DocumentCode :
787360
Title :
Ergodic sum capacity maximization for CDMA:Optimum resource allocation
Author :
Kaya, Onur ; Ulukus, Sennur
Author_Institution :
Dept. of Electr. & Comput. Eng., Univ. of Maryland, College Park, MD, USA
Volume :
51
Issue :
5
fYear :
2005
fDate :
5/1/2005 12:00:00 AM
Firstpage :
1831
Lastpage :
1836
Abstract :
We solve for the optimum signature sequence and power allocation policies that maximize the information-theoretic ergodic sum capacity of a code-division multiple-access (CDMA) system subject to fading. We show that at most N users may transmit at any given channel state, where N is the processing gain; and those users who are transmitting should be assigned orthogonal signature sequences. We also show that the power allocation policy that maximizes the capacity together with the choice of these signature sequences is single-user water-filling over sets of channel states that are favorable to each user. That is, the capacity maximizing signaling scheme is shown to dictate that the users allocate their powers and signature sequences in such a way that they always avoid interference from each other.
Keywords :
channel allocation; channel capacity; code division multiple access; fading channels; interference (signal); iterative methods; optimisation; power control; sequences; CDMA system; capacity maximizing signaling scheme; code-division multiple-access; ergodic sum capacity; fading channel state; interference avoidance; optimum resource allocation; orthogonal signature sequence; power allocation policy; single-user iterative water-filling; Channel capacity; Channel state information; Context; Fading; Interference; Multiaccess communication; Power control; Random variables; Resource management; Wireless communication; Code-division multiple access (CDMA); fading channels; interference avoidance; iterative water-filling; power control; signature sequence optimization; sum capacity;
fLanguage :
English
Journal_Title :
Information Theory, IEEE Transactions on
Publisher :
ieee
ISSN :
0018-9448
Type :
jour
DOI :
10.1109/TIT.2005.846413
Filename :
1424320
Link To Document :
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