Wlan

For the past ten years, heterogeneous networks wired and wireless had tended to integrate seamlessly, offering
effective and reliable service for medical operations. One of the problems encountered by network practitioners is the seamless integration of network components into healthcare delivery. As a multiplexing hospital model, the implementation certainly presents some challenges. The major technical and performance issues involve are as following. The operating parameters should keep aligned to the Quality of Service (QoS) requirement throughout simulation. Bandwidth utilisation of wireless networking is a challenging issue for real-time multimedia transmission. IEEE 802.11 provides relatively lower data rate than wired networks, thus the developer tends to adopt a more compromised solution: either reduce the file size or compress the image packets. Communication performance that varies constantly with the impact of signal strength, traffic load and interference. As stated radio signal senses as a curve and attenuates greatly while metallic object and
microwave exist within the active range. To ensure devices do not interfere with other electronic equipments (e.g. heart monitors), assert wireless spectrum has to be managed appropriately. This research paper aims to develop a generic hospital network scenarios using Wireless Local Area Network (WLAN) over OPNET Simulation, to evaluate the performance of the integrated network scenario for Intensive Care Units (ICU).  This research makes use of computer simulation and discusses various aspects of the network design, so as to discover the performance behaviour pertaining to effect of traffic type, traffic load and network size. In the ICU scenario, the performance of video conference degrades with network size, thus, a QoS-enabled device is recommended to reduce the packet delay and data loss. IEEE 802.11a suits in hospital environment because it mitigates interference on the 2.4GHz band where most wireless devices operate. Experiment examines the effect of signal strength in WLAN. It is convinced that -88dBm is the best signal strength threshold. Although 802.11a generates slightly lower throughput than 802.11g, this issues can be addressed by placing more APs in the service area. It is convinced that 802.11a suits the hospital environments, because it mitigates interference on the popular 2.4GHz band where most wireless devices operate. It is important for medical devices which require future upgrade and Bluetooth deployment.

The IEEE 802.11ai is an upcoming fast initial link setup (FILS) amendment that could enable a STA to achieve secure link setup in less than 100 ms. A successful link setup process will then allow the STA to send IP traffic with a valid IP address through the AP. In this paper, we first present a performance analysis on how well the legacy 802.11 can support FILS. We then demonstrate that the rate at which the medium saturates is mainly dependent on the offered load which has strong dependencies on the active scan rates (i.e., amount of transmitted probe request frames) and number of responding APs (i.e., amount of transmitted probe response frames) among others. Moreover, the average active scanning duration per channel could be maintained below 5 ms provided the medium is not saturated. Our results also indicate that a combination of the enhanced distributed channel access (EDCA) procedure and the proposed active scanning enhancements provides at least 20% and up to 250% improvements in supporting the functional requirements of FILS as compared to the 802.11 EDCA and legacy distributed coordination function (DCF), respectively.

Many corporations are seriously concerned about security of networks and therefore, their network supervisors are still reluctant to install WLANs. In this regards, the IEEE802.11i standard was developed to address the security problems, even though the mistrust of the wireless LAN technology is still existing. The thought was that the best security solutions could be found in open standards based technologies that can be delivered by Virtual Private Networking (VPN) being used for long time without addressing any security holes for the past few years. This work, addresses this issue and presents a simulated wireless LAN of IEEE802.11g protocol, and analyzes impact of integrating Virtual Private Network technology to secure the flow of traffic between the client and the server within the LAN, using OPNET WLAN utility. Two Wireless LAN scenarios have been introduced and simulated. These are based on normal extension to a wired network and VPN over extension to a wired network. The re...

La démocratisation des réseaux Wi-Fi a grandement simplifié le déploiement des infrastructures domestiques et professionnelles. Même si cette évolution est extrêmement positive, gardons-nous de penser que cette technologie est exempte de défauts. Contrairement aux réseaux filaires qui ne peuvent être attaqué que de façon distante, depuis Internet, un réseau sans fil pourra toujours être pénétré localement.

Low noise amplifier is a crucial and essential component in RF receiver design. It amplifies the received weak RF signal with minimum noise contribution. Designing Low noise amplifier with CMOS technology is one of the important topics in research fields due to its advantages of low power, low cost and higher integration. Applications of LNA include WLAN, WSN and UWB applications. In this paper a detailed survey is provided for various LNA design techniques. The designed circuit is simulated using Advanced Design System (ADS) software.

