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Various wireless local area network technologies are developed for Internet of Things of which Long-Range Wide Area Network is preferred for low power long range communication. In the LoRa network, multiple LoRa nodes can simultaneously communicate with a LoRa gateway which causes the interference problem. This article presents an approach for estimating the association time duration between each LoRa node and the LoRa gateways for transmitting the data of end users to the LoRa gateways with high packet delivery ratio. The approach uses a Beta distribution based reputation model for estimating the association time duration between each LoRa node and LoRa gateways and Bayesian Game strategy which accommodates unknown private information of the LoRa nodes. The approach is validated by simulating the LoRa network using network simulator-3. We also demonstrate an on-campus traffic monitoring system to detect the reckless driving action and estimate the vehicle speed using sensors embedded nodes deployed along both sides of the road.

With the establishment of the economic New Area, preliminary results have been achieved in the construction of the business environment, and some experience has been accumulated, but there are still many problems. The most important of these is the issue of business safety. The security system in commercial areas generally adopts manual shifts. This management method is increasingly unsuitable for urban development. Therefore, the unattended electronic fence system emerges from time to time, but its security has become an urgent problem to be solved. This article designs the electronic fence system project based on intelligent video surveillance and wireless local area network technology. This article designs the electronic fence system based on intelligent video surveillance and wireless local area network technology. First, design a pulsebased electronic fence system. Under the control of the FPGA, by sending pulses to the electronic fence, the frontend detection fence subsystem can detect the pulse signals, and implement the pulse signals to the FPGA through wireless local area network technology. After feature extraction and pulse signal recognition, determine whether an abnormal situation has occurred. Secondly, an intelligent video surveillance system based on wireless local area network is designed to record the surrounding video information 24 h, and use related target detection technology to locate and record abnormal conditions. The experimental results show that the design system can well judge the occurrence of abnormal conditions and record the abnormal conditions in real time, which can ensure the safety.

In this letter, a low-profile and wideband substrate integrated waveguide (SIW) antenna is proposed and validated for full-duplex systems. The proposed antenna operates at 4.9 GHz and 5.8 GHz Wireless Local Area Network (WLAN) bands. Each resonator of the antenna consists of a modified half-mode SIW (HMSIW) cavity, and excited by a 50 $\Omega$ coaxial probe. The wideband response is achieved by coupling the fundamental TE\textsubscript{10} mode with the perturbed TE\textsubscript{10} mode of the HMSIW cavity. The compactness of the proposed design is obtained using two rectangular slots near the closed-ends of the cavities. By properly optimizing the overall geometry, the proposed design exhibits a 10-dB fractional bandwidth of 8.2 \% (4.78--5.2 GHz) and 7.7 \% (5.70--6.16 GHz) in the lower (4.9 GHz) and upper frequency band (5.8 GHz), respectively. The bandwidths of both frequency bands can be controlled by adjusting the coupling between modes. A high isolation ( $>$ 30 dB) between the two ports is observed due to series of metallic vias between them. This antenna has compact size (0.34 $\lambda_{g}^{2}$ ) with high gains of 5.24 dBi and 5.37 dBi at 4.9 GHz and 5.8 GHz, respectively.

The shared nature of the wireless medium induces contention between data transport and backward signaling, such as acknowledgment. The current way of TCP acknowledgment induces control overhead which is counter-productive for TCP performance especially in wireless local area network (WLAN) scenarios. In this paper, we present a new acknowledgment called TACK (``Tame ACK''), as well as its TCP implementation TCP-TACK. TACK seeks to minimize ACK frequency, which is exactly what is required by transport. TCP-TACK works on top of commodity WLAN, delivering high wireless transport goodput with minimal control overhead in the form of ACKs, without any hardware modification. Evaluation results show that TCP-TACK achieves significant advantages over legacy TCP in WLAN scenarios due to less contention between data packets and ACKs. Specifically, TCP-TACK reduces over 90% of ACKs and also obtains an improvement of up to 28% on goodput. A TACK-based protocol is a good replacement of the legacy TCP to compensate for scenarios where the acknowledgment overhead is non-negligible.

The indoor positioning problem is not the unavailability of indoor positioning technology, but the difficulty of arriving at an acceptable compromise of technical constraints like cost, performance, ease of use, and availability of technologies. In a developing country such as the Philippines, these constraints have more weight and can restrict the advancement of indoor positioning.This study investigates the use of Bluetooth Low Energy (BLE) and Wireless Local Area Network (WLAN) in Euclidean distance computation, which implies prospect use for indoor positioning through trilateration. It is a proof-of-concept study that BLE and WLAN, using readily-available services such as Nearby Application Programming Interface (API) and beacon simulators, can be used for indoor positioning. This method offers a better trade-off between cost, power, and accuracy.Nearby API and a regular beacon simulator application were used as beacons. The received signal strength interface (RSSI) was measured and used to calculate the Euclidean distance. From each beacon were calculated four different distances, Nearby yielding a maximum error of 26% and a minimum of 4%. The beacon simulator was less accurate and had a maximum error of 60.5% and a minimum of 4%. This shows that it is possible to calculate Euclidean distance using WLAN and BLE, and that Nearby API, which uses both, was more accurate than the beacon simulator, which used only BLE.

A compact dual-band ram horn-like folded antenna is presented in this work. The antenna is based on a ram horn-like folded strip, asymmetric microstrip feeding (AMF) technique, partial ground, and protruding stub at the ground plane. The dimension of the proposed antenna is 0.11 λ g × 0.17 λ g at 2.3 GHz (10 × 15 mm2). The proposed shape is achieved through the combination of two circular arcs with different radii. The antenna operates at 2.3 GHz and 5.8 GHz with a measured bandwidth of 100 MHz and 820 MHz, a gain of 0.62 dBi and 2.2 dBi, and radiation efficiency of 93.67% and 99.87%, respectively. The prototype of the proposed antenna is fabricated and measured. The measured result shows a good agreement with the simulated result. The parametric study of the proposed antenna is performed and results are presented. Besides, a comparative study between the antennas proposed in this work and the state of the art is performed and presented. The proposed antenna is comparatively small in size than all the recently reported works in the literature while ensuring good radiation characteristics. Therefore, the antenna proposed in this work is a better candidate for future portable sub-6GHz fifth-generation (5G), Advance Long-term Evolution (LTE-A), Worldwide Interoperability for Microwave Access (WiMAX), and Wireless Local Area Network (WLAN) applications.

