behaviors found on field, debug with designer to help expedite the fix.

·      As a team leader backup in automation, select test cases to be automated, design test configuration, develop test scripts by Tcl & Expect, maintain testing tools like MGTS

·      Participated in TS/TI document reviews and gave valuable feed back to teammate

·      Being point of technical contact for call flow, give help to other team members.

 

System Test Engineer, Open Platform System I&V, Dec. 2000 - Oct. 2002

·      Generate test cases and TS/TI according to product requirement. Focus on Signaling Stack, TCAP over MTP, and ISUP over SIGTRAN, etc, served as HLR, MG service nodes.

·      Write test scripts used by test tools INET, MGTS

·      Trouble shooting, raise and follow-up Trouble Reports.

·      On-site technical support for China Unicom CDMA project in China

 

Aug.1994 - May 2000: Beijing Network Branch, China Telecom

Network and System Engineer, Beijing Network Technical Center

 

Working in the 3^rd level network support center, as team leader of E10B group, take all technical responsibilities of Alcatel E10B systems in Beijing PTSN Network, technically reporting to the company Chief Engineer.

 

·      Technical support for 2^nd line; debug on switches and signaling interworking across whole network; In charge of acceptance test, extension, software upgrade and subscriber cutover.

·      Develop test cases and execute SS7 signaling network test, concentrates on the compatibility between ISUP, TUP and CAS across various switches including Nortel Supernode STP, Ericsson AXE10 tandem, Alcatel S12 tandem, 24bit SS7 signaling and IWU between 14bit & 24bit; supervised SPC upgrade from 14 bit to 24 bit on E10B systems.

·      Design and test ISDN trial network, includes feature test, compatibility test between user terminals and switches, ISDN DSS1 and ISUP signaling test on different systems.

 

EDUCATION AND TRAINING

 

Sep.1990 - Jul.1994              Bachelor of Engineering in Computer Telecommunication

                                     Beijing University of Posts & Telecommunications, Beijing, China

 

Sep.1998 - Oct.1998              Alcatel 1000 E10 2^nd Level Course

                                          Alcatel CIT Training Center, Lannion, France

 

Nov.2002 - Dec.2002              CDMA IS-95 & IS-2000, CDMA System Survey

                                          Ericsson Training Center, Montreal, Canada

 

Feb.2013 - Feb.2013              LTE Protocols and Signaling

                                          Award Solutions, Richardson, Texas

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