The IEEE 802.11ac is an emerging very high throughput (VHT) WLAN standard that could achieve PHY data rates of close to 7 Gbps for the 5 GHz band. In this paper, we introduce the key mandatory and optional PHY features, as well as the MAC enhancements of 802.11ac over the existing 802.11n standard in the evolution towards higher data rates. Through numerical analysis and simulations, we compare the MAC performance between 802.11ac and 802.11n over three different frame aggregation mechanisms, viz., aggregate MAC service data unit (A-MSDU), aggregate MAC protocol data unit (A-MPDU), and hybrid A-MSDU/A-MPDU aggregation. Our results indicate that 802.11ac with a configuration of 80MHz and single (two) spatial stream(s) outperforms 802.11n with a configuration of 40 MHz and two spatial streams in terms of maximum throughput by 28% (84%). In addition, we demonstrate that hybrid A-MSDU/AMPDU aggregation yields the best performance for both 802.11n and 802.11ac devices, and its improvement is a function of the maximum A-MSDU size.

Wireless local area network (WLAN) has been widely used in many sectors. The popularity gained is due to many reasons, such as ease of installation, installation flexibility, mobility, reduced cost-of-ownership, and scalability. However, regardless of the benefits mentioned above, WLAN have some security threats, in which anyone who use it or intend to use it should be aware. This paper begins by introducing the concept of WLAN. The introductory section gives brief information on the WLAN components and its architecture. In order to examine the WLAN security threats, this paper will look at Denial of Service, Spoofing, and Eavesdropping. This paper will also tell about the reasons of loss of data and the security measures that are involved to reduce the loss of data from hackers by using the data confidentiality and prevention and access control mechanism.

An E-shaped printed monopole antenna with loaded resonant elements suitable for penta-band multi-input multi-output (MIMO) application is proposed. The simple E-shaped monopole antenna results in a single resonance, and by loading the vertical arm of the antenna with narrow slots and stubs, a multi-band antenna can be obtained. The slots so placed on the antenna create L-shaped resonance paths which are multiples of λ g /4, and stubs resonate at λ g /4. The antenna is designed for operation over the UMTS, WiMAX and WLAN frequencies 2.1, 2.5, 3.5, 5.2, 5.8 GHz. A two element array of such antennas with close spacing of λ g /15 is suitable for MIMO application. The array has low mutual coupling, low envelope correlation, high efficiency and good radiation patterns over all five frequency bands. Simulation and measurement results are compared and discussed.

Voice over IP is a major trend in applications for wireless networks, but even so it is not immune to the risks usually related with IP networks. Proposed solutions for VoIP security are already in the market, but these solutions must take into account the real-time constraint of voice service and their mechanisms should address possible attacks and overhead associated with it. One of these solutions is to use IETF IPSec
to guarantee confidentiality in order to address security design
holes of wireless VoIP networks. This article performs an experimental comparison of the impact of encryption mechanisms on voice speech quality in widely deployed wireless technologies: 802.11 and Bluetooth. Evaluates the upper bound on number of simultaneous VoIP calls which can be placed in a single cell of both networks when security is applied and uses the computational model E-Model to assess quantitatively the quality of service.

This paper presents the design of a compact circular microstrip patch antenna for WLAN applications which covers the band 5.15 to 5.825 GHz. The antenna is designed using 1.4mm thick FR-4 (lossy)substrate with relative permittivity 4.4 and a microstrip line feed is used. The radius of the circular patch is chosen as 7.62mm. To reduce the size and enhance the performance of the proposed antenna, a circular slot is loaded on circular patch and a square slot is etched on the ground plane of dimension 30mm×30mm. Design of the antenna is carried out using CST Microsoft Studio Sonimulation Software. The proposed antenna resonates at 5.5 GHz with a wider bandwidth of 702 MHz and it provides low return loss of-31.58 dB, good gain of 3.23 dB and directivity of 4.28 dBi and high efficiency of around 79% against the resonance frequency. The geometry of the proposed circular antenna with reduced size and its various performance parameters such as return loss, bandwidth, VSWR, gain, directivity, efficiency and radiation pattern plots are presented and discussed.

