Ivan Pena

Generalization of the Lee Method for the Analysis of the Signal Variability

The Lee method, which was recommended by the International Telecommunications Union (ITU) and the European Conference of Postal and Telecommunications Administrations (CEPT) to obtain the local mean values of the received signal along a route, was developed for a Rayleigh distribution in the ultrahigh-frequency (UHF) band. This paper describes the generalization of this method to any propagation channel and frequency band and describes the methodology to obtain the parameters involved. The Generalized Lee Method is based on field data samples, which allows estimating the mean values without the requirement of a priori knowing the distribution function that better fits the propagation channel. The accuracy in obtaining the averaging interval is also improved. The Generalized Lee Method is solved for ground-wave propagation at the medium-wave (MW) band, taking data from field trials of a Digital Radio Mondiale (DRM) transmission. The results show that the values considerably differ from those obtained for a Rayleigh channel and prove that the method allows the adequate differentiation of long-term and short-term signals. The Generalized Lee Method completes the results obtained by Lee and Parsons and makes better characterization of the spatial variability possible.

Analysis of the DVB-T Signal Variation for Indoor Portable Reception

A study of DVB-T (Digital Video Broadcasting-Terrestrial) signal variability for indoor reception environments is stated in this paper. A commercial signal was measured and analyzed in order to obtain C/N threshold values that account time and space fluctuations. In this way, results increase the accuracy of the values provided by the ETSI (European Telecommunications Standards Institute) standard and other studies that assume static propagation channels. On the other hand, the fading influence due to people walking near the reception antenna has been proved as critical for correct reception. Characterization of this effect has been made in terms of its depth and duration. The results obtained results improve DVB-T network planning and could be also relevant for other technologies sharing similar frequencies and bandwidths.

Next generation of broadcast multimedia services to mobile receivers in urban environments

This paper analyses the possibility of receiving high data rate multimedia services in the non-stationary urban mobile scenario using the digital video broadcast standard DVB-T2. The work focuses on the complex urban mobile environment and presents a comparison between the different configuration parameters and the data rates associated to different video services. The study is based on the experience operating an experimental DVB-T2 network in urban environments, where portable and vehicular reception scenarios have been tested. The results show the system performance and the feasible video quality. The paper explores the coverage for various video services, including HDTV and 3DTV options, and proposes some scenarios for the deployment of broadcasting networks transmitting multimedia services to mobile receivers.

Carrier and Noise Measurements in the Medium Wave Band for Urban Indoor Reception of Digital Radio

This paper presents a study of indoor digital radio reception in the Medium Wave band. The results are based on a large database of measurements in indoor locations in cities in northern Spain in frequencies from 600 to 1600 kHz. The paper proposes a prediction model for indoor field strength. The results are combined with indoor noise levels to study the statistics of available C/N (Carrier to Noise) ratios. The model is intended to help broadcasters planning digital broadcasting networks in Medium Wave for indoor reception. Signal time and space variability have also been studied and reference values are provided in the paper. The paper includes curves to calculate indoor losses in respect to ground wave propagation values provided by ITU-R P.368.

Accuracy Analysis of the Millington's Prediction Method in the Medium Waveband

Millingtons field strength prediction method is analyzed under different simulation conditions on the basis of the results of a medium waveband (MW or medium wave band extends from 530 to 1600 kHz) digital radio mondiale (DRM) measurement campaign. Millington technique applies the reciprocity condition by simply averaging the forward and reverse field strength values. This simplified approach could be a source of field strength prediction error in the MW planning tools. Critical path features for the fulfillment of the reciprocity condition are identified and their influence on predicted values is stated. Reciprocity effect on the predictions error is evaluated by means of the difference between digital medium wave field strength measured values of certain critical selected paths, and the corresponding Millingtons method predicted ones. It has been found that the prediction error can be as high as 15 dB when comparing Millingtons method results and measurements but the simple reciprocity approach made by Millington procedure is not the most remarkable source of error

Analysis of the electric field strength location variability in the UHF band for mobile and portable multimedia broadband services in SFN networks

This paper describes the location variability of the received field strength derived from the statistical analysis of data obtained during a set of tests carried out in the cities of Bilbao and Madrid. The systems and services referred in this study are those ones operating in UHF band, specifically in TV Bands IV and V (470 – 860 MHz). Their evaluation has been based on the empirical references of standards originated inside the DVB (Digital Video Broadcasting) Consortium. Nevertheless, the obtained results can be extrapolated to the deployment of other standards operating in similar frequencies with a comparable bandwidth such us MediaFlo, ATSC M/H and so on. The main conclusion of this work is that the current values recommended by ITU-R and ETSI are pessimistic for SFN and MFN scenarios, different reception environments and digital terrain database granularities sizes below 100 meters (“small areas” according to the planning procedures). In that case, the standard deviation of the received field strength values is always lower than 3 dB.

Location correction factor for coverage planning tools for DRM (Digital Radio Mondiale) in the 26 MHz band

DRM (Digital Radio Mondiale) is the only digital radio system standardized for the high frequency bands. The traditional application of these bands is the broadcasting service by means of the ionospheric propagation to cover large areas at long distances. However, the 26 MHz band is nowadays scarcely used because it presents worse ionospheric propagation conditions than the lower frequencies, partially due to the 11 year period sunspot cycle. Nevertheless, some companies and research institutions have tested the possibility of using the DRM standard in these frequencies for local broadcasting due to the potential of this band for tropospheric (line of sight) propagation. New planning tools must be developed for this new application of the DRM future networks. This paper studies the signal spatial variability, an important parameter needed in the coverage prediction planning tools.

Cloud Transmission system performance in portable indoor environments

This paper presents some field trials carried out in Bilbao (Spain) for testing the feasibility of Cloud Transmission (Cloud-Txn) reception in fixed and pedestrian indoor scenarios. Therefore, the main objective of this study is to analyze the Cloud-Txn system coverage features so as to determine the optimum transmission power level to ensure a good coverage in indoor scenarios. The results will be useful for planning purposes in this kind of scenarios.

Statistical Characterization of Medium Wave Spatial Variability Due to Urban Factors

The recently developed digital radio systems for the medium wave (MW) band require accurate field strength prediction methods for coverage calculi. Traditional prediction methods do not consider the influence of urban factors on MW ground-wave propagation. This influence causes signal strength time and spatial variability which in turn, provoke drop-outs below reception threshold values. In this letter the ground-wave spatial variability is statistically analyzed in urban environments by means of empirical data from four extensive field trials. The experiments were carried out in different urban environments and at different frequencies of the MW band. Prior to the analysis, long-term and short-term components of the signal were separated by means of the generalized Lee method (GLM). The results show the attenuation caused by different urban factors. These attenuation values should be added to the signal strength predicted median values in order to ensure correct reception.

Empirical Analysis of the Sample Correlation for the Planning of Field Trials in the Digital Broadcasting Services at MF Band

The recent digital broadcasting services developed for the MF and HF bands require the accurate definition of the measurement conditions to be applied both in the planning of future field trials and in the analysis of the signal variability. This paper describes the outcomes of the necessary distance between adjacent measuring points of field trials, which must be uncorrelated samples. Furthermore, it is demonstrated that the analysis of the distance between uncorrelated samples allows validating the normalization process of the received signal. The study has been carried out for several reception environments.