Prof. LIEW Soung-Chang 劉紹強教授

Professor (FIEEE, FIEE, FHKIE)
Education: BS, MS, PhD (MIT)
Research Area: Networking Theory, Internet and Applications, Wireless Communications and Networking
Tel: (852) 3943-8352
Fax: (852) 2603-5032
Address: Rm 709 SHB
Email: soung [@] ie.cuhk.edu.hk

Prof. Liew's personal website
Prof. Liew's research group

Research Interests

  • Wireless Communications and Networking
  • Internet Protocols and Applications
  • Multimedia Communications
  • Broadband Communications Networks
  • Packet Switch Design and Performance Analysis

Courses Taught

  • Advanced Engineering Physics
  • Computer Networks
  • Network Software Design and Programming
  • Probability Theory
  • Telecommunication Switching and Network Systems


Professor Soung Chang LIEW received his  S.B., S.M., E.E., and Ph.D. degrees from the Massachusetts Institute of Technology. From 1984 to 1988, he was at the MIT Laboratory for Information and Decision Systems, where he investigated Fiber-Optic Communications Networks. From March 1988 to July 1993, Professor Liew was at Bellcore (now Telcordia), New Jersey, where he engaged in Broadband Network Research. He is currently Professor and Division Head at the Department of Information Engineering, the Chinese University of Hong Kong (CUHK). He was Department Chairman from 2006 to 2009, and Associate Dean of Engineering from 2004 to 2006. Besides his appointment at CUHK, Professor Liew is Adjunct Professor of Peking University and Southeast University in China.

Professor Liew's research interests include wireless communications and networking, Internet protocols, multimedia communications, and packet switch design. His recent research highlights have been in the field of wireless communications and networking:

  • Professor Liew’s research group conceived and pioneered the concept of Physical-layer Network Coding (PNC), a subfield in Network Coding that is attracting wide followings in the wireless research community recently. This paper made the observation that nature often performs implicit network coding operations which can be exploited to improve network performance. In wireless relay networks, exploiting the superposition of electromagnetic waves, a form of network coding, allows throughput to be doubled. There have been several international journal issues dedicated to the topic of PNC.
  • Professor Liew’s research group won the best paper awards in the 1st IEEE International Conference on Mobile Ad-hoc and Sensor Systems (IEEE MASS 2004) the 4th IEEE International Workshop on Wireless Local Network (IEEE WLN 2004). These papers contributed to the understanding of wireless CSMA networks, particularly on their performance and operational stability.
  • Professor Liew’s research group invented TCP Veno, a version of TCP that circumvents the shortcoming performance bottlenecks of conventional TCP in wireless networks. TCP Veno has been incorporated into Linux OS and recent Android products.
  • Professor Liew’s research group was among the first to study the transport of VoIP over Wi-Fi. A paper of the group pointed out the significant overhead incurred when VoIP is carried over Wi-Fi, and proposed an aggregation technique to solve the problem. The paper is the most cited work under the keyword search “VoIP WLAN” in Google Scholar, and under the title search “VoIP” in Web of Science.
  • Professor Liew co-initiated and directed the Area of Excellence in Information Technology of Hong Kong, a HK$51m multiyear umbrella research project with participants from major universities in Hong Kong.
  • Professor Liew initiated and built the first inter-university ATM network testbed in Hong Kong in 1993.
  • Professor Liew is the recipient of CUHK Research Excellence Award in 2013.

At CUHK, Professor Liew teaches Engineering Physics, Probability Theory, Computer Networks, Network Programming, Multimedia Communications Systems, and Broadband Packet Switching and Networking. He is the co-author of an advanced-level textbook, Principles of Broadband Switching and Networking. At CUHK, Professor Liew was a recipient of a university-wide exemplary teaching award when it was first established in 1999, for his teaching excellence in engineering.

Besides academic activities, Professor Liew is very active in the industry. He co-founded two technology start-ups that focused on Internet Software. One of the start-ups was co-founded with Professor Charles Kao (Winner of Nobel Prize in Physics, 2009) in the 90s, during the early days of the Internet. Working with a property developer, the company built the first residential intranet in the region (probably the world). Professor Liew has been a consultant for the Hong Kong Applied Science and Technology Research Institute (ASTRI) since its inception in 2001, providing technical advice as well as helping to formulate R&D directions and strategies in the areas of Wireless Internetworking, Applications, and Services. Some of the wireless technologies he co-invented at ASTRI are the key components behind commercial products sold around the world.

Professor Liew is Fellow of IEEE, IET and HKIE. He is Editor of IEEE Transactions on Wireless Communications and Editor of International Journal of Ad Hoc and Sensor Wireless Networks. Professor Liew has published over 150 refereed technical papers (mostly IEEE). He is the holder of nine U.S. patents.

