Internet of Underground Things: Sensing and Communications on the Field for Precision Agriculture

The projected increases in World population and need for food have recently motivated adoption of information technology solutions in crop fields within precision agriculture approaches. Internet of underground things (IOUT), which consists of sensors and communication devices, partly or completely buried underground for real-time soil sensing and monitoring, emerge from this need. This new paradigm facilitates seamless integration of underground sensors, machinery, and irrigation systems with the complex social network of growers, agronomists, crop consultants, and advisors. In this paper, state-of-the-art communication architectures are reviewed, and underlying sensing technology and communication mechanisms for IOUT are presented. Recent advances in the theory and applications of wireless underground communication are also reported. Major challenges in IOUT design and implementation are identified

Drone Technology in Precision Agriculture: Are There No Environmental Concerns?

The adoption of drones in precision agriculture is expanding at a rapid rate, and expected to rise even faster as improvements in the technology result in cheaper models. Studies on the economic impact of drone technology in precision agriculture present optimistic projections of increased global food production. But increased food production almost always comes with significant environmental concerns. This paper examines the environmental concerns of drone technology in precision agriculture. The methodology of this paper is theoretical analysis and extrapolation of current literature in order to reveal the gap which future research needs to fill. While proposing a new area that has not received the close attention of experts and researchers, the paper reveals future scenarios of environmental issues around the various methods of drone applications in agricultural practices. Keywords: Drone technology, precision agriculture, agricultural practices, environmental impact, food security words DOI: 10.7176/JEES/10-9-08 Publication date:September 30th 202

Electromagnetic Characteristics of the Soil

The electromagnetic characteristics of the soil are discussed in this chapter. The characteristics of porous bedrock, soil medium, and impacts of rain attenuations are also presented. The models of dielectric soil properties are studied with a rigorous focus on the constitutive parameters of subsurface soil medium. Moreover, the permittivity and wavenumber in soil are explained. In addition, the frequency-dependent dielectric properties such as dispersion in soil, absorption characteristic, and penetration depth versus frequency are reviewed. Furthermore, the effective permittivity of soil–water mixture for through-the soil-propagation mechanism is analyzed thoroughly

Impacts of Soil Type and Moisture on the Capacity of Multi-Carrier Modulation in Internet of Underground Things

Unique interactions between soil and communication components in wireless underground communications necessitate revisiting fundamental communication concepts from a different perspective. In this paper, capacity profile of wireless underground (UG) channel for multi-carrier transmission techniques is analyzed based on empirical antenna return loss and channel frequency response models in different soil types and moisture values. It is shown that data rates in excess of 124 Mbps are possible for distances up to 12 m. For shorter distances and lower soil moisture conditions, data rates of 362 Mbps can be achieved. It is also shown that due to soil moisture variations, UG channel experiences significant variations in antenna bandwidth and coherence bandwidth, which demands dynamic subcarrier operation. Theoretical analysis based on this empirical data show that by adaption to soil moisture variations, 180% improvement in channel capacity is possible when soil moisture decreases. It is shown that compared to a fixed bandwidth system; soilbased, system and sub-carrier bandwidth adaptation leads to capacity gains of 56%-136%. The analysis is based on indoor and outdoor experiments with more than 1; 500 measurements taken over a period of 10 months. These semi-empirical capacity results provide further evidence on the potential of underground channel as a viable media for high data rate communication and highlight potential improvements in this area

Underground Wireless Channel Bandwidth and Capacity

The UG channel bandwidth and capacity are vital parameters in wireless underground communication system design. In this chapter, a comprehensive analysis of the wireless underground channel capacity is presented. The impact of soil on return loss, bandwidth, and path loss is discussed. The results of underground multi-carrier modulation capacity are also outlined. Moreover, the single user capacity and multi-carrier capacity are also introduced with an in-depth treatment of soil texture, soil moisture, and distance effects on channel capacity. Finally, the chapter is concluded with a discussion of challenges and open research issues

