Channel Monitoring#

This module includes functions for channel monitoring feature.

The functions in this module are available when channel monitor feature (OPENTHREAD_CONFIG_CHANNEL_MONITOR_ENABLE) is enabled.

Channel monitoring will periodically monitor all channels to help determine the cleaner channels (channels with less interference).

When channel monitoring is active, a zero-duration Energy Scan is performed, collecting a single RSSI sample on every channel per sample interval. The RSSI samples are compared with a pre-specified RSSI threshold. As an indicator of channel quality, the channel monitoring module maintains and provides the average rate/percentage of RSSI samples that are above the threshold within (approximately) a specified sample window (referred to as channel occupancy).

Functions#

otError
otChannelMonitorSetEnabled(otInstance *aInstance, bool aEnabled)

Enables or disables the Channel Monitoring operation.

bool
otChannelMonitorIsEnabled(otInstance *aInstance)

Indicates whether the Channel Monitoring operation is enabled and running.

uint32_t
otChannelMonitorGetSampleInterval(otInstance *aInstance)

Get channel monitoring sample interval in milliseconds.

int8_t
otChannelMonitorGetRssiThreshold(otInstance *aInstance)

Get channel monitoring RSSI threshold in dBm.

uint32_t
otChannelMonitorGetSampleWindow(otInstance *aInstance)

Get channel monitoring averaging sample window length (number of samples).

uint32_t
otChannelMonitorGetSampleCount(otInstance *aInstance)

Get channel monitoring total number of RSSI samples (per channel).

uint16_t
otChannelMonitorGetChannelOccupancy(otInstance *aInstance, uint8_t aChannel)

Gets the current channel occupancy for a given channel.

Function Documentation#

otChannelMonitorSetEnabled#

otError otChannelMonitorSetEnabled (otInstance *aInstance, bool aEnabled)

Enables or disables the Channel Monitoring operation.

Parameters
[in]aInstance

A pointer to an OpenThread instance.

[in]aEnabled

TRUE to enable/start Channel Monitoring operation, FALSE to disable/stop it.

Once operation starts, any previously collected data is cleared. However, after operation is disabled, the previous collected data is still valid and can be read.

Note

  • OpenThread core internally enables or disables the Channel Monitoring operation when the IPv6 interface is brought up or down, for example in a call to otIp6SetEnabled().


Definition at line 82 of file include/openthread/channel_monitor.h

otChannelMonitorIsEnabled#

bool otChannelMonitorIsEnabled (otInstance *aInstance)

Indicates whether the Channel Monitoring operation is enabled and running.

Parameters
[in]aInstance

A pointer to an OpenThread instance.

Returns

  • TRUE if the Channel Monitoring operation is enabled, FALSE otherwise.


Definition at line 92 of file include/openthread/channel_monitor.h

otChannelMonitorGetSampleInterval#

uint32_t otChannelMonitorGetSampleInterval (otInstance *aInstance)

Get channel monitoring sample interval in milliseconds.

Parameters
[in]aInstance

A pointer to an OpenThread instance.

Returns

  • The channel monitor sample interval in milliseconds.


Definition at line 102 of file include/openthread/channel_monitor.h

otChannelMonitorGetRssiThreshold#

int8_t otChannelMonitorGetRssiThreshold (otInstance *aInstance)

Get channel monitoring RSSI threshold in dBm.

Parameters
[in]aInstance

A pointer to an OpenThread instance.

Returns

  • The RSSI threshold in dBm.


Definition at line 112 of file include/openthread/channel_monitor.h

otChannelMonitorGetSampleWindow#

uint32_t otChannelMonitorGetSampleWindow (otInstance *aInstance)

Get channel monitoring averaging sample window length (number of samples).

Parameters
[in]aInstance

A pointer to an OpenThread instance.

Returns

  • The averaging sample window.


Definition at line 122 of file include/openthread/channel_monitor.h

otChannelMonitorGetSampleCount#

uint32_t otChannelMonitorGetSampleCount (otInstance *aInstance)

Get channel monitoring total number of RSSI samples (per channel).

Parameters
[in]aInstance

A pointer to an OpenThread instance.

The count indicates total number samples per channel by channel monitoring module since its start (since Thread network interface was enabled).

Returns

  • Total number of RSSI samples (per channel) taken so far.


Definition at line 135 of file include/openthread/channel_monitor.h

otChannelMonitorGetChannelOccupancy#

uint16_t otChannelMonitorGetChannelOccupancy (otInstance *aInstance, uint8_t aChannel)

Gets the current channel occupancy for a given channel.

Parameters
[in]aInstance

A pointer to an OpenThread instance.

[in]aChannel

The channel for which to get the link occupancy.

The channel occupancy value represents the average rate/percentage of RSSI samples that were above RSSI threshold ("bad" RSSI samples).

For the first "sample window" samples, the average is maintained as the actual percentage (i.e., ratio of number of "bad" samples by total number of samples). After "window" samples, the averager uses an exponentially weighted moving average. Practically, this means the average is representative of up to 3 * window last samples with highest weight given to the latest kSampleWindow samples.

Max value of 0xffff indicates all RSSI samples were above RSSI threshold (i.e. 100% of samples were "bad").

Returns

  • The current channel occupancy for the given channel.


Definition at line 156 of file include/openthread/channel_monitor.h