Call Roaming - Motorola ST7000 Product Information Manual

• Roaming and registration fail before the radio receives the random access acknowledgment and the
radio goes back to the last serving cell.
• The radio discovers a link failure on the serving cell, the link failure is shorter than the predefined
timer and the radio is not in the transmit inhibit mode.
• The radio discovers a link failure on the serving cell and is in the transmit inhibit mode. In this case,
the radio always goes back to the serving cell without registration and stays in the transmit inhibit
mode until the mode is turned off.
NOTICE: When two or more scenarios occur at the same time, the radio registers with
signaling.
If the radio discovers a link failure on the serving cell, a specific timer starts counting. If the link failure
remains after the timer expires, then the radio acts as during a normal link failure. If the link failure
ends before timer expires, then the radio goes back to the serving cell without registration. This
mechanism ensures that unnecessary registration is avoided.
When a radio is out of the serving cell range for a period shorter than configured in the codeplug, then
the radio does not register to go back in the range.
2.14.4

Call Roaming

The radio continually monitors neighbor cells and scans the highest ranked neighbor cell.
When the state of the highest ranked neighbor cell is sufficiently better than the serving cell, or when
the radio has lost the serving cell, the radio employs cell reselection procedures using the following
methods:
• If not in a call - undeclared cell reselection.
• If in a call and not transmitting or link failure occurs - unannounced cell reselection.
• If transmitting in a call, and a neighbor has been scanned, and the cells are synchronized -
announced type-1 or type-2 cell reselection.
• If transmitting in a call and no neighbor has been scanned or the cells are not synchronized -
announced type-3 cell reselection.
For compatibility with systems that do not support type-1 or type-2 cell reselection, the radio can be
provisioned to never perform these types of reselections.
The radio decides on the need for cell reselection, based on comparison of the signal strength and the
service level between the serving cell and neighbor cells. The service level criteria are based on the
following criteria listed in priority order:
1 System Wide Services available (Local or Wide Trunking)
2 Valid or Invalid Subscriber Class
3 Relinquishing criteria
4 Congestion level
5 Security Class
6 Subscriber Class
7 Home Location Area (Home Location area)
8 LA Boundary
9 Cell Load
The radio prefers a cell that has a higher service level to one with a lower service level. If the radio is
operating on a serving cell that has a lower service level than a neighbor cell, the radio roams to the
neighbor, even during a call.
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MN002955A01-AA
Chapter 2: Services and Features
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