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Network traffic and load are only expected to increase. Data is lost while being sent between nodes and devices as a result of traffic congestion at bottlenecks. WLANs are becoming the go-to technology for access in hotspot locations, workplaces, and residences. A station in a wireless local area network may be able to connect to several access points (APs). So, deciding which AP is "optimum" from a selection of potential candidates is a pertinent question. The user merely associates the AP with the strongest received signal strength while using IEEE 802.11. But this could lead to a substantial load imbalance among a number of APs. With only a minor modification to the load distribution mechanism, adopting load balancing can improve efficiency and utilization in addition to reducing processing delays. To increase the effectiveness of the WLAN, we provide a dynamic load balancing strategy in this paper. The network and user overhead will be reduced by the suggested dynamic strategy. The suggested method utilizes network load and throughput as performance criteria for performing load balancing. The method's viability is checked using Riverbed Modeller Simulator. The experimental findings validate the effectiveness of the proposed technique in enhancing network throughput and reducing access point congestion. [ABSTRACT FROM AUTHOR]

In this paper, a reconfigurable 2×2 and 4×4 MIMO antenna is designed for UWB X-band wireless applications. The proposed design uses square patch radiating electromagnetic energy and a novel ground structure and consists of a reconfigurable module enabling to set the operating mode using PIN diodes. The antenna allows rejecting 5 GHz WLAN and 7 GHz DSS interference by introducing “Γ-T” shape type stubs embedded on the radiating patch. The proposed design has reconfigurable features by using RF PIN diodes switch controlled by embedded module. Analysis of the proposed structure’s performance shows a good agreement between simulated results and actual outcomes measured in real-worlds scenarios. [ABSTRACT FROM AUTHOR]

This paper presents a planar CPW-fed Ultrawideband (UWB) antenna with two independently tunable notch bands. The proposed design consists of a modified Rhombus-shaped monopole structure that is integrated with a dual band-stop filter based on hexagonal split ring resonators (HSRR). The antenna is capable of suppressing multiple frequency bands within ultrawideband range (3.1–11 GHz) such as WLAN and X-band downlink satellite communication frequency bands with an independent tunable mechanism to fulfill the on-demand band rejection. The frequency reconfigurability of the two notch bands is obtained by loading the hexagonal filter arms with two varactor diodes (for each band). Details of antenna design steps and reconfigurability mechanism are illustrated. The notch band element is explained using equivalent circuit model and surface current distribution at lower and higher notch frequency bands. A prototype of the proposed design is printed on the RO4003C (ϵ r = 3.55) substrate printed circuit board (PCB) and tested to authenticate the performance. The proposed antenna volume is 21.5 ▪ 48 ▪ 1.524 mm3 and demonstrates an omnidirectional radiation pattern in E and H planes with an average gain of 3.7 dBi across the operational passbands, while a sharp reduction in gain of -6.8 dBi and -3.5 dBi is achieved at the lower and higher notch bands, respectively. Continuous tuning is achieved experimentally from 5.08 to 5.77 GHz and 7.75 to 8.52 GHz for the lower and higher notch bands, respectively. Excellent agreement is observed between the simulated and measured results. Application areas include radio-frequency identifications, ground-penetrating radar, and wireless communications. [ABSTRACT FROM AUTHOR]

A novel miniature wideband rectangular ring antenna is proposed for 4.6–6.2 GHz which is compatible with IoT applications. The wideband response of the proposed antenna is achieved by a partial ground and stair step structure. Because modifying the width and etching the ground plane does not improve the impedance matching over a large bandwidth, a triangular shape DGS is inserted in the partial ground plane to increase the antenna bandwidth with enhanced return loss. The wideband features of the antenna were explored here by incorporating different DGS shapes such as triangles, rectangle, pentagon, circle, and oval in the partial ground. The results have been successfully verified through measurement. The simulated fractional bandwidth is greater than 29% at 4.6–6.2 GHz whereas the measured fractional bandwidth is 27.6% at 4.75–6.2 GHz. In both cases, the maximum return loss is greater than 55 dB. The gain of the antenna is greater than 2.6 dB with good efficiency and nearly omnidirectional radiation pattern in shape. Due to its compact size and outstanding performance, the suggested stair step-shaped rectangular ring antenna could be a promising choice for IoT and wireless applications. [ABSTRACT FROM AUTHOR]

The handover procedure of IEEE 802.11 wireless local area networks (WLANs) introduces significant delay, which can degrade the quality of service (QoS) especially for delay-sensitive applications. Although studies have been conducted to support handover in SDN-based WLAN, there is no research to reduce the channel scanning procedure that takes up the most delay time in the handover process. The channel scanning procedure is essential to determine the appropriate access point (AP). To mitigate this problem, this paper proposes a SWITCH: SDN-WLAN integrated handover scheme for QoS-Guaranteed mobile service. In SWITCH, each AP periodically broadcasts beacon frames through different channels in a predetermined order that includes the operating channel information of the AP. This allows mobile stations (MSs) to receive the beacon frames of nearby APs, and therefore they can determine the appropriate APs for handover without the channel scanning procedure. By reporting the information of the newly moved AP to the SDN controller, a flow rule is installed in advance to provide fast handover, and packet loss is reduced by buffering data destined for MS. In addition, the proposed scheme can adaptively operate SWITCH to consider the user location and QoS requirement of flow to save radio resource overhead. Performance evaluation results demonstrate that SWITCH can reduce the handover delays, flow table utilization ratio and radio resource overhead while improving the network throughput. [ABSTRACT FROM AUTHOR]

A dual band microstrip antenna for WIMAX and WLAN applications is analyzed and presented in this paper. The proposed antenna has semicircular slot in patch and Defected Ground Structure (DGS) technique for the improvement of its bandwidth and gain. Computer Simulation Technology (CST) software is used to design and simulate the performance characteristics. The proposed antenna has the dimensions as 28 x 26•6𝑚𝑚². The fabricated antenna provides a good reflection coefficient of -48 dB and -44.5 dB at a center frequency of 3.4 GHz and 5.5 GHz. Gain achieved by the antenna is 2.72 dB and 3.87 dB for WLAN and WIMAX application. Good agreements have been found between simulated and measured results. These results confirm that the fabricated antenna is very promising for WLAN and WIMAX applications. [ABSTRACT FROM AUTHOR]

The wireless sensor network has many limitations like packet delay, packet loss, acknowledgement loss, complexity, scalability, robustness and energy efficiency which reduces the performance and the lifetime of the network. To improve that, the novel Consistent Routing protocol (CRP) is introduced along with the cluster formation method which is Long Lasting Energy Efficient Network (LLEEN) also called as L2E2N. The CRP is the dynamic routing protocol, which is developed to reduce the packet delay and packet loss during the transmission and also the efficiency of the transmission like throughput will be maintained even though the length of the packet is varied. The L2E2N is proposed to improve the lifetime of the network by consuming less energy during the transmission. The nodes should react during transmission like the rate of accepting packets which is equal to the rate of delivering packets, that can be possible in this L2E2N without consuming more energy. The performance measure is taken as throughput for the clusters with different sizes with respect to the energy consumption as the packet length is increased in terms of bytes. [ABSTRACT FROM AUTHOR]

The IEEE 802.11ad innovation has enabled the impact of remote devices in unauthorized 60 GHz unlicensed frequency band at Giga bits per second information transfer rate in speed concentrated 5G applications. We have presented an innovative work that deals with the upgradation of the ability of IEEE 802.11ad wireless LAN to make it suitable for wireless applications. An exact examination on the IEEE 802.11ad analysis has been carried out in this work to achieve the greatest throughput. This has pulled attraction in broad consideration for accomplishing the pinnacle transmission rate of 8 Gbit/s. IEEE 802.11ad is a convention utilized for extremely high information rates (around 8 Gbit/s) and for short range remote correspondence of around 1 to 10 meters. The Multi-layer with Multi-User Multiple Input Multiple-Output (MLMU-MIMO) innovation has enabled transmission of multiple information packets all the while from the WLAN IEEE 802.11 ad Access Point (AP) to various receivers by means of different wireless applications. To help the MLMU-MIMO innovation at Medium Access Control (MAC), a new method called Simultaneous Transmission for Enhanced Throughput (STET) has been presented for enhancement of the transmission rate of the wireless standard. A mathematical model has been used for the evaluation of the performance of an IEEE 802.11ad AP empowering the STET allocation technique. This STET model can help determination of the throughput improvement of a STET technique, for example, audio information, images, good quality and foundation impact. The main goal of this work is to analyze the improvement of the STET allocation technique in regard to the usage of rare frequency band, when obtaining spectrum access between the various access points. The theoretical and simulation outcomes are also confirmed by Riverbed modeler 17.5 simulation tool. [ABSTRACT FROM AUTHOR]

This paper proposes a dual-band Fabry-Pérot Cavity Antenna (FPCA) operating at two important WLAN bands - the 2.4 GHz band and 5.8 GHz band. It exhibits Circular Polarization (CP) at 2.4 GHz and Linear Polarization (LP) at 5.8 GHz. The proposed antenna uses only a single Partially Reflecting Surface (PRS) layer to achieve good 3dB gain bandwidths in both the bands. The cavity height of the antenna is also significantly reduced by using an Artificial Magnetic Conductor (AMC) ground plane. The antenna achieves a 3dB axial ratio bandwidth (AR-BW) of 7.9% at 2.4 GHz with peak measured gains of 14.3 dBi and 15.5 dBi at 2.4 GHz and 5.8 GHz respectively. The antenna also exhibits a 3dB gain BW of 7.8% in the first band and 5.5% in the second band. [ABSTRACT FROM AUTHOR]

CR enabled radio environment provides the seamless operating framework to cope with the requirements of next generation wireless systems like higher data rates, massive machine time communication and interference free coexistence scenarios of wireless technologies. Traffic characterization studies assist to optimize coexistence framework by providing necessary information about the usage patterns of wireless services in observed radio bands. Prior knowledge about the observed sparse wireless local area network (WLAN) data traffic is a key for opportunistic radio resource allocation and utilization in the given coexistence scenarios of WLAN either with cellular systems (including 5G-NR/4G Long Term Evolution (LTE)) or with low power wireless systems (including Bluetooth and ZigBee). Parametric methodology is adapted to model the sparse WLAN data traffic observed in 2.4 GHz Industrial, Scientific and Medical (ISM) band as spectral and temporal activity. The multivariate Gaussian mixture model (MGMM) is proposed in both scenarios where either dependency is considered between the observed WLAN data traffic or assuming that the observed traffic is independent and identically distributed (i.i.d). It is to be validated that in order to have an efficient characterization of sparse WLAN data traffic, the dependency (correlation) between neighbored frequency subbands must be considered. By considering the dependency either between neighbored frequency subbands or neighbored time domain signals actually help to characterize the sparse WLAN data traffic in more realistic way which could not be possible by assuming them i.i.d. Such statistics to characterize sparse data traffic really help as user activity for efficient allocation and utilization of radio resources in CR enabled coexistence scenarios of wireless technologies where WLAN acitivity is considered nominal either as secondary user or classify it grey spectrum as primary user. [ABSTRACT FROM AUTHOR]

