Ariton E. Xhafa

Member of Technical Staff

Communications System Architecture Group,

Texas Instruments, Inc., Dallas, Texas

Ariton.jpg

Education

 

Areas of Interest

Wireless communications, queueing and networking, quality of service in cellular networks, indoor wireless LAN's, OFDM, handover management, resource allocation and scheduling, and wireless sensor networks.

 

Employment History

§         Texas Instruments, Inc., Dallas, TX, April 2004-Present

o       Doing research on multiple access control  (MAC), quality of service (QoS) in wireless networks that use IEEE 802.11 and IEEE 802.16 technologies, 3G, and 4G wireless networks.

 

§         Research Associate, Department of Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, PA, October 2003-March 2004

o       Performing research on resource allocation and scheduling in wireless networks and occasionally giving lectures on Optical Communications Network

 

§         Research Assistant, Center for Wireless and Broadband Networking, Department of Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, PA, January 2002 - August 2003

o       Project: “High-speed internet via HVAC ducts”

-          Identify network issues and feasible solutions for indoor wireless networks that use HVAC ducts

 

§         Teaching Assistant, Department of Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, PA, Fall 2002 – Spring 2003

o       Courses: Wireless Networks, Data Telecommunications Networks.

-          Responsibilities include: recitations, designing/grading homework and exams

 

§         Project Engineer, Center for Wireless and Broadband Networking, Department of Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, PA, January 2001 – December 2001

o       Project: “High-speed internet via HVAC ducts”

-           Perform theoretical research and make field measurements on assessment of the practical channel capacity of HVAC ducts and designing of “radio-friendly” ducts.

-          Theoretical and practical implementations issues of OFDM in HVAC ducts

-          Write and implement an OFDM simulator

 

§         Research Engineer, Nokia Networks, Pittsburgh, PA, August 2000 – December 2000

o       Project: “GPRS-136/HS network dimensioning and planning”

-          Developed a general framework for network dimensioning in GPRS-136

-          Developed network dimensioning tool software in MATLAB

-          An optimum algorithm for network planning was presented

-          Practical guidelines were provided for GPRS-136 network planning

 

§         Research Engineer, Clearwire Technologies, Buffalo, NY, Summer 1999

o       Project: Fixed Wireless Internet Access via Clearwire Radios

-          Tested the wireless radio protocol of Clearwire Technologies

-          Suggested and improved the performance of the wireless radio protocol for Internet traffic

 

§         Lecturer, University at Buffalo, Upperbound Program, Summer 2000

o       Course: Introduction to Internet

-           Prepared the incoming freshman computer surviving skills to excel in the university environment

-           Hosting weekly lectures, prepare course plan, design projects and exams

-           Topics Covered: Web Design, E-mail Systems, UNIX/Windows Systems

 

§         Lecturer, University at Buffalo, LS AMP, Summer 2000

o       Course: Research Methods

-          Taught graduating seniors how to become successful researcher

-          Topic Covered: Types of reality, human inquiry, deductive and inductive theory construction, causality, obtrusive and unobtrusive research, variations in experimental design.

 

§         Lecturer, University at Buffalo, Fall 1999

o       Course: Probability and Statistic Inference for Engineers

-           Taught juniors the concepts of probabilities and application to research

-           Hosting weekly lectures, prepare course plan, design exams and homework

-           Topics Covered: Concepts of probability, one random variable, two random variables, conditional distributions, statistics and hypothesis testing.

 

§         Teaching Assistant, University at Buffalo, Fall 1997- Spring 2000

o       Courses: Telecommunication and Data Networks, Applied Probability and Statistics, Digital Principles, Circuit Analysis

-          Responsibilities include: recitations, designing/grading homework and exams

 

§         Research Assistant, Eastern Mediterranean University, Spring 1997

o       Project "Use of error correcting codes in Code Division Multiple Access (CDMA) Multi-user Detection"

-          Developed an algorithm to study the performance of error correcting codes in CDMA Multi-user detection.

