School of Engineering

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Department of Electrical and Computer Engineering

Chadi Abou Rjeily

Research interests

C. Abou-Rjeily holds the position of associate professor of electrical engineering at the Lebanese American University. He currently serves as an associate editor for the IEEE Transactions on Communications. His research interests are in code construction and transceiver design for wireless communication systems.

Coherent Space-Time Codes for Ultra-Wideband Communications:

In this context, we assume perfect channel state information at the receiver side. Given the carrier-less nature of the UWB communications, the space-time code design is more challenging since the constructed codes must verify an additional set of constraints. We constructed some families of codes that permit to achieve a full transmit diversity order while transmitting at a full rate. Some families of codes are exclusive to non-conventional modulations used with UWB and they satisfy all the construction constraints of the perfect codes in addition to the constraint of being totally-real. We also proposed new adapted optimal decoding algorithms that have good convergence times. The current areas of research include the construction of new families of codes having a lower decoding complexity.

Rate-1 coherent space-time codes for pulse position modulations:

We considered the problem of space-time code constructions for pulse position modulations that can be used in wireless optical communications and UWB communications. We constructed the first known families of codes that achieve a full transmit diversity order without introducing any additional constellation extension with PPM. In general, the achieved rates are less than one but for some given values of the number of antennas and the dimensionality of the constellation, the proposed codes can achieve a rate of one symbol per channel use. The properties of the codes render them suitable for low-cost UWB terminals.

Non-coherent space-time codes for pulse position modulations:

In this context, we assume that there isn’t any kind of channel state information available at the transmitter or the receiver. We proposed the first known non-coherent codes that can be associated with non-coherent detectors based on energy integration. Moreover, the proposed codes are shape-preserving with PPM. The current research consists of boosting the performance of these codes that, in general, suffer from reduced rates imposed by the simplified structure of the receiver. These codes are suitable for sensor nodes having a very simple architecture.

Cooperation in UWB wireless networks:

We consider the case where different terminals can cooperate to enhance the quality of their communications with their respective destinations. New Decode-and-Forward and Amplify-and-Forward cooperation strategies that are exclusive to UWB were proposed and analyzed. The diversity-multiplexing tradeoffs over the realistic indoor UWB channels were established. New optimal distributed space-time codes were proposed for impulse radio UWB networks. The current research is in studying appropriate relay-selection protocols that are adapted to the above scenario.  Joint synchronization, environment-aware processing and distributed computations can also be key issues for the UWB systems that profit from very high localization capabilities because of their high temporal resolution.

Selected publications

Journal papers:

