Classification of Handoff Schemes in a Wi-Fi-Based Network

2019 ◽  
pp. 300-332 ◽  
Author(s):  
Abhishek Majumder ◽  
Samir Nath
Keyword(s):  
Wireless Lan ◽  
Handoff Management ◽  
Wireless Applications ◽  
Handoff Latency ◽  
Handoff Delay ◽  
Comprehensive Comparison ◽  
Management Schemes ◽  
Single Radio ◽  
Handoff Schemes

Handoff management of the users is one of the major issues wi-fi-based wireless LAN. The total handoff process can be divided into three phases, namely scanning, authentication, and re-association. If mobile client frequently changes its position while accessing internet, number of handoffs also increases proportionally. Frequent handoffs affect the quality of service of different wireless applications because of large handoff latency. Many schemes have been developed for reducing handoff delay. In this chapter, handoff management schemes have been classified based on the phase in which the scheme works. Thus, the techniques have been classified as scanning-based schemes, authentication-based schemes, and re-association-based schemes. This chapter also classifies the handoff schemes into two categories based on the number of radios used: single-radio-based handoff schemes and multi-radio-based handoff schemes. The schemes under each of the class have been discussed in detail. A comprehensive comparison of all the schemes has also been presented in this chapter.

scholarly journals Economical effect on doubling of COVID-19 cases: examples of rich versus poor countries

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Osama Ali Maher ◽  
Dmitry Mun ◽  
Fatma Giha ◽  
Mayouson Ali ◽  
Saverio Bellizzi
Keyword(s):  
Health System ◽  
Work Force ◽  
Epidemiological Data ◽  
Content Type ◽  
Poor Countries ◽  
Complex Emergencies ◽  
Internal Conflicts ◽  
Comprehensive Comparison ◽  
The Government

Purpose The paper aims to examine some economical, political and health system indicators on the transmission of the COVID-19 transmission within the national system. The main objective is to investigate what are the most effective indicators which have led to the declared numbers by countries. Design/methodology/approach This study combined multiple sets of data to describe best the economical status of the health system including the government spending on the health system to draw some conclusion regarding the behavior of the pandemic. Findings Complex emergencies and internal conflicts negatively affected the quality of the reported cases and the size of the pandemic. The health work force was the most determinant factor of the health system. It can sometimes be impossible to understand the epidemic only with epidemiological data or health system one; economical aspects of health system and political situation have to be added to the equation. Originality/value The research according to the authors’ knowledge is the most comprehensive comparison so far that investigate the non-covid aspects from a political side in particular in complex emergencies and war situation added health system indicators.

scholarly journals Penerapan Quality Of Service (QoS) dengan Metode PCQ untuk Manajemen Bandwidth Internet pada WLAN Politeknik Negeri Madiun

2019 ◽  
Vol 2 (1) ◽  
pp. 7
Author(s):  
Hendrik Kusbandono ◽  
Eva Mirza Syafitri
Keyword(s):  
Quality Of Service ◽  
Packet Loss ◽  
Wireless Lan ◽  
Quality Of Services ◽  
Ip Address

