Increasing Coverage of nRF51822 BLE module

[Vaio]

For some sort of geofencing application, we want to include the BLE module nRF51822 into a Base Station (BS), and a small mobile device (MS). The MS should detect the presence of a signal from the BS. If it is/is not present, certain actions are being triggered.

1.) While the maximum TxPower seems to be +4dBm, I heard that using an amplifier one can send up to the regulated limit of +20dBm.

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2.) Alternatively, I heard on the nRF51822 a custom protocol can be implemented. The design goal would be to reach maximum coverage (ideally, beyond walls inside a house).

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For both cases, the same questions arise:

Does anybody have experience / more infos on this? Mainly:

• what is the maximum coverage (in theory and practice)?
• what are the implications on power consumption (as this will be done in the BS, it shouldn't really matter)?

Thanks!

[Håkon Alseth]

Hi,

Note that ~200m LOS is with 250 kBit data rate. With BLE this might be 50-100 meters line-of-sight.

You're correct. BLE can only do 1MBit data-rate, so if BLE does not satisfy your range requirements, then I would recommend checking out our proprietary protocols (ESB or Gazell) and set the on-air data rate to 250 kBit. You could also add an RF PA, but note that BLE does not allow more than +10 dBm output power. Using a proprietary protocol, then you can go over this limit, but you have to make sure that you're within teleregulatory requirements.

Using a good antenna (like a WiFi antenna) will most likely give you better coverage, but it may not be enough. What I would do is to test this out with both BLE and 250kBit proprietary protocol, and see if the range is acceptable.

Best regards Håkon