Last decades stood witness to the remarkable achievement of the wireless technologies in terms of connecting the people all over the world. Recently, there are growing interests from both academia and industry in another direction – to provide ubiquitous connectivity among machines. Such a paradigm shift from human-type communications (HTC) toward machine-type communications (MTC) is mainly driven by the emergence of Internet of Things (IoT). To pave the way for IoT, in this talk we will focus on how to embed MTC’s unique features of massive connectivity, ultra-reliability, and low latency into the 5G networks.
First, we will study a massive IoT connectivity scenario in which a massive number of IoT devices can potentially connect to the network, but at any given time only a fraction of potential devices are active due to the sporadic device traffic. Based on the state evolution of the approximate message passing (AMP) algorithm, we analytically prove that the device activity detection error probability goes down to zero as the number of antennas at the base station goes to infinity. Therefore, massive multiple-input multiple-output (MIMO) ideally suits massive IoT connectivity. Second, we will study an industry automation scenario in which the controller has to send the commands to the actuators in a reliable and timely manner. Based on the observation that tasks in the factories are generally assigned to groups of actuators working in close proximity, we investigate a two-phase protocol, in which the controller sends the commands to the carefully selected group leaders in the first phase, which relay the commands to their group members via the device-to-device (D2D) communication techniques in the second phase. Such a scheme is shown to significantly improve the reliability of the low latency communications in the factories.
Dr. Liang Liu received the B.Eng. degree from the Tianjin University in 2010, and the Ph.D. degree from the National University of Singapore in 2014. He is currently an Assistant Professor in the Department of Electronic and Information Engineering at the Hong Kong Polytechnic University. Before that, he was a Research Fellow in the Department of Electrical and Computer Engineering at National University of Singapore from 2017 to 2018, and a Postdoctoral Fellow in the Department of Electrical and Computer Engineering at University of Toronto from 2015 to 2017. His research interests include the next generation cellular technologies and machine-type communications for Internet of Things.
Dr. Liang Liu is the recipient of the IEEE Signal Processing Society Young Author Best Paper Award, 2017, and the best student paper award for International Conference on Wireless Communications and Signal Processing (WCSP), 2011. He is recognized by Clarivate Analytics as a Highly Cited Researcher, 2018.