In order to facilitate the deployment of wireless systems in medical environments, channel measurements at 2.4GHz band have been performed in a hospital bedroom. Based on measurements in different line-of-sight (LOS) and non-line-of-sight (NLOS) scenarios, we determine the large-scale path loss and different small-scale fading parameters. Applying the channel models in our MATLAB simulation env...

The ability to predict transmission loss or field strength distribution is crucial for determining coverage in planning personal communication systems. This paper presents a practical method to accurately predict entire average transmission loss distribution in complicated urban environments. The method uses a 3D propagation model based on radiosity and a simplified city information database in...

Non-line-of-sight (NLOS) propagation, which widely exists in wireless systems, will degrade the performance of wireless positioning system if it is not taken into consideration in the localization algorithm design. Different from existing approaches which treat NLOS measurements as outliers and only work when there is a large number of measurements, in this paper, we propose to use Maximum Like...

In this study, a hybrid TOA/RSSI wireless localization is proposed for accurate positioning in indoor UWB systems. The major problem in indoor localization is the effect of Non-Line of Sight (NLOS) propagation. To mitigate the NLOS effects, an unconstrained nonlinear optimization approach is utilized to process Time-of-Arrival (TOA) and Received Signal Strength (RSS) in the location system.TOA ...

The major problem of indoor localization is presence of Non-line-of-sight (NLOS) channels. In order to perform NLOS identification, in this paper, we propose a novel NLOS identification technique based on threshold selection using the ratio of kurtosis and maximum slope of energy block of the received signal using energy detector. In particular, IEEE 802.15.3c 60 GHz channel models are used as ...

This paper presents the node localization of static blind sensor nodes and the mobile anchor nodes. Each of the sensor nodes determines its own position by itself is localization. Obstacles blocking between the direct path, called as Non-Line-Of-Sight (NLOS), which causes NLOS error. The propagation of this error results in unreliable localization and significantly decreases localization accura...

We perform a performance evaluation of ZigBee mesh networks based on XBee modules, in terms of packet delay and received signal strength (RSSI). We evaluate the performance for both line-of-sight (LOS) and non-line-of-sight (NLOS) environments in buildings and a parking lot. The results of our study are useful for building wireless sensor networks and communication networks of mobile robots whe...

This paper presents field trials carried out with a Low Data Rate Location Tracking Ultra Wide Band Impulse radio testbed developed within the project PULSERS. Ranging measurements have been conducted in environments with different propagation conditions: multipath-free (anechoic chamber), Line-of-Sight (LOS) and Non Line-of-Sight (NLOS). Results show very accurate ranging performance (better t...

This article will introduce a method for locating mobile stations (MSs) in outdoor suburban non-line-of-sight (NLOS) environment. The measurements used to locate the MS are taken from three base stations and a satellite. Such a setup of measurements is named the hybrid-network-GPS system. The proposed method uses constraint nonlinear optimization to minimize the NLOS error. The problem is simpl...

Many Vehicular Ad Hoc NETwork (VANET) applications achieve a decent packet delivery ratio using mobility information in the beacon messages broadcasted to the singlehop neighbors. Recently it has been found that if two VANET nodes are not within a line of sight (LoS), the performance of the employed VANET applications can be significantly degraded. Most of the existing VANET researches assume t...