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Author Cianca, E. ♦ De Fina, S. ♦ De Luise, A. ♦ Ruggieri, M. ♦ Prasad, R.
Source IEEE Xplore Digital Library
Content type Text
Publisher Institute of Electrical and Electronics Engineers, Inc. (IEEE)
File Format PDF
Copyright Year ©2002
Language English
Subject Domain (in DDC) Computer science, information & general works ♦ Data processing & computer science ♦ Natural sciences & mathematics ♦ Physics ♦ Electricity & electronics
Subject Keyword Power control ♦ Multiaccess communication ♦ Satellites ♦ AWGN channels ♦ Propagation delay ♦ Target tracking ♦ Tracking loops ♦ Fading ♦ Statistics ♦ Bit error rate
Abstract This paper aims at clarifying the role of the outer loop power control for CDMA satellite systems with on-board power constraints. If the inner loop of the power control is perfect, the channel turns into a AWGN channel and there is no need of the outer loop. In satellite CDMA systems, due to the longer propagation delay with respect to a terrestrial system, the inner loop of power control is only partly able to track power variations due to fast fading. Moreover, the Rice factor, which characterizes the channel statistics, can widely vary even if the user does not move but just because of the change of the elevation angle. Because of that, a wide range of target SNIR (and larger than in typical terrestrial systems) may be necessary to get the same BER performance. Therefore, the outer loop power control turns out to be essential to minimize the dynamic of the power link margins and avoid capacity degradations induced by the systematic use of static link margins. A semi-analytical model for the capacity evaluation has been developed, which is specifically intended for the power-limited satellite-to-mobile link with multi satellite reception. We found that the capacity gain with respect to a pure SNIR-based strategy (i.e., only inner loop) can reach the 40% of the total capacity in a single reception scheme. A smaller, but still noticeable capacity gain of the order of 20 - 30% is observed in presence of satellite diversity. Therefore, any dimensioning of CDMA satellite systems should not neglect this component of the power control.
Description Author affiliation :: Center for TeleInfrastructur, Aalborg Univ., Denmark
ISSN 15361276
Education Level UG and PG
Learning Resource Type Article
Publisher Date 2006-04-01
Publisher Place U.S.A.
Rights Holder Institute of Electrical and Electronics Engineers, Inc. (IEEE)
Volume Number 5
Issue Number 4
Size (in Bytes) 346.10 kB
Page Count 4
Starting Page 733
Ending Page 736

Source: IEEE Xplore Digital Library