In this research paper, a compact wideband monopole antenna of the dimensions 20 × 20 × 1.6 m m 3 (i. e. t o t a l v o l u m e = 640 m m 3) is presented. The proposed antenna configuration has simplified design in which the ground plane, as well as the radiating patch, are on the same plane. This design renders one side of the substrate consummately empty resulting in an overall design which is more facile to fabricate. It is excited by Coplanar Waveguide (CPW) feeding technique. The proposed structure has a fractional bandwidth of 40.56% (4.3–6.45 GHz) in simulation and 34.41% (4.4–6.38 GHz) in measurements for S 11 < −10 dB criteria. It has linearly increasing gain over its entire operational bandwidth and has a maximum peak realized gain of 4.7 dB at 6.4 GHz in simulation and about 3.8 dBi at 6.3 GHz in measurement. The designed antenna is suitable for WLAN and WiMAX of the range corresponding to 4.70–6.19, 5.5–5.7 and 5–6 GHz. To overcome the major drawback of narrow bandwidth in printed patch antenna, the uniquely designed split patch technique is used to achieve wide bandwidth. The antenna time-domain analysis is detailed by keeping it in side-to-side and face-to-face orientations. This analysis resulted in a stable performance which is very much required from a wideband antenna. All the necessary antenna simulations are done using HFSS and are validated by fabricating a model of it. [ABSTRACT FROM AUTHOR]

Wireless communications, involving electronic devices, are increasingly important. Performance is a fundamental issue, leading to more reliable and efficient communications. Security is also, no doubt, most important. Laboratory measurements were achieved about several performance aspects of Wi-Fi IEEE 802.11a 54 Mbps WPA2 links. Our study enriches performance evaluation of this technology, using accessible equipments (HP V-M200 access points and Linksys WPC600N adapters). New accurate results are given, namely at OSI level 4, from TCP and UDP experiments. TCP throughput is measured against TCP packet length. Jitter and percentage datagram loss are evaluated versus UDP datagram size. Results are examined for point-to-point, point-to-multipoint and four-node point-to-multipoint links. Comparisons are also made mainly to related data obtained for Open links. Conclusions are extracted about performance of the links. [ABSTRACT FROM AUTHOR]

Wireless communications, involving electronic devices, are increasingly important. Performance is a fundamental issue, leading to more reliable and efficient communications. Security is also, no doubt, most important. Laboratory measurements were achieved about several performance aspects of Wi-Fi IEEE 802.11a 54 Mbps WPA2 links. Our study enriches performance evaluation of this technology, using accessible equipments (HP V-M200 access points and Linksys WPC600N adapters). New accurate results are given, namely at OSI level 4, from TCP and UDP experiments. TCP throughput is measured against TCP packet length. Jitter and percentage datagram loss are evaluated versus UDP datagram size. Results are examined for point-to-point, point-to-multipoint and four-node point-to-multipoint links. Comparisons are also made mainly to related data obtained for Open links. Conclusions are extracted about performance of the links. [ABSTRACT FROM AUTHOR]

This paper presents an inexpensive and simple dual-band bisected psi antenna for 3G, Wi-Fi, WLAN, and WiMAX applications is presented. The antenna comprises a bisected psi-shaped patch on a low-price FR4 substrate with a cropped ground plane on the other side, and is fed by a 50ζ microstrip line. It operates at two distinct frequency bands of 1.87-2.76 GHz and 5.16-5.75 GHz with |S11|≤ -10 dB. [ABSTRACT FROM AUTHOR]

An analysis of shorting pin loaded compact triple-band antenna with triple-mode characteristics is carried out in this paper. The antenna structure is designed with a rectangular patch loaded with open edge slots to excite the fundamental TM10 mode at 2.51 GHz and two modified inverted F-shaped defected ground structures (DGS) for the TM20 and TM30 modes at 5.26 GHz and 8.18 GHz, respectively. A design formula for the fundamental resonant frequency of the basic structure is presented using multiple linear regression technique. The experimental results show good agreement with the simulated results. [ABSTRACT FROM AUTHOR]

In this paper a new antenna design technique is introduced in order to achieve tri-band operation as well as antenna miniaturization. The technique consists of using two concentric first-iterative hexagonal rings connected to each other as a radiating patch fed with a Y-shaped microstrip line. The proposed antenna operates at three frequency bands to cover 2.4/5.8 GHz WLAN bands and 3.5/5.5 GHz WiMAX bands applications. The numerical analysis and simulation are carried out with CST MWS. The measured return losses of the proposed antenna show good performance and good agreement with the simulated ones. Consequently the proposed antenna with compact size of 9.7 mm x 17 mm x 1.63 mm is well suited for wireless applications. [ABSTRACT FROM AUTHOR]

In summer's high temperature weather, the air quality of the stadium is not good, which seriously affects the health of the sports crowd. Therefore, the monitoring technology of air pollutant concentration in the stadium in summer's high temperature weather is studied. The monitoring of air pollution indicator is analyzed based on WLAN. According to the monitoring results of air pollution indicator obtained, the concentration of air pollutants is monitored by support vector machine. The experimental results show that the proposed method is time-consuming and has good performance. [ABSTRACT FROM AUTHOR]

Antenna plays major role in increasing the communication standards to meet the requirements of modern technology driven industries and personal data services. In this paper a novel patch antenna for 2.4GHz WLAN applications presented. The proposed antenna has novel shaped radiator along with modified ground plane with 24-25mm² overall dimension. The proposed antenna developed on the FR4 substrate with dielectric permittivity of 4.4 and height of the substrate is 1.6mm and loss tangent of 0.002 to achieve lower return loss possible. The proposed antenna simulated in an integral based solver simulation software called CST Microwave studio v2019 and obtained results such as VSWR 1.31, return loss -17.29dB with bandwidth of 130MHz, gain of 3.93dBi and efficiency of 82.96%. This antenna suitable for WLAN applications which uses 2.4GHz resonant frequency. [ABSTRACT FROM AUTHOR]

