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Book Routing Algorithm Analysis for a Nanosatellite Constellation in Low Earth Orbit

Download or read book Routing Algorithm Analysis for a Nanosatellite Constellation in Low Earth Orbit written by S. McKenzie-Picot and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper examines possible routing algorithms in a proposed network of nanosatellites with the goal of finding networking methods that could be effectively used in a dynamic environment with limited computing power. Three routing algorithms were created and their performance was compared to Dijkstra's shortest path algorithm. The chaos method transmitted to accessible satellites at random. The minimum distance method transmitted to the closest unused satellite. The grouping method grouped satellites by their physical position in the network and made transmission decisions based on these groups. Each algorithm was run for every possible combination of source and destination satellite in the network to find average transmission times, distances, and number of network nodes used. It was found that the grouping method had performance comparable to Dijkstra's algorithm while requiring less computing power, and was acceptable for high-speed network requirements, such as live voice. The chaos method was acceptable for lower speed applications and for satellites that had little computing power, and the minimum distance method improved on chaos method with little extra computing power required.

Book A Performance Analysis of Dynamic Routing Algorithms in an IRIDIUM Like Low Earth Orbit Satellite System

Download or read book A Performance Analysis of Dynamic Routing Algorithms in an IRIDIUM Like Low Earth Orbit Satellite System written by Stephen R. Pratt and published by . This book was released on 1999-03-01 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt: This research presents a first of its kind comparative analysis of the Extended Bellman-Ford and Darting algorithms, using the Iridium low earth orbit (LEO) satellite system configuration for the simulation environment. The algorithms are compared to one another via discrete-event computer simulation and evaluated based on their ability to route real-time voice communications under low, medium, and high network loading conditions. The algorithms' ability to meet real-time voice constraints is evaluated with a full and degraded satellite constellation using an algorithmic satellite removal method. The investigation results indicate that both algorithms are suitable for use in a LEO environment and are capable of meeting the real-time voice communications requirements as long as a load-balancing mechanism is in place to route traffic around heavily loaded satellites. The results also indicate that the Iridium system is robust, capable of meeting the real-time voice constraints even when the constellation is degraded.

Book Communication Link Analysis for a Nanosatellite Constellation in Low Earth Orbit

Download or read book Communication Link Analysis for a Nanosatellite Constellation in Low Earth Orbit written by S. McKenzie-Picot and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper explores the quality of intersatellite links for a constellation of nanosatellites. In order to characterise satellite performance, the data throughput at various powers, frequencies and antenna gains was calculated and nanosatellite constellations were modelled using Systems Tool Kit (STK). It was found that constant access between a ground station anywhere on Earth and the constellation is possible. It was also found that, depending on the transmission frequency chosen, a nanosatellite constellation can support data rates up to 7.7 Mbps, sufficient for standard definition live video streaming.

Book Routing and Quality of Service in Broadband LEO Satellite Networks

Download or read book Routing and Quality of Service in Broadband LEO Satellite Networks written by Hoang Nam Nguyen and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: Routing and Quality-of-Service in Broadband LEO Satellite Networks describes mechanisms for supporting Quality-of-Service (QoS) strategies that consider properties of low earth orbit satellite networks and their effects on link handover. A graph model representing the dynamic topology of a satellite constellation is introduced based on a new parameter, lifetime. Novel routing and resource reservation algorithms as well as connection admission control strategies are proposed to minimize the handover blocking probability while maintaining QoS requirements. The author also discusses the roles of satellites in an all-IP mobile network architecture and the problems of mobility, QoS provisioning, and routing. This work will be of particular interest to researchers and professionals working on mobility networking in next generation networks.

Book Performance Analysis of Dynamic Routing Protocols in a Low Earth Orbit Satellite Data Network

Download or read book Performance Analysis of Dynamic Routing Protocols in a Low Earth Orbit Satellite Data Network written by Richard F. Janoso and published by . This book was released on 1996-12-01 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt: Modern warfare is placing an increasing reliance on global communications. Currently under development are several Low Earth Orbit (LEO) satellite systems that propose to deliver voice and data traffic to subscribers anywhere on the globe. However, very little is known about the performance of conventional routing protocols under orbital conditions where the topology changes on a scale of minutes rather than days. This thesis compares two routing protocols in a LEO environment. One (Extended Bellman-Ford) is a conventional terrestrial routing protocol, while the other (Darting) is a new protocol which has been proposed as suitable for use in LEO networks. These protocols are compared via computer simulation in two of the proposed LEO systems (Globalstar and Iridium), under various traffic intensities. Comparative measures of packet delay, convergence speed, and protocol overhead are made It was found both protocols were roughly equivalent in end-to-end delay characteristics, though the Darting protocol had a much higher overhead load and demonstrated higher instability at network update periods. For example, while steady state end-to- end delays were within a few milliseconds, in one case Darting showed an increase of 764% in convergence time over Extended Bellman-Ford with an increase of 149% in overhead. Over all cases, Darting required an average of 72.1% more overhead than Extended Bellman-Ford to perform the same work. Darting was handicapped by its strong correlation between data traffic and protocol overhead. Modifications to reduce this overhead would result in much closer performance.