Vehicular Ad hoc Networks (VANETs) allow for vehicle-to-vehicle and vehicle-to-infrastructure communications using wireless local area network technologies. The distinctive features of their candidate applications (e.g., collision warning and local traffic information for drivers), resources (e.g., computational sources), and their ability to collect various data from their environment (e.g., vehicular traffic flow patterns) make VANETs a rich resource for information and resources. In this paper, we propose a new methodology to use VANETs to optimize signal control at traffic intersections as well as to create Vehicular Cloud (VC) computing environments. We theoretically analyze the traffic flow patterns in a given road intersection by using the diffusion approximation model. We calculate the probability of clearing the intersection and demonstrate the effect of the traffic patterns on the optimal choice of the traffic signal control parameters. Then, we employ our theoretical analysis to propose a potential solution to construct VANET-assisted VCs. Experimental results verify the correctness of our analysis.

Device-to-device (D2D) communication technology is widely acknowledged as an emerging candidate to alleviate the wireless traffic explosion problem for the next generation wireless local area network (WLAN) IEEE 802.11ax. In this paper, we integrate D2D communication into IEEE 802.11ax for maximizing the spectrum efficiency. Due to the spectrum scarcity, the number of available resource units (RUs) is typically less than D2D pairs and stations (STAs), which makes the management of spectrum resources more complex. To tackle this issue, we design an efficient resource management algorithm for uplink random access and resource allocation in D2D-enabled 802.11ax, which provides more channel access and resource reuse opportunities for STAs and D2D pairs. Specifically, we propose an enhanced back-off mechanism and derive the optimal contention window (CW) by a theoretical model, which improves the uplink random access efficiency. To tackle the complex interference problem in RU scheduling phase, we develop an efficient and low-complexity resource allocation algorithm based on the maximal independent set (MIS), which can schedule multiple D2D pairs to share the same RU with the specific STA. Simulation results demonstrate that the proposed algorithm significantly improves the network performance in terms of system throughput, collision rate, complete time, and channel utilization.

The IEEE 802.11ba is a new Wireless Local Area Network (WLAN) standard to incorporate the Wake-up Radio (WuR) technology into the existing IEEE 802.11 system, where Distributed Coordination Function (DCF) is employed. IEEE 802.11ba holds importance for the Internet of Things (IoT) network deployment due to its low power WuR characteristics and backward compatibility with legacy WLAN networks. In this letter we model the mechanism of wake-up radio devices and investigate the interaction between the wake-up radio devices and the legacy devices in the coexisting scenario. The model can be utilized to quantify the behavior of WuR devices under a legacy WLAN network.

We investigate indoor human multi-target tracking in cartesian coordinates based on range, Doppler and Angle-of-Arrival measurements obtained with a four-antenna passive bistatic radar capturing 802.11ax Wi-Fi signals. A reference antenna selection method is described to perform angle processing correctly when dealing with target detection diversity among antennas. The tracking is performed by an Unscented Kalman Filter (UKF) to handle the non-linear relation between the measurement space and the state space. A Joint Probabilistic Data Association Filter is coupled to the UKF to handle the data association between tracks and measurements when dealing with multiple targets. Simulations are performed to determine the tracking parameters under heavy constraints and identify key scenarios. An experimental setup is built using Universal Software Radio Peripherals, featuring an over-the-air phase calibration for angle processing with an anchor antenna. It is used to validate the proposed single and multi-target tracking scheme., info:eu-repo/semantics/published

In this work, a novel triband antenna is developed for wireless local area network (WLAN), worldwide interoperability for microwave access (WiMAX), and Bluetooth application. The proposed antenna i...

An omnidirectional wireless local area network (WLAN) loop-slot antenna with common-mode current (CMC) suppression is proposed in this communication. First, based on the analysis of the equivalent model of odd–even mode, the feeding coaxial line is led out at the voltage-zero point of the loop-slot element, which suppresses the CMC over the full band. Second, through the theory of array, three loop-slot elements form an array to obtain omnidirectional radiation. Finally, the physical size is reduced by loading Stubs T in the slot. The roundness of the radiation pattern is modified by the Stubs T and the chamfering edge of the antenna. A prototype of the proposed antenna was fabricated and measured. The measured results show that the antenna achieves $\vert \text{S}_{11}\vert dB in bands of 2.15–2.65 and 4.85–5.92 GHz. In addition, the roundness is 0.95 dB at 2.4 GHz, 1.84 dB at 5.2 GHz, and 2.43 dB at 5.8 GHz. The antenna effectively suppresses the CMC to keep a favorable roundness over a wide band, showing its potential in WLAN communication systems.

To attain high quality of service (QoS) with efficient power consumption with minimum delay through Wireless Local Area Network (WLAN) through mesh network is an important research area. But the existing real-time routing system involves multiple hops with time varying mobility channels for fastest data propagation is greatly degraded with power utilization factor through congestion traffic queue. Required allocation and resource management through desired access points plays vital roles in which multiple hops demands delay rates by interconnected data nodes. In order to achieve high throughput with minimum delay the QoS in real-time data communication have to be concentrated by using Viterbi decoder with convolution codes. By undertaking IEEE 802.11 WLAN physical layers afford multiple transmission rates by engaging various modulations and channel coding schemes, major point arises to pinpoint the desired transmission rate to enhance the performance. Because each node exhibits different dynamic characteristics based on the token rings passed from the server to the end links. In order to validate the real-time traffic with power consumption and average delay communication, an improved Viterbi decoder is designed with convolution codes to determine accurate channel estimation based on learning the utilization ration of the needed to execute the current wireless channel optimization. The proposed methodology can attain accurate channel estimation without additional implementation effort and modifications to the current 802.11 standard. And each node is capable to choose the optimized transmission rate, so that the system performance can be improved with very minimum power with high packet transmission ratio with minimum traffic rate to improve QoS. The proposed scheme also offers an appealing combination of the allocation of transmission rate and the current link condition. Based on the basic relationship between them, the proposed decoding scheme maximizes the throughput with periodic learning of channel variation and system status.

A wideband decoupled dual-antenna pair is proposed and designed for 5G mobile terminal applications, with the help of characteristic mode theory. Parasitic strip and defective ground structure are used simultaneously to realize broadband and high isolation. Based on the proposed decoupled antenna pair, an eight-element multiple-input--multiple-output (MIMO) antenna is presented by placing four pairs at both side frames. By etching slits on the system ground, the mutual coupling between antenna pairs is effectively reduced. A prototype of the proposed antenna array is successfully fabricated and measured. Both simulated and experimental results indicate that the proposed eight-element MIMO antenna can completely cover n77/n78/n79 bands of the 5G New Radio and wireless local area network 5 GHz band. Furthermore, an isolation better than 15 dB is achieved between any two ports.

The past two decades have witnessed an unprecedented growth in the study and implementation of different short-range wireless services. However, the deployment of multiple short-range communication techniques has led to an overpopulation of the radio spectrum. Ultrawide-band (UWB) technology aims to offer an alternative to this spectrum scarcity as it can coexist with other radio technologies [Bluetooth, Worldwide Interoperability for Microwave Access (WiMAX), and Wireless Local Area Network (WLAN)] while causing minimal interference. The prospects of UWB technology allowing high data rate (up to 500 Mb/s) with low power consumption (l0.5 mW) up to a typical range of 10 m have escalated their demands over other short-range communication systems.

In an Internet-of-Things (IoT) environment, congestion and scarcity problems may occur because many mobile stations (STAs) access wireless networks simultaneously. The IEEE 802.11ax/802.11be standards for large-scale wireless communications have defined a trigger frame (TF) to control multiple STAs. During resource allocation, the downlink (DL) transmission is divided in a control period from the access point (AP) to multiple STAs. The resource allocation (RA) is then assigned to an uplink (UL) transmission by a TF and a DL period from the AP to STAs. However, because the DL transmission should be considered separately in terms of the control and DL periods, it is necessary to analyze the DL transmission. We propose a scheduled MU transmission (SMT) algorithm for enhanced UL and DL MU MIMO transmissions. In this study, we analyze and systematically model medium access control (MAC) performance when the DL transmission is divided in the control and data periods when the UL coexists with the DL data transmission. To achieve this, we mathematically analyze the time-efficient throughput, estimate the transmission and collision probabilities for wireless local area network (WLAN) STAs, and generalize the transmission interval. In addition, we propose an access category (AC) for the TF that is defined in the DL transmission. All data transmissions are defined as the ACs for basic channel access, but the AC is not defined for the TF. Therefore, we clarify the transmission by defining the AC of the TF to control the UL transmissions of various STAs. Evaluation results demonstrate that the SMT algorithm can improve the MAC throughput by up to 70% – 87% compared to UL and DL MU MIMO transmissions.

This article proposes a microstrip bandpass filter patch antenna for remote access, particularly for vehicular applications. The antenna comprises split ring resonator (SRR) defected ground structure. The antenna design and filter are integrated to collaboratively work as filtenna (integrated filter antenna) for enhanced performance by reducing the total power consumption in the system. The objective of this paper is to carry out a detailed study of the effects of SRR parameters on the proposed filtenna. The investigation is carried out on the width of the slit opening of the SRR slot and the rotation of the inner square shaped ring structure in clockwise direction. The proposed filtenna is designed to provide a tuneable frequency operation. Simulation is performed on high frequency structural simulator which demonstrates good output response making filtenna design suitable for intelligent vehicular communication, particularly dedicated short-range communication-based applications at 5.9 GHz band and wireless local area network applications. The proposed filtenna is smaller in size, has low insertion loss, displays high selectivity and exhibits brilliant out of-band execution.

In smart cities, the Internet-of-Thing (IoT) provides an enabling communication infrastructure to support tremendous amount of data exchange. Most IoT applications, e.g., wireless local area network, Bluetooth and so forth, utilize the channel-hopping scheme to suppress the transmission security threats. In this paper, to reduce the mutual interference and external jamming attacks, multiple novel channel-hopping patterns, i.e., traditional no-hit-zone (NHZ) hopping pattern and generalized NHZ hopping pattern, are introduced to suit to IoT networks. Particularly the design of probabilistic hopping pattern is first proposed, which has the various usage probabilities with regard to various channels. The properties of these hopping patterns are investigated by the step-to-step examples. Then, the error-rate performance of the multi-node IoT systems adopting these hopping patterns in the presence of jamming attacks is comprehensively analyzed. The extensive simulations show that the traditional/generalized NHZ hopping patterns are in favor of combating the mutual interference but with the limited capability of reducing jamming attacks, while the probabilistic hopping pattern possesses the opposite feature, that is, it has the predominant merit in suppressing jamming attacks. Thus, the novel channel-hopping pattern-based IoT could provide the secure transmission for communication applications in smart cities. Note that, as the physical-layer security technique, the channel-hopping patterns investigated in this paper are convenient to integrate with the security policies implemented in upper layers (e.g., encryption, authentication and so forth).

Wi-Fi Direct (WFD) has attracted much attention in recent years as a device-to-device communication technology that enables the sharing and diffusion of information in disaster areas that lack existing communication infrastructures. In WFD, mobile devices such as smartphones and tablets establish communication groups (a wireless local area network (WLAN)), and transmit and/or receive data by Wi-Fi among devices autonomously. However, WFD is not effective for spreading data throughout a wide range because it randomly selects communication partners and needs to wait uselessly for random lengths of time to maintain access control. Thus, we propose a novel and efficient information diffusion method exploiting WFD and delay-tolerant networking (DTN). This method involves a unique virtual cell design based on device locations and enables efficient information diffusion without interference by assigning communication times to the virtual cells. As there is no deterministic means of evaluating multihop communication exploiting WFD and a mathematical model is needed to quantitatively indicate the performance of our method, we further construct a performance evaluation model using the reaction–diffusion model, which is a partial differential equation used to mathematically describe the spread of epidemic diseases. The effectiveness of this proposed diffusion method is evaluated exploiting the constructed model.

Voice Over Internet Protocol (VoIP) is a voice communication technology (voice) that uses IP which can be done electronically and in realtime. In building VoIP devices used such as IPPBX Server, IPPBX Gateway IP and other supporting devices such as mikrotik. To design VoIP generally implemented using a local area network (LAN) or a wireless local area network (WLAN). In this study, an analysis of the quality of VoIP network communication is to determine the problems caused by communication using VoIP, so that VoIP can be used to maximize the existing internet network. This VoIP network can save costs when communicating such as video communications or video conferencing.

This paper presents a 2.4–6 GHz highly integrated broadband GaN power amplifier (PA) with three stages for 2.4-/5-GHz dual-band 802.11ax application. A compact external output matching network is introduced to realize broadband output matching, while reducing the loss of the output matching network and saving the chip area. A novel topology of coupled resonators is exploited for the broadband inter-stage matching to cover the 802.11ax bands from 2.4 to 6 GHz. In the proposed topology, the coupling between the primary and secondary resonators is through a series inductor and a series capacitor. Compared with other conventional coupled resonators, the proposed topology produces an additional complex pole, further extending the bandwidth. The PA was designed and fabricated in Wolfspeed 0.25- $\mu \text{m}$ GaN-on-SiC technology. The implemented PA achieves a saturated output power (Psat) of 35.2–36.3 dBm with a maximum power added efficiency (PAE) of 38–53% from 2.4 to 6 GHz. When tested with an 80-MHz, 256-quadratic-amplitude modulation (QAM) 802.11ax signal, the PA delivers an average output power of 27.1 and 25.7–27.2 dBm with a PAE of 20.9% and 18.4–24.6% in the 2.4-GHz and 5-GHz wireless local area network (WLAN) bands, respectively, while meeting the specification of error vector magnitude (EVM) below −32 dB.

Four dual-band shorted patch antennas (SPAs) with a low profile of 1 mm ( $0.008\lambda $ at 2.4 GHz) integrated into a square-ring structure of size 66 mm $\times66$ mm (about 0.53 $\lambda \times 0.53\lambda $ at 2.4 GHz) for 4 $\times {4}$ multiinput-multioutput (MIMO) operation are presented for mobile device applications. Each SPA consists of a larger shorted patch and a smaller shorted patch to, respectively, generate the 2.4 GHz band (2400–2484 MHz) and 5.8 GHz band (5725–5875 MHz) for dual-band wireless local area network (WLAN) operation. Two SPAs are orthogonally connected with the first SPA’s larger shorted patch and the second SPA’s smaller shorted patch sharing a common metal wall at the corner of the square-ring structure. By repetitively connecting the third SPA to the second one and finally the fourth SPA to the third and first ones, the proposed design can generate four decoupled waves in the 2.4 GHz/5.8 GHz WLAN bands with very low envelope correlation coefficients of less than 0.1. With 1 mm low profile, the proposed WLAN MIMO antennas are expected to find applications in integration with the back cover of the mobile device.

Despite unprecedented advancements, wireless local area network (WLAN) technologies for the Internet of Things (IoT), such as IEEE 802.11ah (i.e., WiFi-HaLow), are prone to serious security threats, owing to their constrained computational and memory resources, which limit the use of heavyweight intrusion protection and security protocols. To address this problem, security administrators (sec-admins) must perform regular and comprehensive vulnerability assessments of IoT devices. An Internet-wide port scan (IWPS) is the initial step. However, the medium access control mechanism of IEEE 802.11ah, designed specifically for heterogeneous IoT traffic and low-power operations, can degrade network performance in the case of traditional port-scan traffic. Moreover, Internet-security (IPSec) protocol support is mandatory for IPv6-enabled IoT devices to ensure data confidentiality, integrity, and availability. Although the objective of a port scan is to improve IoT security, the resultant network performance can adversely affect IPSec services. Therefore, in this study, we optimize the IWPS to maximize the IoT security over IEEE 802.11ah WLAN. To this end, we propose novel mathematical models to evaluate IoT security based on port-scan network performance and IPsec services, which derives an optimal scan rate for sec-admins. The effectiveness of the proposed framework is verified by comprehensive numerical analysis, which shows that our approach minimizes the risk to IoT devices while probing them at an optimal scan rate.

The creation of context-aware services in pervasive computing environments has driven the wide development of wireless local area network (WLAN)-based indoor positioning systems. One of the main challenges in WLAN-based indoor positioning is the severe fluctuation of received signal strength (RSS), which may cause the RSS patterns to be mismatched and the positioning to be inaccurate. In this paper, an indoor positioning algorithm that combines the fingerprint scheme with mobility prediction is proposed. Since the mobility prediction is performed according to the moving speed and direction of the mobile client, the resulting location estimation is more stable compared to the use of RSS alone. Experimental results show that the proposed positioning algorithm can mitigate the impact of the RSS fluctuation and has better positioning accuracy and stability than previous fingerprint-based approaches.

