Wi-Fi sensing: applications and challenges Khalili, Abdullah; Soliman, Abdel-Hamid; Asaduzzaman, Md ...
Journal of engineering (Stevenage, England),
March 2020, Volume:
2020, Issue:
3
Journal Article
Peer reviewed
Open access
Wi-Fi technology has strong potentials in indoor and outdoor sensing applications; it has several important features which makes it an appealing option compared to other sensing technologies. This ...study presents a survey on different applications of Wi-Fi-based sensing systems such as elderly people monitoring, activity classification, gesture recognition, people counting, through the wall sensing, behind the corner sensing, and many other applications. The challenges and interesting future directions are also highlighted.
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A deep neural network (DNN)-based Wi-Fi/pedestrian dead reckoning (PDR) indoor positioning system using an adaptive robust factor-graph model is proposed in this study for the indoor positioning of ...smartphones. In Wi-Fi positioning, the authors use a DNN to extract robust features from fluctuant Wi-Fi signals in the off-line phase, and obtain more accurate positioning results by computing posterior probabilities in online positioning. Acceleration, gyroscope, and magnetometer data are used to calculate attitude angle, step frequency, and step length, respectively. Received Wi-Fi signal strength is susceptible in complex indoor environments, and PDR errors accumulate over time. A factor-graph model with adaptive robust adjustment is proposed to fuse the positioning results of Wi-Fi and PDR, and it overcomes such shortcomings as slow update frequency and gross errors of Wi-Fi and PDR errors accumulated over time, respectively. When the absence of PDR occurs, hidden Markov model is introduced to smooth multiple DNN-based Wi-Fi positioning estimates at the unknown point to obtain the optimal solution. Experimental results show that the proposed system is more robust and has better accuracy under different motion gestures (held-in-hand, dangling, and calling).
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Data communication standards are comprised of two components: The "protocol" and "signal/data/port specifications for the devices involved." The protocol describes the format of the message and the ...meaning of each part of the message. To connect any device to the bus, an external device must be used as an interface which will put the message in a form which fulfills all the electrical specifications of the port. These specifications are called the "Standard." The most famous such serial communication standard is the RS-232. In IT technology, communication can be serial or parallel. Serial communication is used for transmitting data over long distances. It is much cheaper to run the single core cable needed for serial communication over a long distance than the multicore cables that would be needed for parallel communication. It is the same in wireless communication: Serial communication needs one channel while parallel needs multichannel. Serial Communication can also be classified in many other ways, for example, synchronous and asynchronous; it can also be classified as simplex, duplex and half duplex. Because of the wide spread of serial communication from home automation to sensor and controller networks, there is a need for a very large number of serial communication standards and protocols. These have been developed over recent decades and range from the simple to the highly complicated. This large number of protocols was necessary to guarantee the optimum performance for the targeted applications. It is important for communication engineers to have enough knowledge to match the right protocol and standard with the right application. The main aim of this book is to provide the reader with that knowledge.The book also provides the reader with detailed information about: * Serial Communication * Universal Asynchronous Receiver Transmitter (UART) * Universal Synchronous/Asynchronous Receiver Transmitter (USART * Serial Peripheral Interface (SPI) * eSPI * Universal Serial Bus (USB) * Wi-Fi * WiMax * Insteon The details of each technology including specification, operation, security related matters, and many other topics are covered. The book allocates three chapters to the main communication standards. These chapters cover everything related to the most famous standard RS-232 and all its variants. Other protocols such as: I2C, CAN, ZigBee, Z-Wave, Bluetooth, and others, are the subject of the authors separate book Microcontroller and Smart Home Networks.
This study presents a Wi-Fi-based passive indoor positioning system (IPS) that does not require active collaboration from the user or additional interfaces on the device-under-test (DUT). To maximise ...the accuracy of the IPS, the optimal deployment of Wi-Fi Sniffers in the area of interest is crucial. A modified Genetic Algorithm (GA) with an entropy-enhanced objective function is proposed to optimize the deployment. These Wi-Fi Sniffers are used to scan and collect the DUT's Wi-Fi received signal strength indicators (RSSIs) as Wi-Fi fingerprints, which are then mapped to reference points (RPs) in the physical world. The positioning algorithm utilises a weighted k-nearest neighbourhood (WKNN) method. Automated data collection of RSSI on each RP is achieved using a surveying robot for the Wi-Fi 2.4 GHz and 5 GHz bands. The preliminary results show that using only 20 Wi-Fi Sniffers as features for model training, the offline positioning accuracy is 2.2 m in terms of root mean squared error (RMSE). A proof-of-concept real-time online passive IPS is implemented to show that it is possible to detect the online presence of DUTs and obtain their RSSIs as online fingerprints to estimate their position.
