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Cumulative number of rain storms for which the indicated duration (T R ) has been exceeded in Gera Lario (L), Fucino (F), and Montreal (M).
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We have investigated how rain attenuation statistics, necessary to
design fixed satellite systems working at frequencies greater than 10
GHz, are transformed to those applicable to the design of mobile
satellite systems working in the same frequency bands and weather
conditions in the special case of vehicles driven in zig-zag patterns to
simulate...
Contexts in source publication
Context 1
... to the satellite so that it always depends on intervals of the true rain-rate space (time) series measured by the fixed observer. Moreover, very unlikely a vehicle will be driven along this orthogonal direction for a significant distance (and time) to experience a constant . The rain-rate field travels rigidly according to its (random) velocity . Fig. 2 shows the cumulative number of rain storms for which the indicated value of has been exceeded for the three sites (once normalized to the total number of rain storms, the curves become the cumulative probability distributions of ). Notice that the value calculated from (1) is at best an estimate of the length of a section, seen by the ...
Context 2
... a given , we can estimate according to (1). As a consequence the curves of Fig. 2, once normalized, give the cumulative distributions of too, e.g., by assuming km/h for Gera Lario and Fucino, and km/h for Montreal. For the latter site, the values of the speed estimated for each single rain storm yields a probability distribution of not significantly different from that calculated with the average ...
Context 3
... conclusion, to estimate we need to calculate the average distance (or, equivalently, the average duration of rain storms, , as ) covered by the fixed terminal and the average distance covered by the vehicles (or the derived parameter ). Let us estimate these parameters. The probability distribu- tion of can be calculated from the curves shown in Fig. 2. Now, Fig. 7 shows the probability distribution of obtained from the simulations. From these curves, we have calculated and , and then from (15), we have derived and , and finally from (14), the corresponding values of . These results are reported in Table ...
Similar publications
Based on experimental data, we have reported a reliable method to
scale the cumulative time T<sub>F,T</sub>(A) that rain attenuation A
(dB) is exceeded in a fixed satellite system to the time
T<sub>M,T</sub>(A) that it is exceeded in a satellite system for mobile
terminals. Zigzag routes and ring-roads simulated city patterns;
straight routes simul...
Using data from a dual-frequency microwave link it is possible to identify periods of transmission affected by melting snow. This is because, in melting snow, the relation between attenuation and the amount of precipitation is nonlinear and depends on the frequency in a way that differs from the dependence in rain. This implies that the ratio of th...
The movements of clouds and moist air are responsible for temporal
changes in sky radiation temperatures. Detailed are measurements of the
sky radiation temperatures made during periods of cloud movement and
light rain. The measurements were made over the frequency bands 26 to 40
GHz (in the ka-band) and 90 to 98 GHz (in the w-band) using a direct...
In this paper, a new clutter suppression technique is introduced.
This clutter suppression method uses both Doppler and polarimetric
information. Polarimetric properties of the target and clutter are
calculated per Doppler frequency cell and, based on this information,
clutter suppression is performed. This new clutter suppression technique
is demo...
The rain attenuation and attenuation distribution have been obtained using the measured rain drop size distribution (DSD) and the ITU-R model of rain rate distribution over the frequency range of 10-200 GHz at three locations in the Indian region, to indicate the variability in the rain attenuation pattern in the tropical region. The prevailing DSD...
Citations
... This involves the calculation of static (i.e., long-term) and dynamic (i.e., short-term) parameters of rain attenuation. A key factor in the conversion of fixed rain-attenuation statistics into mobile rain-attenuation statistics is the velocity factor ξ, defined as [28,29]: ...
Unmanned aerial systems (UAS) have recently gained popularity, and they are envisioned as an integral parts of the current and future wireless and mobile-radio networks. Despite the exhaustive research on air-to-ground channels, there are insufficient studies, experimental campaigns and general channel models related to air-to-space (A2S) and air-to-air (A2A) wireless links. This paper presents a comprehensive review of the available channel models and path-loss prediction for A2S and A2A communications. Specific case studies attempting to extend current models’ parameters and provide important knowledge of the channel behavior in combination with UAV flight characteristics are also provided. A time-series rain-attenuation synthesizer is also presented that describes quite accurately the impact of the troposphere at frequencies above 10 GHz. This specific model can be also applied to both A2S and A2A wireless links. Finally, scientific challenges and gaps that can be used for future research on the upcoming 6G networks are highlighted.