IEEE 802.11s introduces MAC-layer extensions to enable vendor-independent and inter-operable WLAN mesh networks. Featuring automatic device interconnection and routing, 802.11s networks provide a higher scalability, flexibility, and robustness compared to common centralized WLAN infrastructures. As logical Peer-to-Peer (P2P) networks exhibit many of the characteristics of physical WLAN mesh networks on the application layer, it is obvious to consider solutions where both technologies interact to leverage robust distributed wireless applications, such as collaborative data distribution and synchronization in future smart cities. Envisioned scenarios include the administration and update deployment to specific device groups or the distributed caching and delivery of on-demand multi-media content to selected end points within a city-area wireless mesh network. Nevertheless, common P2P protocols, such as BitTorrent (BT), do not consider the structure of the physical underlay as they were primarily designed to be used over wired communication networks, such as large parts of the Internet. Hence, the default BT peer selection mechanism does not adapt to the network topology and varying medium utilization in wireless multi-hop networks. We present MeNTor , a set of optimizations to enable underlay-aware BT peer selection in WLAN mesh networks. It relies on cross-layer integration of default 802.11s information, only requiring minor extension of the BT application layer without introducing any MAC-layer modifications or traffic overhead. Our solution was evaluated in a 25-node real-world mesh test bed, using 10 different seed/leecher placements and comparing 18 parameter combination variants of MeNTor . Results show that average download times can be reduced by 30–40%, depending on the seed/leecher placement and parameter combination variant. Finally, we recommend the variant that performed best across all scenarios as prospective default configuration. [ABSTRACT FROM AUTHOR]

This work presents a compact, quad-band planar antenna intended for assimilation into flexible and conformal devices. The CPW-fed semicircular shaped prototype with rake-shaped slots is designed, realized and characterized experimentally. The frequency bands covered by the proposed radiator are centered at 2.5, 3.7, 5.5 and 8 GHz with measured impedance bandwidths of 16%, 13.5%, 11.8% and 14.63%, respectively. The proposed antenna is thus enabled to support WLAN, ISM, Bluetooth, WiMAX, LTE and X-band applications. The antenna exhibits a significant gain. The radiation characteristics of the proposed radiator are measured in concave and convex bent shapes at various radii to analyze its flexibility. Performance of the antenna remains almost unaffected in the bent situation. Measurements demonstrate good coherence with simulations. The compactness and good performance of the design both in bent and unbent conditions proves it to be the better contender for future multiband conformal wireless applications. [ABSTRACT FROM AUTHOR]

A comb shape rectangular slotted 1 × 4 microstrip patch array antenna is proposed and designed for wireless local area network applications. The functional parameters of the antenna namely, return loss, VSWR, radiation pattern are analyzed. The FR4 substrate is used to the proposed antenna. The dimension of proposed antenna is 143mm of width and 71mm of length and the patch dimension is 29.6mm of width and 38mm of length. The return loss and VSWR of 1 × 4 array antenna is -34.8815dB and 1.012, respectively. The rectangular slots are taken in equal length and width in order to enhance the performance. [ABSTRACT FROM AUTHOR]

The presented paper evaluates and compares the performance of routing protocols in Wireless Ad Hoc network and also discusses the application of ad hoc mode of wireless local area network (WLAN) in emergency health services for a hospital. The vital data of patients within a hospital are monitored and communicated to doctors within the hospital. The proposed scenario helps in managing any emergency situation to a great extent and reduces the delays which may be crucial for such emergency situations. In the proposed study, the doctors and patients are assumed to be mobile so as to mimic the real situation. However, the movement of patient and doctors are confined to a limited range. [ABSTRACT FROM AUTHOR]

The increasing importance of wireless communications, involving electronic devices, has been worldly recognized. Performance is an essential issue, leading to more reliable and efficient communications. Security is also critically important. Laboratory measurements were performed about several performance aspects of Wi-Fi IEEE 802.11a WPA2 and WPA point-to-multipoint links. Our study contributes to the performance evaluation of this technology, using available equipments (HP V-M200 access points and Linksys WPC600N adapters). New detailed results are presented and discussed, namely at OSI level 4, from TCP and UDP measurements: TCP throughput, jitter and percentage datagram loss. Comparisons are made to corresponding results obtained for WPA2 and WPA point-to-point, and Open links. Conclusions are drawn about the comparative performance of the links. [ABSTRACT FROM AUTHOR]

Nowadays, providers of wireless services try to find appropriate ways to increase user data throughput mainly for future 5G cellular networks. Utilizing the unlicensed spectrum (ISM bands) for such purpose is a promising solution: unlicensed frequency bands can be used as a complementary data pipeline for UMTS LTE (Universal Mobile Telecommunication System - Long Term Evolution) and its advanced version LTE-Advanced, especially in pico- or femtocells. However, coexisting LTE and WLAN services in shared ISM bands at the same time can suffer unwanted performance degradation. This paper focuses predominantly on co-channel coexistence issues (worst case) between LTE and WLAN (IEEE 802.1 In) services in the ISM band. From the viewpoint of novelty, the main outcomes of this article are follows. Firstly, an appropriate signal processing approach for coexisting signals with different features in the baseband is proposed. It is applied in advanced link-layer simulators and its correctness is verified by various simulations. Secondly, the influence of IEEE 802.1 In on LTE data and control channel performance is explored. Performance evaluation is based on error rate curves, depending on Signal-to-lnterference ratio (SIR). Presented results allow for better understanding the influence of IEEE 802.1 In on the LTE downlink physical control channels (PCCH) and are valuable for mobile infrastructure vendors and operators to optimize system parameters. [ABSTRACT FROM AUTHOR]

