Results 271 to 280 of about 32,263 (311)

Error Correcting Codes for Satellite Communication Channels

IBM Journal of Research and Development, 1976
This paper addresses the problem of efficient forward error correction on differentially encoded, quadriphase-shift-keying (DQPSK) channels. The approach is to design codes to correct the most probable error patterns. First the probability distribution of error patterns is derived.
Chin-Long Chen, Robert A. Rutledge
openaire   +1 more source

The Satellite Channel

1991
Communication between points is achieved by analog or digital modulation of information onto carriers, and by transmission of the carriers as an electromagnetic field from one point to the other. As we discussed in Chapter 2, the amount of received carrier power invariably determines the ability of the receiver to demodulate or decode the information ...
openaire   +1 more source

Contention resolution and channel estimation in satellite random access channels

2012 1st IEEE International Conference on Communications in China (ICCC), 2012
We consider the random access channel (RACH) of a multi-beam satellite system with universal frequency reuse. We benefit from the spatial diversity and the strong directivity of multiple antennas at the satellite to resolve contentions and perform channel estimation.
Lei Xiao, Laura Cottatellucci
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MAP decoding for satellite channels

Proceedings of Vehicular Technology Conference - VTC, 2002
Error correction coding can be used to mitigate fading and interference in wireless communication systems. Decoding is most effective when soft information is fed to the decoder. Practical receivers often have a concatenation of decoders, such as an equalizer followed by an error correction decoder.
H. Koorapaty, S. Chennakeshu, null Yi-Pin Wang, R. Ramesh   +3 more
openaire   +1 more source

Satellite communication over quantum channel

Acta Astronautica, 2006
Abstract Quantum computing offers revolutionary solutions in the field of computer sciences, applying the opportunities of quantum physics which are incomparably richer than classical physics. Although quantum computers are going to be the tools of the far future, there are already a few algorithms to solve problems which are very difficult to handle
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Estimation of LEO satellite channels

Proceedings of ICICS, 1997 International Conference on Information, Communications and Signal Processing. Theme: Trends in Information Systems Engineering and Wireless Multimedia Communications (Cat. No.97TH8237), 2002
In this paper, we propose a new channel estimation algorithm for low Earth orbit satellite digital communications. Low Earth orbit satellite channels impart severe spreading in delay and Doppler on the transmitted signal. We model the channel as a tapped-delay-line filter with time-varying complex coefficients.
L.M. Davis, I.B. Collings, R.J. Evans
openaire   +1 more source

Satellite Channel Modelling for Rain Fading

21st International Communications Satellite Systems Conference and Exhibit, 2003
In Ka band and above the transmitted signal can be attenuated severely by precipitation, clouds and for other meteorological reasons. In this paper a channel model is presented which generates an attenuation time-series modelling this type of attenuation.
openaire   +2 more sources

A model of mobile satellite channel

International Conference on Communication Technology Proceedings, 2003. ICCT 2003., 2004
The signal propagation character in a communication channel is the base of communication system design. The factors that affect the signal in the mobile satellite channel are analyzed here and a new channel model is presented. The new model is based on layered Markov chain, and most of the factors affecting the communication signal are included in it ...
null Dexiang Meng, null Weiling Wu
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A secrecy model in satellite fading channels

MILCOM 2017 - 2017 IEEE Military Communications Conference (MILCOM), 2017
The Hoyt distribution can be used to characterize two types of fading in satellite communications. In this paper, the secrecy of the Hoyt-Hoyt fading channel is investigated. A set of exact formulas of the probability of strictly positive secrecy capacity are derived. Profile examples are illustrated to show the effects of secrecy capacity.
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Channel simulation on LEO satellites

IEEE Antennas and Propagation Society International Symposium. 1999 Digest. Held in conjunction with: USNC/URSI National Radio Science Meeting (Cat. No.99CH37010), 2003
A channel simulation program in the Ka-band has been developed to study the characteristics of the communication link between the ground station and the ROCSAT-1. The effects of orbital parameters, power level, antenna radiation patterns, rain attenuation, transmission data rate, and internal noise source on the carrier-to-noise ratio are studied.
null Jeng-Fu Kiang, null Yung-Chang Chen, null Le-Gen Shi   +2 more
openaire   +1 more source