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SATEL OY
// SATELLAR MANUAL // RADIO UNIT // USER GUIDE // V. 1.8
6. Data transmission
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6.7 Link specific network settings with packet routing
With QAM-radio it is possible to adjust modulation level, handshake and retransmission also for each
radio link in the network separately. These settings can be done either via CU WEB GUI or by using
SATEL NETCO Design stack.
6.7.1 Link specific QAM modulation
Typically modulation settings must be the same throughout the network. With QAM-radios it is pos-
sible to enable link specific modulation mode which makes it possible to adjust each radio link with
a best usable modulation level. Same modem can communicate with neighboring modems using
different modulation which is selected based on the requirements for the specific radio path.
For example: A network consists of six modems using 25kHz channel width: modem A which is mas-
ter and remote modems B, C, D, E and F so that the distance between master modem A and modems
B, C and D is relatively short, distance between A and E is longer and finally connection between A
and F is close to maximum range that can be achieved. In order for connection to be robust it is man-
datory to use modulation level of 2-QAM for the connection between master modem A and remote F.
If all of the network would be having the same modulation scheme, the only solution would be
selecting 2-QAM for the whole network thus setting a maximum airspeed ~20.2 kpbs for every radio
link. However, with link specific QAM modulation it is possible to manually select e.g.
64-QAM for links A - B, A - C and A - D
-> ~121 kbps
16-QAM for A - E
->~ 80.6 kbps
2-QAM for A - F
-> ~ 20.2 kbps