... 1997 [4] Fade durations. 1998 [5] Satellite communications with mobile transmitters/receivers. ...
We have updated the global Synthetic Storm Technique (referred to as the global SST) by reformulating it according to a larger database of rain rate time series collected in several sites in different climatic regions. For each site, the average annual probability distribution of rain attenuation obtained with the global SST, PSST,gloA, in a slant path, was compared with that given by the full SST, PSSTA, which we have considered as experimental data. The test was performed for frequency ranging from 10 to 100 GHz, for elevation angle θ ranging from 20° to 60° and for annual probabilities 10% to 0.01%. The global SST tends to underestimate the attenuation by approximately 10% for elevation angle θ≤30° and about 20% for 30°<θ<60° in the probability range 10% to 0.1%, and approximately 15% in the probability range 0.1% to 0.01%. For any probability, the error is zero for θ=90° because at the zenith, the global SST coincides with the full SST.
... The standard deviation of the duration of rain events is 234 min; therefore, this random variable is only approximately exponential, as Figure 1 also shows. The PDs of the duration of rainy time and rain events for Fucino, Gera Lario (see Figure 2 of [6]) and Prague show similar features. ...
... In Section 2, we have already carried out the first step for arriving at the final model of P R (R), namely we have estimated P o by scaling P ro (T) according to (6). Now, we proceed, first by defining an intermediate variable, r T (mm/h), calculated in the maximum rainy time T d . ...
SUMMARY We have developed, tested and discussed a theory for de-integrating the probability distribution (PD) of the daily rain rate to the PD of the rain rate integrated in 1 min, through many simple steps, with a good or very good precision, for a large range of probabilities and in many sites. The theory can also estimate the number of rain events (in the sense of rainstorms), NR, their average duration and the (conditional) PD of daily rainy time. The theory needs only three inputs, measured on site: the daily rain rate PD, the number of rainy days, ND (only for finding NR) and the PD of the rain rate integrated in two consecutive and disjoint couples of days. The theory contains two complementary parts, both successfully tested: the first deals mainly with duration of daily rainy time and rain events, and the second deals with the main issue, namely de-integrating daily rain rate PDs in 1-min PDs. We have tested the theory on duration of rainy time in Spino d'Adda, Gera Lario, Fucino and Prague and subsequently with real (blind) field tests in Milan, Lugano, many sites in the USA, and Canada. The sites tested belong to very different climatic regions. Nevertheless, the predictions are generally very close to the experimental data. The theory, and its powerful predictions, can be useful for several research communities: radio propagation, agriculture, climatology, hydrology and applied meteorology. For all disciplines and applications, seasonal studies or even monthly studies could be pursued because the data banks available can be very large, even for restricted sub-data banks. The theory will estimate its parameters on on-site seasonal, or monthly, measurements. Future developments could deal with de-integrating large-area and long-time integrated rain rate, observed by means of meteorological satellites, for obtaining ‘point’ 1-min rain rate PDs concerning a small homogeneous area. We have tested the theory to sites with very different climates and for latitudes between 65°N and 28°N. Therefore, we think that the theory can be applied globally in this latitude range because its parameters are derived from local measurements and, perhaps, down to the tropics. Because of the simplicity of the theory, and its use of few local measurements, it may be applied also to equatorial sites. This, however, is only a conjecture because we have not tested the theory directly there. Copyright © 2013 John Wiley & Sons, Ltd.
... Upon unavailability of measured data concerning rain fading in mobile satellite links, the only way forward in this regard is to rely on well-established channel modeling approaches developed for fixed terminals. This is the spirit of the pioneering work carried out by Matricciani et al. [22,[25][26][27] that offers a simple methodology for transforming rain attenuation statistics of a fixed satellite link into a mobile satellite link. Respectively, building upon this method-outlined in Section 2.2-the present work extends recent intense research on furnishing a reliable rain attenuation time series synthesizer from the fixed to the mobile framework. ...