Abstract: The 802.11e Task Group has established to enhance Quality of Service (QoS) provision for time-bounded services in the current IEEE 802.11 Medium Access Control (MAC) protocol. The QoS is introduced throughout Hybrid Coordination Function Controlled Channel Access (HCCA) for the rigorous QoS provision. In HCCA, the station is allocated a fixed Transmission Opportunity (TXOP) based on its TSPEC parameters so that it is efficient for Constant Bit Rate streams. However, as the profile of Variable Bit Rate (VBR) traffics is inconstant, they are liable to experience a higher delay especially in bursty traffic case. In this paper, we propose an integrated solution called Adaptive Feedback-based HCCA (AF-HCCA) for supporting video stream that shows the variability on both packet size and generation interval. The AF-HCCA improves both polling and TXOP assignment mechanisms which efficiently schedules the TS based on their actual need. Simulation experiments have been conducted to show that the proposed scheduler not only enhances the packet delay, but also improves the channel utilization by mitigating the over-pollling issue. [ABSTRACT FROM AUTHOR]

With the wide deployment of Wireless Local Area Network (WLAN), the WLAN Received Signal Strength (RSS) based indoor mapping has attracted significant attention for various of Location-based Services (LBSs). In this paper, we propose a new simultaneous pathway mapping and behavior understanding approach by crowdsourced sensing of WLAN RSS. First of all, a batch of WLAN RSS sequences with known locations are collected to optimize the parameters in density clustering by using the concept of Jaccard Coefficient (JC). Secondly, the wavelet analysis is considered for each RSS sequence with unknown locations to mitigate the noise interference, and then the process of multidimensional scaling approach based dimension reduction is followed to reduce the computation cost involved in density clustering. Thirdly, based on the RSS and timestamp relations of RSS measurements, the density clustering is conducted to merge the RSS measurements at unknown locations into different clusters. Finally, the pathway mapping and behavior understanding are realized according to the indoor mapping from the signal into physical space. The extensive experimental results show that the proposed approach can achieve superior pathway mapping performance compared with the well-known WILL and CIMLoc approaches. [ABSTRACT FROM AUTHOR]

In this paper, a novel compact band pass filter (BPF) is proposed for Wireless Local Area Network (WLAN) (2.2 GHz - 2.6 GHz) Application. The proposed BPF configuration is composed of a low pass filter (LPF). The transformation is due to the introduction of DMS structures (Defected trip Micros Structure) on the two micro strip lines. The lumped equivalent model of proposed BPF is also presented and analyzed. The resulting filter has been found to possess a compact size of 20mm×20 mm. The measured filter performances are |S21| less than 0.5 dB, |S11| more than 60 dB, and center frequency of proposed filter is around 2.4 GHz. The simulations in this work were performed using CST microwave software, whose calculations are based on The Finite Integration Technique (FIT) and ADS (Agilent Advanced Design System) are based on the Method of Moments (MOM). [ABSTRACT FROM AUTHOR]

The applications of Wireless Sensor Networks (WSN) are progressively adopting for various smart home services such as home automation, controlling smart home household appliances, constrained application services in a smart home, etc. However, enabling a seamless and ubiquitous WSN communication between the smart home appliances is still a challenging job. Therefore, in this paper, we propose a smart home control system using an Actuator based ZigBee networking (AZNET). The working of the proposed system is further divided into three phases, 1) an interference avoidance system is adopted to mitigate the effect of interference caused due to the co-existence of IEEE 802.11x based wireless local area networks (WLAN) and WSN, 2) a sensor-based smart light control system is used to fulfill the light requirement in the smart home using the sunlight with light source, and 3) an autonomous home management system is used to regulate the usage time of the electronic appliances in the smart home. The smart is tested in real time environment to use the sunlight with light sources in a various time of the day. Similarly, the performance of the proposed smart home is verified through simulation using C# programming language. The results and analysis revealed that the proposed smart home is less affected by the interference and efficient in reducing the energy consumption of the appliances available in the smart home scenario. [ABSTRACT FROM AUTHOR]

The research on WiFi-based fingerprint positioning has become an important topic in the field of indoor positioning due to its low-cost deployment and widespread applications. However, received signal strength (RSS) from access points (APs) may be missed due to factors such as Green WiFi or AP malfunctions. Traditional approach often set the missed RSS to a predetermined default value, which may not be accurate. We propose a fingerprint recovery framework based on tensor-ring nuclear norm minimization (TRNNM) algorithm which uses the correlation of RSS to recover missed fingerprints in both offline and online phases, called TR-ReFloc. In the offline phase, the radio map in tensor form is recovered by tensor ring (TR) decomposition. In the online phase, depending on different user requirements, there are two stages to generate the positioning results. First, rapid results are generated in coarse positioning stage. Next, high-precision results generated in fine positioning stage by recovering the missed fingerprints using the correlation of test points (TPs) are closed to the current TP. Experiments demonstrate that the proposed framework is robust for recovering missed RSS and can maintain localization accuracy within 2 m even in cases of high missing rate, demonstrating significant improvement over traditional methods. [ABSTRACT FROM AUTHOR]

