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,

Power-wise, I do not believe that you will run into issues, as the base station will act as a master device (always in RX mode) and it's most likely connected to the wall.

We're usually reluctant to say anything on the range, as this varies in different environments. If you're in a building where the walls are thick and made of concrete, this will reduce range across different rooms.

If you reduce the on-air datarate (supports 2M, 1M, 250k), you should get better coverage. When running on 2 MBit on-air datarate, the range is around 10-15 meters in an office environment. 250 kBit in an open area (outside, line-of-sight), you will get more than 200 meters. This is with a well-tuned design.

However, in buildings you will always have walls, wifi, and other factors that comes into play.

The best way to test this is to get two eval-kits, set them up with 250 kBit mode and test it in your natural application environment.

Best regards Håkon