Abstract

Abstract
In this work we present a study addressing the load modulation for wireless power transfer in underwater applications. A voltage-mode class-D in a series-series resonance topology is analyzed with simplified equations provided to describe the operation of the wireless power system, including the influence of the load on the primary side. The analysis is validated through simulation results provided for a resistive load modulation using component SPICE models, including the characterization of coupling coils in salt water.

Abstract
This paper presents a predictive current control algorithm for a synchronous buck converter using an extended Kalman filter (EKF) algorithm. The predictive approach avoids the need of current-sensing circuitry and provides insensitivity to Gaussian noise sources at the output of the buck converter, which is the same as the control loop input. The method requires a model for the buck converter, the EKF design, and current loop tuning. All these prerequisites are described in this work along with the implementation of the algorithm in a state of the art microcontroller. Simulation and experimental results show that while maintaining a good step response, the proposed method provides better results than standard methods when Gaussian noise is present at the output voltage. © 2017 Inderscience Enterprises Ltd.

Abstract

Abstract
The TERAPOD project aims to investigate and demonstrate the feasibility of ultra high bandwidth wireless access networks operating in the Terahertz (THz) band. The proposed TERAPOD THz communication system will be developed, driven by end user usage scenario requirements and will be demonstrated within a first adopter operational setting of a Data Centre. In this article, we define the full communications stack approach that will be taken in TERAPOD, highlighting the specific challenges and aimed innovations that are targeted.

Abstract
Demands for underwater communication systems are increasing due to the ongoing expansion of human activities in underwater environments such as environmental monitoring, underwater exploration, offshore oil field exploration and monitoring, port security, and tactical surveillance. As such, there is a serious requirement to improve the performance of underwater communication systems in order to effectively use the equipment and the resources. The high cost, lack of flexibility, and operational disadvantages of wireline (particularly optical fiber) systems to provide real-time communication in underwater applications become restrictive for many cases. This triggers the growing demand for underwater wireless links. Acoustic communications suffer from a very small available bandwidth, very low celerity, and large latencies due to the low propagation speed. Underwater wireless optical communications (UWOC) which are able to achieve data rates of hundreds of Mbps (even up to Gbps) for short ranges, typically several tens of meters, appear as an attractive alternative or complementary solution to long-range acoustic communications. In fact, water is relatively transparent to light in the visible band of the spectrum and absorption takes its minimum value in the blue-green spectral range (450 nm-550 nm) [1,2]. Thanks to the ability of providing unprecedentedly high-rate data transmission, the UWOC technology enables the establishment of high-speed and reliable links for underwater missions employing robotics or autonomous underwater vehicles (AUVs), for instance. In addition, it is highly energy efficient, compared to the traditional technique of acoustic communication, and also has much less impact on marine animal life (see Figure 11.1) [3,4]. In particular, it is harmless to the cetaceans and coral. © 2017 by Taylor & Francis Group, LLC.