In accordance with the deployment requirements of WLAN node in college student dorms and its features of application environment, this paper studies the relevance among factors like radio-frequency signal transmission characteristics, communication distance, AP height and transmission path, etc., with a case study of AP radio frequency 2.4GHz. Experiments show that the attenuation of wireless network signal in student dorms conforms to Keenan-Motley model. When AP is fixed, the signal strength received by laptop generally reduces with the increase of communication distance, yet just opposite with packet loss rate. When deploying AP, 1.25-1.75 height is ideal, and one-side coverage of 3 dorm rooms optimal. Based on the above researches, a relational model of AP height, communication distance and received signal strength is established. In it, model parameter K and AP height display a cubic polynomial relationship, and attenuation coefficient n and AP height show a quadratic polynomial relationship. Experiment results demonstrate that this model can satisfactorily predict the received signal strength of different AP heights and communication distances, providing technical support for wireless network deployment in student dorms. [ABSTRACT FROM AUTHOR]

A compact coplanar waveguide (CPW) fed ultrawideband (UWB) printed circular monopole antenna (PMA) with triple frequency notched function is presented and validated here on a low cost FR4 Epoxy substrate. Here the antenna loaded with three single circular ring SRRs to create triple frequency notching in 3.5 GHz for WiMAX, 5.5 GHz for WLAN, and 7.9 GHz for X-band satellite communication systems, respectively. The SRR design equations are analyzed in detail here. Return loss and voltage standing wave ratio (VSWR) are used to show the effect of these rings. Measured result shows a close correlation to the theoretical results. [ABSTRACT FROM AUTHOR]

We present a robust optimisation approach to energy savings in wireless local area networks, that incorporates both link capacity fluctuations and user mobility under Bertsimas and Sim's robust optimization paradigm. Preliminary computational results are discussed. [ABSTRACT FROM AUTHOR]

Fingerprint positioning is a main stream and key technique for seamless positioning systems. In this paper, we develop a performance evaluation testbed for fingerprint based Wireless Local Area Network (WLAN) positioning system. The testbed consists of positioning server, positioning terminal, Access Point (AP) units, positioning accuracy analysis system and testing scenarios. Different from other testbeds tended to focus on testing in same situation, in the proposed testbed, a couple of scenarios are set to test the positioning system including indoor and outdoor environments. Handset-side positioning mode and network-side positioning mode are provided simultaneously. Variety of motion models, such as static model, low-speed model and high-speed model are considered as well as different positioning algorithms. Finally, some implementation cases are analyzed to verify the credibility of the testbed. [ABSTRACT FROM AUTHOR]

A miniaturized dual-band v-shaped monopole antenna fed by v-stub is presented. The proposed antenna performs two resonant modes covering dual-band of wireless standards, for operating in the IEEE 802.11 a,g,n WLAN (5.15-5.35 GHz and 5.725-5.825 GHz) and IEEE 802.16e WiMAX (3.3-3.69 GHz and 5.25-5.85 GHz) bands. The antenna is printed on a 1.6-mm thick FR-4 substrate and the relative permittivity of 4.4, is fed by cross v-strip line a 50Ω with SMA connector. The antenna size is 18 mm × 26 mm × 1.6 mm in dimensions. The measured results show that the miniaturized size antenna achieves a broad operating bandwidth of 3.24–3.71 GHz and 4.85-5.87 GHz for | S 11 | < -10 dB and omnidirectional beam. The measured gains of the antenna at 3.5 GHz and 5.5 GHz frequencies are 1.51 dBi and 2.34 dBi, respectively. [ABSTRACT FROM AUTHOR]

This paper presents the design of triple band compact microstrip patch antenna with fractal elements. The antenna has been designed on FR4 substrate with thickness 1.6mm, dielectric constant 4.4 and resonant frequency of antenna is 3.2GHz. Gain of antenna is improved by addition of fractal elements to the nine corners of the nonagon patch. Introduction of fractal elements improved the gain from 1.24dB to 7.96dB and miniaturization takes place due to the decrease in resonant frequency from 3.38GHz to 2.88GHz on increasing the iteration number. The three iterations of antenna is designed and simulated by using HFSS V13 software and the designed antennas covers the frequency bands of WLAN, WiMax and other wireless applications which comes under the frequency ranges of S-band, C-band and X-band. [ABSTRACT FROM AUTHOR]

In contention-based wireless local area networks (WLAN), adjacent WLAN access points (APs) and stations (STAs) using the same channel may degrade their performance due to contention. To solve this problem, researchers have studied various distributed channel selection schemes, where APs select the least congested channel among all available channels. However, the existing distributed channel selection schemes rarely consider contention from upstream transmission of STAs. Therefore, it is difficult to find the least congested channel in a WLAN environment where both upstream and downstream transmissions exist. In this paper, we propose a novel distributed channel selection scheme which decides a channel with minimum number of interfering STAs as the least congested channel. Unlike the existing schemes, the proposed scheme considers the contention from both downstream and upstream transmissions. In the proposed scheme, an AP can perceive the number of interfering STAs by receiving the beacon frames from its neighboring APs. For practical implementation of our proposed scheme, we also define the additional information elements of the beacon frame according to the IEEE 802.11 standard. By performing a system level simulation and experiment using a test bed, we evaluate and analyze the performance of the proposed scheme by comparing it with that of the least congested channel selection (LCCS) and the client-assisted channel assignment optimization (CACAO) schemes. The simulation result shows that the proposed scheme increases the network throughput by 11% and 20% compared to the LCCS and CACAO schemes, respectively. Under test environment, we confirm that the proposed scheme can enhance the data rate of AP up to three times comparing to that of the LCCS scheme. [ABSTRACT FROM AUTHOR]

