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The specific of such scenarios is the signal propagation path, since a part of the route is located above the water surface. The radio signal is reflected from the water surface, as a result an inter-symbol interference (ISI) appears at the receiver side. In order to overcome the ISI effects, the guard interval between the air frames should be increased. Depending on the equipment type, the following configuration options for increasing the guard interval are available:
- R5000 series InfiLINK 2x2 and InfiMAN 2x2 with TDMA technology support, InfiLINK Evolution and InfiMAN Evolution - disable the "short guard interval mode" parameter using the "rfconfig rf5.0 -shortgi" command for the 40 and 80 MHz channels (if other channel sizes are used, the long guard interval is already in use and cannot be modified);Quanta 5 devices - increase the "GI" parameter;
- InfiLINK XG / InfiLINK XG 1000 - make sure that the "Short Cyclic Prefix" option is disabled in the "Radio Settings" section.
On devices of the Quanta 5, Quanta 6 and Quanta 70 families, the guard interval size is set automatically.
Rolling should also be taken into account in such projects. In order to maintain the position of the CPE relative to the BS, a roll compensation device with a gyroscopic function can be used.
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The following projects were implemented by InfiNet in accordance with the above scenario: