The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
The delay caused by the reflected ray in broadband communication has a great influence on the communications in subway tunnel. This paper presents measurements taken in subway tunnels at 2.4 GHz, with 5 MHz bandwidth. According to propagation characteristics of tunnel, the measurements were carried out with a frequency domain channel sounding technique, in three typical scenarios: line of sight (LOS),...
The radio channels between nodes of an indoor peer-to-peer network show specific fast fading characteristics. Depending on the mobility and on the scattering properties of the environment, different kinds of fading distributions can occur: Ricean fading between static nodes, but also Rayleigh or even double-Rayleigh fading between mobile nodes. We investigate fast fading in indoor peer-to-peer networks...
In this paper, an efficient approach to model the diffuse scattering in the ultra wide band (UWB) indoor channel is presented. It extends 3D ray tracing by associating a scattering cluster with each interaction point of the ray. The scattering clusters were defined by examining the simulated responses of each object while taking into account its surfaces roughness or small details. The comparisons...
Self-optimization of the neighbor cell list (NCL) is expected to improve handover performance and reduce the need for site surveys. 3GPP Long Term Evolution (LTE) has introduced automatic neighbor relation (ANR), which enables a base station to manage neighbor cells on the basis of measurements made by mobiles. Because the radio coverage changes during network operations, it is essential to immediately...
Cell isolation or the inter-cell interference is an important characteristic of radio networks. The cell isolation together with link performance limits the achievable user throughput and the capacity for a 1-reuse link adaptive packet access systems such as LTE. In this paper, cell isolation is measured as geometry factors and assessed through UE measurements in two different networks utilizing different...
During almost fifty years, fade duration distribution (FDD) of random signals has been an open research topic. However, for Weibull fading channels, closed form solutions are still unknown. Minimum duration outage (MDO) definition is decisive to complement the traditional outage concept and it has been reported, up to now, only for Log-normal shadowing, Rayleigh fading and Nakagami fading. In this...
The increasing demand of indoor broadband access encourages the diffusion of the "home base stations", known as femtocells. Their self installation nature envisages interference problems due to a possible overload of local femtocell installations in the same area. To reduce the interference among femtocells we propose and analyze the performance of a dynamic frequency selection strategy,...
Directional properties of the radio channel are of high importance for the development of reliable wireless systems operating in the 60 GHz frequency band. Using transfer functions measured from 61 to 65 GHz in a conference room we have extracted estimates of the multi-path component parameters using the SAGE algorithm. In the paper we compare results for line-of-sight (LOS) scenarios and the corresponding...
In this paper, we present statistical models for wideband and ultra-wideband (UWB) radio channels for working machine cabin environment. Based on a set of measurements, it was found that such a small and confined space causes mostly diffuse multipath scattering rather than specular paths. The amplitude of the channel impulse responses in the wideband case is mostly Rayleigh distributed small-scale...
A millimeter-wave (mm-wave) impulse radio is an attractive alternative to existing high-speed mm- wave radio systems because of the potential for a simpler transceiver architecture. This paper studies the feasibility of a mm-wave impulse radio system for home and office use by considering state-of-the- art transceivers and multiple-input multiple-output measured propagation channels as well as the...
Many applications in vehicular communications require the collection of vehicular position traces. So far this has been done by recording and transmitting unencoded or merely linearly filtered position samples. Depending on the sample frequency and resolution, the resulting data load may be very large, consuming significant storage and transmission resources. In this paper, we propose a method based...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.