... In a series of publications [22,[25][26][27], Matricciani et al. proposed an easy-to-apply methodology for transforming rain attenuation statistics of a fixed satellite link into a mobile satellite link. Using the physical/mathematical formulation of the synthetic storm technique [30], it can be shown that the stochastic process of rainfall rate measured using a moving rain gauge meter has similar statistical properties to the one measured using the rain gauge at a fixed position. ...
... A first-hand confirmation of this behavior was recently demonstrated through radar data in [31]. A key factor for converting fixed rain attenuation statistics (denoted hereafter by the subscript F) into mobile rain attenuation statistics (denoted hereafter by the subscript M) is the speed factor x defined as [22,[25][26][27] ...
Past studies on the railway satellite channel (RSC) at Ku band and above consider exclusively the attenuation coming from the metal power arches (PAs) along the railway route, producing significant though deterministic periodical fast fading. Nevertheless, limited attention has been given to model tropospheric effects on the RSC. The present paper takes a more comprehensive view of the RSC by introducing a novel stochastic dynamic model of rain fading in mobile satellite systems on top of the diffraction because of PAs. The proposed approach builds upon well-established research on rain attenuation time series synthesizers employing stochastic differential equations. It is shown that this propagation tool may provide significant aid, in general, in mobile satellite system simulations and in the design of fade mitigation techniques (FMTs), particularly aiming at the railway scenario. The tool enables the generation of fade events, fade duration statistics, rain attenuation power spectrum and predicting the necessary FMT control loop margin. This is particularly useful for the RSC because most of the proposed FMTs focusing on PAs are not appropriate for compensating atmospheric fading.
... Upon unavailability of measured data concerning rain fading in mobile satellite links, the only way forward in this regard is to rely on well-established channel modeling approaches developed for fixed terminals. This is the spirit of the pioneering work carried out by Matricciani et al. [22,[25][26][27] that offers a simple methodology for transforming rain attenuation statistics of a fixed satellite link into a mobile satellite link. Respectively, building upon this method-outlined in Section 2.2-the present work extends recent intense research on furnishing a reliable rain attenuation time series synthesizer from the fixed to the mobile framework. ...
... In a series of publications [22,[25][26][27], Matricciani et al. proposed an easy-to-apply methodology for transforming rain attenuation statistics of a fixed satellite link into a mobile satellite link. Using the physical/mathematical formulation of the synthetic storm technique [30], it can be shown that the stochastic process of rainfall rate measured using a moving rain gauge meter has similar statistical properties to the one measured using the rain gauge at a fixed position. ...
... A first-hand confirmation of this behavior was recently demonstrated through radar data in [31]. A key factor for converting fixed rain attenuation statistics (denoted hereafter by the subscript F) into mobile rain attenuation statistics (denoted hereafter by the subscript M) is the speed factor x defined as [22,[25][26][27] ...
Export Date: 13 July 2012, Source: Scopus, doi: 10.1002/sat.991, Language of Original Document: English, Correspondence Address: Panagopoulos, A.D.; School of Electrical and Computer Engineering, National Technical University of Athens, 9 Iroon Polytechniou Str, Zografou, GR 15780, Greece; email: thpanag@ece.ntua.gr, References: (2003) Second Generation Framing Structure, Channel Coding and Modulation Systems for Broadcasting, Interactive Services, News Gathering and Other Broad-band Satellite Applications, , ETSI EN 302 307 v.1.1.2, Digital Video Broadcasting (DVB);
... Synthetic storm techniques are an effort to distinguish between these two processes, based on measurements of the received signal strength data or point rain rate and estimates of local wind speed and direction [22], [23]. 2) The case of links from mobile terminals to satellites in geostationary orbit has been considered by others in recent years, e.g., in [23] and [24]. In such cases, the movement of the terminal with respect to both the storm and nearby structures that may temporarily block the path must also be accounted for. ...
