Search results for "Wi-Fi"
showing 7 items of 57 documents
WIDAR: Bistatic WI-fi Detection And Ranging for off-the-shelf devices
2013
The huge spread of wireless networks and the success of location-aware applications require novel indoor po- sitioning mechanisms based on existing technologies such as IEEE 802.11. Taking inspiration from the RADAR, we propose WIDAR: a bistatic WI-fi Detection And Ranging system for off- the-shelf devices. WIDAR implementation is based on the USRP2 platform and is able to locate 802.11 stations while they operate in existing legacy networks. No substitution or repositioning of the Access Points is necessary. WIDAR works passively and does not expect any dedicated action from the target WiFi node. No airtime is wasted and the target cannot even detect that it is being ranged. Such features …
Using self-deferral to achieve fairness between Wi-Fi and NR-U in downlink and uplink scenarios
2022
Wireless networks operating in unlicensed bands generally use one of two channel access paradigms: random access (e.g., Wi-Fi) or scheduled access (e.g., LTE License Assisted Access, LTE LAA and New Radio-Unlicensed, NR-U). The coexistence between these two paradigms is based on listen before talk (LBT), which was, however, designed for random access. Meanwhile, scheduled systems require that their transmissions start at the beginning of a slot boundary. Synchronizing this boundary to the end of LBT usually requires transmitting a reservation signal (RS) to block the channel. Since the RS is a waste of channel resources, we investigate an alternative self-deferral approach (gap-based access…
A spatial role-based authorization framework for sensor network-assisted indoor WLANs
2009
©2009 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE. Article also available from publisher: http://dx.doi.org/10.1109/WIRELESSVITAE.2009.5172549 In this paper, we propose a spatial role-based authorization framework which specifies authorization based on both role and location constrains in a wireless local area network with assistance from a sensor network. The framework performs a location-restricted verificati…
Energy efficiency in wireless networks
2013
Tämä pro gradu -työ on sekundääritutkimuksena tehty kirjallisuuskatsaus energiatehokkuuden tarkastelusta langattomissa verkoissa. Työssä tarkastellaan erilaisia mobiiliverkkojen energiansäästömahdollisuuksia. Pääpaino työssä on suunnattu erityisesti 3G ja LTE -verkkoihin, kuitenkin eksoottisempiakaan verkkoja unohtamatta. Työ alkaa erilaisten mobiiliverkkojen energiansäästösyiden ja tutkimusmotivaattoreiden tunnistamisella ja jatkuu langattomien verkkojen energian kulutuksen jaotuksella, sekä erilaisten energiansäästömahdollisuuksien vertailuilla. Työn empiirisessä osassa nostetaan lisäksi esille lyhyt Octave-simulaatio kollaboroivan mobiilipilven noodien energiansa…
Exploring User Acceptance of Free Wireless Fidelity Public Hot Spots : An Empirical Study
2008
Research regarding commercial and free wireless fidelity (Wi-Fi) public hot spots acceptance and adoption is sketchy. Therefore, it has become imperative to understand the critical factors that affect their acceptance. The focus of this study is free Wi-Fi public hot spot users, with the objective to better understand their user acceptance. In doing so, this study integrated two well-established initial acceptance models, specifically, the technology acceptance model and the diffusion of innovation theory. This study was conducted using an on-line survey that collected data from 129 users. It uses the Partial Least Square (PLS) technique to examine the relationship between variables. The re…
On the effects of transmit power control on the energy consumption of WiFi network cards
2009
Transmit power control has been largely proposed as a solution to improve the performance of packet radio systems in terms of increased throughput, spatial reuse and battery lifetime for mobile terminals. However, the benefits of transmit power control schemes on these different performance figures may strongly depend on the employed PHY technology and channel access mechanism. In this paper, we focus on the effects of power control on the energy consumption of WiFi network cards. By means of several experimental tests carried out under different operation conditions and modulation schemes, we try to justify why the reduction of the transmission power has a marginal effect on the overall en…
Energy Efficient Optimization for Wireless Virtualized Small Cell Networks With Large-Scale Multiple Antenna
2017
Wireless network virtualization is envisioned as a promising framework to provide efficient and customized services for next-generation wireless networks. In wireless virtualized networks (WVNs), limited radio resources are shared among different services providers for providing services to different users with heterogeneous demands. In this paper, we propose a resource allocation scheme for an orthogonal frequency division multiplexing-based WVN, where one small cell base station equipped with a large number of antennas serves the users with different service requirements. In particular, with the objective to obtain the energy efficiency in the uplink, a joint power, subcarrier, and antenn…