User's Manual

Configuring the Subscriber Unit’s Maximum Modulation Level
Manual Revision 1.0
3-7
Configuring the Subscriber Unit’s
Maximum Modulation Level
This section describes how to configure the maximum modulation level
for BreezeACCESS VL Subscriber Units.
NOTE
If the unit is associated with the AU, then the final configuration of the Maximum
Modulation Level parameter may be performed remotely, for example, from the site of
the AU or from another site.
1. If the SNR of the SU at the AU is too low, it is recommended that
you configure the Maximum Modulation Level parameter to a value
that is lower than the maximum supported by the unit. This can
decrease the number of retransmissions due to attempts to transmit
at modulation levels that are too high for the actual quality of the
link.
2. Check the SNR of the SU at the AU. You can use Telnet to view the
SNR values in the MAC Address Database, which can be accessed
from the Site Survey menu. If the ATPC algorithm is not enabled in
both AU and SU, the test should be done with the Initial Power Level
at the SU configured to its maximum value. If the SNR is lower than
the values required for the maximum modulation level according to
Table 3-2, it is recommended that you decrease the value of the
Maximum Modulation Level.
NOTE
The SNR measurement at the AU is accurate only when receiving transmissions from
the applicable SU. If necessary, use the Ping Test utility in the Site Survey menu to
verify data transmission.
3. Configure the Maximum Modulation Level according to Table 3-2,
using the typical SNR values. It is recommended that a 2 dB margin
be added to compensate for possible measurement inaccuracy or
variance in the quality of the link.
To configure the Maximum Modulation Level: