In this paper, we survey techniques for routing and performance analysis of Low Earth Orbit (LEO) systems. We first review the basic structure of LEO satellite communications and present the main characteristics of LEO systems. The dynamic characteristics of LEO systems make the performance analysis and routing problem quite complicated. In this study, we review some of the proposed solutions t...

In this paper we propose a serial-parallel correlator (SPC) for the purpose of PN code acquisition in a low earth orbit (LEO) satellite environment. To reduce the effect of severe Doppler in a LEO satellite channel, we combine the SPC with an FFT technique to combat the carrier frequency offset due to Doppler shift. By using the FFT technique we omit the need for an additional search over the f...

LEO satellite networks play a very important role in broadcasting Internet and connecting remote places at the time of natural calamities. Routing plays a very important role in faster data transfer by taking shortest path. LEO satellite networks are the preferred choice due to less propagation delay and packet loss as compared to GEO satellite network. The multimedia applications and live tran...

Future satellite communication systems proposed use geosynchronous (GEO) satellites, medium earth orbit (MEO), and low earth orbit (LEO) constellations with fast packet switching and quality of service (QoS) provisioning. In this paper, we present broadband GEO, MEO and LEO satellite network QoS models and simulated performance results. This paper proposes a new method of bandwidth allocation d...

In space, radio frequencies (RFs) are usually used for long-distance linkage. However, recent progress in optics and laser technologies, especially in fiber optics, is ushering in an era of inter-orbit communications using laser beams. Both RFs and optical waves are electromagnetic waves, but optical waves offer many advantages in space, including reduced mass, power, and volume of equipment, h...

Due to the high mobility of low earth orbit (LEO) satellites, there is a significant number of handover attempts in a LEO satellite mobile communication system, causing a high handover failure rate. This paper proposes an Adaptive Channel Reservation Scheme (ACRS) which gives an overall optimal success rate for both handover and new call initialisation. ACRS is able to adapt to the local traffi...

There is an increasing demand for interconnecting LAN's at high data rates, e.g. remote X-Applications. Due to the lack of B-ISDN before the second decade of the next century, satellite systems are the only alternative. We compare the End-to-End cell delay of a geostationary satellite system with a low earth orbit satellite system by means of simulation. The comparison shows that the use of LEO...

This paper focuses on the radio resource management in low earth orbit-mobile satellite systems (LEOMSSs) based on a time division multiple access (TDMA) air interface. A novel demand–assignment medium access control (MAC) protocol, named DRAMAþ (dynamic resource assignment multiple access}enhanced version), is proposed, where voice and Web traffic sources obtain transmission slots through requ...

This paper presents the evaluation performance of a hybrid satellite constellation network which provides internet access based Transport Control Protocol (TCP). The evaluated satellite network uses the constellation topology operating on Low Earth Orbit (LEO). The COMMStellationTM satellite system implemented using network simulator 2 (NS-2). In this paper, we modified a congestion window cont...

Due to population distribution and economic flourish diversity, the low earth orbit (LEO) satellite network carries unbalanced traffic load, which leads that parts of satellite links are congested while others are underutilized. Furthermore, the congested inter-satellite links result in high queuing delay and packet dropping ratio. To ensure an intelligent scheduling of traffic over entire sate...