3,835 research outputs found
Performance Analysis of Protocol Independent Multicasting-Dense Mode in Low Earth Orbit Satellite Networks
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® 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
A Wised Routing Protocols for Leo Satellite Networks
This Study proposes a routing strategy of combining a packet scheduling with
congestion control policy that applied for LEO satellite network with high
speed and multiple traffic. It not only ensures the QoS of different traffic,
but also can avoid low priority traffic to be "starve" due to their weak
resource competitiveness, thus it guarantees the throughput and performance of
the network. In the end, we set up a LEO satellite network simulation platform
in OPNET to verify the effectiveness of the proposed algorithm.Comment: The 10th Asian Control Conference (ASCC), Universiti Teknologi
Malaysia, Malaysi
A Handover Strategy in the LEO Satellite-Based Constellation Networks with ISLs
Abstract A new handover strategy named minimal-hops handover (MHH) Received 2003-06-05 Due to various economic and technical constraints, terrestrial mobile networks can only provide communication services with a limited coverage. Recently, in response to increasing demand of real-time multimedia services and the truly global coverage required by personal communication services (PCS), there is a vast research on non-geostationary orbit (NGSO) satellites systems, especially on low earth orbit (LEO) satellite constellations with an altitude between 700 km and 1 500 km. LEO satellite constellations equipped with inter-satellite links (ISLs), such as Iridium, Teledesic, Courier and so on, usually have onboard switching (OBS) and onboard routing (OBR) facilities and form an independent network in space. Direct connectivity between any pair of satellite mobile users can be achieved through the satellites and ISLs without any essential usage of the terrestrial core network. For the wide application prospect, they have already been the focus of the research on the satellite communication systems Key words low earth orbit(LEO) satellite-based constellation networks; time propagation delay; quality of services (QoS); inter-satellite link (ISL); inter-satellite handover In the LEO constellations, although handover procedure is closely correlated with rerouting, almost all the existing strategies pay more attention to the handovers themselves and ignore the rerouting. In this way, this paper proposes a new strategy name
Survey of Inter-satellite Communication for Small Satellite Systems: Physical Layer to Network Layer View
Small satellite systems enable whole new class of missions for navigation,
communications, remote sensing and scientific research for both civilian and
military purposes. As individual spacecraft are limited by the size, mass and
power constraints, mass-produced small satellites in large constellations or
clusters could be useful in many science missions such as gravity mapping,
tracking of forest fires, finding water resources, etc. Constellation of
satellites provide improved spatial and temporal resolution of the target.
Small satellite constellations contribute innovative applications by replacing
a single asset with several very capable spacecraft which opens the door to new
applications. With increasing levels of autonomy, there will be a need for
remote communication networks to enable communication between spacecraft. These
space based networks will need to configure and maintain dynamic routes, manage
intermediate nodes, and reconfigure themselves to achieve mission objectives.
Hence, inter-satellite communication is a key aspect when satellites fly in
formation. In this paper, we present the various researches being conducted in
the small satellite community for implementing inter-satellite communications
based on the Open System Interconnection (OSI) model. This paper also reviews
the various design parameters applicable to the first three layers of the OSI
model, i.e., physical, data link and network layer. Based on the survey, we
also present a comprehensive list of design parameters useful for achieving
inter-satellite communications for multiple small satellite missions. Specific
topics include proposed solutions for some of the challenges faced by small
satellite systems, enabling operations using a network of small satellites, and
some examples of small satellite missions involving formation flying aspects.Comment: 51 pages, 21 Figures, 11 Tables, accepted in IEEE Communications
Surveys and Tutorial
Hybrid Satellite-Terrestrial Communication Networks for the Maritime Internet of Things: Key Technologies, Opportunities, and Challenges
With the rapid development of marine activities, there has been an increasing
number of maritime mobile terminals, as well as a growing demand for high-speed
and ultra-reliable maritime communications to keep them connected.
Traditionally, the maritime Internet of Things (IoT) is enabled by maritime
satellites. However, satellites are seriously restricted by their high latency
and relatively low data rate. As an alternative, shore & island-based base
stations (BSs) can be built to extend the coverage of terrestrial networks
using fourth-generation (4G), fifth-generation (5G), and beyond 5G services.
Unmanned aerial vehicles can also be exploited to serve as aerial maritime BSs.
Despite of all these approaches, there are still open issues for an efficient
maritime communication network (MCN). For example, due to the complicated
electromagnetic propagation environment, the limited geometrically available BS
sites, and rigorous service demands from mission-critical applications,
conventional communication and networking theories and methods should be
tailored for maritime scenarios. Towards this end, we provide a survey on the
demand for maritime communications, the state-of-the-art MCNs, and key
technologies for enhancing transmission efficiency, extending network coverage,
and provisioning maritime-specific services. Future challenges in developing an
environment-aware, service-driven, and integrated satellite-air-ground MCN to
be smart enough to utilize external auxiliary information, e.g., sea state and
atmosphere conditions, are also discussed
- …