International Telecommunication Union Radiocommunication Research Articles

Radio propagation measurements and modeling for standardization of the site general path loss model in International Telecommunications Union recommendations for 5G wireless networks

AbstractThe International Telecommunications Union Radiocommunication Sector (ITU‐R) Study Group 3 identified the need for a number of radio channel models in anticipation of the World Radiocommunications Conference in 2019 when the frequency allocation for 5G will be discussed. In response to the call for propagation path loss models, members of the study group carried out measurements in the frequency bands between 0.8 GHz up to 73 GHz in urban low‐rise and urban high‐rise as well as suburban environments. The data were subsequently merged to generate site general path loss models. The paper presents an overview of the radio channel measurements, the measured environments, the data analysis, and the approach for the derivation of the path loss model adopted in Recommendation ITU‐R P.1411‐10 (2019‐08).

Calculation Method of Spectrum Requirement for IMT-2020 eMBB and URLLC With Puncturing Based on M/G/1 Priority Queuing Model

The major use cases for IMT-2020 include enhanced mobile broadband (eMBB) and ultra-reliable and low latency communication (URLLC). URLLC packets occur sporadically, but each time, available resources with favorable conditions are required for their timely and trusted transmissions. To this end, an overlapping scheme of puncturing a part of resources scheduled to an eMBB packet for URLLC packets is proposed. Such a scheme causes inevitable damages to eMBB packets. Thus, additional delays due to possible retransmissions of damaged packets should be considered in the calculation of spectrum requirement for IMT-2020. So far, the method provided by International Telecommunication Union Radiocommunication Sector (ITU-R) based on an M/G/1 non-preemptive priority queuing model has been widely used in calculating spectrum requirements for mobile broadband services. In this work, we extend it to reflect the puncturing of URLLC on eMBB. We fully consider additional delays due to retransmissions by exploiting the concept of delay cycle. Numerical simulations validate the accuracy of our analytical results. Furthermore, we provide an algorithm to calculate spectrum requirement for IMT-2020 using the same input parameters as in the method of ITU-R.

Rain Attenuation at Millimeter Wave and Low-THz Frequencies

Wave attenuation through rain with different rainfall rates at millimeter wave ( f = 77 GHz) and low-terahertz (Low-THz) ( f = 300 GHz) frequencies is studied in this article. Rain has pronounced impacts on electromagnetic wave propagation and one of the well-known effects is attenuation of the transmitted wave. Attenuation at both frequencies and hydrometeor properties [rainfall rate and drop size distribution (DSD)] are measured simultaneously. The measured DSD is fit with gamma and Weibull distributions and is also compared to the frequently used distribution Marshall and Palmer (MP) model; Weibull is shown to be a better fit to the measured DSDs. Theoretical prediction of attenuation as a function of rainfall rate (up to about 20 mm/h) is determined using Mie scattering theory, and the fit gamma and Weibull, and MP distribution models; as well as using the International Telecommunications Union Radiocommunication Sector (ITU-R) recommendation. The calculations are evaluated by comparing them to the experiment. The measured results at 77 GHz best agree with the ITU-R recommendation whereas at 300 GHz, the calculation based on Mie scattering and the Weibull distribution exhibits the best fit to the measured data. The measured data that exceed the theoretical prediction are analyzed and interpreted based on their corresponding observed drop size properties, for the first time.

Seasonal and diurnal trends of surface refractivity in a tropical environment using ground-based automatic weather stations

The seasonal and diurnal trends of surface refractivity were derived using International Telecommunication Union Radio assembly model (ITU-R P.453-13) in two locations of entirely different vegetation characteristics in Nigeria. Atmospheric refractivity is a function of temperature, pressure as well as humidity. These meteorological variables were applied to the model to compute the refractivity parameter. Atmospheric refraction or refractivity is a key component in radio wave propagation. Real-time measurement data from a network of ground-based automatic weather station (AWS) installed at 3 m height were used and the monthly trends of surface refractivity at both stations (Lagos and Anyigba) were derived; the trends showed a month-to-month variability signifying the dynamic nature of the Earth’s atmosphere. The monthly trends in both stations show high refractivity values in the rainy months and low refractivity values in the dry months. A drop in refractivity value was observed in Lagos in the month of August, due to the cessation in rainfall as a result of a phenomenon referred to as August break. The diurnal variations were also determined and results obtained showed that the lowest refractivity value in the dry season observed in Lagos is higher than the highest refractivity value in rainy season observed in Anyigba. This is attributed to the fact that Lagos is located along the coast of the South Atlantic Ocean, therefore, the monsoon has a direct influence on its atmosphere, while Anyigba is an inland station with a mixture of savannah vegetation. Overall, the diurnal variations show high values in the morning and evening hours and low values in the afternoon hours in both seasons in Anyigba, while in Lagos we observed a surprising result, such as a rise in refractivity value at pre-noon and a post-noon drop. This unacquainted observation is probably due to excessive precipitation in the area caused by the influence of massive emissions from the South Atlantic Ocean, these emissions are mainly a result of the trapped heat due to warming of surface water.