Book A Performance Analysis of Dynamic Routing Algorithms in an Iridium like Low Earth Orbit Satellite System

Download or read book A Performance Analysis of Dynamic Routing Algorithms in an Iridium like Low Earth Orbit Satellite System written by Stephen R. Pratt (CAPT, USAF.) and published by . This book was released on 1999 with total page 234 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Performance Analysis of Protocol Independent Multicasting Dense Mode in Low Earth Orbit Satellite Networks

Download or read book Performance Analysis of Protocol Independent Multicasting Dense Mode in Low Earth Orbit Satellite Networks written by Mark D. Saeger and published by . This book was released on 2003-03-01 with total page 131 pages. Available in PDF, EPUB and Kindle. Book excerpt: This research explored the implementation of Protocol Independent Multicasting - Dense Mode (PIM-DM) in a LEO satellite constellation. PIM-DM is a terrestrial protocol for distributing traffic efficiently between subscriber nodes by combining data streams into a tree-based structure, spreading from the root of the tree to the branches. Using this structure, a minimum number of connections are required to transfer data, decreasing the load on intermediate satellite routers. The PIM-DM protocol was developed for terrestrial systems and this research implemented an adaptation of this protocol in a satellite system. This research examined the PIM-DM performance characteristics which were compared to earlier work for On- Demand Multicast Routing Protocol (ODMRP) and Distance Vector Multicasting Routing Protocol (DVMRP) - all in a LEO satellite network environment. Experimental results show that PIM-DM is extremely scalable and has equivalent performance across diverse workloads. Three performance metrics are used to determine protocol performance in the dynamic LEO satellite environment, including Data-to- Overhead ratio, Received-to-Sent ratio, and End- to-End Delay. The OPNET(registered) simulations show that the PIM-DM Data-to- Overhead ratio is approximately 80% and the protocol reliability is extremely high, achieving a Receive-to-Sent ratio of 99.98% across all loading levels. Finally, the PIM-DM protocol introduces minimal delay, exhibiting an average End-to-End Delay of approximately 76 ms; this is well within the time necessary to support real-time communications. Though fundamental differences between the DVMRP, ODMRP, and PIM-DM implementations precluded a direct comparison for each experiment, by comparing average values, PIM-DM generally provides equivalent or better performance.

Book Multicast Routing Algorithms and Failure Analyses for Low Earth Orbit Satellite Communication Networks

Download or read book Multicast Routing Algorithms and Failure Analyses for Low Earth Orbit Satellite Communication Networks written by Jae Soong Lee and published by . This book was released on 2002-08-01 with total page 125 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the rapidly changing environment of mobile communications, the importance of the mobile satellite (e,g,, low earth orbit satellites (LEOsats)) networks will increase due to their global visibility and connection. Multicasting is an effective communication method in terms of frequency spectrum usage for a LEO network. It is devised to provide lower network traffic (i,e,, one-to-many transmissions). This research examines the system performance of two dissimilar terrestrially-based multicasting protocols: the Distance Vector Multicast Routing Protocol (DVMRP) and the On Demand Multicast Routing Protocol (ODMRP). These two protocols are simulated in large group membership density and in the presence of satellite failures. Two different algorithms are developed and used to select critical satellites for degrading a LEO network constellation. The simulation results show that the ODMRP protocol successfully reconfigured routes in large group membership density areas and in satellite failure conditions. Results also show that the ODMRP provided reliable packet delivery. However, ODMRP showed an enormous end-to-end delay in severe satellite failure conditions. This result is attributable to the delayed route refreshing procedure of ODMRP. In contrast, the DVMRP suffered from broken routes and complexity in the large group membership density and in satellite failure conditions. It had a smaller packet delivery ratio than the ODMRP (approximately 85,5% versus 98,9% for the 80 user case). The DVMRP showed scalable and stable end-to-end delay under multiple failed satellite conditions. The large group membership density and the multiple satellite failure conditions provide a more complete assessment for these two protocols.