 

Publications

Journal Papers
 

  1. A. E. Xhafa, A. Batra and A. Zaks, “On the 20/40 MHz coexistence of overlapping BSSs in WLAN”, Academy Publishing Journal of Networks, vol. 3, no. 7, pp. 56-63, July 2008, invited paper.
  2. A. E. Xhafa and O. K. Tonguz, “Handover performance of priority schemes in pcs networks”, IEEE Transactions on Vehicular Technology, vol. 57, no. 1, pp. 565-577,  Jan. 2008.
  3. A. E. Xhafa, O. K. Tonguz, A. G. Cepni, D. D. Stancil, P. V. Nikitin, and D. Brodtkorb, “On the capacity limits of HVAC duct channel for high-speed Internet access”, IEEE Transactions on Communications, pp. 335-342, vol. 53, no. 2, February 2005.
  4. A. E. Xhafa and O. K. Tonguz, “Dynamic priority queuing of handover calls in wireless networks: An analytical framework”, IEEE Journal on Selected Areas on Communications, special issue on Advanced Mobility Management and QoS Protocols for Next Generation Wireless Internet, vol. 22, no. 5, pp. 904 – 916, June 2004.
  5. O. K. Tonguz, A. E. Xhafa, D. D. Stancil, A. G. Cepni, P. V. Nikitin, and D. Brodtkorb, “A simple path loss prediction model for HVAC systems”, IEEE Transactions on Vehicular Technology, vol. 53, no. 4, pp. 1203-1214, July 2004.
  6. P. V. Nikitin, D. D. Stancil, O. K. Tonguz, A. E. Xhafa, A. G. Cepni, and D. Brodtkorb, “HVAC duct system as an indoor wireless communication channels: impulse response characteristics”, IEEE Transactions on Communications, pp. 1736-1742, vol. 51, no. 10, Oct. 2003.
  7. P. V. Nikitin, D. D. Stancil, A. G. Cepni, A. E. Xhafa, O. K. Tonguz, and D. Brodtkorb, “Novel mode content analysis technique for antennas in multimode waveguides”, IEEE Transactions on Microwave Theory and Techniques, vol. 51, no. 12, pp. 2402-2408, December 2003.
  8. P. V. Nikitin, D. D. Stancil, A. G. Cepni, O. K. Tonguz, A. E. Xhafa, and D. Brodtkorb, “Propagation model for HVAC duct as a communication channel”, IEEE Transactions on Antennas and Propagation, vol. 51, no. 5, pp. 945-951, May 2003.
  9. O. K. Tonguz and A. E. Xhafa, “Improving handover performance in wireless networks: dynamic priority queuing versus guard channel method”, IEE Electronics Letters, vol. 38, no. 7, pp. 338-339, March 2002.

 

