Supply chain management aims to achieve both efficiency and low cost. Backscatter technology provides a low-energy consumption approach for critical links in the supply chain, such as warehouse ...management and cargo identification. Traditional backscatter systems achieve tag data transmission through dedicated hardware or controlled transmission sources. An additional access point (AP) can be used to ensure that the original data are always known in tag data decoding. These requirements increase the deployment costs and are not suitable for large-scale applications. To address these challenges, we introduce CRCScatter, a backscatter system based on a cyclic redundancy check (CRC) reverse algorithm, with an uncontrolled source and a single-AP receiver. The CRCScatter decoder at the receiver uses the constraints within 802.11b WiFi packets to recover the original packet and decode tag data from the backscatter packet. Our Matlab simulation results show that CRCScatter is effective in the low signal-to-noise ratio (SNR) regime, and its average decoding time is independent of the length of tag data. By appending redundant bits in tag data, the decoding accuracy of CRCScatter can be improved. In summary, CRCScatter presents a backscatter communication mode based on ambient WiFi signals with fewer hardware requirements and low deployment costs. Furthermore, the decoding idea of calculating unknown data based on the packet constraints has the potential to expand to different types of excitation packages.
A flexible and compact tri-band antenna based on highly conductive graphene assembled film (GAF) is proposed. The antenna has a small size of <inline-formula> <tex-math notation="LaTeX">42\times ...30.5\times 1.025 </tex-math></inline-formula> mm3, including three complementary split-ring resonators (CSRR) to realize triple band-notched characteristics. The GAF antenna effectively offers three operating bands of 2.28-2.56 GHz, 3.28-3.85 GHz, and 5.06-7.30 GHz, satisfying the Wi-Fi 7 band at 2.45/5.2/5.8/6 GHz, WiMAX band at 3.5/5.5 GHz, and 5G sub-6 NR n78 band, with the peak realized gains of 1.66/1.97/3.58 dBi. The GAF antenna performance is relatively stable with regard to the operating band and radiation pattern under bending condition. To demonstrate the practical application, the GAF antenna is installed on a commercially available router for data rate experiments. The results indicate that this brief expands the RF applications of carbon-based materials, and endows Wi-Fi antennas with more operating frequency bands, more compact configuration, lighter weight, better mechanical stability, and conformal ability, which is superior for integration in Wi-Fi/WiMAX/5G communication and conformed on various devices.
Location-based services have become more and more important with the development of the Internet of Things (IoT) technology in recent years. Global Navigation Satellite System (GNSS) is widely used ...for positioning outdoors while it is still challenging to realize accurate and universal 3D indoor localization in complex indoor environments. Crowdsourcing-based positioning method is proposed aiming at autonomously constructing the navigation database based on the pedestrians' daily-life data. This paper proposes an autonomous 3D indoor localization algorithm using the combination of crowdsourced Wi-Fi fingerprinting and Micro-Electro-Mechanical System sensors (3D-CSWS). An enhanced complementary filter is applied to provide accurate attitude information by integrating multi-sensor data with the detection of external acceleration and quasi-static magnetic field. In addition, the gradient descent (GD) algorithm is proposed to optimize the forward pedestrian dead reckoning and the optimized trajectories are weighted fused to construct the final navigation database after quality evaluation. In the on-line phase, the adaptive particle filter is used to integrate the results of Wi-Fi fingerprinting and multiple sensors to provide accurate and concrete 3D indoor localization performance. The real-world experimental results demonstrate that the proposed 3D-CSWS is proved to achieve autonomous and precise 3D indoor localization performance among complex indoor environments.