Teknologi <em>Wireless</em> LAN difungsikan untuk memfasilitasi kemudahan untuk koneksi jaringan, tidak lain termasuk jaringan internet. Manajemen <em>bandwidth</em> merupakan mengalokasikan suatu <em>bandwidth</em> yang berfungsi untuk mendukung kebutuhan atau keperluan suatu jaringan internet agar memberikan jaminan kualitas layanan suatu jaringan QoS (<em>Quality of Services</em>). Dengan tujuan untuk mengetahui bagaimana kualitas layanan dan kinerja jaringan <em>Wireless</em> LAN (WLAN), serta mengoptimalkan pembagian <em>bandwidth</em> secara merata ke sejumlah <em>client</em> yang aktif. Metode penelitian ini adalah penerapan <em>Quality </em><em>of Service</em> (QoS) yang digunakan untuk mengukur kualitas <em>b</em><em>andwidth</em> internet yang berjalan pada Wireless LAN dengan parameter <em>download</em>, <em>upload</em>, <em>throughput</em>, <em>delay</em>, <em>jitter</em>, dan <em>packet loss</em><em> </em>dan manajemen <em>bandwidth</em> dengan PCQ (<em>Per Connection Queue</em>). Hasil penelitian ini adalah pada rentang waktu 08.00 s/d 16.00 WIB quota IP Address dinamis habis, sehingga tidak dapat mengkoneksikan ke hotspot PNM-MHS. Menunjukkan rata-rata nilai sebelum dilakukan manajemen <em>bandwidth </em>metode PCQ pada <em>throughput</em> adalah 374,98 Kbps, nilai <em>delay</em> adalah 40,16 ms dengan kategori latensi “Sangat Bagus”, nilai <em>jitter</em> adalah 99,43 ms dengan kategori degradasi “Sedang”, nilai <em>packet loss</em> adalah 23,94 % dengan kategori degredasi “Sedang”. Sedangkan setelah melakukan manajemen <em>bandwidth </em>nilai <em>throughput</em> adalah 362,56 Kbps, nilai <em>delay</em> adalah 29,84 ms dengan kategori latensi “Sangat Bagus”, nilai <em>jitter</em> adalah 55,53 ms dengan kategori degradasi “Bagus”, nilai <em>packet loss</em> adalah 14,29 % dengan kategori degredasi “Bagus”. Manajemen <em>bandwidth </em>metode PCQ bekerja dengan sebuah algoritma yang akan membagi <em>bandwidth</em> secara merata ke sejumlah client yang aktif. PCQ ideal diterapkan apabila dalam pengaturan <em>bandwidth</em> kesulitan dalam penentuan <em>bandwidth</em> per client.

Multicommodity-Based Delay Analysis for Heterogeneous Wireless Services in Core Network

2012 ◽  
Vol 198-199 ◽  
pp. 1733-1738
Author(s):  
Xiao Wei Qin ◽  
Feng Chen
Keyword(s):  
Access Network ◽  
Core Network ◽  
Wireless Applications ◽  
Core Networks ◽  
Service Delay ◽  
Wireless Access Network ◽  
The Cost ◽  
Mathematics Problem ◽  
Minimal Cost Flow

With the explosive growth of wireless applications, the subscribers’ requirements of QoS (Quality of Service) are increasing as well. In this paper, the upper bound of the tolerant delay of services in wireless access network is investigated, by mapping core network onto a cost-variable directed graph, where the cost is construed as the average service delay of the flows traveling in core network that depends on the current load. A multicommodity minimal cost flow mathematics problem is then derived and solved by Price-directive Decomposition and Lagrangian Relaxation. Simulations are carried out in two typical core networks and some valuable conclusions are gained.

Mobility and Enterprise 2.0

2010 ◽  
pp. 516-530
Author(s):  
François J.N. Cosquer ◽  
Annie Ohayon-Dekel
Keyword(s):  
Tacit Knowledge ◽  
Wireless Lan ◽  
Emergency Services ◽  
Mobile Technologies ◽  
Success Factor ◽  
Full Potential ◽  
Enterprise 2.0 ◽  
Productivity Level ◽  
Mobility Support

The emergence of Web 2.0 and its rapid adoption by the corporate world, known as Enterprise 2.0, has radically modified access to tacit knowledge and significantly reduced business latency. Meanwhile, technology for wireless LAN and mobile communication, combined with advances in handsets, has allowed for superior quality of experience with acceptable productivity level. Combining mobility with Enterprise 2.0 is the next big step in evolution. This article presents the drivers for Enterprise 2.0 and the challenge of tapping tacit knowledge and, in parallel, the evolution of wireless and mobile technologies. The era of mobile broadband life is made possible, creating new ways of use and expectations for Millennials. The next business generation will be able to unleash the full potential of mobility and Enterprise 2.0. Three scenarios selected from different vertical domains—healthcare, education and emergency services—illustrate the benefits of mobility and Enterprise 2.0 in action. With the expected continued strong growth of wireless access, mobility support is one, if not the, key success factor for Enterprise 2.0.

scholarly journals Evaluation of a class of NLFM radar signals

2019 ◽  
Vol 2019 (1) ◽  
Author(s):  
Sebastian Alphonse ◽  
Geoffrey A. Williamson
Keyword(s):  
Search Space ◽  
Frequency Function ◽  
Radar Signal ◽  
Optimized Design ◽  
Nonlinear Frequency ◽  
Signal Design ◽  
Signal Model ◽  
Radar Systems ◽  
Comprehensive Comparison