Conference Papers
 

  1. A. E. Xhafa, X. Lu, and D. P. Shaver, “Coexistence of collocated IEEE 802.11 and Bluetooth technologies in 2.4 GHz ISM band”, International Conference on Access Networks, Las Vegas, Oct. 2008, accepted
  2. A. E. Xhafa, A. Batra and A. Zaks, “On the Coexistence of Overlapping BSSs in WLANs”, IEEE Vehicular Technology Conference, Fall 2007, pp. 189-193, Baltimore, MD, Sept. 2007.
  3. A. E. Xhafa, S. Kangude, and X. Lu, “MAC performance of IEEE 802.16e”, IEEE Vehicular Technology Conference, Fall 2005, Vol. 1, pp. 685 - 689, Dallas, TX, Sept. 2005.
  4. A. E. Xhafa, P. Sonthikorn, and  O. K. Tonguz, “Handover in indoor wireless networks that use HVAC ducts: Analysis and impacts”, IEEE Global Telecommunications Conference, (GLOBECOM'04), Vol. 2,  pp. 903 - 907, Dallas, TX, Dec. 2004.
  5. A. E. Xhafa and O. K. Tonguz, “Extending WLAN coverage via utility pipes”, IEEE Vehicular Technology Conference, Fall 2004, Vol. 2, pp. 1093 - 1097, Los Angeles, CA, 26-29 Sept. 2004.
  6. A. G. Cepni, D. D. Stancil, A. E. Xhafa, P. V. Nikitin, O. K. Tonguz, and D. Brodtkorb, “Capacity of multi-antenna array systems for HVAC ducts”, IEEE International Conference on Communications (ICC 2004), vol. 5, pp. 2934-2938, Paris, France, 20-24 June 2004.
  7. A. E. Xhafa and O. K. Tonguz, “Does mixed lognormal distribution channel holding time affect the handover performance of guard channel scheme?” IEEE Global Telecommunications Conference, (GLOBECOM'03), vol. 6, pp. 3452-3456, Dec. 1-5, San Francisco, CA, USA, 2003.
  8. A. E. Xhafa, P. Sonthikorn, O. K. Tonguz, P. V. Nikitin, A. G. Cepni, B. Henty, D. Stancil, and D. Brodtkorb, “Seamless handover in buildings using HVAC ducts: A new system architecture”, IEEE Global Telecommunications Conference, (GLOBECOM'03), vol. 6, pp. 3093-3097, Dec. 1-5, San Francisco, CA, USA, 2003 .
  9. D. D. Stancil, P. V. Nikitin, A. G. Cepni, A. E. Xhafa, O. K. Tonguz, B. Henty, and D. Brodtkorb, “RF channel properties of heating and ventilation ducts”, Progress In Electromagnetics Research Symposium  Program (PIERS 2003 ),  October 13–16, 2003 Honolulu, Hawai, USA.
  10. A. E. Xhafa and O. K. Tonguz, “Reducing handover time in heterogeneous networks”, IEEE Vehicular Technology Conference, Fall 2003, vol. 4, pp. 2222-2226, 6-9 Oct. 2003.
  11. P. V. Nikitin, D. D. Stancil, A. G. Cepni, A. E. Xhafa, O. K. Tonguz, K. Areklett, and D. Brodtkorb, “Antennas in waveguide propagation environment”, IEEE Antennas and Propagation Symposium 2003, vol. 2, pp. 1181-1184, June 22-27, 2003.
  12. P. V. Nikitin, D. D. Stancil, A. G. Cepni, A. E. Xhafa, O. K. Tonguz, and D. Brodtkorb, “Propagation modeling of complex HVAC networks using transfer matrix method”, IEEE Antennas and Propagation Symposium 2003, vol. 2, pp. 126-129, June 22-27, 2003.
  13. P. V. Nikitin, D. D. Stancil, A. G. Cepni, A. E. Xhafa, O. K. Tonguz, and D. Brodtkorb, “Novel mode content analysis technique for multimode waveguide”, IEEE Microwave Symposium 2003, vol. 3, pp. 1827-1830, June 8-13, 2003.
