Software Defined Channel Sounder for Power Line Communications

Most power line channel sounders are based on expensive lab instruments. This work presents an alternative based on software defined radio platforms. These can be later also employed as communication modems, decreasing costs and deployment times. We implemented and evaluated two channel sounding techniques: frequency hopping and sliding correlator. The results suggest that frequency hopping might be a better candidate for power line channels due to the expected low signal-to-noise ratio

Pulses in the Sand: Impulse Response Analysis of Wireless Underground Channel

Wireless underground sensor networks (WUSNs) are becoming ubiquitous in many areas and designing robust systems requires extensive understanding of the underground (UG) channel characteristics. In this paper, UG channel impulse response is modeled and validated via extensive experiments in indoor and field testbed settings. Three distinct types of soils are selected with sand and clay contents ranging from 13% to 86% and 3% to 32%, respectively. Impacts of changes in soil texture and soil moisture are investigated with more than 1,200 measurements in a novel UG testbed that allows flexibility in soil moisture control. Time domain characteristics of channel such as RMS delay spread, coherence bandwidth, and multipath power gain are analyzed. The analysis of the power delay profile validates the three main components of the UG channel: direct, reflected, and lateral waves. It is shown that RMS delay spread follows a log-normal distribution. The coherence bandwidth ranges between 650 kHz and 1.15MHz for soil paths of up to 1m and decreases to 418 kHz for distances above 10m. Soil moisture is shown to affect RMS delay spread non-linearly, which provides opportunities for soil moisture-based dynamic adaptation techniques. The model and analysis paves the way for tailored solutions for data harvesting, UG sub-carrier communication, and UG beamforming

A Statistical Impulse Response Model Based on Empirical Characterization of Wireless Underground Channel

Wireless underground sensor networks (WUSNs) are becoming ubiquitous in many areas. The design of robust systems requires extensive understanding of the underground (UG) channel characteristics. In this paper, an UG channel impulse response is modeled and validated via extensive experiments in indoor and field testbed settings. The three distinct types of soils are selected with sand and clay contents ranging from $13\%$ to $86\%$ and $3\%$ to $32\%$, respectively. The impacts of changes in soil texture and soil moisture are investigated with more than $1,200$ measurements in a novel UG testbed that allows flexibility in soil moisture control. Moreover, the time-domain characteristics of the channel such as the the RMS delay spread, coherence bandwidth, and multipath power gain are analyzed. The analysis of the power delay profile validates the three main components of the UG channel: direct, reflected, and lateral waves. Furthermore, it is shown that the RMS delay spread follows a log-normal distribution. The coherence bandwidth ranges between \SI{650}{kHz} and \SI{1.15}{MHz} for soil paths of up to \SI{1}{m} and decreases to \SI{418}{kHz} for distances above \SI{10}{m}. Soil moisture is shown to affect the RMS delay spread non-linearly, which provides opportunities for soil moisture-based dynamic adaptation techniques. Based on the measurements and the analysis, a statistical channel model for wireless underground channel has been developed. The statistical model shows good agreement with the measurement data. The model and analysis paves the way for tailored solutions for data harvesting, UG sub-carrier communication, and UG beamforming

Wireless Underground Channel Modeling

A comprehensive treatment of wireless underground channel modeling is presented in this chapter. The impacts of the soil on bandwidth and path loss are analyzed. A mechanism for the UG channel sounding and multipath characteristics analysis is discussed. Moreover, novel time-domain impulse response model for WUC is reviewed with the explanation of model parameters and statistics. Furthermore, different types of the through-the-soil wireless communications are surveyed. Finally, the chapter concludes with discussion of the UG wireless statistical model and path loss model for through-the-soil wireless communications in decision agriculture. The model presented in this chapter is also validated with empirical data

A First Look at Forensic Analysis of sailfishos

SailfishOS is a Linux kernel-based embedded device operation system, mostly deployed on cell phones. Currently, there is no sufficient research in this space, and at the same time, this operating system is gaining popularity, so it is likely for investigators to encounter it in the field. This paper focuses on mapping the digital artifacts pertinent to an investigation, which can be found on the filesystem of a phone running SailfishOS 3.2. Currently, there is no other known publicly available research and no commercially available solutions for the acquisition and analysis of this platform. This is a major gap, as the adoption of this OS is accelerating in emerging markets on low-cost devices. This paper presents many of the major forensics points of interest, such as call and text, log, phonebook, web browser artifacts as well as hardware-specific features

A Study of DAS delays and their Impact on the Wireless Channels with Application to Indoor Localization

This research evaluates the Distributed Antenna Systems (DAS) introduced delays and their effects on the indoor channel in simulcast situations where the effect of delays is most prevalent. Different simulcast cases that form the basic building blocks are analyzed to form an understanding of the problem. Two case studies of important indoor environments are presented. Importance of improving ray tracing simulations to include propagation and DAS delays is highlighted. The paper also introduces a DAS element representation and delay mapping model and explores techniques of engineering DAS delays to optimize location estimation by ranging and RF fingerprinting to achieve E911 mandated accuracy. A brief description is introduced for a Software Defined Radio (SDR) implementation of a Correlation Channel Sounder and the possible application of channel sounding for indoor DAS. The paper suggests procedures to produce a full DAS delay profile and ways to optimize it for location estimation

A Wireless Channel Sounding System for Rapid Propagation Measurements

Abstract—Wireless systems are getting deployed in many new environments with different antenna heights, frequency bands and multipath conditions. This has led to an increasing demand for more channel measurements to understand wireless propagation in specific environments and assist deployment engineering. We design and implement a rapid wireless channel sounding system, using the Universal Software Radio Peripheral (USRP) and GNU Radio software, to address these demands. Our design measures channel propagation characteristics simultaneously from multiple transmitter locations. The system consists of multiple battery-powered transmitters and receivers. Therefore, we can set-up the channel sounder rapidly at a field location and measure expeditiously by analyzing different transmitters’ signals during a single walk or drive through the environment. Our design can be used for both indoor and outdoor channel measurements in the frequency range of 1 MHz to 6 GHz. We expect that the proposed approach, with a few further refinements, can transform the task of propagation measurement as a routine part of day-to-day wireless network engineering 1. I