Promising Noises About Media Sound? A Progress Report on the NGA/AdvSS Developments in the ITU-R in 2018/2019

This paper introduces the basic concept of next-generation audio (NGA)/International Telecommunications Union - Radiocommunication (ITU-R) Advanced Sound System (AdvSS), which is intended to provide the next generation of sound accompanying television for broadcast and broadband, and possibly also for radio services. Recent years have seen the standardization of the end-to-end elements of such a system, including the options for the basic ingredients of future sound services, arrangements for loudspeakers, the necessary metadata, and rendering of the delivered signals to loudspeaker feeds. Progress in these areas is outlined in this paper.

On the Determination of a Compensation Model for Rain Degraded Digital DTH Links over a Tropical Location

Ku-band satellite remains the most cost-effective distribution channel for digital television services in terms of global coverage and wide bandwidth availability. However, signal attenuation due to rain remains the bane of the reception quality and the continuous availability. In the clear-sky, the minimum signal loss between a Ku-satellite and an earth station is about 205 dB. The amount of rain rate and the site’s latitude further compound this minimum signal attenuation. Existing reported research works are mainly limited to modelling of rain-induced attenuation without porting research findings into compensation product in terms of appropriate mitigation technique. This study is aimed at developing a robust compensation model for the rain-induced digital satellite television services for an improved quality and availability of service in Nigeria, with a specific objective of determining the optimal dish size for compensating the signal attenuation on the digital satellite TV downlink. The methodology employed involves rain data collection from the International Telecommunication Union-Radiocommunication (ITU-R) worst rain zone in Nigeria. The determination of appropriate dish sizes for different parts of Nigeria was carried out. A compensation model was derived for the rain degraded DTH link; and practical dish size of 1.5 m, for 48 dBW satellite footprint, was found to be adequate for compensating Ku satellite signal attenuation, regardless of rainstorm in Nigeria.

Path Loss Determination Using Linear and Cubic Regression Inside a Classic Tomato Greenhouse.

The production of tomatoes in greenhouses, in addition to its relevance in nutrition and health, is an activity of the agroindustry with high economic importance in Spain, the first exporter in Europe of this vegetable. The technological updating with precision agriculture, implemented in order to ensure adequate production, leads to a deployment planning of wireless sensors with limited coverage by the attenuation of radio waves in the presence of vegetation. The well-known propagation models FSPL (Free-Space Path Loss), two-ray, COST235, Weissberger, ITU-R (International Telecommunications Union—Radiocommunication Sector), FITU-R (Fitted ITU-R), offer values with an error percentage higher than 30% in the 2.4 GHz band in relation to those measured in field tests. As a substantial improvement, we have developed optimized propagation models, with an error estimate of less than 9% in the worst-case scenario for the later benefit of farmers, consumers and the economic chain in the production of tomatoes.

Estimation of Rainfall Rate Cumulative Distribution in Indonesia Using Global Satellite Mapping of Precipitation Data

.

Video Luminance Levels for Human Skin Tones in Hybrid Log-Gamma Video

<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">This paper presents current work undertaken by the British Broadcasting Corp. (BBC) to look at the representation of human skin tones in International Telecommunication Union-Radiocommunication (ITU-R) Recommendation BT.2100 high dynamic range video systems. Specifically, the author presents luma values for a range of skin tones, categorized by the Fitzpatrick scale, which can be used as a lineup guide by cameramen, racks/shader operators, and colorists. The effect of makeup is also covered.</i>