In our day-to-day life, securing the confidential data and communicating the same to the authorized receiver are the biggest challenges. In Defense, Medical and Banking domains, the security over wireless medium should be high. SMS4-BSK is designed to provide a faster encryption with the required security over Wireless Local Area Network (WLAN). A novel SMS4-BSK architecture is proposed in this paper. The new design is implemented in Kintex 7 FPGA and it is proved that the new architecture can perform encryption and decryption faster than the existing SMS4 architectures. The proposed cryptosystem is capable of resisting cryptanalysis over Ciphertext-only attack, Known-plaintext attack, Chosen-plaintext attack, and Chosen-ciphertext attack. Finally, the possible ways of changes that can be made for improving speed are discussed.

World energy demand is increasing as a result of population growth and industrial development. Nowadays, in Peru, electricity consumption has significantly increased. Elec- tric companies in Peru depend on their staff to record the consumption of meters; on the other hand, users do not have the easiness of monitoring their consumption day by day or the access to the information of their consumption. Given the problem described, in this project, the development of a smart meter based on Wi-Fi communication technology is presented. The Wi-Fi transmission allows saving the consumption of a user in a database. The present research project implements an intelligent electric consumption meter that can calculate and display the monetary expenditure of a residence. The implemented prototype has an electronic system that records the electrical energy consumption by means of sensing the current and voltage signals through a developed algorithm that is able to calculate the electrical energy consumption in kilowatt per hour. This in order to provide the user with easy access to information in real-time and to help them in managing their consumption better. The proposed solution intends to contribute to the saving of electrical energy, which represents a saving in monthly billing for the user and overall a reduction in Peruvian household's CO2 emissions.

This paper proposes a reconfigurable circular microstrip antenna to serve the wireless communication applications that make use frequency bands such as ISM (Industrial Scientific and Medical), WLAN (Wireless Local Area Network), UMTS (Universal Mobile Telecommunications Service). Reconfigurability is achieved with the help of four MEMS (Micro-Electro-Mechanical Systems) switches to change the frequency and radiation properties of the antenna. By choosing either of the two states of each of the MEMS switches, the radius of the circular patch is varied and subsequently the operating resonant frequency. This gives rise to multiple configurations of the antenna to serve for different wireless applications. Defected Ground Structure is employed in this design to lower the resonant frequency and improve the bandwidth. Concentric rings are implemented along with a core circular patch in order to increase the radiating area of the patch in association with the MEMS-based switches to operate in toggle mode of ON and OFF. The concentric rings also helping in obtaining dual-frequency behavior of the antenna and the measured results are showing good agreement with the simulation results.

In wireless communication systems, the performance of the receiver is very sensitive to time and frequency offsets. In particular, orthogonal frequency division multiplexing (OFDM) systems are highly vulnerable to those offsets due to inter-carrier interference (ICI) and inter-symbol interference (ISI). To solve this problem, wireless local area network (WLAN) systems transmit a preamble for synchronization. In this paper, we propose a joint time and frequency offsets estimation technique based on convolutional neural network (CNN) for WLAN systems. In the proposed technique, the correlation between the received signal and the transmitted preamble is performed first. Then the frequency offset is coarsely compensated by several hypothesized offsets. The compensated signals are inputted to the proposed CNN and the CNN predicts the time and frequency offsets. The estimation performance is examined through computer simulation. According to the results, the proposed time offset estimator shows 3 dB to 6 dB performance gain, and the frequency offset estimator shows much lower root mean square error (RMSE) performance than the conventional technique at low SNRs

Fingerprint-based indoor positioning uses pattern recognition algorithms (PRAs) to estimate the users’ locations in wireless local area network environments, where satellite-based positioning methods cannot work properly. Traditionally, the training phase of PRA is separately conducted for $x$ and $y$ coordinates. However, the received signal strength from access points is a unique fingerprint for each measured point, not for $x$ and $y$ coordinates separately. In this letter, we propose a method to jointly employ the $x$ and $y$ coordinates during the training phase using a novel PRA-based Gaussian process regression (GPR), named 2D-GPR. Experimental results show that the proposed 2D-GPR improves the accuracy of positioning more than $40cm$ in limited data samples and has a lower calculation cost compared with conventional GPR.

A compact quarter-mode substrate integrated waveguide (QMSIW)-based self-quadruplexing antenna is proposed for compact radio frequency (RF) front ends. The QMSIW-based self-quadruplexing antenna has four unequal resonators resonating at the Industrial, Scientific, and Medical (ISM) band (2.45 GHz), fifth-generation (5G) band (3.5 GHz), wireless local area network (WLAN) band (4.9 GHz), and wireless fidelity band (5.4 GHz). All four resonators radiate through the open-ended wall of the QMSIW resonator and the arc-shaped slot inside the cavity. By properly optimizing the locations and dimensions of the resonators, higher isolation ( $>$ 29.9 dB) is gained. In fact, all four resonators operate on a common grounded substrate with negligible interference. A dummy rectangular device is used to keep the printed circuit board (PCB) and antenna in it to measure the S -parameters and radiation properties. The proposed antenna has a lower circuit size (0.23 $\lambda _{g}^{2}$ ), reasonable gain ( $>$ 3.85 dBi), high efficiency ( $>$ 82.7 %), and high isolation ( $>$ 29.9 dB). Based on the above-mentioned attributes, it is a good candidate for compact RF front ends.

In recent years, propagation channel characteristics have been effectively used in several applications such as motion sensing and position detection. Considerable attention has been paid to channel-sounding methods that are easy to utilize using low-cost devices. This paper presents a device-free indoor location estimation method using the spatio-temporal features of radio propagation channels using a 2.4 GHz-band three-by-three multiple-input-multiple-output (MIMO) channel sounder developed using commodity wireless local area network (WLAN). The measurement results demonstrated a reasonable performance of the proposed method with a small number of antennas.

