Title :
Bound on mutual information for DS-CDMA spreading over independent fading channels
Author_Institution :
Lincoln Lab., MIT, Lexington, MA, USA
Abstract :
We consider using DS-CDMA over channels which decorrelate in frequency. We allow the bandwidth to increase while maintaining a fixed total average power. The bandwidth over which we transmit is divided into several slices, each of which has its own spreading sequence. We show that for a large bandwidth DS-CDMA spreading is not advantageous when the channel truly decorrelates in frequency or when the channel bandwidth slices are correlated but not jointly estimated.
Keywords :
Gaussian processes; Markov processes; correlation methods; fading; pseudonoise codes; spread spectrum communication; time-varying channels; DS-CDMA; Gauss-Markov model; bandwidth scaled spreading method; correlated channel bandwidth slices; decorrelation; independent fading channels; mutual information bound; spreading sequence; time varying channel; total average power; Bandwidth; Channel capacity; Decorrelation; Fading; Frequency; Laboratories; Multiaccess communication; Mutual information; Semiconductor device measurement; Time measurement;
Conference_Titel :
Signals, Systems & Computers, 1997. Conference Record of the Thirty-First Asilomar Conference on
Conference_Location :
Pacific Grove, CA, USA
Print_ISBN :
0-8186-8316-3
DOI :
10.1109/ACSSC.1997.680053
