نتایج جستجو برای: uwb
تعداد نتایج: 4839 فیلتر نتایج به سال:
The UWB (Ultra Wide Band) technology can play an effective role in FCS (Fieldbus Control System). But the channel acquisition time of UWB is high, and a lot of packets are short in FCS. So the efficiency of FCS based on UWB will significantly reduce. In this paper, a CSMA/CA protocol with D-UF (Dynamic Length Mechanism for Unite Frame) is proposed. The characteristics of UWB and size of data pa...
Ultra wideband (UWB) is a promising technology for short range and high-speed wireless communications such as home entertainment, wireless video downloading, wireless LAN, wireless USB and so on. This dissertation studied several important issues in the application of UWB technology and its contributions are summarized as follows. First, a 2-stage optimal UWB pulse shaping filter design procedu...
This paper proposes a hybrid multiband (MB) ultra wideband (UWB) system with direct sequence (DS) spreading. The theoretical error analysis for the DS-MB-UWB multiple access system with Rake receiver in the presence of multipath and narrowband interference is developed. The developed theoretical framework models the multiple access interference (MAI), multipath interference (MI) and narrowband ...
Physical layer attacks allow attackers to manipulate (spoof) ranging and positioning. These attacks had real world impact and allowed car thefts, executions of unauthorised payments and manipulation of navigation. UWB impulse radio (UWB-IR) has emerged as a prominent technique for precise ranging that allows high operating distances despite power constraints by transmitting multi-pulse symbols....
The paper presents results of a co-existence measurement study between multiple ultra wideband (UWB) transmitters and a Universal Mobile Telecommunications System (UMTS) mobile phone. Two environments were explored: an anechoic chamber with one operating UMTS link and a true operational UMTS network. A large number of FCC compatible UWB transmitters were used to generate interference for an act...
Ultra-wideband (UWB) systems having a bandwidth on the order of gigahertz have recently received wide attention both in the U.S. and in Europe. The family of UWB systems may communicate either by generating ultra-wideband signals or with the aid of innovatively combining conventional narrowband, wideband, or broadband signals. At the time of writing, UWB systems have only been implemented using...
In this paper, we have investigated printed monopole antennas, which is basically printed microstrip antenna with etched ground plane for UWB applications. In particular, we have simulated two types of UWB printed monopole antennas: circular and modified circular disk monopole antennas. Simple rectangular microstrip lines are used for feeding the printed monopole antennas. This UWB monopole ant...
Ultra-Wideband1 (UWB) is a radio transmission scheme that uses extremely low power pulses of radio energy spread across a wide spectrum of frequencies. UWB has several advantages over conventional continuous wave radio communications including potential support for high data rates, robustness to multipath interference and fading. We present an overview of UWB technology and its use in data comm...
An experimental testbed is described for the characterization of indoor channels with sufficient spatial resolution and sufficient bandwidth to study the practical capacities of MIMOUWB systems. UWB measurements have been made in both frequency and time domains for mutual validation. The opportunity has been taken in this paper to extract narrowband transmission loss models from the resulting U...
−This paper studies the interference effects from 4 types of ultra wide band (UWB) sources on a narrowband π/4-shift differential quadrature phase keying (DQPSK) transmission system by simulation. The culprit UWB sources were: multi-band orthogonal frequency-division multiple-access (MB-OFDM), direct-sequence code-division multiple-access (DS-CDMA), DS spread spectrum UWB (DS-SS UWB), and addit...
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