| Summary: | 碩士 === 國立中央大學 === 電機工程學系 === 85 === This thesis introduces an application of fuzzy logic control
theory tothe power control in a direct-sequence, code-division
multiple-access(DS-CDMA) over the satellite mobile fading radio
channels. The conventionalclosed loop control algorithms allow
the base station to send a power command to either raise or
lower each user transmitting signal power levelby a fixed power
step, however, open loop control uses the down-link received
signal power as a reference varying its transmitting power. The
fixed step approach is actually an integral control whose power
increment is determined according to the bang-bang-like control
policy. However, this control scheme suffers from poor system
stability, larger overshoot,and long rise time. To overcome this
difficulty, a fuzzy logic control isintroduced, whose input
variables are the received power error and error variation. Use
this policy to determine each user's transmitting power inorder
to maintain all user's signal power received at the base station
nearlyequal and to achieve better system stability and control
performance.
|
|---|
