scholarly journals TETRA Backhauling via Satellite: Improving Call Setup Times and Saving Bandwidth

2014 ◽  
Vol 2014 ◽  
pp. 1-16 ◽  
Author(s):  
Anton Donner ◽  
Jawad Ahmed Saleemi ◽  
Javier Mulero Chaves
Keyword(s):  
Disaster Management ◽  
Satellite Communications ◽  
Propagation Delay ◽  
Satellite Networks ◽  
Setup Times ◽  
Signal Delay ◽  
Management Scenarios ◽  
Satellite Link ◽  
Core Networks ◽  
Call Setup

In disaster management scenarios with seriously damaged, not existing, or saturated communication infrastructures satellite communications can be an ideal means to provide connectivity with unaffected remote terrestrial trunked radio (TETRA) core networks. However, the propagation delay imposed by the satellite link affects the signalling protocols. This paper discusses the suitability of using a satellite link for TETRA backhauling, introducing two different architectures. In order to cope with the signal delay of the satellite link, the paper proposes and analyzes a suitable solution based on the use of a performance enhancing proxy (PEP). Additionally, robust header compression (ROHC) is discussed as suitable technology to transmit TETRA voice via IP-based satellite networks.

scholarly journals Optimal approach for building scheduling algorithm in satellite communication

2018 ◽  
Vol 7 (2.28) ◽  
pp. 181
Author(s):  
Ali M. Al-Saegh
Keyword(s):  
Quality Of Service ◽  
Communication Networks ◽  
Satellite Communication ◽  
Scheduling Algorithm ◽  
Satellite Communications ◽  
Satellite Networks ◽  
Communication Links ◽  
Optimal Approach ◽  
Proper Solutions

Building scheduling algorithms in satellite communication links became a necessity according to the typical problems that satellite networks suffers from, such as congestions, jamming, mobility, atmospheric impairment, and achieving the quality of service (QoS) requirements. However, building efficient algorithms needs several considerations that should be taken into account. Such as satellite and earth station node(s), link parameters and specifications, along with the service requirements and limitations. This paper presents efficient approach for accumulating the effective considerations that the designer should employ as a framework for building proper and efficient scheduling algorithm. The proposed approach provides proper solutions to the satellite communications impairments and satisfies the quality of service requirements in satellite communication networks.  

scholarly journals LIFT: a Local IPSec-aware Freezing Protocol to improve TCP Performance in Satellite Networks

2017 ◽  
Vol 2 (4) ◽  
pp. 347 ◽  
Author(s):  
Giovanni Ciccarese ◽  
Mario De Blasi ◽  
Sebastiano Elia ◽  
Cosimo Palazzo ◽  
Luigi Patrono
Keyword(s):  
Mobile Host ◽  
Satellite Networks ◽  
Web Page ◽  
Tcp Performance ◽  
Link Layer ◽  
Satellite Link ◽  
Channel Conditions ◽  
Simulation Results ◽  
Link Layer Protocol ◽  
Mean Time

In this paper a protocol, local to the satellite link, is defined in order to boost TCP performance in mobile integrated wired-satellite Internet. It has been conceived to help to overcome the well known retransmissions competition problem that arises when a satellite reliable link layer protocol is used to face satellite link errors. This protocol, called Local IPSec-aware Freezing proTocol (LIFT), has been designed to allow the satellite gateway, even in the presence of communications secured by IPSec, to freeze the TCP sender when it perceives a possible delay due to satellite channel conditions. The effectiveness of LIFT has been evaluated, using the ns-2 tool, in terms of Web page download mean time for a satellite mobile host. Simulation results have shown that the adoption of LIFT protocol provides substantial improvements in TCP performance.

