Optimizing System Originated Calls; Hand-Off - Nortel Meridian Companion Reference Manual

Page 100 of 102 Appendix D: Key planning concepts

Optimizing system originated calls

Hand-off

553-3601-106 Standard 2.00 September 1996
• Base Stations for a cell center should be close together.
• Base Station radios at a cell center should have exactly the same
coverage.
• Base Stations at a cell center should not be too close to a concrete or
marble column.
• Base Stations should be on the same side of a concrete or marble
column.
• Cell centers should be kept apart from each other.
• The -45 dBm contours of different cells should not overlap each other;
however a slight overlap is not serious.
• Use the left-right-skip method to plan multi-floor sites.
Hand-off occurs when an active radio link to a portable is transferred to
another radio in the system. When a link is not connected to the closest
available Base Station radio, or the user moves from one cell center to another,
the system "hands off" to an available Base Station radio at a closer cell center.
Audio quality depends on keeping the distance between the portable and Base
Station as short as possible. The Base Station radio requests a hand-off when
there is any decrease in signal strength, no matter how slowly the decrease
occurs. There is no absolute threshold at which the hand-off request is made.
It is only important that the signal strength decreases.
The system waits for responses from the prospective Base Station radios and
assigns the Base Station radio with the strongest signal strength to pick up the
call.
The system requests only one Base Station radio in each of the adjacent cells
and the radio neighbour cells to check the link.