Adaptivity using DAA (Detect and Avoid)

This page describes the Adaptivity module, which allows CC23xx or CC27xx devices to more efficiently meet regulatory requirements tied to some specific regions of the world.

To enable this module, open SysConfig and go to BLE → Advanced Setting → and check the Adaptivity using DAA checkbox.

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Figure 160. Enabling Adaptivity using DAA

Once the module is enabled, the Adaptivity Configuration panel should appear in SysConfig.

There are two Utilization Based Modes that allows your application to select the level of control for transmit (TX) usage on BLE channels.

  1. Adaptative Mode: when channel utilization exceeds a defined threshold, then the Adaptivity will be enabled.

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    Adaptative Mode

  2. Fixed Mode: adaptivity is always enabled whenever the TX power is above 10 dBm.

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    Fixed mode

In both cases, the total transmit (TX) power (Pout) gain is in dBm and is set to 0 if not used. The valid range is -20dBm to 20dBm (negative value allowed to supports board attenuation).

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Figure 161. External gain power set to 0 dBm by default

This should include gain from any external PA as well as any antenna gain. This will relax the detection threshold level (TL) according to the formula:

TL = -70 dBm/MHz + 10 × log10 (100 mW / Pout)

where TL is the detection threshold and Pout is the equivalent omni-directional radiated power in mW.

Bluetooth LE uses frequency hopping to counteract narrowband interference problems and therefore is classified under the category of Adaptive FHSS. These are the restrictions that apply to it according to the MIIT (The Ministry of Information Industry Technology):

Adaptive FHSS using DAA

Limit

Channel availability

When channel is unavailable for 1s or 5 * N hopping channels * Channel occupation time, whichever is larger

Channel Holding time

Max hold time is 40ms. If hold time is more than 40 ms idle time no less than 5% of dwell time and no less than 100 µs

Short Control Transmission signals

Transmissions allowed on unavailable channels as long as duty cycle is less or equal than 10%