Propagation Delay Characteristics Analysis in LEO Satellite Multi-Beam Antenna Coverage

2013 ◽  
Vol 791-793 ◽  
pp. 1931-1935
Author(s):  
Ming Ma ◽  
Xi Luan ◽  
Bin Li ◽  
Jian Jun Wu
Keyword(s):  
Satellite Communications ◽  
Propagation Delay ◽  
Satellite System ◽  
Calculation Model ◽  
Propagation Delays ◽  
Characteristics Analysis ◽  
Leo Satellite ◽  
Communications System ◽  
Calculated Analysis

In this paper a calculation model of propagation delays of satellite beams is introduced for LEO multi-beam satellite communications system. Based on actual parameters and beam coverage patterns of the Iridium and Globalstar system, the maximum propagation delay differentials in several typical beams from the center to the edge of the satellites coverage are calculated. Analysis of these results can provide reference for analyzing the feasibility of LEO multi-beam satellite system compatible with uplink synchronization in LTE.

scholarly journals First Evidences of Ionospheric Plasma Depletions Observations Using GNSS-R Data from CYGNSS

2020 ◽  
Vol 12 (22) ◽  
pp. 3782
Author(s):  
Carlos Molina ◽  
Adriano Camps
Keyword(s):  
Electromagnetic Waves ◽  
Satellite Communications ◽  
Study Data ◽  
Global Navigation Satellite Systems ◽  
Ionospheric Scintillation ◽  
Electron Content ◽  
Signal Delay ◽  
Total Electron ◽  
Satellite Systems ◽  
Plasma Depletions

At some frequencies, Earth’s ionosphere may significantly impact satellite communications, Global Navigation Satellite Systems (GNSS) positioning, and Earth Observation measurements. Due to the temporal and spatial variations in the Total Electron Content (TEC) and the ionosphere dynamics (i.e., fluctuations in the electron content density), electromagnetic waves suffer from signal delay, polarization change (i.e., Faraday rotation), direction of arrival, and fluctuations in signal intensity and phase (i.e., scintillation). Although there are previous studies proposing GNSS Reflectometry (GNSS-R) to study the ionospheric scintillation using, for example TechDemoSat-1, the amount of data is limited. In this study, data from NASA CYGNSS constellation have been used to explore a new source of data for ionospheric activity, and in particular, for travelling equatorial plasma depletions (EPBs). Using data from GNSS ground stations, previous studies detected and characterized their presence at equatorial latitudes. This work presents, for the first time to authors’ knowledge, the evidence of ionospheric bubbles detection in ocean regions using GNSS-R data, where there are no ground stations available. The results of the study show that bubbles can be detected and, in addition to measure their dimensions and duration, the increased intensity scintillation (S4) occurring in the bubbles can be estimated. The bubbles detected here reached S4 values of around 0.3–0.4 lasting for some seconds to few minutes. Furthermore, a comparison with data from ESA Swarm mission is presented, showing certain correlation in regions where there is S4 peaks detected by CYGNSS and fluctuations in the plasma density as measured by Swarm.

Propagation Delay Difference Estimation for Initial Random Access in LTE Compatible Mobile Satellite Communications System

2013 ◽  
Vol 846-847 ◽  
pp. 647-650
Author(s):  
Cheng Mei Li ◽  
Jian Jun Wu ◽  
Xiao Ning Zhang ◽  
Xi Luan ◽  
Hai Ge Xing
Keyword(s):  
Estimation Method ◽  
Random Access ◽  
Satellite Communications ◽  
Propagation Delay ◽  
Satellite System ◽  
Satellite Systems ◽  
Access Channel ◽  
Geo Satellite ◽  
Mobile Satellite ◽  
Delay Difference

In this paper, a two-step propagation delay difference estimation method is proposed for LTE compatible multi-beam satellite systems to ensure the initial random access (RA). For GEO satellite system, there exists a large propagation delay difference, we cannot directly apply the LTE delay estimation method. To deal with this issue, we first divide a satellite beam into some layered small sub-areas according to the different delay difference values. Then, two types of Physical Random Access Channel (PRACH) preamble burst format are given. The detailed PRACH parameters are provided. Finally, simulations are performed and the results verify the availability of our proposed design.

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