Abstract: The main objective is to discuss the security features and weakness of IEEE 802.15, IEEE802.11 and IEEE802.16 i.e. Wireless PAN, Wireless LAN and Wireless WAN networks. Bluetooth, Wi-Fi and Wi-Max are the three most widely used wireless networking technologies. These networks are exposed to many types of risks and have various flaws in their respective protocol structure. Bluetooth belongs to a category of Short-range Wireless technologies, Wireless LAN or Wi-Fi is the LAN network we use in our home, offices or buildings etc to provide user the network availability whereas WI-MAX is used on a bigger scale MAN i.e. providing the network coverage on a metro scale through cellular networks to compensate the wired broadband services. In this Paper, study of these popular wireless communication standards in current scenario, evaluating their security features in terms of various metrics. This dissertation focuses on the various types of attacks on these networks and the countermeasures to overcome them.
Keywords: Bluetooth, WiFi, WiMAX, wireless network security, Lan Network, WLAN, WWAN, broadband communication.
Title: A COMPARATIVE ANALYSIS OF SAFETY MEASURES ATTACK IN WI-FI, WI-MAX AND BLUETOOTH
Author: A. Sivasankari, Mrs. S. Sudarvizhi, D. Mohana priya
International Journal of Computer Science and Information Technology Research
ISSN 2348-120X (online), ISSN 2348-1196 (print)
Research Publish Journals

The WLAN is operated in some high traffic area where the radiation beam produced by the antenna is to be utilized with optimum efficiency. The aim of those antennas is to produce some directive and switched beams rather than producing Omni-directional pattern since these beam patterns are considered to be wastage in some non-used or low traffic areas. Hence, the antenna systems producing the directive and switched beams should be highly preferred for the WLAN application. A smart antenna array system performs the adaptive beam forming by focusing the beam in the desired direction and creating nulls in other directions to avoid the interference and the wasting of the beams. This is performed by the operating the phase shifting in its feed network and different ports. This paper investigates the performance of the different array patterns with different phase shifting for the optimum performance of the WLAN applications in a high congested indoor environment.

The worldwide introduction of third generation mobile phone networks, coupled with advanced handsets capable of hosting rich client applications, provides a new context for mass access information systems. This infrastructure provides the opportunity to move on from the client-server and intranet models of mobile computing and build more sophisticated mass-client architectures that distribute processes and data transparently between servers and mobile clients using personalisation, push technologies and location aware services. This paper discusses the technical platform for 3G and WLAN based mobile information systems and explores an example application that leverages some of the key features of this platform using Java APIs.

Handover means transferring an on going call or data sessions one cell to another. Vertical handover may be referred to a process of transferring call connected to a network/data session from one channel connected in a cell to the core network of another. A suitably equipped device may be able to use both technologies at a time, the high speed Wireless LAN and cellular technology. Wireless LAN connections generally provide higher bandwidth but smaller coverage area as compared cellular networks which have lower bandwidth and wide coverage. Thus the user can use a Wireless LAN connection whenever it’s available, while when it isn’t available can switch to a cellular connection as an alternative. Vertical handover refers to automatic switching the communication/data session from one technology to the other. The architecture and algorithm with which the handover decisions are made is also implemented. Vertical Handover provides benefits like less power consumption and saves money by switching to available WLAN connections which are cheaper than UMTS.

We present in this paper a compact low profile inverted-F Multi band antenna (IFMBA) system with MIMO feature for WiFi – WLAN - WiMAX applications. The proposed antenna IFMBA suits for 2.4, 3.5 & 5 GHz operations in multi-path propagating environments with capability to reduce the deep fading caused. It has a smart feature of low profile, near omni directional patterns and placed on printed circuit diplexer feed network of compact size for multiband operation. This antenna is useful for indoor small cell base station applications with support for polarization diversity / spatial diversity. Presented in this paper here is the IFMBA with simulated results, prototyped and results from measurement, from which it is evident that the measured results are in close agreement with that of simulated. The targeted 10 dB return loss bandwidth is achieved and its near omni directional radiation patterns are validated by experimental measurements.

Networks are prone to security attacks, and wireless infrastructure network is more vulnerable. The number of people preferring Wireless networks compared to the wired network has seen an expansion of user base owing to the fast and easy installation of wireless infrastructure. Security issues also increases proportionally as the number of users increases. One of the major security issues witnessed in wireless networks is denial-of service (DoS) attack. A denial-of service (DoS) attack can be defined as an attempt to make the network resource unavailable to its intended users, which may be to temporarily interrupt or suspend services of a host connected to the Internet. Therefore it is imperative to understand the extent of, the effect of denial of service attack on normal network performance. In this paper the effect on network performance due to Denial of Service attack is evaluated by measuring the throughput, number of packets received and the number of packets lost and then comparing it with a network which is not under attack.