A multiple access, spread-spectrum communication
system processes a plurality of information signals received by a Radio Carrier
Station (RCS) over telecommunication lines for simultaneous transmission over a
radio frequency (RF) channel as a code-division-multiplexed (CDM)
signal to a group of Subscriber Units (SUs). The RCS receives a call request
signal that corresponds to a telecommunication line information
signal, and a user identification signal that identifies a user to receive the call. The RCS includes a plurality of
Code Division Multiple Access (CDMA) modems, one of which provides a global
pilot code signal. The modems provide message code signals synchronized to the global
pilot signal. Each modem combines an information signal with a message code signal to provide a CDM processed signal. The RCS includes a
system channel controller is coupled to receive a remote call. An RF
transmitter is connected to all of the modems to combine the CDM processed signals with the global
pilot code signal to generate a CDM signal. The RF
transmitter also modulates a
carrier signal with the CDM signal and transmits the modulated
carrier signal through an
RF communication channel to the SUs. Each SU includes a CDMA modem which is also synchronized to the global
pilot signal. The CDMA modem despreads the CDM signal and provides a despread information signal to the user. The
system includes a
closed loop power control system for maintaining a minimum system transmit
power level for the RCS and the SUs, and
system capacity management for maintaining a maximum number of active SUs for improved system performance.