Proposed Measured Display Characterization File for HDR Consumer Displays

The advent of wide color gamut and high-dynamic-range (HDR) imaging has upended long-established standards for display monitors and changed the very definition of display calibration. With the International Telecommunications Union-Radiocommunication BT.7091 standard, which in retrospect looks like a calm and pastoral monoculture, the nature of display calibration was straight-forward, i.e., adjust the behavior of the video display until its output matches the standard as closely as possible. The changes created by HDR can be seen most clearly by describing the way HDR color volume mapping works. An HDR TV’s color volume-mapping algorithm looks at the metadata that shows how the content was mastered, compares that metadata to the definition of the HDR TV’s capabilities, and applies some very intelligent mapping to make the HDR content appear as accurately as possible on the TV. A new kind of calibration process is needed to provide color accuracy while not affecting the intended behavior of the TV’s Color Volume Remapping algorithm. No standard exists for the format or mechanism of this process. This paper proposes a standard for self-description in video displays that will allow mapping algorithms to best display a variety of HDR content on a variety of display devices with differing capabilities.

Development of a New Global Model for Estimating One-Minute Rainfall Rate

One-minute rain rate exceeded for 0.01% of an average year (known as R0.01) is an important parameter, which is required in rain fade models for planning both satellite and terrestrial links, especially in the microwave and millimeter-wave bands. This paper presents the development of a new global model for estimating high-resolution R0.01. The model is developed using the Climate Hazards Group Infrared Precipitation with Stations (CHIRPS), ERA-Interim reanalyzed total precipitable water, and the cumulative distribution functions of the measured R0.01 via genetic algorithm. The newly proposed model performs better than the International Telecommunication Union Radio Sector (ITU-R) recommendation and widely used ITU-R P.837-6 model, particularly over the tropical regions, where ITU-R P.837-6 strongly underestimates R0.01. Overall, when compared to ITU-R P.837-6, the estimated R0.01 by the proposed model is improved by ~15%. Furthermore, the proposed model can provide R0.01 with a much higher spatial resolution (~5 km) as compared to ITU-R P.837-6 (~110 km). Another key advantage of the proposed model over ITU-R P.837-6 is that the inputs required for this model are readily available from meteorological database as well as from space-based observing system. This paper also investigated the long-term (1981–2016) trends in R0.01. The analysis revealed significant increasing trends in R0.01 over most parts of the globe, India and northern part of Southern America exhibited the strongest ( $\sim 0.5\,\,\text {mm}\cdot \text {h}^{-1}\cdot $ year−1) increasing trends. It is anticipated that R0.01 obtained with the newly proposed model will have large implications in rain attenuation modeling for planning both terrestrial and earth–satellite microwave links.

A novel measurement strategy to evaluate the human head as a transition medium for inductive ear-to-ear communication.

This manuscript introduces a novel concept for measuring coil coupling for extremely loose-coupled coils (coupling factors k<10-6; mutual inductance values M<10-10 H). Such a coupling is found everywhere where the ratio of solenoid diameter to coil spacing is >50. Measuring these quantities with a low-power technology requires a sophisticated setup that goes beyond the sensitivity of state-of-the art approaches. The methodology is validated using laboratory measurements with three sets of solenoids (two ferrite-cored, one air-cored) and numerical simulations with COMSOL Multiphysics 5.2a, Stockholm, Sweden. The concept is then employed to investigate the channel characteristics for inductive through-the-head communication within the 3.155-3.195 MHz band. This selected part of the spectrum is in accordance with International Telecommunication Union Radio Regulation 5.116 for low-power wireless hearing aids. By applying a phantom solution, we demonstrate that human tissue layers are transparent for magnetic fields within these frequencies. However, the influence from the relative coil arrangement is evaluated in detail as it restricts the communication range significantly. The coupling results for off-the-shelf Sonion, Roskilde, Denmark, RF 02 AA 10 solenoids considering both lateral and axial displacements might be of special interest for a number of near-field applications.

On-Site Permittivity Estimation at 60 GHz Through Reflecting Surface Identification in the Point Cloud

Accurate site-specific radio propagation simulations provide an important basis for cellular coverage analysis. The quality of these simulations relies on the accuracy of environmental description and electrical properties of constituent materials. This paper presents a novel method of on-site permittivity estimation. The method utilizes an accurate geometrical database of the environment for identifying flat and smooth surfaces producing reflections. The method exploits a limited number of on-site channel sounding to extract reflected multipaths and compare them with ray tracing based on the environmental database. The permittivity of the identified reflecting surfaces is estimated by solving an inverse reflection problem. The method was experimentally tested with limited radio channel measurements at 60 GHz in a large empty office room. The identified reflecting surfaces are classified according to their mean permittivity estimates, showing their consistency with physical material evidence and the permittivity database in the International Telecommunication Union Radiocommunication Recommendation (ITU-R P.2040-1). The estimated permittivity values are visualized as a 3-D map, giving an intuitive understanding of materials constituting the environment. This paper demonstrates on-site permittivity estimation and material classification without the need for isolated measurements of composite materials in an anechoic chamber or in situ measurements of built environments.

