DocumentCode :
1530076
Title :
Capacity of Rayleigh fading channels under different adaptive transmission and diversity-combining techniques
Author :
Alouini, Mohamed-Slim ; Goldsmith, Andrea J.
Author_Institution :
Dept. of Electr. Eng., California Inst. of Technol., Pasadena, CA, USA
Volume :
48
Issue :
4
fYear :
1999
fDate :
7/1/1999 12:00:00 AM
Firstpage :
1165
Lastpage :
1181
Abstract :
We study the Shannon capacity of adaptive transmission techniques in conjunction with diversity-combining. This capacity provides an upper bound on spectral efficiency using these techniques. We obtain closed-form solutions for the Rayleigh fading channel capacity under three adaptive policies: optimal power and rate adaptation, constant power with optimal rate adaptation, and channel inversion with fixed rate. Optimal power and rate adaptation yields a small increase in capacity over just rate adaptation, and this increase diminishes as the average received carrier-to-noise ratio (CNR) or the number of diversity branches increases. Channel inversion suffers the largest capacity penalty relative to the optimal technique, however, the penalty diminishes with increased diversity. Although diversity yields large capacity gains for all the techniques, the gain is most pronounced with channel inversion. For example, the capacity using channel inversion with two-branch diversity exceeds that of a single-branch system using optimal rate and power adaptation. Since channel inversion is the least complex scheme to implement, there is a tradeoff between complexity and capacity for the various adaptation methods and diversity-combining techniques
Keywords :
Rayleigh channels; adaptive systems; cellular radio; channel capacity; diversity reception; optimisation; radio links; BER; Rayleigh fading channel; Rayleigh fading channel capacity; Shannon capacity; adaptive transmission; average received carrier-to-noise ratio; average transmit power; bit error rate; capacity gains; capacity penalty; cellular radio; channel inversion; closed-form solutions; constant power; diversity branches; diversity-combining; fixed rate; link spectral efficiency; mobile radio links; optimal power adaptation; optimal rate adaptation; single-branch system; two-branch diversity; upper bound; Bandwidth; Bit error rate; Channel capacity; Closed-form solution; Degradation; Diversity reception; Fading; Helium; Upper bound; Wireless communication;
fLanguage :
English
Journal_Title :
Vehicular Technology, IEEE Transactions on
Publisher :
ieee
ISSN :
0018-9545
Type :
jour
DOI :
10.1109/25.775366
Filename :
775366
Link To Document :
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