Radio Environment Maps: The Survey of Construction Methods

Abstract

Radio environment maps (REMs) and geolocation database represent an important source of information for the operation of cognitive radio networks, replacing or complementing spectrum sensing information. This paper provides a survey of methods for constructing the radio frequency layer of radio environment map (RF-REM) using distributed measurements of the signal levels at a given frequency in space and time. The signal level measurements can be obtained from fixed or mobile devices capable of sensing radio environment and sending this information to the REM. The signal measurements are complemented with information already stored in different REM content layers. The combined information is applied for estimation of the RF-REM layer. The RF-REM construction methods are compared, and their advantages and disadvantages with respect to the spatial distribution of signal measurements and computational complexity is given. This survey also indicates possible directions of further research in indirect RF-REM construction methods. It emphasizes that accurate RF-REM construction methods should in the best case support operation with random and clustered signal measurements, their operation should not be affected by measurements outliers, and it must estimate signal levels comparably on all RF-REM locations with moderate computational effort.

Wireless sensing – enabler of future wireless technologies

“…REM is defined as a multidimensional database consisting of past, current, and predicted information on the radio scene, elements, and environment [14]. The radio scene encompasses wireless capable devices or network users' behavior and wireless transmission (communication or sensing) activities in the network/region.…”

Dynamic Spectrum Management with Network Function Virtualization for UAV Communication

“…The global objective of CDs is to perform spectrum awareness, along with additional functions of sensing a radio frequency (RF) environment, identifying RF patterns, and extracting characteristics in the RF. Some technologies are commonly utilized when constructing CDs, such as the spectrum sensing methods reviewed in [88], identification of spectrum opportunities [14], or utilization of radio environment maps (REMs) [55]. In accordance with the prediction of the PUs' traffic model, two groups of detectors are then categorized, i.e., reactive detector and proactive detector [78], based on reactive sensing and proactive sensing approaches, respectively.…”

Radio environment maps for military cognitive networks: density of small-scale sensor network vs. map quality

“…In general, REM is considered to be a database which stores comprehensive and up-todate information on the radio spectrum. It is assumed that this information is composed of geographical features, available services, spectral regulations, positions and activities of radios, and policies adopted by the user and/or service providers, as well as knowledge from the past [7].…”

“…Computational complexity of the different interpolation methods was widely discussed in [7]. Asymptotic computational complexity and calculated complexity for scenarios with 13, 20, and 26 sensors were compared in Table 5.…”