System Level Study of LTE-Advanced Multiple Antenna System with Inter-Band Carrier Aggregation

Spatial Multiplexing (SM) multiple antenna systems and Carrier Aggregation (CA) are techniques introduced in Long Term Evolution- Advanced (LTE−Advanced) to support high data rates by increasing the number of transmission paths and the available bandwidth respectively. Therefore, in this study we evaluate the performance of LTE-Advanced physical downlink shared channel for single and SM multiple antenna systems in two different frequency bands. The radio channel is modelled using an enhanced Three-Dimensional (3D) international telecommunication union-radio communication sector channel model integrated with base station and user mobile 3D antenna patterns. Except the total received power, similar channel statistics are observed for both frequency bands. The study is performed considering 1x1, 2x2, 4x4 antenna systems in a macro-cell urban environment at Component Carries (CC) of 2600 MHz and 800 MHz to model bands 7 and 20 of CA_7-20 respectively. The performance is evaluated in terms of throughput and SM gain for many base stations and user positions considering various modulation and coding schemes. We used the computationally efficient received bit information rate algorithm to compute the throughput as a function of channel structure and signal to noise ratio. As expected higher throughput is observed for the 800 MHz band over the 2600 MHz band. This is due to the higher total received power of the 800 MHz band. The novel SM gain results show that the SM gain depends on the operating band and it’s less than the number of spatial links. Moreover, the efficiency of inter-band CA in increasing the data rates is a function cell radius and the number of spatial streams.

Analysis of ITU‐R VHF/UHF propagation prediction methods performance on irregular terrains covered by forest

In the scope of very high-frequency (VHF) and ultra high-frequency (UHF) terrestrial communication or broadcasting systems planning, the use of point-to-area propagation prediction methods is expected. The benchmarking of such models on different scenarios is very helpful to assist the system planner in choosing those most suited to the site in hands. In this sense, this study provides a comparative performance analysis of the International Telecommunication Union radio communication sector (ITU-R) recommendations P.526, P.1546, and P.1812 and a few other models on a site marked by the presence of irregular terrain covered by forest. A set of measurements at 563 MHz at different spots in Rio de Janeiro city with such features was taken as reference. The best prediction performance was achieved by the P.526 and P.1812 methods, in addition to a wedge diffraction model, with path loss mean errors between -5 and 3 dB, and standard deviations between 8.7 and 9.2 dB. Such results were observed when the presence of the forest layer was incorporated adding a representative clutter height.

Rec.2100 color gamut revelation using spectrally ultranarrow emitters

We theoretically simulate the performance of ultranarrow emitters for the first time to achieve record high coverage for the International Telecommunication Union Radiocommunication Sector BT.2100 (Rec.2100) and National Television System Committee (NTSC) color gamut. Our results, employing more than 130-m parameter sets, include the investigation into peak emission wavelength and full width at half maximum (FWHM) values for three primaries that show ultranarrow emitters, i.e., nanoplatelets are potentially promising materials to fully cover the Rec.2100 color gamut. Using ultranarrow emitters having FWHM as low as 6 nm can provide the ability to attain 99.7% coverage area of the Rec.2100 color gamut as well as increasing the NTSC triangle to 133.7% with full coverage. The parameter set that provides possibility to fully reach Rec.2100 also has been shown to match with D65 white light by making use of the correct combination of those three primaries. Furthermore, we investigate the effect of the fourth color component on the CIE 1931 color space without sacrificing the achieved coverage percentages. The investigation into the fourth color component, cyan, is shown for the first time to enhance the Rec.2100 gamut area to 127.7% with 99.9% coverage. The fourth color component also provides an NTSC coverage ratio of 171.5%. The investigation into the potential of emitters with ultranarrow emission bandwidth holds great promise for future display applications.

