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The "Radio settings" section allows to configure radio parameters to establish wireless connection.

Radio settings are divided into the following categories:

Radio frontend

ParameterDescription
Unit role

One units must be set to Master and the other one to Slave.

Please note that the following settings must be equal for "master" and "slave" unit to establish the radio link:

  • Center frequency - there are two ways:
    • Manually via "Downlink center frequency" and "Uplink center frequency" parameters. In this case wireless link will be setup at once.
    • Automatically with "Automatic selection of center frequency" function. In this case frequency channel grids must be set on both units. At the initial phase Master unit will select its center frequency automatically from grid, after that Slave unit will scan frequencies from its grid and wireless link will be established when Slave will find the center frequency which Master operates on.
  • Channel width - should be the same and set manually on both units.

When a wireless link has been established Slave unit will continuously inherit radio frontend parameters from Master unit excluding frequency channel grids. So, if you change some values on Master they will be set on Slave automatically.

Fixed center frequency

Available only on the Slave unit.

  • Enabled - center frequency must be set manually on wich the Slave unit will operate.
  • Disabled - center frequenct will be selected automatically based on frequency channel grids.
Automatic selection of center frequency

There are several way to define center frequencies:

  • Frequency selection off - center frequency will be set manually.
  • DFS and radar detection - center frequency will be set automatically according to frequency channel grids. In this mode Master unit will switch to the different frequency if high level interference or radar will be detected. Slave unit will switch too after some time.
Independent UL/DL center frequencies

Units may transmit on diffrerent center frequencies.

  • Enabled - uplink and downlink frequencies can be set to different values.
  • Disabled - uplink and downlink frequencies will be the same.

NOTE

Downlink - the direction from Master to Slave, Uplink - the direction from Slave to Master. These directions are correct for the whole link and do not depend on the roles of the devices.

Power limit

This parameter limits the transmitter power, there are two modes:

  • Transmitter output power - limits the power of transmitter to the set value.
  • EIRP - limits the total system power calculated as:
Tx Power + Antenna gain + Cable loss
Radio frontend settings description

Figure - Radio frontend settings

Air frame

ParameterDescription
Channel width

Channel width, shoud be the same on both Master and Slave units. Available values: 3.5, 5, 7, 10, 14, 15, 20, 28, 30, 40, 50, 56 MHz.

Frame length

Frame period affects the following wireless link metrics:

  • The greater frame period the more payload will be transmitted in one frame. Greater values increase latency.
  • The lower frame period the less payload will be transmitted in one frame. Lower values decrease latency.

Please note that frame period value is strongly depends on interference conditions. If larger frames will be dropped the larger payload is lost and system performance is decreased significantly. If smaller frames will be dropped the smaller payload is lost. Available values: 1, 2, 5, 10 ms.

Guard interval

Guard interval is intended for intersymbol interference elimination. One of the intersymbol interference reasons is multipath propagation in which a wireless signal from a transmitter reaches the receiver via multiple paths. Guard interval affects payload size. So it should be increased only in case of significant intersymbol interference.

Uplink/Downlink ratio

Allows to configure quotes for uplink and downlink directions. Available values depend from:

  • Channel width.
  • Frame period.
Air frame settings description

Figure - Air frame settings

Automatic modulation and transmit power control

ParameterDescription
AMC strategy

There are following AMC strategies available:

  • Normal - represents a balance between the error rate and throughput values.
  • Conservative - assumes using higher CINR thresholds in order to minimize the error rate.
  • Agressive - lowers the thresholds in order to use higher modulation levels and thus increase the throughput.
  • Disabled - disables automatic modulation control.
Automatic transmit power control

ATPC allows to control transmitter output power automatically based on target RSSI value. If actual RSSI level is lower then unit increases transmitter output power of the remote unit and vice versa. ATPC could not set value that may exceed the "Power limit" value.

  • The Master unit manages the transmit power of Slave unit.
  • The Slave unit manages the transmit power of Master unit.
Target RSSIRSSI value which will be used by ATPC as target.
AMC and ATPC settings description

Figure - AMC and ATPC settings

Frequency channel grids

The frequency grid allows to limit the scan range in case the center frequency is automatically selected. Also Instant DFS will use these restrictions when monitoring the noise situation. Narrow grid of available frequencies speeds up scanning and link establishing process. Manual center frequency selection will also be limited to the values indicated in the grid.


Figure - Frequency channel grids
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