Kai Niu
Portrait
Research Fellow
Logo Nanyang Technological University

I am a Research Fellow in the College of Computing and Data Science at Nanyang Technological University. I received my B.E. and M.E. degrees from the School of Electronic and Information Engineering at Xi'an Jiaotong University, and my Ph.D. degree from the School of Electronics Engineering and Computer Science at Peking University. My research interests broadly span wireless sensing, mobile computing, and autonomous systems.

Google Scholar
Education
  • Peking University
    Peking University
    Ph.D. in Computer Software and Theory
    Sep. 2016 - Jul. 2021
  • Xi’an Jiaotong University
    Xi’an Jiaotong University
    M.E. in Computer Technology
    Sep. 2013 - Jul. 2016
  • Xi’an Jiaotong University
    Xi’an Jiaotong University
    B.E. in Computer Science and Technology
    Sep. 2009 - Jul. 2013
Experience
  • Xiaomi Inc.
    Xiaomi Inc.
    Senior Algorithm Engineer
    Sep. 2021 - Nov. 2025
Honors & Awards
  • Excellent Doctoral Dissertation Award, ACM SIGMOBILE China
    2022
  • National Scholarship
    2014
  • National Encouragement Scholarship
    2010&2012
News
2025
[Dec. 2025] Joined the College of Computing and Data Science (CCDS) at Nanyang Technological University as a Research Fellow.
Dec 01
Selected Publications (view all )
WiCaliper: Simultaneous Material and 3D Size Sensing for Everyday Objects Using WiFi

Zhiyun Yao, Kai Niu, Xuanzhi Wang, Rong Zheng, Junzhe Wang, Duo Zhang, Daqing Zhang

IEEE Journal on Selected Areas in Communications 2025 JSAC

[Paper]

WiCaliper: Simultaneous Material and 3D Size Sensing for Everyday Objects Using WiFi

Zhiyun Yao, Kai Niu, Xuanzhi Wang, Rong Zheng, Junzhe Wang, Duo Zhang, Daqing Zhang

IEEE Journal on Selected Areas in Communications 2025 JSAC

[Paper]

Wi2DMeasure: WiFi-based 2D Object Size Measurement

Xuanzhi Wang, Junzhe Wang, Kai Niu, Jie Xiong, Fusang Zhang, Enze Yi, Anlan Yu, Zhiyun Yao, Daqing Zhang

Proceedings of the 22nd ACM Conference on Embedded Networked Sensor Systems 2024 SenSys'24

[Paper]

Wi2DMeasure: WiFi-based 2D Object Size Measurement

Xuanzhi Wang, Junzhe Wang, Kai Niu, Jie Xiong, Fusang Zhang, Enze Yi, Anlan Yu, Zhiyun Yao, Daqing Zhang

Proceedings of the 22nd ACM Conference on Embedded Networked Sensor Systems 2024 SenSys'24

[Paper]

WiProfile: Unlocking Diffraction Effects for Sub-Centimeter Target Profiling Using Commodity WiFi Devices

Zhiyun Yao, Xuanzhi Wang, Kai Niu, Rong Zheng, Junzhe Wang, Daqing Zhang

Proceedings of the 30th Annual International Conference on Mobile Computing and Networking 2024 MobiCom'24

[Paper]

WiProfile: Unlocking Diffraction Effects for Sub-Centimeter Target Profiling Using Commodity WiFi Devices

Zhiyun Yao, Xuanzhi Wang, Kai Niu, Rong Zheng, Junzhe Wang, Daqing Zhang

Proceedings of the 30th Annual International Conference on Mobile Computing and Networking 2024 MobiCom'24

[Paper]

BFMSense: WiFi Sensing Using Beamforming Feedback Matrix

Enze Yi, Dan Wu, Jie Xiong, Fusang Zhang, Kai Niu, Wenwei Li, Daqing Zhang

21st USENIX Symposium on Networked Systems Design and Implementation 2024 NSDI'24

[Paper] [Code]

BFMSense: WiFi Sensing Using Beamforming Feedback Matrix

Enze Yi, Dan Wu, Jie Xiong, Fusang Zhang, Kai Niu, Wenwei Li, Daqing Zhang

21st USENIX Symposium on Networked Systems Design and Implementation 2024 NSDI'24

[Paper] [Code]

Understanding the Diffraction Model in Static Multipath-Rich Environments for WiFi Sensing System Design

Xuanzhi Wang, Anlan Yu, Kai Niu, Weiyan Shi, Junzhe Wang, Zhiyun Yao, Rahul C Shah, Hong Lu, Daqing Zhang

IEEE Transactions on Mobile Computing 2024 TMC

[Paper]

Understanding the Diffraction Model in Static Multipath-Rich Environments for WiFi Sensing System Design

Xuanzhi Wang, Anlan Yu, Kai Niu, Weiyan Shi, Junzhe Wang, Zhiyun Yao, Rahul C Shah, Hong Lu, Daqing Zhang

IEEE Transactions on Mobile Computing 2024 TMC

[Paper]