  1. Chadi Abou-Rjeily and Mustapha Hamad, “Exploiting the relays’ backup RF antennas for enhanced FSO cooperative communications”, OSA Optics Express, vol. 25, no. 13, pp. 14545-14557, June 2017.
  2. Chadi Abou-Rjeily, “Performance Analysis of Power Line Communication Systems with Diversity Combining under Correlated Lognormal Fading and Nakagami Noise”, IET Communications, vol. 11, no. 3, pp. 405-413, February 2017.
  3. Chadi Abou-Rjeily, “Transceiver Grouping: A Novel Diversity Method for Collaborative Multiuser FSO Communications”, IEEE Transactions on Wireless Communications, vol. 16, no. 1, pp. 154-168, January 2017.
  4. Chadi Abou-Rjeily, “Permutation-Based Noncoherent Space-Time Codes with Analog Energy Detection for IR-UWB Communications with PPM”, IEEE Transactions on Wireless Communications, vol. 15, no. 8, pp. 5541-5554, August 2016.
  5. Chadi Abou-Rjeily and Zeina Noun, “Impact of Inter-Relay Cooperation on the Performance of FSO Systems with any Number of Relays”, IEEE Transactions on Wireless Communications, vol. 15, no. 6, pp. 3796-3809, June 2016.
  6. Chadi Abou-Rjeily, “Unitary Space-Time Pulse Position Modulation for Differential Unipolar MIMO IR-UWB Communications”, IEEE Transactions on Wireless Communications, vol. 14, no. 10, pp. 5602-5615, October 2015.
  7. Chadi Abou-Rjeily, “Performance analysis of FSO communications with diversity methods: Add more relays or more apertures?”, IEEE journal on selected areas in communications, vol. 33, no. 9, pp. 1890 – 1902, September 2015.
  8.  Chadi Abou-Rjeily, “Distributed Space-Time Codes for Full-Duplex IR-UWB Amplify-and-Forward Cooperation”, IEEE transactions on wireless communications, vol. 14, no. 4, pp. 2144 - 2155, April 2015.
  9. Chadi Abou-Rjeily and Alfred Abdo, “Serial Relaying over Gamma-Gamma MIMO FSO Links: Diversity Order and Aperture Allocation”, IEEE communications letters, vol. 19, no. 4, pp. 553 - 556, April 2015.
  10. Chadi Abou-Rjeily and Serj Haddad, “Inter-Relay Cooperation: A New Paradigm for Enhanced Relay-Assisted FSO Communications”, IEEE transactions on communications, vol. 62, no. 6, pp. 1970 - 1982, June 2014.
  11. Chadi Abou-Rjeily, “All-Active and Selective FSO Relaying: Do We Need Inter-Relay Cooperation?”, IEEE/OSA journal of lightwave technology, vol. 32, no. 10, pp. 1899 - 1906, May 2014.
  12. Chadi Abou-Rjeily, “Achievable Diversity Orders of Decode-and-Forward Cooperative Protocols over Gamma-Gamma Fading FSO Links”, IEEE transactions on communications, vol. 61, no. 9, pp. 3919 - 3930, September 2013.
  13. Chadi Abou-Rjeily, “Performance Analysis of Selective Relaying in Cooperative Free-Space Optical Systems”, IEEE/OSA journal of lightwave technology, vol. 31, no. 18, pp. 2965 - 2973, September 2013.
  14. Chadi Abou-Rjeily, “A Symbol-by-Symbol Cooperative Diversity Scheme for Relay-Assisted UWB Communications with PPM”, IEEE journal on selected areas in communications, vol. 31, no. 8, pp. 1436-1445, August 2013.
  15. Chadi Abou-Rjeily, “Power Allocation for Quantum-Limited Multihop Free-Space Optical Communication Systems”, IEEE communications letters, vol. 16, no. 12, pp. 2068-2071, December 2012.
  16. Chadi Abou-Rjeily, “Performance Analysis of UWB Systems over the IEEE 802.15.3a Channel Model”, IEEE transactions on communications, vol. 59, no. 9, pp. 2377-2382, September 2011.
  17. Chadi Abou-Rjeily, “A 2*2 Shape-Preserving ST Code for UWB Communications with Multipulse PPM”, IEEE transactions on wireless communications, vol. 10, no. 8, pp. 2402-2406, August 2011.
  18. Chadi Abou-Rjeily, “On the Optimality of the Selection Transmit Diversity for MIMO-FSO Links with Feedback”, IEEE communications letters, vol. 15, no. 6, pp. 641-643, June 2011.
  19. Chadi Abou-Rjeily and Serj Haddad, “Cooperative FSO Systems: Performance Analysis and Optimal Power Allocation”, IEEE journal of lightwave technology, vol. 29, no. 7, pp. 1058-1065, April 2011.
