Radio Propagation Loss Research Articles

An Experimental Investigation Into GbE Wireless Data Communication at 24 GHz in Non-Line-of-Sight and Multipath Rich Environments

Rapid growth in the telecommunication industry has placed wireless technology at the frontier for both consumer and commercial applications. Recently, interest in Gb/s throughput has focused attention on unlicensed millimeter (mm)-wave opportunities such as the 24.1-24.2-, 28-, 38-, and 57-64-GHz bands. Here, we present the first investigation of real-time, 24-GHz, GbE, wireless data communication in non-line-of-sight (NLOS) and multipath-rich scenarios. Our results show that wireless systems deployed in this band can deliver up to 1.25-Gb/s aggregate data rates in typical modern building environments while penetrating a range of commonly used construction materials. Channel modeling using MATLAB simulation for the prediction of radio propagation loss along the corridors was performed. Comparison of the simulation model and the experimental results showed good agreement. © 2014 IEEE.

Localization Algorithm based on Improved Weighted Centroid in Wireless Sensor Networks

Location technology is becoming more and more important in wireless sensor networks. The weighted centroid localization offers a fast and simple algorithm for the location equipment in wireless sensor networks. The algorithm derives from the centroid measurement and calculation device of the adjacent anchor in the average coordinate. After the analysis of the radio propagation loss model, the most appropriate log-distance distribution model is selected to simulate the signal propagation. Based on the centroid algorithm and the weighted centroid algorithm, this paper proposes an ellipse centroid localization algorithm. This algorithm makes use of ellipse’s characteristic to estimate the unknown node’s coordinate. The main idea of ellipse centroid localization algorithm is the precision control factor that can control the algorithm’s location precision. In ellipse centroid localization algorithm, node is extended as anchor in order to strengthen anchor density’s dynamic characteristic. The simulation result shows the ellipse centroid localization algorithm is more effective than the centroid algorithm and the weighted centroid precision algorithm

지하철 터널에서의 18GHz 무선영상신호 전파특성 측정

지하철 무선영상전송을 위한 전용주파수로 분배된 18GHz 대역에 대하여, 지하철 터널구간에서 무선영상전송용 무선장치를 이용하여 전파경로손실특성을 측정하고 전파도달범위를 분석하였다. 측정결과, 터널 내에서 거리에 따른 경로손실지수는 2.0~2.6으로서 일반적인 실외 무선환경에서보다 전송손실이 작았으며, 일반 도로 터널보다는 전송손실이 큰 것으로 나타났다. 터널 구조면에서 보면 직사각형 터널보다 아치형 터널에서 전송손실이 작았으며, 복선터널보다 단선터널에서 전송손실이 작은 것으로 나타났다. 직선구간에서의 안정적인 전파도달범위는 520m로 분석되었다. 곡선구간에서는 경로손실지수가 5.0 이상까지 측정되어 경로손실이 크게 나타났으며, 가시거리통신이 확보되지 않을 경우 일반적인 실외무선환경보다 경로손실이 크다는 것을 확인하였다. 곡선구간에서의 안정적인 전파도달범위는 300m로 분석되었다. 이상과 같은 지하철 터널구간에서의 수신신호강도 측정결과는 18GHz 무선 지상국 설치 간격 최적화 및 지하철 전파환경에 최적화된 핸드오버알고리즘 구현 등 무선영상전송시스템 설계에 활용할 수 있다. This paper presents an experimental study on the radio propagation characteristics in subway tunnel at 18GHz frequency band which has been assigned to video transmission between train and wayside. The radio propagation tests are carried out in the subway tunnel of Seoul Metro using the antenna and communication devices of the prototype video transmission system. The measurement results show that 18GHz radio propagation in subway tunnel has smaller path loss than that of general outdoor radio environment. It is also cleared that the arch-type tunnels have smaller radio propagation losses than rectangular tunnels, and single track tunnels have smaller pass loss than double track tunnels. From the measurements, the radio propagation coverage is worked out as 520 meters. The curved tunnels which cannot have LOS communication between transmitter and receiver have large pass losses and fluctuation profile along distance. The radio propagation coverage along curved tunnels is worked out as 300 meters. These investigation results can be used to design the 18GHz radio transmission system for subway tunnel by providing the optimized wayside transmitter locations and handover algorithm customized to the radio propagation characteristics in subway tunnels.

