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Vectron
10.6.2 Monitoring of the environment
Both sides, basestation and endpoint regularly and independently perform RSSI scans of all accessible
hopping channels and time slots. The basestation broadcasts on its dummy bearer a list of allowed hop-
ping channels and time slots. Any endpoint maintain a list of quietest channels, i.e. preferred values (l,k)
for setting up a connection.
10.6.3 Setting up a connection
Connection setup is always initiated by the endpoint. It selects values (l,k) depending on its RSSI meas-
urements and the information received through the dummy bearer from the basestation. It then starts
transmission on the selected traffic bearer b(i,l,k).
The basestation regularly scans through all accessible bearer positions. This is referred to the Primary
Scan function of the basestation. Information about the primary scan is broadcast on the dummy bearer,
so when the endpoint establishes a traffic bearer this is done exactly at the time when the basestation
scans the respective bearer position. This allows the basestation to answer the bearer establishment
procedure and set up a connection.
10.6.4 Connection maintenance
As long as the connection is required (by higher layer protocols) it remains on the selected traffic bearer
b(i,l,k) unless a bearer handover procedure is invoked.
During the connection both transceivers monitor the quality of service on the traffic bearer. This is done
through RSSI measurements in adjacent time slots and bit error measurements. In case the quality of
service falls below a certain threshold, a handover procedure is started. It is always initiated by the end-
point.
During handover a new bearer b(i,l_new,k_new) is established and the old bearer is closed down. Selec-
tion of the new bearer happens according to the same rules as for a new connection, i.e. involve RSSI
measurements.
© Höft & Wessel AG
Lin
02.02.2001
1.00
HW90195UserMan.doc
Subject to amendment, errors excepted
page 63/70
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