Embracing Distributed Acoustic Sensing in Car Cabin for Children Presence Detection

Yuqi Su, Fusang Zhang, Kai Niu, Tianben Wang, Beihong Jin, Zhi Wang, Yalan Jiang, Daqing Zhang, Lili Qiu, Jie Xiong

Proceedings of the ACM on Interactive, Mobile, Wearable and Ubiquitous Technologies 2024 IMWUT/UbiComp'24

[Paper]

Embracing Distributed Acoustic Sensing in Car Cabin for Children Presence Detection

Yuqi Su, Fusang Zhang, Kai Niu, Tianben Wang, Beihong Jin, Zhi Wang, Yalan Jiang, Daqing Zhang, Lili Qiu, Jie Xiong

Proceedings of the ACM on Interactive, Mobile, Wearable and Ubiquitous Technologies 2024 IMWUT/UbiComp'24

[Paper]

Enabling WiFi Sensing on New-generation WiFi Cards

Enze Yi, Fusang Zhang, Jie Xiong, Kai Niu, Zhiyun Yao, Daqing Zhang

Proceedings of the ACM on Interactive, Mobile, Wearable and Ubiquitous Technologies 2024 IMWUT/UbiComp'24

[Paper]

Enabling WiFi Sensing on New-generation WiFi Cards

Enze Yi, Fusang Zhang, Jie Xiong, Kai Niu, Zhiyun Yao, Daqing Zhang

Proceedings of the ACM on Interactive, Mobile, Wearable and Ubiquitous Technologies 2024 IMWUT/UbiComp'24

[Paper]

WiMeasure: Millimeter-level Object Size Measurement with Commodity WiFi Devices

Xuanzhi Wang, Kai Niu, Anlan Yu, Jie Xiong, Zhiyun Yao, Junzhe Wang, Wenwei Li, Daqing Zhang

Proceedings of the ACM on Interactive, Mobile, Wearable and Ubiquitous Technologies 2023 IMWUT/UbiComp'23

[Paper]

WiMeasure: Millimeter-level Object Size Measurement with Commodity WiFi Devices

Xuanzhi Wang, Kai Niu, Anlan Yu, Jie Xiong, Zhiyun Yao, Junzhe Wang, Wenwei Li, Daqing Zhang

Proceedings of the ACM on Interactive, Mobile, Wearable and Ubiquitous Technologies 2023 IMWUT/UbiComp'23

[Paper]

Placement Matters: Understanding the Effects of Device Placement for WiFi Sensing

Xuanzhi Wang, Kai Niu, Jie Xiong, Bochong Qian, Zhiyun Yao, Tairong Lou, Daqing Zhang

Proceedings of the ACM on Interactive, Mobile, Wearable and Ubiquitous Technologies 2022 IMWUT/UbiComp'22

[Paper]

Placement Matters: Understanding the Effects of Device Placement for WiFi Sensing

Xuanzhi Wang, Kai Niu, Jie Xiong, Bochong Qian, Zhiyun Yao, Tairong Lou, Daqing Zhang

Proceedings of the ACM on Interactive, Mobile, Wearable and Ubiquitous Technologies 2022 IMWUT/UbiComp'22

[Paper]

Rethinking Doppler Effect for Accurate Velocity Estimation With Commodity WiFi Devices

Kai Niu, Xuanzhi Wang, Fusang Zhang, Rong Zheng, Zhiyun Yao, Daqing Zhang

IEEE Journal on Selected Areas in Communications 2022 JSAC

[Paper]

Rethinking Doppler Effect for Accurate Velocity Estimation With Commodity WiFi Devices

Kai Niu, Xuanzhi Wang, Fusang Zhang, Rong Zheng, Zhiyun Yao, Daqing Zhang

IEEE Journal on Selected Areas in Communications 2022 JSAC

[Paper]

Unlocking the Beamforming Potential of LoRa for Long-range Multi-target Respiration Sensing

Fusang Zhang, Zhaoxin Chang, Jie Xiong, Rong Zheng, Junqi Ma, Kai Niu, Beihong Jin, Daqing Zhang

Proceedings of the ACM on Interactive, Mobile, Wearable and Ubiquitous Technologies 2021 IMWUT/UbiComp'21

[Paper]

Unlocking the Beamforming Potential of LoRa for Long-range Multi-target Respiration Sensing

Fusang Zhang, Zhaoxin Chang, Jie Xiong, Rong Zheng, Junqi Ma, Kai Niu, Beihong Jin, Daqing Zhang

Proceedings of the ACM on Interactive, Mobile, Wearable and Ubiquitous Technologies 2021 IMWUT/UbiComp'21

[Paper]

WiFi-Sleep: Sleep Stage Monitoring Using Commodity Wi-Fi Devices

Bohan Yu, Yuxiang Wang, Kai Niu, Youwei Zeng, Tao Gu, Leye Wang, Cuntai Guan, Daqing Zhang

IEEE Internet of Things Journal 2021 IoTJ

[Paper]