Because the motion of a low Earth orbit (LEO) satellite across the sky causes the Earth-space path to very quickly pass through any rain cells in the vicinity, the degree of rain fading on such paths changes more rapidly and leads to steeper fade slopes than in the geostationary case. Because comprehensive measurement data have not yet been compiled for fading on LEO links in the Ka-band, we have used simulations based on Goldhirsh's method for determining the key parameters of the well-known EXCELL model of a horizontal rain structure from long-term global rain statistics to obtain plausible estimates of the fade slope distributions for selected scenarios. The results that we obtained for geostationary satellites closely match those observed at selected sites during the Advanced Communications Technology Satellite program. The results that we obtained for LEO satellites show how fade slopes will steepen as 1) the altitude of the satellite decreases; 2) the frequency band of operation increases; and 3) the average rain rate increases. Furthermore, they suggest that, at a given probability level, the fade slopes could be between two and ten times greater than those for geostationary satellites and that mobile terminals with a clear view of the sky will experience fade slopes that are similar to those encountered by fixed or transportable terminals. These results have important implications for the design of power control algorithms and other fade-mitigation techniques.
... As a consequence, the designer needs reliable and long-term rain attenuation statistics applicable to terminals placed on moving vehicles. These statistics can be very different from those applicable to fixed terminals, linked to the same satellite, because of the relative motion of rainstorms and vehicles [7], [8]. Failure to consider this issue is a theoretical error and oversimplification Manuscript received December 3, 1998; revised April 28, 1999. ...
... Following [7] and [8], we have investigated how, in the long term, the cumulative probability distribution of exceeding a given rain attenuation (dB) in a fixed satellite system is transformed into that applicable to a satellite system for mobile terminals working in the same geographical area, at the same carrier frequency and weather conditions. The results reported below allow such a transformation and are of general application. ...
... We have investigated three general patterns, according to how vehicles are driven: a) zigzag routes and b) ring-roads to simulate city patterns and c) straight routes to simulate freeways. Vehicle speed was modeled as a log-normal random variable after the mathematical model derived from measurements performed in Europe [8]. ...
Based on experimental data, we have reported a reliable method to
scale the cumulative time T<sub>F,T</sub>(A) that rain attenuation A
(dB) is exceeded in a fixed satellite system to the time
T<sub>M,T</sub>(A) that it is exceeded in a satellite system for mobile
terminals. Zigzag routes and ring-roads simulated city patterns;
straight routes simulated freeways. In all cases, T<sub>M,T</sub>(A) can
be expressed as T<sub>M,T</sub>(A)=ξT<sub>F,T</sub> (A) with a
probability scaling factor ξ independent of A. The simulations have
been made at 19.77 GHz with satellite elevation angle θ of
30.6°, 45°, 60°, 80°, and 90°. For the horizontal
structure of rain, we have used a very large number of rain-rate maps of
rain storms randomly observed in 1989-1992 by a meteorological radar
placed at Spine d'Adda (northern Italy). The vehicle speed was modeled
as a log-normal random variable. We found: (a) in zigzag routes,
T<sub>M,T</sub>(A)<T<sub>F,T</sub>(A), i.e., ξ<1, with results
depending on vehicle speed modeling and starting conditions; (b) in a
ring-road, there is no difference between fixed and mobile systems
(ξ=1); and (c) in straight freeways, T<sub>M,T</sub>(A)≪T<sub>F,T
</sub>(A)(ξ≪1); T<sub>M,T</sub>(A) can change significantly in
different straight lines and in opposite directions (anisotropy and
asymmetry) for medium-large attenuation. When compared to zigzag routes
or ring-roads, the performance in straight freeways is the most
optimistic. For θ>30.6° and for the same pattern, ξ is
fairly independent of θ. Since the radar rain maps are a reliable
estimate of the horizontal structure of rain, the findings, which can be
considered frequency-independent, stand as a very good prediction of the
results obtainable by experiments
... However, it is usually assumed that the same degree of shadowing is experienced on both links. A major problem for communication at the Ka band and beyond is attenuation due to rain, particularly in tropical and sub-tropical regions where such attenuation can easily exceed 20 dB [10, 40, 72,102103104105. Under severe rain attenuation, the channel model is reasonably represented by a flat fading Rayleigh distributed channel [98]. ...