A fractal frequency selective surface (FSS) has been presented for hard coated energy saving glass (ESG) used in modern building architecture. Without FSS, the presence of coating on ESG surface blocks the transmission of useful radio frequency (RF)/microwave signals. The FSS consists of two self-similar cross dipole elements designed in the coating to provide a low-pass response from 0 GHz to 2.1 GHz with two additional band-stop responses at 2.45 GHz and 5.25 GHz. An average transmission loss of less than 2 dB has been achieved in the low-pass band while attenuations of 36 dB and 30 dB have been achieved for 2.45 GHz and 5.25 GHz wireless local area network (WLAN) bands, respectively, providing required security. The low-pass response improves the transmission of useful RF/microwave signals. However, the amount of removed coating due to FSS design is relatively higher, but heat loss has been minimized by pasting an inexpensive thin solar film on the back side of glass. This thin film has provided additional thermal insulation with almost no blockage to transmission of useful RF/microwave signals. A detailed parametric analysis has been done and their effect on FSS structure has been described. An equivalent circuit model has also been presented for the proposed FSS structure. A finite prototype containing 7 × 7 elements have been constructed and evaluated. The measured results have been found to be in good agreement with the simulated results. The proposed FSS design is an excellent candidate for WLAN security.

In this paper, the design of an antenna array with enhanced bandwidth is presented. The antenna array includes 16 elements (4 x 4) based on RT5880 with height of 1.575 mm, dielectric constant of 2.2 and loss tangent of 0.0009 and it is yielded at the central frequency of 5.8 GHz for Wireless Local Area Network (WLAN) applications. In addition, in order to enhance bandwidth for antenna, the paper proposes a new metasurface. The metasurface, which is a lattice of 3 x 3 cells, is printed on a substrate of FR4 (h = 1.6 mm, ɛr = 4.4, and tanδ = 0.02) and it acts as an artificial magnetic conductor reflector. The final prototype with an overall dimension of 123 x 120 x 3.315 mm3 was fabricated and measured. The antenna witnesses an impedance bandwidth of 5.1-7.5 GHz at -10 dB (41%) and a peak gain of 17.65 dBi for measurement. The simulation results are confirmed by measurement ones to verify the performance of the proposed antenna.

This article presents a cross-layer design of backbone-assisted wireless local area network (WLAN) for dense WLAN deployment. The popularity of 802.11-based WLANs leads to dense WLAN deployment in geographically limited space, including dense access points (AP) and dense users. With dense APs, an AP could overhear packets destined for other APs. Backbone-assisted WLAN is a new system architecture where cooperative APs share the overheard packets through a backbone network, thereby reducing packet retransmission and improving system throughput. Conventional WLAN, such as Wi-Fi, uses Stop-and-Wait ARQ. This article argues that Stop-and-Wait does not work well with backbone-assisted WLAN because of large backbone delays. We first show that with a variant of Selective Repeat ARQ tailored for backbone-assisted WLAN, a single-user backbone-assisted WLAN system can achieve substantial throughput improvement over that with Stop-and-Wait ARQ. Then, we put forth a new system architecture targeted for dense users, referred to as network-coded backbone-assisted WLAN, in which multiple users are allowed to transmit simultaneously. A distinguishing feature of this system is the joint use of physical-layer network-coding (PNC) decoding and multiuser decoding (MUD) in multipacket reception. This article is the first attempt to design an ARQ for multiuser backbone-assisted WLAN. Our overall system design solves a PNC sequence obfuscation problem and addresses long packet latency in Selective Repeat ARQ. Experiments on our software-defined radio prototype indicate that network-coded Ethernet-backbone-assisted WLAN can achieve high system throughput and low packet latency. Specifically, the system throughput can outperform an MUD-only multiuser WLAN and a single-user WLAN by 60 and 100 percent, respectively. Overall, we believe that network-coded backbone-assisted WLAN is a viable solution for boosting throughput and reducing latency in dense WLAN environments.

This paper presents the development of a compact monopole antenna bioinspired in the Opuntia ficus-indica plant-shape, generated by Gielis formula, built in fiberglass substrate, with hybrid feed by transmission line and probe, for wireless local area network band at 5 GHz. By using the plan-shape, it is possible to increase the perimeter of the design and thus reduce its total area, which can be employed in the development of compact antennas with larger electrical length. Results of the bioinspired plant-shape antenna is compared to the square-shape antenna, and the proposed antenna presents a more compact structure, with a reduction of 62.5% in the total area, with a value of 108.4 mm2, narrower bandwidth, and a directive radiation pattern, with a bandwidth of 1.44 GHz (4.41–5.85 GHz), which covers the 5 GHz WLAN band (5.15–5.85 GHz) and measured gain of 2.6 dBi, at the resonance frequency.

One very rapid change in computer networks is the use of Wireless Local Area Network (WLAN) to access systems both locally and the internet. One way to add an Access Point (AP) so as not to change the configuration of the running software is use the Wireless Distribution System Mesh (WDS) network. The use of WDS mesh at Universitas Muhammmadiyah Jember (UM Jember) enables a slightly different wireless configuration to reduce the connection loss in the user due to the wireless network area coverage. One step is use AP devices into one unit to handle the case of a connection break by utilizing a network service that is WDS Mesh. WDS Mesh can cover Wi-Fi areas at UM Jember, and the results of testing and analysis of client devices for APs that have been configured WDS Mesh with parameters Signal Strength, CCQ, Signal to Noise Ratio Ratio, Throughput is Excellent.