  20. Chadi Abou-Rjeily and Ahmad Slim, “Cooperative Diversity for Free-Space Optical Communications: Transceiver Design and Performance Analysis”, IEEE transactions on communications, vol. 59, no. 3, pp. 653-658, March 2011.
  21. Chadi Abou-Rjeily and Mario Bkassiny, “On the Achievable Diversity Orders over Non-Severely Faded Lognormal Channels”, IEEE communications letters, vol. 14, no. 8, pp. 695-697, August 2010.
  22. Chadi Abou-Rjeily and Zeina Baba, “Achieving Full Transmit Diversity for PPM Constellations with any Number of Antennas via Double Position and Symbol Permutations”, IEEE transactions on communications, vol. 57, no. 11, pp. 3235 - 3238, November 2009.
  23. Chadi Abou-Rjeily and Mario Bkassiny, “Unipolar Space-Time Codes with Reduced Decoding Complexity for TH-UWB with PPM”, IEEE transactions on wireless communications, vol. 8, no. 10, pp. 5086-5095, October 2009.
  24. Chadi Abou-Rjeily, “Pulse Antenna Permutation and Pulse Antenna Modulation: Two Novel Diversity Schemes for Achieving Very High Data-Rates with Unipolar MIMO-UWB Communications”, IEEE journal on selected areas in communications, vol. 27, no. 8, pp. 1331-1340, October 2009.
  25. Chadi Abou-Rjeily, “Orthogonal Space-Time Block Codes for Binary Pulse Position Modulation”, IEEE transactions on communications, vol. 57, no. 3, pp. 602-605, March 2009.
  26. Chadi Abou-Rjeily and Wissam Fawaz, “Space-Time Codes for MIMO Ultra-WideBand Communications and MIMO Free-Space Optical Communications with PPM”, IEEE journal on selected areas in communications, vol. 26, no.6, pp. 938-947, August 2008.
  27. Chadi Abou-Rjeily, Norbert Daniele and Jean-Claude Belfiore, “On the Amplify-and-Forward Cooperative Diversity with Time-Hopping Ultra-Wideband Communication Systems”, IEEE transactions on communications, vol. 56, no. 4, pp. 630-641, April 2008.
  28. Chadi Abou-Rjeily and Wissam Fawaz, “Distributed Information-Lossless Space-Time Codes for Amplify-and-Forward TH-UWB Systems”, IEEE communications letters, vol. 12, no. 4, pp. 298-300, April 2008.
  29. Wissam Fawaz, Ken Chen and Chadi Abou-Rjeily , “A Novel Connection Setup Management Approach for Optical WDM Networks”,  IEEE communications letters, vol. 11, no. 12, pp. 998-1000, December 2007.
  30. Chadi Abou-Rjeily and Jean-Claude Belfiore, “On Space-Time Coding with Pulse Position and Amplitude Modulations for Time-Hopping Ultra-WideBand Systems”, IEEE transactions on information theory, vol. 53, pp. 2490-2509, July 2007.
  31. Chadi Abou-Rjeily and Jean-Claude Belfiore, “A Space-Time Coded MIMO TH-UWB Transceiver with Binary Pulse Position Modulation”, IEEE communications letters, vol. 11, pp. 522-524, June 2007. Manuscript in  PDF
  32. Chadi Abou-Rjeily, Norbert Daniele and Jean-Claude Belfiore, “Space Time coding for Multiuser Ultra-Wideband Communications”, IEEE transactions on communications, vol. 54, pp. 1960-1972, November 2006.
  33. Chadi Abou-Rjeily, Norbert Daniele and Jean-Claude Belfiore, “A 2×2 Antennas Ultra-Wideband System using Biorthogonal Pulse Position Modulation”, IEEE communications letters, vol. 10, pp. 366-368, May 2006.
  34. Chadi Abou-Rjeily, Norbert Daniele and Jean-Claude Belfiore, “Distributed Algebraic Space Time Codes for Ultra-Wideband Communications”, Kluwer journal (Springer - special issue on cooperation in wireless networks).
  35. Julien Keignart, Chadi Abou-Rjeily, Christophe Delaveaud and Norbert Daniele, “UWB SIMO Channel Measurements and Simulations”, IEEE Transactions on Microwave Theory and Techniques, vol. 54, pp. 1812-1819, April 2006.
  36. Benoit Denis, Jean-Benoit Pierrot and Chadi Abou-Rjeily, “Joint Distributed Synchronisation and Positioning in UWB Ad Hoc Networks Using TOA”, IEEE Transactions on Microwave Theory and Techniques, vol. 54, pp. 1896-1911, April 2006.