... Typically the rain rate is not constant over the duration of the storm and so L(R) is modeled statistically from measured surface rain rates. Mobile terminals will generally experience an attenuation, A M dB, which is different from the attenuation, A F dB, of a fixed terminal [102, 103]. A common model applied is one of equal probability of encountering rain: over the long term both fixed and mobile terminals will experience the same number of rain storms, and hence the same number of rain attenuation events such that A M = A F = A dB. ...
There is interest, supported by successful field trials, in the use of satellite communications at the Ka band (30/20 GHz) and beyond to meet emerging demand for broadband interactive multimedia services. The key advantages of operation at Ka band are availability of bandwidth and favorable implications for terminal size, cost and mobility. We study two problems related to bandwidth management of the uplink in a multibeam, CDMA-based, GEO satellite. Our focus is on the delivery of data services with rigid constraints on bit-error rate and elastic constraints on data rate. The first of the two problems concerns the design of the coverage areas of the satellite beams. We were interested specifically in the adaptation of beam shape to inhomogeneity in the geographic distribution of the user population, and in the impact of beam shaping on the set of transmission rates that are compatible with prescribed constraints on transmission powers and signal-to-interference ratios. Assuming that the spatial distribution of users is known, we construct an algorithm which computes beam coverage regions to equilibrate the per-beam user populations. The impact on the set of feasible bit-rate allocations is quantified through numerical experiments. Comparison with uniform beam shapes suggests that the adaptive approach is superior in terms of the number of concurrent transmissions that can be supported. The second problem concerns the allocation of bit rates in a setting where user bit-rate requirements are assumed defined by averages over moving windows of constant length. We use a frame-based channel model characterized by fading coefficients which, though statistically variable, are assumed known to the controller at the start of each frame. The implied temporal elasticity in quality-of-service provides opportunity to achieve economies in transmitted power. The value of such opportunity is quantified by comparison of two extreme cases. We develop an approximate system model which allows optimization of the rate allocation when the number of users is small, and a heuristic which is useful when the number of users is not small. The associated performance results confirm the inverse relationship between the per-bit energy required for transmission and the length of the averaging window.
The Land-Mobile Satellite ChannelPropagation Characteristics of the Land-Mobile Satellite ChannelFrequency and Time SelectivityClear-Sky ModelingTropospheric Channel Modeling at High Frequencies (>10 GHZ)Conclusion
GlossaryCross References
We have presented a picture of the total attenuation to be considered in satellite communication and broadcasting systems in the 10–100 GHz frequency range. Although the findings and methodology are of general interest, the numerical results apply to the Italian (mid-latitude) sites of Fucino and Gera Lario and to slant paths of elevation angles 33° and 32° respectively. The rain attenuation probability distribution P(A), of exceeding the value A (dB) at a given carrier frequency in an average year, has been estimated by the synthetic storm technique and an associated formula, presently derived, which links A to frequency for fixed probabilities. The extra fading due to water vapour, clouds, oxygen and scintillations is estimated by applying the ITU-R formulae. After studying how the received carrier power PR changes as a function of frequency for fixed antenna dimensions and transmitted carrier power PT, we have carried out an exercise to show what first order values of PT we need in an ideal QPSK modulation scheme, with a standard uncoded stream of 64 kbit/s, in a complete earth–satellite–earth connection, with regenerative or transparent transponders, for a given maximum bit error rate tolerated by users. After this analysis we have drawn the following conclusions: (a) the results depend very much on the outage probability and on the site; (b) there are two windows at high outage probabilities, e.g. 1%, the first in the 20–50 GHz frequency range and the second beyond 70 GHz; (c) in the frequency range 50–70 GHz any significant service availability level cannot be achieved because of the very large fading due to oxygen; (d) the transmitted power can show sharp minima which depend significantly on the outage probability and on the site; (e) service availability levels better than 99⋅99% of the year cannot be achieved at frequencies of 30 GHz and above, with ground station antennae of 25 cm or less aperture diameter. © 1998 John Wiley & Sons, Ltd.