The IEEE 802.11be (Wi-Fi 7) standard for WLANs, which is currently under development, will allow for a multiple throughput increase and lower latency in comparison with the previous IEEE 802.11ax ...(Wi-Fi 6) standard. One of the main novelties of IEEE 802.11be to achieve this is the native support for the multi-link feature, and this can be done using single or multiple radio interfaces. When using one radio interface, the device can quickly switch it from a busy channel to a free one and consequently reduce the channel access delay. However, transmission can only be performed in one channel. The usage of multiple radio interfaces allows for simultaneous data transmission on multiple channels, but the radio interfaces can interfere with each other, so the standard describes an operation mode for the mitigation of such interference. In this multiple channels operation mode, one performs either joint synchronized transmission or joint synchronized signal reception. The article describes algorithms for switching a single radio interface of a multi-link device, which allow to increase its throughput. It also compares the performance of multi-link devices with one and several radio interfaces.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Abstract
This paper presents the novel design and fabrication of a square shaped array antenna for transmission in the higher X band and Ku-band. The influence of the constituent square’s size factor ...over the signal quality with the squares positioned in various array configurations is recorded and reported using a discretized design approach. The design was fabricated and tested to meet the needed standards after being optimized using the antenna simulator software. A novel DC shorting approach has been devised and reported to improve antenna performance. Major antenna performance parameters are being observed and found in accord with the literature.
Internet speed tests assess end-to-end network performance by measuring throughput for 10’s of MB of TCP uploads and downloads. While such tests provide valuable insights into network health, they ...are of little use to network administrators since (1) the results are only available on the client that performs the test and (2) the tests can saturate the network, increasing load and worsening performance for other clients. In this paper, we present virtual speed test, a measurement based framework that enables an AP to estimate speed test results for any of its associated clients without any special-purpose probing, with zero end-user co-operation and purely based on passively observable parameters at the AP. We implemented virtual speed test using commodity hardware, deployed it in office and residential environments, and conducted measurements spanning multiple days having different network loads and channel conditions. Overall, virtual speed test has mean estimation error less than 6% compared to ground truth speed tests, yet with zero overhead, and outcomes available at the AP.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The use of automation technology in the field of mixing liquids assists to reduce errors in this process which improved the quality of products. Liquid mixing machines often require a number of ...workers in order to operate the machines which increases the risk to them. This paper proposes wireless design for mixing three different liquids using raspberry pi technology. The design aims to provide lower risk rates, lower cost and high accuracy. The mechanism of mixing the three liquids and filling the tanks is done automatically using raspberry pi and ultrasonic sensors. Users must have to login with the correct IP address and password in order to access the application using a Wi-Fi connection. The system consists of three sub tanks filling the main tank in specifec ratio for each one. The programming of this implemention is accompleshed using python language. The experimental results have proven that the system works successfully and it can be applied in a real environment.
This paper deals with the design of a communication layer between the components of a smart factory or other system. Each member of the Internet of Things has its own control system based on ...microprocessor. All IoT components have to work with programmable analog and digital inputs and outputs and other buses and have to communicate, exchange information and cooperate with each other. The control units are equipped with wifi modules and it is necessary to design program structures for communication. Control units must be able to solve combination and sequential problems based on automata. Closed graphs of control unit automats are interconnected by means of wifi messages. The structure of these messages is designed, which must contain component addresses and transmitted information of various types, character, string, numeric variables and arrays. A general library of functions containing typical elements of automata was designed. This general library has been implemented on two specific production systems and home automation tasks. Keywords: Smart factory; Arduino; Industry 4.0; Wifi communication; automation.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The respiratory rate monitoring plays an important role in different fields of use, ranging from healthcare to daily work and life. Recently, Wi-Fi-based technology using commercial devices has ...attracted much attention due to its noninvasive and low cost. Most of the existing Wi-Fi-based respiratory monitoring systems are based on the Fresnel zone (FZ) model. But when the subject breathes with the body oriented parallel to the tangential direction of the FZ, the signal detection becomes difficult, and this orientation dependency hinders the widespread application of Wi-Fi-based respiratory monitoring. To solve this problem, this article proposes and experimentally validates a novel homofocal hyperbola (HH) model for indoor Wi-Fi sensing. By connecting two transmitting antennas to the same signal source and deploying the antenna position appropriately, the sensing effect makes up for the disadvantage of low perception sensitivity when moving along the tangent direction of the FZ. Then, a human respiratory monitoring system is developed based on the HH model. Specifically, the proposed dominant frequency-to-amplitude ratio (DFAR) method is used for subcarrier selection and respiratory signal detection, and the proposed zero-peak (ZP) detection method is used to calculate the respiratory frequency. Compared with the FZ model, the azimuth range of the HH model that can monitor human respiration is nearly doubled with an error of less than 0.7 bpm.
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