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Radio wave propagation models used in analysis of coverage Rf
| Added: 30-04-2009 Author: Paul Ngai Category: Broadband Internet |
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Propagation modeling objective is to determine the possibility of a satisfactory performance of the system depends on wireless radio wave propagation. RF planning system, the vaccine distribution modeling for RF analysis purposes. This analysis uses the model data and predict Investment Themes RF transmitter coverage area, signal strength received at the end of the wireless link, the loss from transmitter to receiver distance, Tilt angle transmitter antenna, antenna height of building a communication under Line of Sight channel disruption such as the late spread of the ways faded.
Crop models for various purposes, and field environments has been developed by the U.S. government, private organizations and standards bodies such as the International Telecommunications Union (ITU). This is a great example of primary empirical data collected for the purpose of prayer characterize Rising. Since the propagation model is made by using statistical techniques, there is no one model will be compatible with any application. This is a good idea to hire two or more independent models and use the results as an upper limit of expected performance. The following is a list of common near-earth propagation model used.
Longley-Rice
The Longley-Rice model predicts an average length of transmission through disordered lost theme. It is designed for frequencies from 20 MHz to 20 GHz and the length of 1-2,000 km. For example, accounts for the theme, climate, environment and subsoil of curvature of the earth. Longley-Rice model of two modes, point-to-point and region. Step-by-point mode uses themes Detailed data and characteristics to predict losses, which uses the mode general information about ways to predict the behavior Themes losses.
Okumura
The Okumura model is based on measurements taken in 1960 in Tokyo, between 200-1,920 MHz. Test values are used to determine the field strength and the average correction factor. With the correction and reform Urbanization level, Themes Roughness, base station antenna length, height and local phone antenna obstruction. Okumura is a regional force, particularly in urban areas where the number and scope of the overall barrier is several buildings.
Cost 231
Model 231 costs, also called the extension instance when personal computers, are used in many instruments of commercial RF planning for mobile telephony. Cost model 231 MHz frequency distribution 1500-2000, effective transmitter antenna height of 30-200 m, receiver antenna 1-10 m high efficiency and 1-20 km link distance. Model cost less than 231 applications where the base station is on the adjacent roof.
Egli
Egli style basis in accordance with the simplified model test data empirical mathematical formula. The simplicity of implementation makes a popular choice for first use of the analysis. Gently rolling hills will have a height of about 50 feet and no data were recorded between the transmitter and the theme of the recipient system is necessary. Path loss is the adjustment of the average height of the transmit and receive antennas on the ground. One example is the propagation loss equation.
ITU
ITU theme based on diffraction theory model that provides a way to predict the average loss. Example estimated as a function of height loss through the blockage and the first Fresnel transmission link to the area. Sample is ideal for modeling line-of-sight links in every theme and that is good in any way the frequency and length. Barrier in the example account contact center midfielder, making it suitable for use in all cities and open fields. Examples considered valid for the loss of more than 15 dB.
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