  14. P. V. Nikitin, D. D. Stancil, O. K. Tonguz, A. E. Xhafa, A. G. Cepni, and D. Brodtkorb, “RF propagation in an HVAC duct system: impulse response characteristics of the channel”, IEEE Antennas and Propagation Symposium (APS’02), vol. 2, pp. 726-729, 2002.
  15. A. G. Cepni, A. E. Xhafa, P. V. Nikitin, D. D. Stancil, O. K. Tonguz, and D. Brodtkorb, “Multicarrier signal transmission through HVAC ducts: Experimental results for channel capacity”, IEEE Vehicular Technology Conference (VTC Fall 2002), vol. 1, pp. 331-335, 2002.
  16. O. K. Tonguz, D. D. Stancil, A. E. Xhafa, A. G. Cepni, P. V. Nikitin, and D. Brodtkorb, “An empirical path loss model for HVAC duct channel”, IEEE Global Telecommunications Conference(GLOBECOM’02), vol. 2, pp. 1850-1854, Taipei, Taiwan, 2002.
  17. A. E. Xhafa, O. K. Tonguz, A. Cepni, D. Stancil, P. Nikitin, and D. Brodtkorb, “Theoretical limits of HVAC duct channel capacity for high-speed Internet access”, IEEE International Conference on Communications (ICC’02), vol. 2, pp. 936-939, New York, 2002.
  18. D. D. Stancil, O. K. Tonguz, A. E. Xhafa, A. G. Cepni, P. V. Nikitin, and D. Brodtkorb, “High Speed Internet via HVAC Ducts: A New Approach”, IEEE Global Telecommunications Conference (GLOBECOM’01), vol. 6, pp. 3604-3607, San Antonio, Texas, Nov. 2001.
  19. A. Xhafa and O. K. Tonguz, “A New Queuing Scheme for Handoffs in 3G Wireless Networks”, IEEE Vehicular Technology Conference (VTC’01 Fall), pp. 738-742, Atlantic City, USA, Oct. 2001.
  20. A. Xhafa and O. K. Tonguz, “Handoff Priority in Voice/Data Integrated Wireless Networks”, International Conference on Telecommunications(ICT 2001), pp. 273-278, Bucarest, Romania, June 2001.
  21. A. Xhafa and O. K. Tonguz, “Dynamic Priority of Handoff Requests in PCS”, IEEE International Communications Conference (ICC’2001), pp. 341-345, Helsinki, Finland, June 2001.
  22. A. Xhafa and O. K. Tonguz, “Performance of Delay-Dependent Queuing of Handoff Requests with 2 and 3 Priority Classes in PCS”, IEEE Vehicular Technology Conference (VTC Spring 2001), pp. 946-950, Rhodes, Greece, May 2001.
  23. A. Xhafa and O. K. Tonguz, “Dynamic Priority Queuing, Channel Borrowing, and First In First Out Handoff Schemes: A Performance Comparison”, IEEE Vehicular Technology Conference (VTC Spring 2001), pp. 951-955, Rhodes, Greece, May 2001.
  24. O. K. Tonguz, S. Maloo, A. Xhafa, and S. Sheeshia, “Internet Access via LEO Satellite Networks: TCP/IP or ATM?”, IEEE Global Telecommunications Conference (GLOBECOM’99), pp. 301-305, Rio de Janeiro, Brasil, Dec. ‘99
  25. S. Maloo, S. Sheeshia, A. Xhafa, and O. K. Tonguz, “LEO Satellite Networks: Ethernet or ATM?”, IEEE Personal, Indoors and Mobile Radio Communications Conference (PIMRC ’99), pp. 494-497, Sept. ’99.
  26. A. Xhafa and O. K. Tonguz, “Dynamic Priority Queuing of Handoff Requests in Personal Communication Systems: An Analytical Framework for Performance Evaluation”, IEEE Personal, Indoors and Mobile Radio Communications Conference (PIMRC ’99), pp. 1346-1350, Sept. ’99.

