A method for monitoring idling mode connections between a base station and idling
subscriber units that are powered on, but not actively sending data, is provided.
The method includes making available a plurality of orthogonal subchannels within
at least one Code Division Multiple Access (CDMA) radio frequency (RF) channel.
A shared orthogonal subchannel is assigned to at least two different idling subscriber
units, but utilizing different time slots of the shared orthogonal subchannels.
For each idling subscriber unit assigned the shared orthogonal subchannel, a respective
heartbeat signal is sent within its assigned time slot at a data rate that is low
enough to maintain bit synchronization with the base station. The respective heartbeat
signals are tracked within the assigned time slots by selecting an assigned time
slot within the shared orthogonal subchannel, retrieving a previous tracking of
a respective heartbeat signal for an idling subscriber unit associated with the
assigned time slot, determining a current tracking of the respective heartbeat
signal for the idling subscriber unit associated with the assigned time slot, and
updating the tracking of the idling subscriber unit associated with the assigned
time slot based upon its current and previous trackings.
