Yue Xiao
University of Electronic Science and Technology of China, China
Yue Xiao (Member, IEEE) received the Ph.D. degree in communication and information systems from the University of Electronic Science and Technology of China (UESTC), Chengdu, China, in 2007. He is currently a Professor with the National Key Laboratory of Wireless Communications, UESTC. He has led more than 30 research projects in the field of 3G/4G/5G/6G wireless communication systems. He holds over 50 patents related to wireless system design and has authored more than 200 papers in international journals and conferences. His research interests include system design and signal processing for future wireless communication systems. He currently serves as an Area Editor of IEEE Communications Letters, Area Editor of IEEE Open Journal of the Communications Society, and Associate Editor of IEEE Transactions on Communications.
Hardware-efficient MIMO transmission is an important research direction for future wireless networks, including 6G Internet-of-Things applications, where reducing the number of radio-frequency (RF) chains can lower implementation cost and power consumption. This talk introduces phase-shifter direct modulation, which embeds additional information into RF signals through data-driven phase shifts. Unlike approaches based on antenna-index modulation or antenna repositioning, this mechanism enables multiple information streams to be transmitted through multiple antennas sharing a single RF chain. Building on phase-shifter-aided spatial multiplexing (PSSM), the talk presents a series of transceiver designs addressing low-complexity detection over flat and frequency-selective channels, antenna selection and connectivity optimization, and the impact of imperfect phase shifters. It also discusses flexible extensions incorporating superposition coded modulation, generalized spatial modulation, and joint modulation and precoding through antenna-domain amplitude–phase control. Finally, the underlying principle is extended to pinching-antenna systems, where waveguide-induced phase shifts provide an alternative mechanism for RF-chain-efficient spatial multiplexing. Overall, phase-shifter direct modulation offers a simple and hardware-efficient approach to MIMO design, with promising applications in future IoT networks and wireless systems with limited RF-chain resources.