The theoretical bandwidth advantage of CDMA over FDMA in a Gaussian MAC

Author

Chen, Biao ; Willett, Peter

Author_Institution

Connecticut Univ., Storrs, CT, USA

Volume

45

Issue

6

fYear

1999

fDate

9/1/1999 12:00:00 AM

Firstpage

2046

Lastpage

2053

Abstract

We develop an expression for the minimum extra bandwidth needed for a frequency-division multiple-access (FDMA) system to out perform its code-division (CDMA) counterpart uniformly (that is, for all rate n-tuples) in a Gaussian multiple-access channel (MAC). For equal-power sources, the behavior of this factor is as an iterated logarithm of the number of users; hence it increases slowly yet is unbounded. Asymmetric power cases are also studied and it is shown that the equal power scenario provides the least bandwidth expansion factor assuming constant constraint on total power

Keywords

Gaussian channels; channel capacity; code division multiple access; frequency division multiple access; multiuser channels; CDMA; FDMA system; Gaussian MAC; Gaussian multiple-access channel; asymmetric power; bandwidth advantage; bandwidth expansion factor; channel capacity; code-division multiple-access; equal-power sources; frequency-division multiple-access; information theory; iterated logarithm; minimum extra bandwidth; total power constraint; Bandwidth; Decoding; Fading; Frequency division multiaccess; Frequency synchronization; Information theory; Loss measurement; Multiaccess communication; Shape measurement; Transmitters;

fLanguage

English

Journal_Title

Information Theory, IEEE Transactions on

Publisher

ieee

ISSN

0018-9448

Type

jour

DOI

10.1109/18.782131

Filename

782131