Effects of Power Control Error on the System User Capacity of DS/CDMA Cellular Mobile Radios

Eisuke KUDOH

IEICE TRANSACTIONS on Communications   Vol.E75-B    No.6    pp.524-529
Publication Date: 1992/06/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: LETTER
Category: Radio Communication
power control,  CDMA,  spread spectrum,  user capacity,  cellular system,  

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User capacity of a DS/CDMA cellular mobile radio system employing transmitter power control (TPC) is investigated. Assuming log-normally distributed control error, outage probability is evaluated through computer simulations. The user capacity is dramatically decreased as the power control error increases. If the standard deviation is larger than about 2dB, the user capacity is decreased by more than 60%. It is shown that power control error with a standard deviation of less than or equal to 0.5dB is required to accommodate 90% of the maximum user capacity. The capacity decrease in the reverse and forward link channels due to non-uniform user distributions are also investigated. It is shown that if system users are densely distributed within the zone fringe whose thickness is 80% of the radius, the reverse link capacity is decreased by about 22%. The forward link capacity is comparatively insenstitive to non-uniform user distribution.