Specifications

Coverage
Handover
August 08, 2000 68P81095E55-E D-11
Note
An important limitation of this approach is the size of the high site cells. A high
site cell must list all low site cells in its neighbor cell list. If the high site cell's
coverage area includes many low site cells, the neighbor cell list might become
too lengthy. A long neighbor cell list will increase the time required to read the
BCCH information and increase the chance of a dropped or lost call.
Coverage
The prediction of coverage and comparison of coverage to other RF systems is
beyond the scope of this document. However, the current offering of Base and
Subscriber equipment is designed to allow for operations similar to that provided by
common digital cellular systems. The iDEN system utilizes:
• Base receive antenna diversity (multiple /branched antennas)
• Low noise receiver multi-couplers to merge base radio output to the antennas
• Optional state-of-the-art tower mounted pre-amplifiers
This helps maximize the base receive performance and balance the radio link power.
Base transmitters are available providing an average power output of:
• 5-70 Watts (800 MHz)
• 2-40 Watts (800 MHz and 1.5 GHz)
• 5-60 Watts (900 MHz)
Either cavity or hybrid transmitter combiners are then used appropriately to combine
multiple transmit signals on common antennas. The Mobile Stations also use low
noise receiver components and state-of-the-art linear amplifiers.
Dropped Calls
There are many factors and reasons why a call my be lost (dropped) prematurely.
The principle reasons for dropped calls are: inadequate and/or inaccurate handover
parameter measurement
• Inadequate coverage and/or uncontrolled interference
• No adequate server available in time (blocking)
• Signalling failure
• Processing failure