This article presents an $8\times 8$ lattice-reduction-aided (LRA) soft-output multiple-input multiple-output (MIMO) detector for Chinese enhanced ultrahigh throughput (EUHT) wireless local area network (LAN) standard. The preprocessing algorithm combining simplified-sorting Cholesky decomposition and low-complexity decoupled lattice reduction (LDLR) is proposed to reduce computational complexity and latency with parallelism improvement. In addition, K-best detection adopts a sorting-reduced strategy utilizing approximate ordered sequence. Compared with other published LRA K-best detection algorithms, simulation results show that our proposed algorithm has performance improvement. In addition, in order to save hardware resources, a folded K-best architecture and an optimized intermediate storage strategy are introduced. Furthermore, a fully pipelined VLSI architecture is designed in Semiconductor Manufacturing International Corporation (SMIC) 40-nm 1P9M technology to support the $8\times 8.64$ -QAM MIMO-OFDM system. The detector can achieve 3.85-Gb/s data throughput at 641-MHz clock frequency with 0.71- $\mu \text{s}$ latency. The proposed detector is competitive in terms of latency, throughput, and area efficiency to state-of-the-art works and can meet the data-rate requirement of the EUHT standard.

This article presents a parallel sliding-IF 5-6-GHz wireless local area network (WLAN) receiver front-end supporting two-band carrier aggregation (CA), which alleviates potential local oscillator (LO) pulling and crosstalk problems. The supported frequency spacing between any two different carriers ranges from tens to hundreds of MHz. First, a complementary current-reused single-ended LNA with very low noise figure (NF) is developed to guarantee a low noise performance. Second, an active balun-splitter establishes a bridge between the LNA and the following parallel fully differential down-conversion paths. Next, to optimize the performance of the passive double-conversion mixer, a detailed analysis has been conducted and shown that the time offset with specific values between the two LOs maximizes conversion gain and minimizes noise contribution, which enhances harmonic rejection simultaneously. Fabricated in 65-nm CMOS technology, this receiver front-end achieves an average 1.9-dB NF with a 39-dB gain at 5-6 GHz for single-carrier scenario, degraded by 0.4 dB with 35-dB gain for two-band CA scenario. It consumes 35 and 60 mA with 1.2-V supply for single carrier and two-band CA scenario, respectively. The total area is 0.56 mm². Accepted version

This paper presents a four-port pattern diversity antenna with a 3-D printed all-dielectric superstrate for 5.2 GHz Wireless Local Area Network (WLAN) access points. The topology of four-port coaxi...

An important goal of indoor positioning systems is to improve positioning accuracy as well as reduce power consumption. In this paper, we propose an indoor positioning method based on the received signal strength (RSS) fingerprint. The proposed method used a certain criterion to select fixed access points (FPs) in an offline phase instead of an online phase for location estimation. Principal component analysis (PCA) was applied to reduce the features of the RSS measurements but retain the most information possible for establishing the positioning model. Then, a kernel-based ridge regression method was used to obtain the nonlinear relationship between the principal components of the RSS measures and the position of the target. We thoroughly investigated the performance of the proposed method in realistic wireless local area network (WLAN) and wireless sensor network (WSN) indoor environments and made comparisons with recently developed methods. The experimental results indicated that the proposed method was less dependent on the density of the reference points and had higher positioning accuracy than the commonly used positioning methods, and it adapts to different application environments.

This paper proposes integrating multiple antennas into wearable devices for application in fifth-generation (5G) communications and the Internet of Things (IoT). The frequency bands covered were wireless local area network 2.4-GHz/5-GHz channels (2410–2484 MHz), the global positioning system (1575 MHz), narrowband IoT band 8 (880–960 MHz), Global System for Mobile Communications 850/900, and the 5G frequency range 1 n77/78/79 band (3300–5000 MHz). The antennas were configured as a $2\times2$ multiple-input multiple-output system (MIMO). The antenna resonance contribution integrates the slot mode, monopole mode of the three-dimensional frame, and loop coupling monopole mode. The configuration of the independent matching circuits facilitated the effective control of the desired mode and the coverage of the desired bands. All integrated antennas were placed in a watch device ( $37\times 43\times8$ mm3) with a metal body and a metal strap. An integrated miniaturized antenna was designed. The diversity gain and multiplexing efficiency between the MIMO antennas were 9.97dB and above −2dB, respectively. Favorable diversity performance was confirmed. The channel capacity of the $2\times $ 2 MIMO array was determined to be 8.8 bps/Hz. Moreover, its performance was evaluated through the addition of a hand tissue module. The impact of metal straps on antenna radiation performance was discussed. The specific absorption rate (SAR) was examined, and the best results obtained under an SAR of 1 g and 10 g were 0.25 and 0.58 W/kg, respectively. The findings demonstrate the suitability of the antenna for practical applications in 5G communication systems and the IoT.

There are surplus applications in modern smart cities where localization of indoor environments is critical ranging from surveillance and trailing in smart structures to the localized wireless distribution of advertising content in shopping malls. These applications are only successful if a robust and cost-effective real-time system is developed for precise localization. Another aspect considered for indoor localization is power consumption. Recent wireless standards such as Bluetooth Low Energy (BLE) and LoRa consume less power which makes them a perfect candidate for indoor localization. This work aims to carry out an experimental evaluation which would help to decide which wireless standard i.e., Wi-Fi, Bluetooth Low Energy (BLE), and LoRa are most suitable for indoor localization. Experiments are carried out using trilateration in three multiple environments. RSSI is used to calculate the coordinates of a sensor node. Results obtained from the experiment show that Wi-Fi is most accurate with an average error of 0.54 m. LoRa is second most accurate with an average error of 0.62 m and BLE is the least accurate with an average error of 0.82 m. These results can be used to decide which wireless standard is best suited for indoor localization.

In the last decade, deep neural network (DNN)-based object detection technologies have received significant attention as a promising solution to implement a variety of image understanding and video analysis applications on mobile edge devices. However, the execution of computationally intensive DNN-based object detection workloads in mobile edge devices is insufficient in fulfilling the object detection requirements with high accuracy and low latency, owing to the limited computation capacity. In this paper, we implement and evaluate a DNN-based object detection offloading framework to improve the object detection performance of mobile edge devices by offloading computation-intensive workloads to a remote edge server. However, preliminary experimental results have shown that offloading all object detection workloads of mobile edge devices may lead to worse performance than executing the workloads locally. This degradation is obtained from the inefficient resource utilization in the edge computing architectures, both for the edge server and mobile edge devices. To resolve the aforementioned problem with degradation, we devise a device-aware DNN offloading decision algorithm that is aimed to maximize resource utilization in the edge computing architecture. The proposed algorithm decides whether or not to offload the object detection workloads of edge devices by considering their computing power and network bandwidth, and therefore maximizing their average object detection processing frames per second. Through various experiments conducted in a real-life wireless local area network (WLAN) environment, we verified the effectiveness of the proposed DNN-based object detection offloading framework.

