iDEN Mobile Operations
Some of the iDEN mobile
operations are:
Control Channel Acquisition
When first powered up, an
iDEN mobile radio scans selected iDEN frequencies and locks
on to the designated control channel. The control channel
carries information continuously broadcast by the fixed
end system regarding system identification and timing parameters
for the mobile radio to use when it operates on the system.
The control channel also defines the maximum transmit power
that radios on the system may use.
Mobile Synchronization
In its operational mode,
the mobile radio aligns its frequency and transmit timing
to the outbound signal received from the fixed end system.
Mobile Registration
Each mobile radio in an
iDEN system is identified by an international mobile station
identifier (IMSI), which is assigned to it when it is first
placed in service and performs an initial registration with
the fixed end system. When making its registration request,
the mobile radio supplies its international mobile equipment
identifier (IMEI) to the fixed end system. After determining
the validity of the IMEI, the fixed end station assigns
an IMSI to the subscriber radio.
Mobile Assisted Handovers
When operating in a moving
vehicle, an iDEN mobile radio can assist the fixed end system
in determining when a handover to another cell should be
executed. Whenever the mobile radio is not actually transmitting
or receiving a signal from the fixed end system, it monitors
outbound signals from neighboring cells and measures the
received power and signal quality of these signals. When
it determines that the signal from a neighboring cell is
of higher quality than the signal from the fixed end system
in its currently assigned cell, it transmits a handover
request to the fixed end system. The iDEN infrastructure
can also query a mobile radio for a measurement report.
The mobile radio then transmits data back to the fixed end
system indicating the received signal strength detected
and measured by the mobile radio. |
