Title :
The theoretical bandwidth advantage of CDMA over FDMA in a Gaussian MAC
Author :
Chen, Biao ; Willett, Peter
Author_Institution :
Connecticut Univ., Storrs, CT, USA
fDate :
9/1/1999 12:00:00 AM
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;
Journal_Title :
Information Theory, IEEE Transactions on