A compact planar inverted-F antenna (PIFA) dual band two-unit multiple-input multiple-output (MIMO) antenna system withhigh isolation is developed. The proposed MIMO antenna that consists of two PIFA elements has the advantage of compactstructure and multi-band for mobile device. The proposed antenna can cover the frequency range from 2.36 GHz to 2.52 GHz and 5.05 GHz to 5.98 GHz, therefore, it includes applications: High Performance radio Local Area Network/2 (5.2 GHz/5.6 GHz),Wireless Local Area Network (2.4 GHz/5.2 GHz/5.8 GHz), Bluetooth (2.4 GHz) and Worldwide Interoperability for MicrowaveAccess (5.5 GHz). By integrating a +shaped slots in the ground plane, we can increase the isolation between elements of theproposed antenna. The maximum gain of the proposed MIMO-antenna is 10.07 dB at 2.44 GHz and 9.97 dB at 5.55 GHz. [ABSTRACT FROM AUTHOR]

Nowadays, several interesting patch antenna structure is proposed. In this paper, we are proposing a new rectangular structure in the form of a dollar-symbole, fed by a microstrip line is made with FR4 substrate, a thickness of 1.6 mm, and a relative permittivity of 4.4. The ground plane on the antenna is printed, while contain two slots. The resulting antenna has been found to possess a compact size of 30 mm × 30 mm, and suitable for wireless local area network (WLAN). Two resonant frequencies are obtained by the proposed antenna. The low-band resonant frequency is located at about 2.4 GHz, with -10 dB impedance bandwidth from about 1.9 GHz to 3 GH, and the high-band resonant frequency is located at about 8.8 GHz, with -10 dB impedance bandwidth from about 7.6 GHz to 10 GHz. In the first part, a comparison study of a patch antenna with slots and without slots is proposed; in the second part, the study of antenna parameters which affect dimensions is presented. [ABSTRACT FROM AUTHOR]

The Wi-Fi becomes very common in different environments today. The availability of control and local wireless LAN in addition to supply a communication channel makes the Wi-Fi the choice of many domestic services and personal applications. This paper proposed a design and implementation of new controlling and monitoring system that used Wi-Fi technology as a network infrastructure topology to connect its parts. This design provides an appropriate interface to the sensors and actuators of the desired environment and provides scalability and flexibility that can manage many hardware interfaces as long as it exists on the range of the Wi-Fi network coverage. The presented system support many environments like home, medical, educational and industrial. Provide monitoring and control using many sensors and actuators. The evaluation shows that the design provides many benefits like, reduced installation costs, where single Wi-Fi system can accomplish many functions with minimal hardware setup. In addition, the presented system is easy deployment, installation, and coverage. [ABSTRACT FROM AUTHOR]

Wireless communication devices such as smartphones are essential in our recent daily life. The devices are also able to apply to understand human behaviors besides connecting a network via high speed communication links. One of such network services includes public wireless LAN services. The service is provided at many public spaces and stores. The stores especially need some added values by the public wireless LAN service. Concrete services such as avoiding disasters and inducement customers via coupons already have begun at many stores in Japan. This study proposes the extraction method of human's standing in line behavior to contribute increasing added values of public wireless LAN services at several stores. The shop owners are able to know how long the standing in line in front of their shops and provide appropriate services to their customers. This study uses wireless LAN frame data on the air. The estimation model with Bayesian estimation method is applied by using the received signal strength in actual wireless LAN frames. It achieved high accuracy of 0.868 through the evaluation experiment by 5-fold cross validation. [ABSTRACT FROM AUTHOR]

Our ancestors have been designing and building structures for centuries to protect themselves from the environment and to sustain the well-being of their occupants. Achieving a healthy indoor environment has become a challenge among design professionals, such as architects, engineers and scientists, due to chemical and physical indoor environmental parameters. Nowadays, we face a new challenge: providing healthy and effective wireless communication in the building environment that pushes the envelope of building design. Wireless communication systems emit Electromagnetic Waves. These high frequency waves exist both inside buildings and the free space around us. There are a variety of RF sources and they cover a wide range of the electromagnetic spectrum, such as cell towers (masts), cordless DECT phones, smart meters, Wi-Fi router/modems, WiMAX networks, cellular phones (mobiles), video games, digital baby monitors, digital TV, audio/video sender receivers, tetra emissions, and wireless burglar alarms and so on. The range of radio frequency (RF) spectrum spans 3 kHz to several hundred GHz. The microwave ranges from 1 GHz to 40 GHz and is used in contemporary point-to-point, wireless, and satellite communications. The purpose of this paper is to evaluate current power intensity levels in building environments and develop guidelines for design professionals by understanding building materials ‘properties. In building design, there are diverse approaches to provisions of wireless communication and constant innovation; however, the construction materials and EMW propagation relationship remains a secondary consideration. Researching EMW propagation issues to develop guidelines for incorporating wireless communication systems into Architectural Design will promote healthy and effective indoor environments. [ABSTRACT FROM AUTHOR]

ZigBee (IEEE 802.15.4) is a wireless mesh networking protocol low in cost, power, data rate, and complexity. To access Lo- cal Area Networks (LAN), 802.11b/g standard is used all over the world as Wi-Fi (Wireless Fidelity) standard. IEEE 802.15.4 Wireless Sensor Networks (WSNs) and IEEE 802.11b/g Wireless Local Area Networks (WLANs) are often collocated, causing a coexistence. The coexistence occurs because these networks share the same 2.4 GHz Industrial, Scientific, and Medical (ISM) band. A Simulation model has been introduced which completely reflects the ZigBee and WiFi coexistence. We have proposed frequency agility based interference avoidance algorithm . However, algorithm detects interference and adaptively switch nodes to safe channel for dynamically avoid WLAN interference with lower latency and energy consumption. The performance of ZigBee under WiFi is empirically evaluated in terms of the packet error rate (PER) and bit error rate (BER). The Simulation results us- ing frequency agility algorithm demonstrate that the design guideline can efficiently mitigate the effect of WiFi interference and enhance the performance of ZigBee networks. [ABSTRACT FROM AUTHOR]