 

Technical Reports

 

  1. D. D. Stancil, O. K. Tonguz, P. V. Nikitin, A. E. Xhafa, and A. G. Cepni, “Assessment of Building HVAC Ducts as High-Bandwidth Communications Channels”, CMU Technical Report, 2001
  2. O. K. Tonguz and A. E. Xhafa, “GPRS Core Network Dimensioning: A Roadmap”, SUNY at Buffalo Technical Report, 2000
  3. O. K. Tonguz, A. E. Xhafa, and P. Roychowdhury, “Performance Evaluation of First Generation Clearwire Radios”, SUNY at Buffalo Technical Report, 1999

 

Honors & Awards

 

  • Carnegie Mellon University, Graduate Conference Fund, 2003
  • IEEE Merit-based Student Travel Grant for Global Communications Conference, San Francisco, CA, 2003
  • Who’s who among students in American Universities and Colleges, 1998, 1999
  • Scatcherd European Scholarship to pursue graduate studies at University of Oxford, 1997 (Declined :-) )
    - Awarded on the basis of academic performance, proposal for research, and letters of recommendation
  • Eastern Mediterranean University Scholarship, North Cyprus, 1992-1997
    - Awarded on the basis of academic performance.
  • Polytechnic University of Tirana Scholarship, Tirana, Albania, 1991-1992
    - Awarded on the basis of academic performance.
  • Golden Medal for Excellence, Vlora, Albania, 1991
    - Awarded on the basis of academic performance in high school and as a winner in regional and national competitions in Mathematics and Physics.

 

Extra Curricular Activities Awards

  • Inwood Soccer Champions, Dallas, TX, Summer 2004, Winter 2007, Summer 2007
  • Carnegie Mellon University Outdoor Soccer Champions, Pittsburgh, PA, Fall 2001
  • University at Buffalo Outdoor Soccer Champions, Buffalo, NY, Summer’2000
  • MVP, West Seneca Soccer League, Buffalo, NY, Summer ’99
  • West Seneca Soccer League Champions, Buffalo, NY, Summer’99

 

Professional Activities

  • Active member of IEEE 802.11n and 802.11s Standards.
  • Technical program committee member for:
    • IEEE International Conference on Communications (ICC 2008), Beijing, China, May 2008.
    • IEEE Wireless Communications and Networking Conference (WCNC 2008), Las Vegas, Nevada, March-April 2008.
    • ACS/IEEE International Conference on Computer Systems and Applications (AICCSA 2008), Doha, Qatar, April 2008.
    • IEEE INFOCOM MOVE Workshop, Anchorage, Alaska 2007.
    • IEEE Wireless Communications and Networking Conference, Hong-Kong, March 2007.
    • 1st International Conference on Access Networks (AccesssNet’06), Athens, Greece, Sept. 2006.
    • IEEE Global Telecommunications Conference (GLOBECOM 2006), San Francisco, CA, Dec. 2006.
    • IEEE International Conference on Communications (ICC 2006), Istanbul, Turkey, May 2006.
    • IEEE Vehicular Technology Conference, Fall 2006, Montreal, Canada, Sept. 2006.
    • IEEE Global Telecommunications Conference (GLOBECOM 2005), Wireless Communications Symposium, St.Luis, MO, Dec. 2005.
    • IEEE International Conference on Communications (ICC 2005), Seoul, Korea, May 2005.
    • IEEE Vehicular Technology Conference, Fall 2004, Los Angeles, CA, Sept. 2004.
  • Session Chair for Access Control and Protocols in IEEE Vehicular Technology Conference, Fall 2004, Los Angeles, CA, Sept. 2004.
  • Session Chair for Access Control and Scheduling: IEEE Global Telecommunications Conference, San Francisco, CA, Dec. 2003.
  • Reviewer for the IEE Electronics Letters, IEE Proceedings on Communications, Kluwer Wireless Personal Communications, IEEE Transactions on Wireless Series, IEEE Transactions on Vehicular Technologies, IEEE Transactions on Communications, IEEE International Conference on Communications, and IEEE Intern. Conf. on Telecomm.
  • Member of the IEEE Communications Society and Engineering in Medicine and Biology Society.
  • Member of Eta Kappa Nu.

 

 

 

Extra Activities

  • Member of Pittsburgh Council for International Visitors, Fall 2002 – April 2004
  • Volunteer on EGO activities in ECE Department at Carnegie Mellon University, September 2000 – March 2004
  • Team Captain for “Los Chavos”, Greater Pittsburgh Soccer League, Summer 2002
  • Participated in intramural soccer tournaments at University at Buffalo and Carnegie Mellon University, Fall 1999 – Spring 2004

 

Contact

Ariton Xhafa
E-mail: arxhafa@yahoo.com


(Last updated: February 15, 2007)

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