WiFi-Sleep: Sleep Stage Monitoring Using Commodity Wi-Fi Devices

Bohan Yu, Yuxiang Wang, Kai Niu, Youwei Zeng, Tao Gu, Leye Wang, Cuntai Guan, Daqing Zhang

IEEE Internet of Things Journal 2021 IoTJ

[Paper]

Understanding WiFi Signal Frequency Features for Position-Independent Gesture Sensing

Kai Niu, Fusang Zhang, Xuanzhi Wang, Qin Lv, Haitong Luo, Daqing Zhang

IEEE Transactions on Mobile Computing 2021 TMC

[Paper]

Understanding WiFi Signal Frequency Features for Position-Independent Gesture Sensing

Kai Niu, Fusang Zhang, Xuanzhi Wang, Qin Lv, Haitong Luo, Daqing Zhang

IEEE Transactions on Mobile Computing 2021 TMC

[Paper]

Exploring LoRa for Long-range Through-wall Sensing

Fusang Zhang, Zhaoxin Chang, Kai Niu, Jie Xiong, Beihong Jin, Qin Lv, Daqing Zhang

Proceedings of the ACM on Interactive, Mobile, Wearable and Ubiquitous Technologies 2020 IMWUT/UbiComp'20 Distinguished Paper Award

[Paper]

Exploring LoRa for Long-range Through-wall Sensing

Fusang Zhang, Zhaoxin Chang, Kai Niu, Jie Xiong, Beihong Jin, Qin Lv, Daqing Zhang

Proceedings of the ACM on Interactive, Mobile, Wearable and Ubiquitous Technologies 2020 IMWUT/UbiComp'20 Distinguished Paper Award

[Paper]

Robust Dynamic Hand Gesture Interaction using LTE Terminals

Weiyan Chen, Kai Niu, Deng Zhao, Rong Zheng, Dan Wu, Wei Wang, Leye Wang, Daqing Zhang

19th ACM/IEEE International Conference on Information Processing in Sensor Networks 2020 IPSN'20

[Paper]

Robust Dynamic Hand Gesture Interaction using LTE Terminals

Weiyan Chen, Kai Niu, Deng Zhao, Rong Zheng, Dan Wu, Wei Wang, Leye Wang, Daqing Zhang

19th ACM/IEEE International Conference on Information Processing in Sensor Networks 2020 IPSN'20

[Paper]

WiMorse: A Contactless Morse Code Text Input System using Ambient WiFi Signals

Kai Niu, Fusang Zhang, Yuhang Jiang, Jie Xiong, Qin Lv, Youwei Zeng, Daqing Zhang

IEEE Internet of Things Journal 2019 IoTJ

[Paper]

WiMorse: A Contactless Morse Code Text Input System using Ambient WiFi Signals

Kai Niu, Fusang Zhang, Yuhang Jiang, Jie Xiong, Qin Lv, Youwei Zeng, Daqing Zhang

IEEE Internet of Things Journal 2019 IoTJ

[Paper]

Towards a Diffraction-based Sensing Approach on Human Activity Recognition

Fusang Zhang, Kai Niu, Jie Xiong, Beihong Jin, Tao Gu, Yuhang Jiang, Daqing Zhang

Proceedings of the ACM on Interactive, Mobile, Wearable and Ubiquitous Technologies 2019 IMWUT/UbiComp'20

[Paper]

Towards a Diffraction-based Sensing Approach on Human Activity Recognition

Fusang Zhang, Kai Niu, Jie Xiong, Beihong Jin, Tao Gu, Yuhang Jiang, Daqing Zhang

Proceedings of the ACM on Interactive, Mobile, Wearable and Ubiquitous Technologies 2019 IMWUT/UbiComp'20

[Paper]

Boosting fine-grained activity sensing by embracing wireless multipath effects

Kai Niu, Fusang Zhang, Jie Xiong, Xiang Li, Enze Yi, Daqing Zhang

Proceedings of the 14th International Conference on emerging Networking EXperiments and Technologies 2018 CoNEXT'18

[Paper] [Code]

Boosting fine-grained activity sensing by embracing wireless multipath effects

Kai Niu, Fusang Zhang, Jie Xiong, Xiang Li, Enze Yi, Daqing Zhang

Proceedings of the 14th International Conference on emerging Networking EXperiments and Technologies 2018 CoNEXT'18

[Paper] [Code]

From Fresnel Diffraction Model to Fine-grained Human Respiration Sensing with Commodity Wi-Fi Devices

Fusang Zhang, Daqing Zhang, Jie Xiong, Hao Wang, Kai Niu, Beihong Jin, Yuxiang Wang

Proceedings of the ACM on Interactive, Mobile, Wearable and Ubiquitous Technologies 2018 IMWUT/UbiComp'18

[Paper]

From Fresnel Diffraction Model to Fine-grained Human Respiration Sensing with Commodity Wi-Fi Devices

Fusang Zhang, Daqing Zhang, Jie Xiong, Hao Wang, Kai Niu, Beihong Jin, Yuxiang Wang

Proceedings of the ACM on Interactive, Mobile, Wearable and Ubiquitous Technologies 2018 IMWUT/UbiComp'18

[Paper]

All publications