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Standard wireless systems are rapidly evolving to support the strict requirements of industrial applications. In this research line, wireless time-sensitive networking (TSN) is gaining momentum, ...thanks to the interest of wired TSN among the industries. A critical aspect of the wireless TSN research is the integration of wired and wireless TSN to create large-scale hybrid TSN networks. This integration is currently being discussed for 5G, whereas the integration between wired TSN and IEEE 802.11 is a step behind. To address this gap in the state of the art, this article discusses the integration challenges of wired TSN and wireless local area network technologies and proposes a hybrid TSN device architecture. Based on the architecture, we have developed a hybrid TSN network proof-of-concept. The proof-of-concept demonstrates that the hybrid TSN architecture can maintain the essential TSN services, including providing guaranteed latency in the 100-microsecond level.
Resource Slicing in Virtual Wireless Networks: A Survey Richart, Matias; Baliosian, Javier; Serrat, Joan ...
IEEE eTransactions on network and service management,
09/2016, Volume:
13, Issue:
3
Journal Article, Publication
Peer reviewed
Open access
New architectural and design approaches for radio access networks have appeared with the introduction of network virtualization in the wireless domain. One of these approaches splits the wireless ...network infrastructure into isolated virtual slices under their own management, requirements, and characteristics. Despite the advances in wireless virtualization, there are still many open issues regarding the resource allocation and isolation of wireless slices. Because of the dynamics and shared nature of the wireless medium, guaranteeing that the traffic on one slice will not affect the traffic on the others has proven to be difficult. In this paper, we focus on the detailed definition of the problem, discussing its challenges. We also provide a review of existing works that deal with the problem, analyzing how new trends such as software defined networking and network function virtualization can assist in the slicing. We will finally describe some research challenges on this topic.
Estimating the number of people present in a given venue in real-time is extremely useful from a security, management, and resource optimization perspective. This article presents the architecture of ...a system based on the use of Wi-Fi sensor devices that allows estimating, almost in real-time, the number of people attending an event that is taking place in a venue. The estimate is based on the analysis of the “probe request” messages periodically transmitted by smartphones to determine the existence of Wi-Fi access points in the vicinity. The method considers the MAC address randomization mechanisms introduced in recent years in smartphones, which prevents the estimation of the number of devices by simply counting different MAC addresses. To solve this difficulty, our Wi-Fi sensors analyze other fields present in the header of the IEEE 802.11 frames, the information elements, to extract a unique fingerprint from each smartphone. The designed system was tested in a set of real scenarios, obtaining an estimate of attendance at different public events with an accuracy close to 95%.
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A Wi-Fi scatter communication method based on microcontroller unit (MCU) is proposed, and an ultra-low power micro Wi-Fi scatter communication device μWi-Fi is designed and implemented. First, ...according to the characteristics of the microcontroller, the software virtual modulation method and the serial communication port direct memory access (DMA) transmission method is proposed to realise Wi-Fi scattering communication. Then the MCU + exclusive OR (XOR) baseband architecture is proposed to further reduce the main frequency of the microcontroller and the system power consumption. The communication test and power consumption measurement results show that μWi-Fi can generate signals conforming to the IEEE802.11b standard, which can be received and forwarded by universal Wi-Fi routers. Its effective communication distance reaches 15 m, its communication peak current reaches 720 μA, and its standby current reaches 390 nA. Compared with traditional internet of things (IOTs) Wi-Fi devices, μWi-Fi can not only reduce the power consumption of Wi-Fi communication by 2–3 orders but also has a simple composition and low cost, which is very helpful for the rapid development of Wi-Fi IoT products.
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Wi-Fi 6 Application in Iot Environment Péter János, Varga; Illési, Zsolt
Interdisciplinary Description of Complex Systems,
6/2022, Volume:
20, Issue:
3
Journal Article, Paper
Peer reviewed
Open access
When thinking of wireless communication solutions for IoT devices, the 5G networking technology is the first thing that comes to mind. Besides this, one cannot overlook the fact that a new wireless ...communication solution is also available, built on the 802.11ax standard. Until now, wireless networking solutions allowed to manage the simultaneous connections of 250 devices via a single router. Meanwhile, the new technology is designed to support 1024 concurrent connections with one router. This enables the management of a large number of Internet of Things devices in smart homes.
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