Research

With the generous funding support from NSERC, CFI, BCKDF, and industrial partners, we carry out leading-edge research in the general area of wireless and mobile communications. Here is a list of our ongoing research projects and selected publications.

Ultra-Reliably Low-Latency Communications

The emerging mission-critical Internet of Things (IoT) brings about a new technical challenge to wireless communications. Applications such as factory automation, self-driving vehicles, and smart cities demand high availability, ultra-high reliability, and very low latency. However, existing wireless systems cannot effectively meet the ultra-reliable and low-latency communication (URLLC) requirements. In this project, we address this challenge following a novel data-oriented approach.
  • H.-C. Yang, S. Choi, and M.-S. Alouini, “Ultra-reliable low-latency transmission of small data over fading channels: A data-oriented analysis,” IEEE Communication Letters, Vol., no., pp., 2020.
  • H.-C. Yang and M.-S. Alouini, “Data-oriented transmission in future wireless systems: towards trustworthy support of advanced Internet of Things,” IEEE Vehicular Technology Magazine, Vol. 14, no. 3, pp. 78{83, September 2019.

Wireless Energy Transfer/Harvesting

Wireless terminals are usually powered by batteries with limited capacity. Powering these terminals through wireless energy transfer/harvesting becomes an attractive solutions, especially for massive machine-type nodes for which charging/replacing batteries becomes impractical. In this project, we design and analyze energy transfer/harvesting systems in practical operating environments.
  • M.-C. Ju, and H.-C. Yang, “Optimum SWIPT relaying in bidirectional nonregenerative relay networks”, IET Communications, Vol. 13, no. 6, pp. 679-686, March 2019.
  • X. Di, K. Xiong, P. Fan, H.-C. Yang, and K. B. Lataief, “Optimal resource allocation in wireless powered communication networks with user cooperation”, IEEE Transactions on Wireless Communications, Vol. 16, no. 12, pp. 7936-7949, December 2017.
  • T. Wu and H.-C. Yang, “On the performance of overlaid wireless sensor transmission with RF energy harvesting”, IEEE Journal of Selected Areas in Communications (JSAC), Vol. 33, no. 8, pp. 1693-1705, August 2015.

Hybrid FSO/RF Transmission

Free space optical (FSO) communications and millimeter wave (mmWave) radio frequency (RF) communications have emerged as effective solutions for high-data-rate wireless transmission over short distances. They exhibit complementary characteristics to atmospheric and weather effects. In this project, we design and analyze several practical hybrid FSO/RF transmission schemes. Both point-to-point and point-to-multi-point scenarios are investigated.
  • T. Rakia, F. Gebali, H.-C. Yang, and M.-S. Alouini, “Cross layer analysis of point-to-multi-point hybrid FSO/RF networks”, Journal of Optical Communications and Network, Vol. 9, no. 3, pp. 234-243, March 2017.
  • T. Rakia, H.-C. Yang, F. Gebali, and M.-S. Alouini, “Optimal design of dual-hop VLC/RF communication system with energy harvesting”, IEEE Communication Letters, Vol. 20, no. 10, pp. 1979 — 1982, October 2016.
  • M. Usman, H.-C. Yang, and M.-S. Alouini, “Practical switching based hybrid FSO/RF transmission and its performance analysis”, IEEE Photonics Journal, Vol. 6, no. 5, 2902713, October 2014.

Physical Layer Security

Physical layer security (PLS) is a novel approach for enhance wireless transmission security by leveraging fading channel characteristics. In this project, we analyze the security performance of various transmission schemes under practical operating environment and characterize the effect of several security performance enhancement solutions.
  • T. Bao, H.-C. Yang, and M. O. Hasna, “On physical layer secrecy performance of multiple antenna transmission with partial legitimate user CSI,” IET Communications, Vol. 13, no. 5, pp. 2285-2295, September 2019.
  • Liao, Z., L. Yang, J. Chen, H.-C. Yang, and M.-S. Alouini, “Physical layer security for dual-hop VLC/RF communication systems,” ,” IEEE Communications Letters, Vol. 22, no. 12, pp. 2603-2606, December 2018.

Cognitive Radio Systems

The spectrum resource suitable for wireless communications becomes increasingly scarce. Measurements have shown that certain licensed RF spectra are seriously underutilized. Cognitive radio can effectively improve the spectrum utilization. In this project, we study the essential design and analysis problem of cognitive radio transmission.
  • W.-J. Wang and H.-C. Yang, “Effect of imperfect spectrum sensing on slotted secondary transmission: energy efficiency and queuing performance”, IEEE Transactions on Cognitive Communications and Networking, Vol. 4, no. 4, pp. 764-772, December 2018.
  • M. Hanif, H.-C. Yang, and M.-S. Alouini, “Transmit antenna selection for power adaptive underlay cognitive radio with instantaneous interference constraint”, IEEE Transactions on Communications, Vol. 65, no. 6, pp. 2357–2367, June 2017.
  • M. Usman, H.-C. Yang, and M.-S. Alouini, “Extended delivery time analysis for cognitive packet transmission with application to secondary queuing analysis”, IEEE Transactions on Wireless Communications, Vol. 14, no. 10, pp. 5300-5312, October 2015.

Massive MIMO Transmission

Massive MIMO technology can achieve very high spectral and power efficiencies. Meanwhile, implementing a large number entails very high hardware and computational complexity. In this project, we develop practical low-complexity solutions for massive MIMO systems and characterize their performance versus complexity tradeoff.
  • M. Hanif, H.-C. Yang, G. Boudreau, E. Sich, and H. Seyedmehdi, “Antenna subset selection for massive MIMO systems: a trance-based sequential approach for sum rate maximization”, Journal of Communications and Networks, Vol. 20, no. 2, pp. 144-155, April 2018.
  • M. Hanif, H.-C. Yang, G. Boudreau, E. Sich, and H. Seyedmehdi, “Low-complexity hybrid precoding for multi-user massive MIMO systems: A hybrid EGT/ZF approach”, IET Communications, Vol. 11, no. 5, pp. 765-771, April 2017.