Rainfall Rate Prediction for Propagation Applications: Model Performance at Regional Level Over Ireland

Three global rainfall rate prediction methods are evaluated in their ability to estimate local precipitation statistics, which are the key to predict the impact of rain on the propagation of electromagnetic waves through the atmosphere. Specifically, the International Telecommunication Union-Radiocommunication Sector (ITU-R) P.837-6, model for rainfall statistics estimation (MORSE), and the ITU-R P.837-7 prediction methods are tested against long-term rainfall data collected in 19 sites in Ireland. The results indicate that the ITU-R P.837-7 prediction method delivers the best performance, and that both the ITU-R P.837-6 prediction method and MORSE exhibit a positive bias, likely due to the overestimation of the yearly rain amount in the maps used as input to such models. The results of the testing activity provide information on the accuracy of rainfall rate prediction methods at regional level, an important factor to consider given the direct link between the magnitude of rain-induced attenuation, and the operational frequency of wireless communication links.

High Frame Rates and the Visibility of Motion Artifacts

Video frame rates, higher than those in conventional use today, have been shown to lead to an increase in perceived quality due to a reduction in the visibility of motion artifacts, specifically motion blur and temporal aliasing. Despite this, frame rates used in television and cinema have remained constant for many years. Although not currently in widespread use, the most recent ultrahigh-definition television (UHDTV) video standard (International Telecommunications Union-Radiocommunication (ITU-R) Recommendation BT. 2020) specifies a higher spatial resolution and a wider dynamic range than its predecessor; it also supports frame rates up to 120 Hz. In this context, we investigate the influence of temporal sampling rate on the visibility of aliasing artifacts. Our results show that impairments in motion quality can be tolerated to a degree, and that it is acceptable to sample at frame rates 50% lower than the critical frame rate (CFR)—the point at which motion artifacts become perceptible. Based on real-world data related to median viewing distances and screen sizes, we make the recommendation that frame rates should be at least 100 Hz in future immersive video formats. Two further experiments show how the CFR is dependent on both stimulus size and luminance. With respect to luminance dependence, our results indicate that the CFR for a bright high-dynamic range display may be 30% higher than that for a conventional low-dynamic range display.

Rural Macrocell Path Loss Models for Millimeter Wave Wireless Communications

Little is known about millimeter wave (mmWave) path loss in rural areas with tall base station antennas; yet, as shown here, surprisingly long distances (greater than 10 km) can be achieved in clear weather with less than 1 W of power. This paper studies past rural macrocell (RMa) propagation models and the current third generation partnership project (3GPP) RMa path loss models for frequencies from 0.5 to 30 GHz adopted from the International Telecommunications Union-Radiocommunication Sector (ITU-R). We show that 3GPP and ITU-R RMa path loss models were derived for frequencies below 6 GHz, yet are being asserted for use up to 30 GHz. Until this paper, there has not been published data to support mmWave RMa path loss models. In this paper, 73-GHz measurements in rural Virginia are used to develop a new RMa path loss model that is more accurate and easier to apply for varying transmitter antenna heights than the existing 3GPP/ITU-R RMa path loss models, and may be used for frequencies from 0.5 to 100 GHz. The measurement system used here has a measurement range comparable to a wideband (800-MHz radio frequency bandwidth) channel sounder with 21.7-dBW effective isotropic radiated power. Measured data verify a new path loss model that uses a close-in free space reference distance with a novel height-dependent path loss exponent (CIH model). This work shows that the CIH model is accurate and stable, and is frequency-independent beyond the first meter of propagation, and effectively models the path loss dependence on base station height in rural channels.

International spectrum management regime: is gridlock blocking flexible spectrum property rights?

PurposeThis paper aims to examine the influence of the international spectrum management regime on the introduction of flexibility in the national allocation of radiocommunication services. This is achieved through focusing on the main elements of the international regime.Design/methodology/approachA qualitative inductive methodology is adopted that examines the different elements of the international radiocommunication service allocation framework. Data are drawn from 66 semi-structured interviews with key stakeholders who are actively involved in International Telecommunication Union Radiocommunication Sector discussions.FindingsThe international radio regulations (RR) are perceived to be more of a framework for harmonisation that does not constrain the flexibility of countries. Countries are only restricted on their borders with their neighbours, and flexibility is already facilitated through a range of different measures. Moreover, several elements of the RR can be used to achieve both, i.e. to promote flexibility and to restrict the decisions of others.Practical implicationsThe international spectrum management regime is not one of the reasons for the unsuccessful practical application of the flexible spectrum property rights concept. This suggests the need for reviewing whether there still is a need for such a concept given the increasing importance of global harmonisation and economies of scales.Originality/valueThis paper sheds light on spectrum property rights from the perspective of the international spectrum management regime. Such a perspective is largely overlooked in the on-going current debate.