Labeling diversity is an efficient technique recently proposed in the literature and aims to improve the Bit Error Rate (BER) performance of Wireless Local Area Network (WLAN) systems with two transmit and two receive antennas without increasing the transmit power and bandwidth requirements. In this paper, we employ labeling diversity with different space-time channel codes such as convolutional, turbo and Low Density Parity Check (LDPC) for both point-to-point and coded-cooperative communication scenarios. Joint iterative decoding schemes for distributed turbo and LDPC codes are also presented. BER performance bounds at an Error Floor (EF) region are derived and verified with the help of numerical simulations for both cooperative and non-cooperative schemes. Numerical simulations show that the coded-cooperative schemes with labeling diversity achieve better BER performances and use of labeling diversity at the source node significantly lowers relay outage probability and hence the overall BER performance of the coded-cooperative scheme is improved manifolds. [ABSTRACT FROM AUTHOR]

In recent years, a large diversity of network-enabled devices have been widely prevalent in home environment. With the prevalence of such devices, wireless home networks enable monitoring and control applications for home user comfort and efficient home management. In the home network, alarm signals must be delivered in real-time to the residents or to the emergency services and some home control applications require the response time to be on the order of a few hundred milliseconds for optimal user experience. Most recently, ZigBee has emerged as one of the most promising technologies for wireless home networking because it is targeted at applications that require a low data rate and long battery life, which are also the features of home network applications. However, its usage in close proximity to Wireless Local Area Networks (WLANs) introduces coexistence problems, resulting in failing to fulfil the response time required by the home control applications. To overcome this problem, we propose to control the WLAN traffic when there exist ongoing ZigBee transmissions and the maximum tolerable delay is not met due to the WLAN interference. We aim to guarantee that the delay experienced by ZigBee sensors (especially, for alarm signals) does not exceed the maximum tolerable delay, while maintaining as high throughput as possible in the WLANs. The simulation results demonstrate that our proposed algorithm can enhance the delay performance of ZigBee networks by mitigating the effect of WLAN interference and improve the throughput in the WLANs. [ABSTRACT FROM AUTHOR]

With the continuing development of the wireless technologies (Wi-Fi, 3G, 4G, WiMax and Bluethooth), the study of wireless multimedia transmissions has gained lately more attention. For example, the expectations of the company leaders on the growth of Wi-Fi video traffic has updated the lines of research on the standard IEEE 802.11e introduced to provide QoS (Quality of Service) to WLAN (Wireless LAN ) networks. In this paper we updated with greater accuracy, using other resources and the experience gained since the emergence of the standard, the work carried out previously on the quantitative impact of each EDCA (Enhanced Distributed Channel Access) parameter on the overall performance of the mechanisms MAC. A quantitative analysis of the optimizations that can be achieved has been performed by simulation. We use a node model EDCA 802.11e with the tool Möbius of the University of Illinois, which supports an extension of SPN (Stochastic Petri Networks), known as HSAN (Hierarchical Stochastic Activity Networks), what favors the contrast with other tools or mathematical resources. We use a realistic scenario formed by Wi-Fi stations with the capacity to transmit voice, video and best effort traffic. The results show that the default setting of EDCA parameters is not optimal, and that with an appropriate selection, very significant improvements can be obtained. [ABSTRACT FROM AUTHOR]

In order to improve the throughput of high-density and large-scale wireless local area networks (WLANs), a novel heuristic algorithm T wo - D imensional O ptimization Integrating C hannel Assignment and P ower Control ( TDOCP ) is proposed. Based on the traffic characteristic analyzed from real network, we take both uplink and downlink traffic into account in network modeling. The analysis of network utility shows that it has a controllable upper bound. So this paper develops a scheme to maximize the upper bound of network utility, and then make network utility converge to the enhanced upper bound. Both channel assignment (CA) and power control (PC) are performed in each iteration. To illustrate the advantages of TDOCP, a compared algorithm O ne- D imensional O ptimization Integrating C hannel Assignment and P ower Control ( ODOCP ) is designed, which implements the least congested channel search (LCCS) in CA, and the power control for AP performance (PCAP) in PC. Only one-dimensional optimization is implemented in each iteration of ODOCP. Extensive simulations show that the network model in this paper is effective, and TDOCP outperforms current popular one-dimensional optimization algorithms LCCS, PCAP, and the compared ODOCP in the aspect of increasing throughput and reducing network delay. [ABSTRACT FROM AUTHOR]

A miniaturized triple-band antenna suitable for wireless USB dongle applications is proposed and investigated in this paper. The presented antenna, simply consisting of a circular-arc-shaped stub, an L-shaped stub, a microstrip feed line, and a rectangular ground plane has a compact size of 16 mm × 38.5 mm and is capable of generating three separate resonant modes with very good impedance matching. The measurement results show that the antenna has several impedance bandwidths for S11 ≤-10 dB of 260 MHz (2.24 GHz to 2.5 GHz), 320 MHz (3.4 GHz to 3.72 GHz), and 990 MHz (5.1 GHz to 6.09 GHz), which can be applied to both 2.4/5.2/5.8 GHz WLAN bands and 3.5/5.5 GHz WiMAX bands. Moreover, nearly-omnidirectional radiation patterns and stable gain across the operating bands can be obtained. [ABSTRACT FROM AUTHOR]