This work demonstrates a measurement-based method to evaluate the throughput performance of wireless local area network (WLAN) devices. The implementation is mainly based on an improved radiated two-stage (RTS) method independent of the request of reception. In this method, the antenna patterns are achieved using the reciprocal channel transmitting and receiving property, while the normal reception information for throughput evaluation is obtained by the amplitude comparison algorithm. Compared with the traditional RTS method and the test method in real scene, the whole throughput measurement can be realized without the special reception request from user equipment, while the channel models simulating the working circumstance can still be applied in constructing comparable test circumstance to save cost. The experimental demonstration proves, for WLAN multiple-input–multiple-output (MIMO) device, that the proposed test method can achieve a comparable test performance with the traditional test method under real scene, while the test time is shortened and the test cost is reduced.

This letter proposes a low-profile substrate integrated waveguide (SIW) cavity backed self-quadruplexing antenna for wearable transceivers. The full-mode circular SIW cavity is split into four unequal quarter-mode SIW (QMSIW) cavities using the two slots on the upper layer of the cavity. The proposed antenna uses C-shaped and arc-shaped slots of different dimensions in each QMSIW resonator to operate at wireless local area network bands (3.5, 4.9, 5.4, and 5.8 GHz). The measured gains are 4.4, 5.07, 5.40, and 5.7 dBi at 3.5, 4.9, 5.4, and 5.8 GHz, respectively. The antenna is simulated and optimized inside a 48 $\times \text{76}\times$ 21 mm3 rectangular device by keeping the device on the chest of a realistic human model. The proposed antenna has unidirectional radiation patterns in all four operating bands with low backward radiations. Thus, it has low specific absorption rate at all four operating bands.

The present paper describes the design of a folded hairpin-line bandpass filter centred at 2.5 GHz applicable for Wireless Local Area Network (WLAN) with improved spurious suppression. The size of ...

In this paper, a low profile 4 × 4 multiple input and multiple output (MIMO) antenna is proposed and designed for wireless local area network (WLAN) application using a square split-ring resonator. Initially, a single square-patch antenna is designed with square-shaped split-ring slot. Subsequently, the two-element MIMO antenna is designed and it is extended to four-element MIMO antenna. Finally, the defected ground structure (DGS) is implemented in order to enhance antenna performance. The antenna elements are placed opposite to each other. The mutual coupling between the antennas elements is reduced by DGS. The proposed single, two and four-element antennas operate at 5.8 GHz for WLAN. The overall performance is measured in terms of S parameter, radiation pattern, and envelope correlation coefficient. The simulated results are verified through measurements. The simulated and measured results demonstrate that the proposed 4 × 4 MIMO antenna is the most suitable for WLAN applications.

Based on a single metallic layer printed circuit board (PCB), a miniaturized dual-band frequency selective surface (FSS) is proposed that could fulfill thin substrate design for curved application and provide stable resonant frequency. Due to the property that the element size can be altered by using different thicknesses of substrate, the FSS could either be designed for the compact size or in a very thin substrate. Two practical designs for dual-band wireless local area network (WLAN) are demonstrated featuring a flexible and straightforward design method. The compact one has an element size of only 5.2% of the free space wavelength at the lower resonant frequency, which is the smallest dual-band WLAN FSS by using only one metallic layer in published literature. Another thin substrate design (0.4 mm PCB) is fabricated and measured to confirm that the FSS exhibits stable resonant frequency on curved surfaces with different curvatures. The measured frequency shift is only 2.2%, which is among the smallest percentage in the literature.

A single-layer microstrip patch antenna (MPA) under the operation of TM10 and TM20 modes for pattern diversity application without needing to rely on any feeding network is proposed for the first time in this letter. Initially, when a thorough analysis on mode excitation and inhibition of the MPA was deeply conducted, it demonstrated that its TM10 and TM20 modes could be independently excited by properly placing two coaxial ports underneath the radiating patch; thus, generating the desired broadside and bidirectional radiation patterns, respectively. Then, two sets of shorting pins are inserted below the core radiator, aiming to raise the resonant frequency of its TM10 mode in proximity to that of the TM20 mode. In addition, the maximum input resistances of these dual radiative modes decrease dramatically as f 10 and f 20 increase, which enables good impedance matching. Finally, the proposed MPA is designed, fabricated, and tested to validate the working principle. The results illustrate that this antenna can operate over the overlapping frequency ranges of 5.83–5.89 GHz with an envelope correlation coefficient of lower than 0.015, while keeping its low-profile thickness of 0.045λ0. Due to its unique advantages of low profile, simple structure, and good diversity, the proposed MPA could be a promising option in wireless local area network (WLAN)-related applications.

Satisfying the increasing volume of data streaming in modern wireless systems will demand energy-efficient RF front ends with gigabit data rates, high integration levels, and low cost. The power amplifier (PA) is the last door in the RF front end for both the digital and analog kingdoms, one that greatly affects the quality of service of the wireless link [1]. Thus, breaking through barriers (i.e., output power, linearity, efficiency, operation band, and even multifunction) in PA design is of paramount importance right now [2]. Consequently, with the aim of meeting the modern requirements of multistandard wireless applications, such as 5G, narrowband Internet of Things (NB-IoT), wireless local area network (WLAN), and future smart communications, various mixed-signal PAs have been developed and proposed in recent years.