Urban mobile radio propagation at 900 MHz

A series of field trials in London and Birmingham have been used to provide a propagation data base in urban areas at 900 MHz. Measured signal strengths are highly correlated with the results of earlier trials at lower frequencies. The excess loss over plane earth predictions varies with location but is generally in excess of 40 dB.     

A measured delay-Doppler scattering function for multipath propagation at 910 MHz in an urban mobile radio environment

A delay-Doppler scattering function is presented for multipath propagation at 910 MHz from a vertical antenna 120 m above a street to a mobile vehicle on another street. The direct path between the transmitting antenna and the mobile vehicle was blocked by many tall (over 100 m) buildings. Major features of the scattering function correspond to gross features of the area.     

Flat suburban area propagation at 820 MHz

The results of a comprehensive mesurement program at 820 MHz designed to determine propagation characterstics in flat suburban terrain are presented. The data are organized to separate the effects of surface features, mobile antenna gain, and land-site antenna height, gain, and type (omnidirective and directive). The data have been collected using a digital data acquisition system to sample each of 18 variables once every three milliseconds. The mobile traveled over 500 route miles in the suburban Philadelphia/Camden, NJ area while probing an 11-square-mile measurement area in collecting these data. The results show propagation characteristics and relative antenna comparisons in flat suburban terrain. These results are compared to earlier urban data and show an environmental advantage of 11 dB for flat open suburban terrain.     

800 MHz mobile radio propagation prediction using Kalman filteringtechniques

A method is presented to derive a propagation model to predict the received median signal voltage for an 800-MHz mobile radio system. Results are given of an investigation into the performance of a particular model that was derived using this method. The method uses a Kalman filter that uses propagation measurements to derive a best fit for a particular propagation model to the measured data. The model that was derived is based on propagation measurements made in the State of Florida. The new propagation model uses a plane-Earth propagation model that is corrected with an environmental propagation loss term that takes into account the various environmental effects near the mobile unit. The parameters in the environmental propagation loss model were determined using a Kalman filter that computes minimum mean square estimates of the parameters using measured propagation data. The environmental propagation loss term accounts for the effects of Earth diffraction, hills, valleys, urban and suburban areas, bare and grass-covered ground, bushes, trees, swamps, and propagation over fresh and salt water. It was found that, with the 800-MHz propagation model derived with this method, the prediction error for the received median signal voltage had a standard deviation of 5.08 dB     

A comparison of prediction methods for 800 MHz mobile radio propagation

The design and installation of a mobile radio system involves the evaluation or prediction of the propagation characteristics associated with the geographical area of interest. A wide variety of prediction techniques has been developed for different mobile environments, so that the task of selecting an appropriate propagation prediction method can be difficult and complex. This is especially true for systems operating in the upper-UHF band of 800-950 MHz, where mobile radio services are rapidly growing. A practical comparison is given of current prediction techniques available in the literature (for slow lognormal fading rather than multipath Rayleigh fading), with an emphasis on three essential criteria to consider in the selection process: the type of terrain or geography covered by each method, the form of prediction provided (e.g., transmission loss estimates, field strength contour maps, etc.), and the implementation difficulty and degree of sophistication.     

Some characteristics of mobile radio propagation at 836 MHz in the Philadelphia area

Mobile radio propagation tests were carried out at 836 MHz from a base station in downtown Philadelphia, Pa., to a mobile which traveled on the city streets. It was found that the median signal power tends to fall off as R^-3for distances greater than 1 to 2 mi from the base station antenna. The mean received-signal level was found to be approximately log-normally distributed with a standard deviation varying from 5 to 10 dB, where the higher values were observed close to the base station.     

High-speed digital transmission experiments in 920 MHz urban and suburban mobile radio channels

Field experiments have been conducted to clarify the feasibility of introducing a newly developed Gaussian filtered minimum shift keying (GMSK) modulation method into 920 MHz mobile radio systems, and have been performed in the Tokyo urban, and the Yokosuka suburban areas.     

Mobile radio propagation in Auckland at 76 MHz

A series of field trials in Auckland at 76 MHz have confirmed that propagation path loss is normally distributed and may be characterised by a fourth-power-law distance dependency. The path loss standard deviation has been found to be dependent on the mobile terminal's environment and on frequency, but is essentially independent of base station antenna height and path length. The excess path loss over plane earth predictions and the standard deviation of path loss have been measured as 14.6, 5.0, 0.8 and 1.0 dB and 6.2, 5.2, 3.7 and 5.0 dB for urban, light urban, suburban and rural environments, respectively.     