AbstractSignal design is an important component for good performance of radar systems. Here, the problem of determining a good radar signal with the objective of minimizing autocorrelation sidelobes is addressed, and the first comprehensive comparison of a range of signals proposed in the literature is conducted. The search is restricted to a set of nonlinear, frequency-modulated signals whose frequency function is monotonically nondecreasing and antisymmetric about the temporal midpoint. This set includes many signals designed for smaller sidelobes including our proposed odd polynomial frequency signal (OPFS) model and antisymmetric time exponentiated frequency modulated (ATEFM) signal model. The signal design is optimized based on autocorrelation sidelobe levels with constraints on the autocorrelation mainlobe width and leakage of energy outside the allowed bandwidth, and we compare our optimized design with the best signal found from parameterized signal model classes in the literature. The quality of the overall best such signal is assessed through comparison to performance of a large number of randomly generated signals from within the search space. From this analysis, it is found that the OPFS model proposed in this paper outperforms all other contenders for most combinations of the objective functions and is expected to be better than nearly all signals within the entire search set.

Application Specific Performance Evaluation of Vertical Handoff in UMTS-WLAN Network

2018 ◽  
Vol 18 (04) ◽  
pp. 1850013 ◽  
Author(s):  
AABHA JAIN ◽  
SANJIV TOKEKAR
Keyword(s):  
Heterogeneous Network ◽  
Mobile Node ◽  
Traffic Load ◽  
Vertical Handoff ◽  
Handoff Management ◽  
Seamless Mobility ◽  
Handoff Latency ◽  
End To End ◽  
Application Specific ◽  
Unnecessary Handoff

The next generation of wireless system is expected to provide multimedia, multi class services any time anywhere with seamless mobility and Quality of Service (QoS). In such environment, vertical handoff management plays an important and challenging role. Some of the main functions of vertical handoff management are: to implement appropriate vertical handoff decision to minimize number of unnecessary handoff, to maintain minimum vertical handoff latency for seamless mobility and to provide guaranteed acceptable QoS required for user satisfaction. Thus, in this paper to avoid unnecessary handoff in integrated heterogeneous network we have proposed that the vertical handoff decision depends on coverage area of the network and the speed of the Mobile Node. Application specific cut-off speed for particular coverage range of network during which handoff is beneficial has been determined. Real time applications like HDTV, MPEG-4, and H.261 are considered in integrated heterogeneous network of UMTS (Universal Mobile Telecommunication System) and WLAN. Vertical handoff latency is analyzed for varied network traffic load, types of application and varied speed of Mobile Node. Effect of Mobile Node speed on packet loss is also analyzed. Finally, to satisfy user with acceptable end to end QoS, especially in the presence of heterogeneous integrated networks where every network has individual QoS, an end to end QoS mapping scheme between UMTS and WLAN integrated network has been proposed. The simulation is performed using Network Simulator NS-2 with NIST (National Institute of Standards and Technology) add on module.

scholarly journals A Wearable Smart Device to Monitor Multiple Vital Parameters—VITAL ECG

Electronics ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 300 ◽  
Author(s):  
Vincenzo Randazzo ◽  
Jacopo Ferretti ◽  
Eros Pasero
Keyword(s):  
Physical Activity ◽  
Health Monitoring ◽  
Low Cost ◽  
Mobile App ◽  
Smart Devices ◽  
Smart Device ◽  
Golden Standard ◽  
Comprehensive Comparison ◽  
Vital Parameters

Smart devices are more and more present in every aspect of everyday life. From smartphones, which are now like mini-computers, through systems for monitoring sleep or fatigue, to specific sensors for the recording of vital parameters. A particular class of the latter regards health monitoring. Indeed, through the use of such devices, several vital parameters can be acquired and automatically monitored, even remotely. This paper presents the second generation of VITAL-ECG, a smart device designed to monitor the most important vital parameters as a “one touch” device, anywhere, at low cost. It is a wearable device that coupled with a mobile app can track bio-parameters such as: electrocardiogram, SpO2, skin temperature, and physical activity of the patient. Even if it not yet a medical device, a comprehensive comparison with a golden standard electrocardiograph is presented to demonstrate the quality of the recorded signals and the validity of the proposed approach.

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