Ergodic Capacity of NOMA-Based Multi-Antenna LMS Systems with Imperfect Limitations

With the rapid development of land mobile satellite (LMS) systems, large scale sensors and devices are willing to request wireless services, which is a challenge to the quality of service requirement and spectrum resources utilization on onboard LMS systems. Under this situation, the non-orthogonal multiple access (NOMA) is regarded as a promising technology for improving spectrum efficiency of LMS systems. In this paper, we analyze the ergodic capacity (EC) of NOMA-based multi-antenna LMS systems in the presence of imperfect limitations, i.e., channel estimation errors, imperfect successive interference cancellation, and co-channel interference. By considering multiple antennas at the satellite and terrestrial sensor users, the closed-form expression for EC of the NOMA-based LMS systems with imperfect limitations is obtained. Monte Carlo simulations are provided to verify theoretical results and reveal the influence of key parameters on system performance.

The Benefit and Importance of Mobile Satellite Signal in Northern Nigeria: GPS Approach

Lack of equipment to study mobile satellites signal propagation in colleges and universities prone this research work. A Handheld GPS receiver used as a tool for training college students to learn mobile satellite signal propagation using Global Positioning System (GPS) approach. These refer to the experimental setup of the equipment that is the connection done between the GPS receiver with a computer. The satellite propagation data received from the GPS machine can be recorded continuously with an updates rate of 2 seconds. The experiment was carried out in an open space environment at predetermine locations using simple setup, where a cheap, readily and available portable GPS receiver were connected to the computer to acquire propagation data. The computer was equipped with a self-developed package graphical user interface (GUI) monitoring the propagation information from the GPS satellites and saving the data. The developed system can be set up anywhere at any location. The sate-up will serve as a database for satellites view and analysis of mobile satellite data orbiting the sky of Northern part of Nigeria. Cost effective referring to a low-cost and readily available GPS receiver that can be easily set-up as compared to equipment designed specifically for an experimental purpose that is normally very expensive.

Antenna Array Based on Fabry–Perot Cavity with Mechanoelectrical Beam Steering

Introduction. Introduction. Low-profile effective antenna systems (AS) with maintained directional characteristics in a wide sector of scanning angles are required for satellite communication at mobile objects. This article investigates the directional characteristics of a subarray based on a Fabry–Perot cavity and an antenna array with mechanoelectrical beam steering.Aim. To investigate a Fabry–Perot based antenna array with mechanoelectrical beam steering and to estimate its gain and directivity at different scanning angles.Materials and methods. Computer simulations were carried out using the finite element method (FEM), finite difference time domain (FDTD) method and template based post-processing.Results. A subarray based on a Fabry–Perot cavity for an antenna array with mechanoelectrical beam steering was simulated. The efficiency of the subarray comprised at least 65 % in the 11.9…12.5 GHz frequency band. An antenna array based on a Fabry–Perot cavity with mechanoelectrical beam steering was developed and investigated. The calculated characteristics of the developed antenna array agreed well with those obtained experimentally. The gain degradation did not exceed 2.5 dB in the 0…70° scanning angle range. The advantages of using antenna elements based on a Fabry–Perot cavity and developing on their basis mobile satellite antenna systems with wide-angle scanning are noted.Conclusion. The use of a radiator based on a Fabry–Perot cavity and the development on it basis an antenna array with mechanoelectrical beam steering provides an antenna efficiency of no less than 0.5 with a gain degradation of no more than 2.5 dB in the scanning angle range 0…70° from 11.9 to 12.5 GHz.

Development of a phased array antenna powered by Rotman printed lens for a mobile satellite communication terminal

Connecting to the Internet whenever and wherever you travel is no longer a luxury. All people have the ability to connect to the Internet and share data away from home. Satellite communications are now an integral part of successful and high-quality communications. Satellite communications antennas are usually installed on mobile ground terminals. Due to its wide coverage and versatility, satellite communications are continuously improving and adapting to the telecommunications needs of many countries, despite the fact that broadband, Internet and fiber - optic communications are used almost everywhere. We know that more than 50 % of all satellites in orbit are communications satellites.

Use of a Unique Mobile Medical Asset in COVID Monoclonal Antibody Treatment

The COVID-19 pandemic and the subsequent surge of patients presented to emergency departments has forever changed the paradigm of delivering emergency care. The highly infectious nature of the 2019 Novel Coronavirus, or COVID-19, mandated strict environmental changes, novel patient care, and flexible strategies to continue to deliver efficient emergency care while maintaining appropriate physical distancing between suspect and non-suspect COVID-19 patients. The engagement of a unique rapidly deployable Mobile Satellite Emergency Department (MSED) with scalable capability from prompt care to resuscitation level allowed the emergency care team to optimize patient care and throughput. The MSED was strategically located adjacent to the ambulance entrance. While initially deployed to increase Emergency Department surge capacity, the MSED was repurposed to cohort and treat COVID patients with the monoclonal antibody, Bamlanivimab, who were expected to be discharged after treatment. This allowed for more efficient use of Emergency Department resources, including physical space and staffing.