This report describes the 3.5 GHz Study. It explains the assumptions, methods, analyses, and system characteristics used to generate the revised exclusion zones for small-cell commercial broadband systems to protect federal radar operations (ship and land based) from aggregate interference in the band 3550–3650 MHz. The 3.5 GHz Study’s exclusion zones are compared with the exclusion zones that were generated in the Fast Track Report, which considered macro-cell operations. This report was reissued in March 2016 to correct typographical errors.

3.5 GHz Exclusion Zone Analyses and Methodology

From a radio frequency propagation perspective, the general focus of the commercial wireless communications community has been primarily on frequencies above 800 MHz. Therefore, there is a limited number of available empirical data and validated prediction methods indicating what type of path loss or signal degradation one should expect in various urban settings at a very high frequency (VHF) range, which is the range of operation for numerous military tactical communications systems. Furthermore, the extensive literature survey revealed that indoor propagation models are particularly lacking in either availability and/or proven fidelity. This paper presents a new general urban path loss model derived from a log-distance path loss model, floor attenuation factor model and path loss measurements taken on campus of The Johns Hopkins University Applied Physics Laboratory (JHU/APL), Laurel, MD, with a measurement hardware suite in 30-88 MHz frequency range. The authors felt that there is a void in the open literature on simple, empirically-verified large-scale path loss models that implicitly address the lower VHF range, more than one urban setting, short communications ranges (<1 km) and low transmitting and receiving antenna heights as well as offer reasonably high fidelity without requiring a lot of information about the site.

VHF General Urban Path Loss Model for Short Range Ground-to-Ground Communications

Actually many Internet of Things (IoT) applications and architectures are being deployed in order to support urban area applications, as for example smart cities. However, other important applications are being deployed in rural areas, as for example agribusiness, in which wireless connectivity is one of the most important issues because wireless broadband commercial technologies are not sustainable from the business model view. In order to attend the actual demand of rural areas, the present work proposes two study cases that optimize coverage and low energy consumption joining LTE and LoRaWAN wireless access technologies. The proposal architecture is based on an element called Intelligent Terminal (IT), which is a gateway that is composed by LTE and LoRaWAN interfaces. The first study case represents a terrestrial vehicular case and the second one represents an unmanned aerial vehicle (UAV) case. The terrestrial study case is used as a reference to get a quantified gain of using UAVs. Considering that every scenario has particularities in terrestrial relief characteristics, it was obtained coverage information of five scenarios with different radius. When the radius coverage is increased, usability of UAV becomes more important. In average, for radius equal to 45 km and an UAV height equal to 50 m the gain of using UAVs is equal to 2 times the coverage than using a terrestrial solution. Other important contribution are parameters of a linear equation that estimate the average coverage gain based on any arbitrary UAV altitude.

Rural area deployment of internet of things connectivity: LTE and LoRaWAN case study

The Longley-Rice and Johnson-Gierhart tropospheric propagation programs are particularly useful in predicting propagation losses for paths over irregular terrain commonly encountered in ground-to-ground, air-to-ground, and air-to-air military tactical scenarios. These programs use an empirical database to statistically weigh knife-edge diffraction losses with losses from multipath interference, smooth-spherical Earth diffraction, and troposcatter modes of propagation. The purpose of this paper is to provide perspective concerning the use of the two programs. Emphasis is placed upon the regions of applicability for the programs and on factors that must be considered in selecting and specifying the input parameters. Numerical results are given for various scenarios and ranges of input parameters.

Use of the Longley-Rice and Johnson-Gierhart Tropospheric Radio Propagation Programs:0.02-20 GHz

We present a unified approach of the description of the spatial and temporal distribution of radio signals within built-up radio communication links. This approach is based on a multiparametric stochastic model, which takes into account the characteristic features of built-up terrain and peculiarities of radio wave propagation related with multiple reflections, diffraction and scattering phenomena caused by obstructions surrounding both terminal antennas, the receiver and the transmitter. To describe fast fading phenomena, we propose a new general distribution of signal strength fast fading, which successfully covers the Ricean distribution in line-of-sight (LOS) and quasi-LOS conditions and the Rayleigh distribution in no line-of-sight multipath conditions usually used for description of land communication links. This new distribution leads to a multiparametric stochastic model. Based on this model, we present a strict estimation of scales of slow and fast fading and present the corresponding correlation functions in space and time domains, which describe slow and fast signal fluctuations. Finally, the power distribution in the angle-of-arrival (azimuth) domain, following the proposed stochastic approach, is considered and analyzed, both for uplink and downlink mobile communication channels

Spatial and temporal distribution of the VHF/UHF radio waves in built-up land communication links

This paper reviews earlier work on radio propagation in urban areas, including data, studies of multi-path fading, and empirical propagation models A model is described, for use with a digital computer, which provides a rapid means of calculating both the median attenuation and the location, or path-to-path, variaability

A.G. Longley

Papers

Radio propagation in urban areas