Compared with Geostationary Orbit (GEO) satellite systems and Medium Earth Orbit (MEO) satellite systems, Low Earth Orbit (LEO) satellite systems provide lower propagation delay as well as higher throughput. Because of these reasons, LEO satellite systems can play a pivotal role in providing services to areas where there is no substantial terrestrial infrastructure. In this paper, a novel kind ...

Abstmct Satellite networks provide global coverage and support a wide range of services. Low Earth Orbit (LEO) satellites provide short round trip delays and are becoming increasingly important. One of the challenges in LEO satellite networks is the development of specialized and efflcient routing algorithms. In this work, a datagram routing algorithm for LEO satellite networks is introduced. T...

Low earth orbit (LEO) satellite has the advantages of global coverage, low propagation delay and low path losses, etc. Combined with orthogonal frequency division multiplexing (OFDM) transmission, LEO satellite system can support very high capacity suitable for wideband multimedia traffic. This paper analyzes the channel model and throughput for LEO OFDM satellite communication system. First, s...

the low earth orbiting (leo) satellites are widely used for geosciences applications. for most applications, precise orbital information of the satellites is required. a combination of the in suite observations and dynamic orbit yields the optimum solution. in order to obtain the combined optimal solution, one needs to analytically or numerically propagate the state vector epoch by an epoch bas...

A three-dimensional ray tracing model with aiming algorithms for global positioning system (GPS) signal is proposed to make simulations conform to the realistic radio occultation (RO) signal propagation. The two aiming algorithms used in this study ensure the initial and end point ray trajectories are located in the prescribed region. In past studies, the ray tracing techniques applied to the R...

This master thesis presents a preliminary investigation into the impact of TCP’s advertised receive buffer size and timer granularity on TCP performance over an erroneous link in a low earth orbit (LEO) satellite environment. Conducted simulations include over 200 different combinations of TCP flavor, advertised receive buffer size, timer granularity, and bit error rates. Results show that TCP ...

Among satellite systems, low earth orbit (LEO) satellite system will make an important role in new fiture communication services, because of its less propagation delay, less power consumption in the user terminal and the satellites, and efficient spectrum utilization using smaller coverage area for each satellite than geostationa y (GEO) counterpart. However, a number of mobility problems that ...

A satellite communications system is based on antennas in a stable orbit above the earth. Satellites serve as relay stations in the sky. The basic idea of satellite communications is that two stations on earth discuss via one or more satellites. So a little bit of satellite-related terminology: 1. Earth station is an antenna on or near the surface of the earth. 2. Uplink is a transmission from ...

We present an analytical model for computing call blocking probabilities in a LEO satellite network that carries voice calls. Both satellite-fixed and earth-fixed constellations with inter-orbit links and hand-offs are considered. The model is analyzed approximately by decomposing it into sub-systems. Each sub-system is solved in isolation exactly using a Markov process, and the individual resu...