Study on effect of wind waves on radar echoes in atmosphere duct oversea

The Wen's wave spectrum model is adopted to describe the rough sea surface, and the relation between wind and ocean waves using sea wave spectrum theory is derived. The improved discrete mixed Fourier transform algorithm and the modified rader scattering coefficient model are used to calculate radio propagation loss and radar cross section respectively. On this basis, the influence of wind waves on radar echoes in the environment of atmosphere ducts is analysed by using numerical calculations. The results show that the influences of wind on propagation loss at different heights are different; wich respect to the propagation loss, rader scattering coefficient influenced by waves of factors is large, which results in large change in the radar echo power.

Propagation Path Loss Prediction Model of Multi-Sensor Network in Forest

During the process of carrying on the master plan and design of multi-sensor network in forest, We must consider the coverage of the signal, how to find the best position, through predicting it from launching and checking to accepting the loss value of the electromagnetic wave checked, Can carry on planning and design. Based on the radio wave propagation loss model in free space and the characteristics of radio wave propagation in forest, this paper proposes the generalized predicting model of radio wave propagation loss, To validate the model, a radio propagation measurement campaign was carried out, The modeling results by measuring the parameters of some trees are good agreement with that of the literature

CONSTRUCTING PATH EFFICIENT AND ENERGY AWARE VIRTUAL MULTICAST BACKBONES IN STATIC AD HOC WIRELESS NETWORKS

For stationary wireless ad hoc networks, one of the key challenging issues in routing and multicasting is to conserve as much energy as possible without compromising path efficiency measured as end-to-end delay. In this paper, we address the problem of path efficient and energy aware multicasting in static wireless ad hoc networks. We propose a novel distributed scalable algorithm for finding a virtual multicast backbone (VMB). Based on this VMB, we have further developed a multicasting scheme that jointly improves path efficiency and energy conservation. By exploiting inherent broadcast advantage of wireless communication and employing a more realistic energy consumption model for wireless communication which not only depends on radio propagation losses but also on energy losses in transceiver circuitry, our simulation results show that the proposed VMB-based multicasting scheme outperforms existing prominent tree based energy conserving, path efficient multicasting schemes.

Path Loss Exponent Estimation for Indoor Wireless Sensor Positioning

Rapid developments in wireless sensor networks have extended many applications, hence, many studies have developed wireless sensor network positioning systems for indoor environments. Among those systems, the Global Position System (GPS) is unsuitable for indoor environments due to Line-Of-Sight (LOS) limitations, while the wireless sensor network is more suitable, given its advantages of low cost, easy installation, and low energy consumption. Due to the complex settings of indoor environments and the high demands for precision, the implementation of an indoor positioning system is difficult to construct. This study adopts a low-cost positioning method that does not require additional hardware, and uses the received signal strength (RSS) values from the receiver node to estimate the distance between the test objects. Since many objects in indoor environments would attenuate the radio signals and cause errors in estimation distances, knowing the path loss exponent (PLE) in an environment is crucial. However, most studies preset a fixed PLE, and then substitute it into a radio propagation loss model to estimate the distance between the test points; such method would lead to serious errors. To address this problem, this study proposes a Path Loss Exponent Estimation Algorithm, which uses only four beacon nodes to construct a radio propagation loss model for an indoor environment, and is able to provide enhanced positioning precision, accurate positioning services, low cost, and high efficiency.

A propagation model for mobile radio propagation loss in an urban area at 800 MHz

AbstractTo understand the propagation structure of the microcells with a tall and medium‐height antenna in an urban area, the fundamental propagation parameters are found and the structural model of the propagation loss was constructed. The fundamental propagation parameters were obtained based on the multivariable analysis of the propagation data at 800 MHz measured in the Tokyo Metropolitan area. These parameters are the distance between the transmitter and receiver, the average building height between the transmitter and receiver, and the base‐station height which have high correlation and regression coefficients with the propagation loss.The relationship of parameters obtained from the model is (20 ‐ α) log(h) for the base‐station height characteristics and (α ‐ 20) log (H) for the building height characteristics if the distance characteristics are α log (d). The relationships of coefficients of the conventional estimation equation and the regression equation obtained by the measured data almost agreed with those of the model so that the validity of the model was confirmed.