Book Evaluation of Routing Algorithm for LEO Satellite Networks

Download or read book Evaluation of Routing Algorithm for LEO Satellite Networks written by Keyur Chauhan and published by . This book was released on 2016-07-15 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Emerging Trends in Expert Applications and Security

Download or read book Emerging Trends in Expert Applications and Security written by Vijay Singh Rathore and published by Springer Nature. This book was released on with total page 473 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Congestion Control and Routing Over Satellite Networks

Download or read book Congestion Control and Routing Over Satellite Networks written by Jinhua Cao and published by . This book was released on 2010 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt: Satellite networks and transmissions find their application in fields of computer communications, telephone communications, television broadcasting, transportation, space situational awareness systems and so on. This thesis mainly focuses on two networking issues affecting satellite networking: network congestion control and network routing optimization. Congestion, which leads to long queueing delays, packet losses or both, is a networking problem that has drawn the attention of many researchers. The goal of congestion control mechanisms is to ensure high bandwidth utilization while avoiding network congestion by regulating the rate at which traffic sources inject packets into a network. In this thesis, we propose a stable congestion controller using data-driven, safe switching control theory to improve the dynamic performance of satellite Transmission Control Protocol/Active Queue Management (TCP/AQM) networks. First, the stable region of the Proportional-Integral (PI) parameters for a nominal model is explored. Then, a PI controller, whose parameters are adaptively tuned by switching among members of a given candidate set, using observed plant data, is presented and compared with some classical AQM policy examples, such as Random Early Detection (RED) and fixed PI control. A new cost detectable switching law with an interval cost function switching algorithm, which improves the performance and also saves the computational cost, is developed and compared with a law commonly used in the switching control literature. Finite-gain stability of the system is proved. A fuzzy logic PI controller is incorporated as a special candidate to achieve good performance at all nominal points with the available set of candidate controllers. Simulations are presented to validate the theory. An effocient routing algorithm plays a key role in optimizing network resources. In this thesis, we briefly analyze Low Earth Orbit (LEO) satellite networks, review the Cross Entropy (CE) method and then develop a novel on-demand routing system named Cross Entropy Accelerated Ant Routing System (CEAARS) for regular constellation LEO satellite networks. By implementing simulations on an Iridium-like satellite network, we compare the proposed CEAARS algorithm with the two approaches to adaptive routing protocols on the Internet: distance-vector (DV) and link-state (LS), as well as with the original Cross Entropy Ant Routing System (CEARS). DV algorithms are based on distributed Bellman Ford algorithm, and LS algorithms are implementation of Dijkstras single source shortest path. The results show that CEAARS not only remarkably improves the convergence speed of achieving optimal or suboptimal paths, but also reduces the number of overhead ants (management packets).

Book Optimization and Scheduling Methodologies to Enable Low Earth Orbit Nano satellite Communication

Download or read book Optimization and Scheduling Methodologies to Enable Low Earth Orbit Nano satellite Communication written by Michelle Song and published by . This book was released on 2018 with total page 63 pages. Available in PDF, EPUB and Kindle. Book excerpt: Communications with low earth orbit (LEO) nano-satellites (nanosats) are challenging due to the short contact time intervals with ground nodes and uncertainty in successful delivery of messages due to the varying signal-to-noise ratio (SNR) in the environment. This thesis presents optimization models to enable minimum-delay store-and-forward communications between terrestrial gateways and remote users (e.g., ships) via nanosats. Optimization models are formulated to enable timely delivery of messages between nanosats and remote users. Unit-sized messages destined for remote users must be routed from gateways to nanosats to final remote destinations. The connection between nanosats and remote users may not always be well established. The uncertainty in knowing if a message needs to be sent again or was successfully delivered is modeled using a chance constraint in the optimization model. A network flow program is formulated to optimize the scheduling and routing of messages from a central command and control center (CCC) to gateways to nanosats and ultimately to the remote user. The decisions are chosen to minimize the total message delivery time while considering the nanosat contact time windows with gateways and remote users and the solar charging time windows of the nanosats. Although the scheduling and routing decisions are binary variables, the optimization models are shown to satisfy the integrality property. Therefore the relaxed network model can be solved much faster than a binary integer problem. Results on a realistic problem are presented. Comparisons are made to consider the difference between a basic deterministic model, a model with energy constraints, and a chance-constrained model (with and without energy constraints). Comparisons are also made to simple greedy heuristics to demonstrate the value of optimization.