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Communication System Performance (communication + system_performance)

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Engineering	100%

Selected Abstracts

The performance evaluation of spatial,temporal algorithms in W-CDMA systems

INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 8 2005
Shiann-Shiun Jeng
Abstract Differing from FDMA, TDMA, and CDMA, space division multiple access (SDMA) uses space resources to improve communication system performance. Utilizing the smart antenna system is an approach to realize the SDMA technique. Smart antenna systems using the beamforming technique can reduce the co-channel interference and multipath fading to increase the channel capacity and communication quality. In this study the smart antenna system and rake receiver are integrated. The performance of spatial,temporal structure applied to the W-CDMA system is evaluated. From the cumulative distribution function simulation results, W-CDMA system with spatial,temporal algorithm can exactly provide SINR gain to improve the system performance and capacity. Copyright © 2005 John Wiley & Sons, Ltd. [source]

Microwave depolarization versus rain attenuation on earth space in Malaysia

INTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS AND NETWORKING, Issue 6 2008
J. S. Mandeep
Abstract The wave propagation experiments using Japanese geostationary satellite Superbird-C have been performed at the Universiti Sains Malaysia earth station. A relationship between rain depolarization and attenuation, valid for earth-space path at microwave wavelengths, is presented. Cumulative rain attenuation and cross-polarization discrimination (XPD) statistics are given for the period of 4 years (2002,2005) at 12.255,GHz. XPD varied from 44,dB at 1% to 16,dB at 0.001% of time the abscissa is exceeded. Comparisons were made with available data sets and with five simple XPD models and the results indicate a good performance by the simple isolation model and the CHU model compared with the others. These results serve as checks on the theoretical models needed for predicting communication system performance in geographical regions especially for equatorial climate where measurements are not available. Copyright © 2008 John Wiley & Sons, Ltd. [source]

BPSK and QPSK non-linear satellite communication system performance in the presence of cochannel interference

INTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS AND NETWORKING, Issue 3 2003
Mihajlo C. Stefanovic
Abstract Taking the uplink and downlink cochannel interference and noise into account, the analytical expressions are derived for determining the bit error probability in detecting a binary phase-shift-keying (BPSK) and a quaternary phase-shift-keying (QPSK) Gray coded signal, transmitted over a satellite system exhibiting amplitude modulation-to-amplitude modulation (AM/AM) conversion effects and amplitude modulation-to-phase modulation (AM/PM) conversion effects. On the basis on the derived theoretic formulae, using real-life system parameters, numerical results are obtained and presented. We point out the explicit comparisons of satellite communication system performance obtained when a satellite transponder amplifier is modelled by a hard-limiter and those obtained when both AM/AM and AM/PM non-linearities of the satellite transponder amplifier are taken into consideration. Copyright © 2003 John Wiley & Sons, Ltd. [source]

W-band physical layer design issues in the context of the DAVID,DCE experiment,

INTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS AND NETWORKING, Issue 2 2004
Claudio Sacchi
Abstract This paper aims at focusing on the aspects concerning the physical layer design for an innovative satellite communication experiment. Such an experiment, denoted by the acronym DAVID,DCE (Data and Video Interactive Distribution,Data Collection Experiment) is based on the exploitation of the W-band (75,110 GHz) for high-bit-rate satellite transmission. The potential advantages of using of the W-band are mainly related to the great bandwidth availability, and to the absence of interference. Moreover, an expected result of the experiment is a substantive improvement in the communication system's performances in the presence of meteorological phenomena (e.g. rain) as compared with the more conventional Ka-band satellite transmission. On the other hand, problems to be faced concern the non-ideal behaviours of hardware devices employed for high-frequency digital transmission. In particular, carrier recovery and timing recovery are the most crucial signal-processing tasks to be carefully considered in the design of the physical level of the system, because they considerably suffer from hardware impairments. The purpose of this work is to illustrate the proposed solutions in terms of the most critical modulation, demodulation and synchronization design issues, together with the effects of non-ideal behaviours of hardware components on BER performances. Copyright © 2004 John Wiley & Sons, Ltd. [source]