Justin D. Rohweller

Bio: Justin D. Rohweller is an academic researcher from Azusa Pacific University. The author has contributed to research in topics: Interface (computing) & Software-defined radio. The author has an hindex of 1, co-authored 2 publications receiving 6 citations.

IoT enabled pico-hydro electric power with satellite back haul for remote himalayan villages

Abstract: This work describes system engineering of an internet-of-things (IoT) connectivity and satellite data transfer for a pico-hydroelectric power generation system. The system is developed for deployment in remote villages in the Nepal Himalayas. The IoT devices are sensors attached to various points in the system which monitor critical system performance metrics such as generator vibrations and output voltage and control important functions. The data is transmitted from IoT devices using Zigbee. The data is then transmitted to the Iridium satellite system so it can be available to an international team of researchers who developed and monitor the performance of the system. This allows for optimization and performance improvements with the goal of perfecting the system so it can be implement in other villages. This work describes the system, why it is needed, and the hardware. The result is an IoT enabled monitoring system with real time data transmitted using satellites.

Systems Engineering a Low Cost Digital Beam Formed Phased Array for IoT Connectivity

Abstract: This work describes the systems engineering and advanced prototype hardware of a digital beam steering receive phased array for IoT device connectivity. It uses low cost software defined radios (SDRs). IoT devices require connectivity for the transfer of data from the point information is gathered to the cloud and user community. In locations where multiband base stations provide connectivity, concerns over interference require the use ‘Smart Base Stations’ which are able to minimize interference and maintain connectivity to IoT devices. Phased arrays can also prolong battery life of IoT devices, increase bit rate (more link budget), provide location services where GPS connectivity does not exist (inside locations), and improve jamming immunity. However, the cost of the hardware can be prohibitive for some applications. A trade study is performed to determine the optimum SDR for the demonstration and a prototype system is constructed and measured to show the feasibility of the approach. The work concludes with suggestion for further work which includes the use of a field programmable gate array to interface between the SDRs and the host system.

Convergence of Satellite and Terrestrial Networks: A Comprehensive Survey

Abstract: The explosive growth of various services boosts the innovation and development in terrestrial communication systems for the implementation of the next generation mobile communication networks. However, simply utilizing limited resources in terrestrial communication networks is difficult to support the massive quality of service (QoS) aware requirements and it is hard to guarantee seamless coverage in far remote regions. Leveraging the intrinsic merits of high altitude and the ability of multicasting or broadcasting, satellite communication systems provide an opportunity for novel mobile communication networks with its tight interaction and complementary characteristics to traditional terrestrial networks. It is believed that the convergence of satellite and terrestrial networks can solve the problems existing in current mobile communication systems and make a profound effect on global information dissemination. In this paper, we make a comprehensive survey on the convergence of satellite and terrestrial networks. First, motivations and requirements of satellite-terrestrial network convergence are identified. Then, we summarize related architectures of existing literature, classify the taxonomy of researches on satellite-terrestrial networks, and present the performance evaluation works in different satellite-terrestrial networks. After that, the state-of-the-art of standardization, projects and the key application areas of satellite-terrestrial networks are also reviewed. Finally, we conclude the survey by highlighting the open issues and future directions.

Study of Data Transfer in a Heterogeneous LoRa-Satellite Network for the Internet of Remote Things

Abstract: In the absence of traditional communication infrastructures, the choice of available technologies for building data collection and control systems in remote areas is very limited. This paper reviews and analyzes protocols and technologies for transferring Internet of Things (IoT) data and presents an architecture for a hybrid IoT-satellite network, which includes a long range (LoRa) low power wide area network (LPWAN) terrestrial network for data collection and an Iridium satellite system for backhaul connectivity. Simulation modelling, together with a specialized experimental stand, allowed us to study the applicability of different methods of information presentation for the case of transmitting IoT data over low-speed satellite communication channels. We proposed a data encoding and packaging scheme called GDEP (Gateway Data Encoding and Packaging). It is based on the combination of data format conversion at the connection points of a heterogeneous network and message packaging. GDEP enabled the reduction of the number of utilized Short Burst Data (SBD) containers and the overall transmitted data size by almost five times.

Challenges Facing the Implementation of Pico-Hydropower Technologies

Abstract: 840 million people living in rural areas across the world lack access to electricity, creating a large imbalance in the development potential between urban and rural areas. Pico-hydropower offers a cost-effective way of accessing electricity, where the resource exists. This paper discusses and critically examines several challenges that remain in implementing pico-hydropower systems, such as local manufacturing, maintenance and repair of turbines, low-head solutions, dealing with variation in the water flow between seasons, the ability to deal with income generating loads and low system power and capacity factor. The solutions to many of these problems exist; several low head turbine systems are appearing on the market, and new power electronic packages are able to improve the system capacity factor. Some turbines are now being designed for local construction using design for manufacturing rules, so only basic workshop tools and process are required to build turbine systems and components, and enabling turbines to be locally repaired. Through the commercialisation and implementation of these solutions, the proliferation of pico-hydropower systems can take place providing low cost sustainable electricity for remote communities, but this requires a stronger emphasis in social awareness and policy. Three critical enabling factors for the success of pico-hydropower projects are identified through this analysis: understanding the local context, financial sustainability and stakeholder awareness.