Browsing by Subject "Wireless Networks"
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Item Efficient and Reliable Cross-technology Communication in Heterogeneous IoT Networks(2022-01-01) Wang, Wei; Zhu, Ting; Computer Science and Electrical Engineering; Engineering, ElectricalWith the exponential growth of the Internet-of-Things (IoT), a huge number of smart devices are crowded in the same Industrial Scientific Medical (ISM) band, including WiFi, Bluetooth, and ZigBee. The coexistence of IoT devices brings new opportunities for these devices to collaborate with each other, which leads to the emergence of Cross-technology Communication (CTC) techniques. However, existing work mainly focuses on improving the physical layer performance. In this dissertations, we explore how to leverage the latest CTC techniques for network layer performance improvements.Specifically, we mainly focus on answering the following question: i) how to leverage the unique feature (i.e., concurrent transmission between WiFi and ZigBee) of packet-level CTC to reduce the network delay; ii) how to utilize physical-level CTC for concurrently routing and flooding; and iii) how to leverage the CTC techniques for simultaneous data dissemination among WiFi and ZigBee devices. We implement our physical layer and network layer design by using off-the-shelf devices and extensively evaluate our system in different settings and scenarios. The evaluation results show that i) our packet-level CTC network protocol - ECT can significantly reduce the packet delivery delay (i.e., 29 times lower than the state-of-the-art solution); ii) our physical-level CTC communication scheme - CRF can improve the throughput of WiFi network by 1.12 times than the state-of-the-art routing protocols and significantly reduce the flooding delay in ZigBee network (i.e., 31 times faster than the state-of-the-art flooding protocol); and iii) our network protocol - Waves can provide reliable data dissemination and is 33.5 times faster than the state- of-the- art protocol in terms of dissemination time.Item Enabling Seamless Communication and RF Sensing among IoT Devices(2020-01-20) Chi, Zicheng; Zhu, Ting; Computer Science and Electrical Engineering; Engineering, ComputerThe exponentially increasing number of internet of things (IoT) devices and the data generated by these devices introduce the spectrum crisis at the already crowded ISM 2.4 GHz band. On one hand, there is no efficient solution to coordinate a large amount of heterogeneous IoT devices that have different communication technologies (e.g., WiFi, ZigBee, and Bluetooth). On the other hand, the crowded wireless traffic potentially introduces opportunities for conducting radio frequency (RF) sensing using pervasively available signals generated by heterogeneous IoT devices. To address these issues, we propose a multi-layer heterogeneous networking system to enable seamless communication and RF sensing among IoT devices. This networking system i) connects IoT devices with different communication protocols by utilizing their unique physical-layer or link-layer features on overlapped frequency band (e.g., ISM 2.4 GHz band); and ii) utilizes the heterogeneous wireless traffic for non-intrusive human activity recognition and monitoring, which provides data support for the emerging smart health and smart home applications. This system aims to significantly increase the throughput and spectrum utilization for wireless communication while keeping the low cost (in terms of energy and deployment) of IoT networks. Furthermore, the system provides sensing capability by using existing RF signals in the air.