Selected Publications from the last three years

A) Network Coding with focus on Physical-Layer Network Coding

  • S. C. Liew, S. Zhang, L. Lu, "Physical-layer Network Coding: Tutorial, Survey, and Beyond," Invited Paper; accepted by Elsevier Phycom, Special Issue of Physical Communication on "Network Coding and Its Applications to Wireless Communications", invited paper, Elsevier Phycom, Special Issue of Physical Communication on "Network Coding and Its Applications to Wireless Communications". A 39-page double-column tutorial paper surveying the research landscape of physical-layer network coding, May 2012. http://dx.doi.org/10.1016/j.phycom.2012.05.002
  • L. Lu, T. Wang, S. C. Liew, S. Zhang, "Implementation of Physical-layer Network Coding," Elsevier Phycom, Special Issue of Physical Communication on "Network Coding and Its Applications to Wireless Communications", http://dx.doi.org/10.1016/j.phycom.2012.02.008, Mar. 2012.
  • F. Wang, S. C. Liew, D. Guo, "Wireless MIMO Switching with Zero Forcing and Network Coding," IEEE J. on Selected Areas in Commun, vol. 30, no. 8, pp. 1452-1463, Sep. 2012.
  • L. F. Xie, P. H. J. Chong, S. C. Liew, Y. L. Guan, "CEO: Consistency of Encoding and Overhearing in Network Coding-Aware Routing," accepted by IEEE Wireless Comm. Letter.
  • S. Zhang, S. C. Liew, H. Wang, "Blind Known Interference Cancellation," accepted by IEEE J. on Selected Areas in Commun.
  • S. Zhang, S. C. Liew, L. Lu, H. Wang, "Blind Known Interference with Parallel Real Valued Belief Propagation Algorithm," IEEE Globecom '12, Dec 2012.
  • Q. Wang, K. H. Tse, L. K. Chen, S. C. Liew, "Physical-layer Network Coding for VPN in TDM-PON," IEEE Photon. Technol. Lett. , vol. 24, no. 23, Dec. 2012.
  • Z. Liu, M. Li, L. Lu, C. K. Chan, S. C. Liew, L. K. Chen, "Optical Physical-layer Network Coding," IEEE Photonic Letter, vol. 24, no. 8, 2012.
  • F. Wang, S. C. Liew, D. Guo, "Wireless MIMO Switching with MMSE Relaying," IEEE ISIT '12, July 2012.
  • L. Lu, T. Wang, S. C. Liew, S. Zhang, "Implementation of Physical-layer Network Coding," IEEE ICC '12, June 2012.
  • L. Lu, S. C. Liew, "Asynchronous Physical-layer Network Coding," IEEE Trans. on Wireless Communications, vol. 11, no. 2, pp. 819-831, Feb. 2012.
  • S. Zhang, S. C. Liew, H. Wang, "Synchronization Analysis for Wireless TWRC Operated with Physical-layer Network Coding," Wireless Personal Communications, Springer, 2011, DOI 10.1007/s11277-011-0473-6.
  • F. Wang, S. C. Liew, D. Guo, “Wireless MIMO Switching with Zero-forcing Relaying, ” Allerton 2011, Sep 2011. 
  • L. Lu, S. C. Liew, S. Zhang, “Optimal Decoding Algorithm for Asynchronous Physical-Layer Network Coding,” IEEE ICC, June 2011. 
  • S. Zhang, S. C. Liew, Q. Zhou, L. Lu, H. Wang, “Non-memoryless Analog Network Coding in Two-Way Relay Channel,” IEEE ICC, June 2011. 

B) Wireless Networks with focus on CSMA Wireless Networks

  • I. W-H Ho, P. P. Lam, P. H. J. Chong, S. C. Liew, "Harnessing the High Bandwidth of Multi-radio Multi-channel 802.11n Mesh Networks," accepted by IEEE Trans. on Mobile Computing.
  • M. Chen, S. C. Liew, Z. Shao, C. Kai, "Markov Approximation for Combinatorial Network Optimization," accepted by IEEE Trans. Info. Theory.
  • L. Fu, S. C. Liew, J. Huang, "Effective Carrier Sensing in CSMA Networks under Cumulative Interference, " accepted by IEEE Trans. on Mobile Computing.
  • C. H. Kai, S. C. Liew, "Applications of Belief Propagation in CSMA Networks," IEEE/ACM Trans. on Networking, vol. 20, no. 4, pp. 1276-1289, Aug. 2012.
  • K. K. Lam, C. K. Chau, M. Chen, S. C. Liew, "Mixing Time and Temporal Starvation of General CSMA Networks with Multiple Frequency Agility ," IEEE ISIT '12, July 2012.
  • C-K Chau, J. Zhang, M. Chen, S. C. Liew, "Interference-safe CSMA Networks by Local Aggregate Interference Power Measurement," WiOpt 2012, May 2012.
  • Fu, H. Kim, J. Huang, S. C. Liew, M. Chiang, “Energy Conservation and Interference Mitigation: From Decoupling Property to Win-Win Strategy,” IEEE Trans. on Wireless Communications, vol. 10, no. 11, pp. 3943-3955, Nov 2011. 
  • I. W-H Ho, P. P. Lam, P H. J. Chong, S. C. Liew, "Real-life Experiments of Multi-radio Multi-channel Wireless Mesh Networks: 802.11n is not any better than 802.11a! " 8th Int. Conf. Information, Communication, and Signal Processing, Oct 2011.
  • H. Dai, S. C. Liew, L. Fu, "Link Scheduling in Multi-Transmit-Receive Wireless Networks," IEEE LCN, Oct 2011. 
  • C. Kai, S. C. Liew, "Temporal Starvation in CSMA Wireless Networks," IEEE ICC, June 2011. 
  • C. K. Chau, M. Chen, S. C. Liew, "Capacity of Large-scale CSMA Wireless Networks", ACM/IEEE Trans. Networking.
  • W. Chen, Y. Wang, M. Chen, S. C. Liew, "On the Performance of TCP over Throughput-optimal CSMA," ACM/IEEE IWQoS, June 2011.