Signals in the Soil: Underground Antennas

Antenna is a major design component of Internet of Underground Things (IOUT) communication system. The use of antenna, in IOUT, differs from traditional communication in that it is buried in the soil. Therefore, one of the main challenges, in IOUT applications, is to establish a reliable communication. To that end, there is a need of designing an underground-specific antenna. Three major factors that can impact the performance of a buried antenna are: (1) effect of high soil permittivity changes the wavelength of EM waves, (2) variations in soil moisture with time affecting the permittivity of the soil, and (3) difference in how EM waves propagate during aboveground (AG) and underground (UG) communications. For the third challenge above, it is to be noted that lateral waves are dominant component in EM during UG2UG communication and suffer lowest attenuation as compared to other, direct and reflected, components. Therefore, antennas used for over-the-air (OTA) communication will not be suitable for UG communication because of impedance mismatch. This chapter focuses on developing a theoretical model for understanding the impact of soil on antenna by conducting experiments in different soil types (silty clay loam, sandy, and silt loam soil) and indoor testbed. The purpose of the model is to predict UG antenna resonance for designing efficient communication system for IOUT. Based on the model a wideband planar antenna is designed considering soil dispersion and soil–air interface reflection effect which improves the communication range five times from the antennas designed only for the wavelength change in soil. Furthermore, it also focuses on developing an impedance model to study the effect of changing wavelength in underground communication. It is also discussed how soil–air interface and soil properties effect the return loss of dipole antenna

Underground Phased Arrays and Beamforming Applications

This chapter presents a framework for adaptive beamforming in underground communication. The wireless propagation is thoroughly analyzed to develop a model using the soil moisture as an input parameter to provide feedback mechanism while enhancing the system performance. The working of array element in the soil is analyzed. Moreover, the effect of soil texture and soil moisture on the resonant frequency and return loss is studied in detail. The wave refraction from the soil–air interface highly degrades the performance of the system. Furthermore, to beam steering is done to achieve high gain for lateral component improving the UG communication. The angle enhancing the lateral wave depends upon dielectric properties and usually ranges from 0∘ to 16∘. These dielectric properties change with the change in soil moisture and soil texture. It is shown from the experiments that optimal UG lateral angle is high at lower soil moisture readings and decreases with decrease in soil moisture. A planar structure of antenna array and different techniques for optimization are proposed for enhanced soil moisture adaptive beamforming. UG channel impulse response is studied from the beamforming aspect to identify the components of EM waves propagating through the soil. An optimum steering method for beamforming is presented which adapts to the changing values of soil moisture. Finally, the limitations of UG beamforming are presented along with the motivation to use it

Current Advances in Internet of Underground Things

The latest developments in Internet of Underground Things are covered in this chapter. First, the IOUT Architecture is discussed followed by the explanation of the challenges being faced in this paradigm. Moreover, a comprehensive coverage of the different IOUT components is presented that includes communications, sensing, and system integration with the cloud. An in-depth coverage of the applications of the IOUT in various disciplines is also surveyed. These applications include areas such as decision agriculture, pipeline monitoring, border control, and oil wells

Decision Agriculture

In this chapter, the latest developments in the field of decision agriculture are discussed. The practice of management zones in digital agriculture is described for efficient and smart faming. Accordingly, the methodology for delineating management zones is presented. Modeling of decision support systems is explained along with discussion of the issues and challenges in this area. Moreover, the precision agriculture technology is also considered. Moreover, the chapter surveys the state of the decision agriculture technologies in the countries such as Bulgaria, Denmark, France, Israel, Malaysia, Pakistan, United Kingdom, Ukraine, and Sweden. Finally, different field factors such as GPS accuracy and crop growth are also analyzed

Modulation Schemes and Connectivity in Wireless Underground Channel

In this chapter, a thorough treatment of the modulation schemes for UG Wireless is presented. The effects of soil texture and water content on the capacity of multi-carrier modulation in WUC are discussed. The multi-carrier capacity model results are analyzed. Moreover, the underground MIMO design for underground communications is explained thoroughly. An analysis of medium access in wireless underground is done as well. Furthermore, the soil properties are considered for cross-layer communications of UG wireless. The performance analysis of traditional modulation schemes is also considered. The soil moisture-based modulation approach is also explored in this chapter. The connectivity and diversity reception approaches are discussed for wireless underground communications. The connectivity and interference models are studied for Ad-Hoc and Hybrid Networks. The topology control mechanisms for maintaining network connectivity are explored for maximizing network capacity under the physical models (e.g., the protocol interference model and physical interference model). Moreover, the underground diversity is examined for 3W-Rake receiver and coherent detection along with experimental evaluation and comprehensive analysis of performance of equalization techniques