Conference papers:

  1. Chadi Abou-Rjeily and George Elhowayek, “A Simple Analog Space-Time Coded Transmitted-Reference MIMO UWB Transceiver”, accepted for publication in the proceedings of the 19 Annual IEEE International Symposium on Personal, Indoor and Radio Communications (PIMRC-08).
  2. Wissam Fawaz and Chadi Abou-Rjeily, “A Simple Quality-of-Service-Based Connection Setup Management Approach for Optical Networks”, accepted for publication in the proceedings of the 2008 IEEE International Conference on Communications  (ICC-08).
  3. Chadi Abou-Rjeily, “A Maximum-Likelihood Decoder for Joint Pulse Position and Amplitude Modulations”, in the proceedings of the 18 Annual IEEE International Symposium on Personal, Indoor and Radio Communications (PIMRC-07), Athens, Greece, pp. 1-5, September 2007.
  4. Chadi Abou-Rjeily and Jean-Claude Belfiore, “A rate-1 2x2 space-time code without any constellation extension for TH-UWB communication systems with PPM”, in the proceedings of the 2007 Vehicular Technology Conference (VTC-Spring07), Dublin, Ireland, pp. 1683-1687, April 2007.
  5. Chadi Abou-Rjeily, Norbert Daniele and Jean-Claude Belfiore, “An optimal 2x2 space-time code for time hopping ultra wideband with binary PPM”, accepted for publication in the proceedings of the 2006 International Symposium on Wireless Communication Systems (ISWCS), Valencia, Spain, pp. 456-460, September 2006.
  6. Chadi Abou-Rjeily, Norbert Daniele and Jean-Claude Belfiore, “Diversity-Multiplexing tradeoff of single-antenna and multi-antenna indoor ultra-wideband channels”, in the proceedings of the 2006 International Conference on Ultra-wideband (ICUWB), Boston, USA, pp. 441-446, September 2006.
  7. Chadi Abou-Rjeily, Norbert Daniele and Jean-Claude Belfiore, “On the decode-and-forward cooperative diversity with coherent and non-coherent UWB systems”, in the proceedings of the 2006 International Conference on Ultra-wideband (ICUWB), Boston, USA, pp. 435-440, September 2006.
  8. Chadi Abou-Rjeily, Norbert Daniele and Jean-Claude Belfiore, “Amplify-and-forward cooperative diversity with space-time coded UWB systems”, in the proceedings of the 2006 International Conference on Ultra-wideband (ICUWB), Boston, USA, pp. 429-434, September 2006.
  9. Chadi Abou-Rjeily, Norbert Daniele and Jean-Claude Belfiore, “MIMO UWB communication systems using modified Hermite pulses”, in the proceedings of the 17 Annual International Symposium on Personal, Indoor and Radio Communications (PIMRC 2006), Helsinki, Finland, pp. 1-5, September 2006.
  10. Chadi Abou-Rjeily, Norbert Daniele and Jean-Claude Belfiore, “Distributed space-time coding with ultra-wideband systems”, in the proceedings of the 17 Annual International Symposium on Personal, Indoor and Radio Communications (PIMRC 2006), Helsinki, Finland, pp. 1-5, September 2006.
  11. Chadi Abou-Rjeily, Norbert Daniele and Jean-Claude Belfiore, “A new family of space time codes for pulse amplitude and position modulated UWB systems”, in the proceedings of the 2006 International Symposium on Information Theory (ISIT), Washington, USA, pp. 2829-2833, July 2006.
  12. Chadi Abou-Rjeily, Norbert Daniele and Jean-Claude Belfiore, “A new full rate fully diverse ST codes with nonvanishing determinant for TH-UWB systems”, in the proceedings of the 2006 International Zurich Seminar on Communications, pp. 198-201, February 2006.
  13. Chadi Abou-Rjeily, Norbert Daniele and Jean-Claude Belfiore, “Performance of MIMO UWB systems with biorthogonal pulse position modulation”, in the proceedings of the 2006 International Zurich Seminar on Communications, pp. 202-205, February 2006.
  14. Chadi Abou-Rjeily, Norbert Daniele and Jean-Claude Belfiore, “Differential space time ultra wide-band communications”, in the proceedings of the IEEE International Conference on Ultra wide-band (ICU), Zurich, September 2005.
  15. Chadi Abou-Rjeily, Norbert Daniele and Jean-Claude Belfiore, “On high data rate space time codes for ultra-wideband systems”, in the proceedings of the IEEE International Conference on Ultra wide-band (ICU), Zurich, September 2005.
  16. Chadi Abou-Rjeily, “On the impact of ISI and MUI on MIMO-UWB communication systems”, invited paper. To be presented at the 2007 Europe Wireless conference (EW), April 2007. Paris, France.

Academic degrees

Ph.D., Communications, l’Ecole Nationale Superieure des Telecommunications, France, 2006
DEA, Telecommunications, l’Ecole Nationale Superieure des Telecommunications, France, 2003
B.E., Electrical Engineering, Lebanese University, Lebanon, 2002

Professional memberships

Dr. Abou-Rjeily is a senior IEEE member since October 2013 and he serves as a reviewer for several international journals and conferences including IEEE transactions on information theory, IEEE transactions on communications and the IEEE communications letters. He was also a member of the technical program committee of the international conferences MCWC-06, M-WCMC-07, PIMRC-08, VTC-09/Spring, VTC-10/Spring, VTC-11/Spring, ICT-12, PIMRC-13 and Globecom-13.


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