Seamless Handover; Air Interface Migration; Dynamic Air Interface Migration - Motorola MTP850 S Product Information Manual

During network reconfiguration, a significant number of radios registered on one cell may roam. This roaming can
cause major congestion on specific cells. In order to avoid the congestion on control channels for the specific cells,
the specified radios roaming should be distributed in time.
As the operation cannot be performed immediately for all the radios, some of the radios must wait longer to roam.
The time cannot be programmed not to cause any of the radios to have inferior roaming capabilities. Thus the
roaming time for the radios is randomized.
The randomization means that after roaming scenario starts, a radio is not sending registration parameters to other
cells at once but waits random time before sending registration PDUs to other cells. Link failures and other related
scenarios are not randomized not to cause any unwanted delays in restoring the link.

Seamless Handover

Seamless handover eliminates voice interruption during calls by enabling the radio to roam faster between cells while
transmitting. Faster roaming is possible because the radio asks its serving cell to perform the reselection and the
SwMI performs all of the roaming signaling. The radio then moves straight to the traffic channel on the new cell and
continues the call without call restoration.

Air Interface Migration

The Air Interface Migration (AIM) feature enables the radio to migrate to a foreign SwMI, that is, the radio
registration in a foreign SwMI is allowed. The AIM also enables the radio to attach the groups in a foreign SwMI and
to make and receive calls and SDS.
The AIM services cover individual call, group call and individually addressed SDS or Status. In order to receive
group calls or group addressed SDS and Status from a group of the current network, the radio has to attach the
nominated group. The radio cannot migrate to a foreign network while it is in an active call. The radio also cannot
attach a foreign group on the current network hence no group-addressed status/SDS messages can be sent to home
network of the migrated radio. After migrating the radio is in the Clear Mode.
When AIM feature is enabled the radio selects the network in the Foreign Net mode (selectable in the radio MMI).
Foreign Network (Foreign Net)
In this mode radio selects the network automatically where the home network is not available. The radio registers
to any network that it finds that is already programmed into its codeplug list of networks, i.e. no user manual
selection is required. Network selection to another network is only performed at initial cell selection following a
link fail and then only if the home network is not available. The radio uses Visiting Short Subscriber Identity
(VSSI).
AIM, DAIM and Any Networks features are mutually exclusive.
This is a selling feature.

Dynamic Air Interface Migration

The Dynamic Air Interface Migration feature offers users a quick and easy way to switch between networks.
Depending on that setting, every time a radio is powered up or a talkgroup is changed, it automatically roams to the
assigned network. If a talkgroup has no particular network assigned, the radio stays on the current network.
This feature consist of these major functionalities:
• It allows your radio to dynamically select the appropriate network after your radio is powered up.
• If you change talkgroup to the one from a different network, radio automatically migrates to this network (in this
feature it is possible to assign network to particular talkgroup in the codeplug). It gives you an option to
automatically migrate to a network which is available in the region (network needs to be first pre-configured in the
codeplug). It is useful in case of loosing signal from dynamically selected network as the radio attempts to
establish communication with any available network.
This feature is useful where quick switching between networks is required, for example when entering a building that
uses its own infrastructure.
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