RE: nRF52 Receiver Senesitivity Enhancement

Andreas — Fri, 01 Jun 2018 07:38:53 GMT

Hi,

The Softdevice does not limit on the sensitivity, the nRF52 radio does. If the signal strength incoming is less than the selectivity spec, the signal will physically not be received. The RSSI in the nRFConnect app is the signal strength of the signal in the smartphone, the sensitivity here will probably not be exactly equal to the nRF52, depending on the WiFi/BT chipset.

In order to increase the wireless range you would want to increase the link budget, not necessarily the sensitivity. In the nRF52832 this can be done by adding a front-end-module, which contains both a PA (for TX) and LNA (for RX). The LNA could improve the sensitivity a couple of dB, and the PA increase the output power. When in a connection it will still be limited by the opposing end of the link, if lower TX power and worse sensitivity the signal will get there, but not 'get back' and there will not be an overall range increase. This means that the FEM is needed in both ends. If connected to a smart phone the increase will be limited by the specs of the smartphone.

Another possibility is to trade up for the nRF52840, which supports the 'Coded PHY' feature of Bluetooth 5. With this you can trade in some datarate for improved sensitivity.

Best regards,

Andreas