Mobile radio propagation in Auckland at 927 MHz

Field trials in Auckland have shown that in the region 800 m to 5 km from a 50 m elevated base-station propagation loss may be characterised by a fourth-power law distance dependency and may be modelled as plane earth propagation loss plus excess loss of 45.6 dB. In the region closer to the base station, the propagation loss has a different characteristic. A `piecewise? model is proposed.     

Mobile radio propagation in Auckland at 851 MHz

A series of field trials undertaken in Auckland at 851 MHz have shown that the median propagation loss may be estimated by the plane earth propagation loss plus a clutter factor of 45.1, 27.0, 21.7 and 18.3 dB for urban, light urban, suburban and rural environments, respectively.     

Mobile radio propagation in Auckland at 465 MHz

A series of field trials in Auckland at 465 MHz have confirmed that propagation path loss may be characterised by a fourth-power-law distance dependency. The excess loss over plane earth predictions has been measured as 37.8, 26.4, 18.6 and 14.1 dB for urban, light urban, suburban and rural environments, respectively.     

910 MHz urban mobile radio propagation: Multipath characteristics in New York city

Small scale statistics of multipath propagation in a heavily built-up urban mobile radio environment are presented. The statistics cover vehicle travel distances on the order of 30 m along streets. Measuring equipment time delay resolution is about 0.1 µs. In some locations, paths with significant amplitudes are observed with excess delays of 9 to 10 µs. The delay spreads (√second central moment of power delay profile) in this environment are on the order of 2 µs. Often the signal at fixed delays has a Rayleigh-distributed amplitude but large departures from the Rayleigh distribution also occur. From the measurements it appears reasonable to model the urban mobile radio channel as a Gaussian quasi-wide-sense stationary uncorrelated scattering channel within a bandwidth of 10 MHz and for intervals along the street of up to 30 m.     

Variability of mobile radio path loss in Auckland at 465 MHz

A series of field trials in Auckland at 465 MHz have confirmed that the variability of mobile radio path loss is approximately normally distributed and can, therefore, be represented by a standard deviation. This standard deviation has been found to be dependent on the mobile terminal's environment and on frequency, but is essentially independent of base-station antenna height and path length. Standard deviations have been measured as 5.2, 4.4, 5.4 and 5.2 dB for rural, suburban, light urban and urban environments, respectively.     

Environment-adaptation mobile radio propagation prediction usingradial basis function neural networks

This paper investigates the application of a radial basis function (RBF) neural network to the prediction of field strength based on topographical and morphographical data. The RBF neural network is a two-layer localized receptive field network whose output nodes from a combination of radial activation functions computed by the hidden layer nodes. Appropriate centers and connection weights in the RBF network lead to a network that is capable of forming the best approximation to any continuous nonlinear mapping up to an arbitrary resolution. Such an approximation introduces best nonlinear approximation capability into the prediction model in order to accurately predict propagation loss over an arbitrary environment based on adaptive learning from measurement data. The adaptive learning employs hybrid competitive and recursive least squares algorithms. The unsupervised competitive algorithm adjusts the centers while the recursive least squares (RLS) algorithm estimates the connection weights. Because these two learning rules are both linear, rapid convergence is guaranteed. This hybrid algorithm significantly enhances the real-time or adaptive capability of the RBF-based prediction model. The applications to Okumura's (1968) data are included to demonstrate the effectiveness of the RBF neural network approach     

Fast-fading characterisation in urban mobile propagation at 855 MHz in Paris

Field trials in Paris at 855 MHz were used to show that fast fading could be characterised with a 1 m sampling step: the normalised field strength is first shown to be highly uncorrelated between two data points and then its statistical distribution is found to be well fitted by a Rayleigh law.     

Wideband characterisation of fading outdoor radio channels at 1800 MHz to support mobile radio system design

The characteristics of mobile radio channels place fundamental limits on the performance of mobile radio communication systems. Reliable information about these characteristics are obtained in this paper by analysing wideband propagation measurements, which were performed by using an high performance wideband channel sounder in mountainous areas in the German Alps and in typical urban areas in Munich. In addition to well known results obtained from propagation measurements in similar scenarios [1, 2], novel aspects of practical relevance enable for a realistic analysis of the performance of mobile radio systems in terms of the discussed channel parameters and support a compromise between system costs and the quality of signal processing with respect to the system availability and reliability.     

Assessment of GTD for mobile radio propagation prediction

The applicability of a GTD-based technique for path loss prediction in cellular radio systems is investigated. The bounds of applicability reported show that such a model could find application in cellular systems with small urban cells and in microcellular systems.<>