nRF6943 or nRF9160 DK (BLE Cellular gateway)

[Ben Li]

Hi, 

I'm trying to build a proof of concept for a BLE gateway that captures data from BLE sensors and sends it to the cloud via LTE-M connection. I'm hoping that the gateway can support 20 concurrent BLE connections. However, I'm stuck in the choice between picking nRF6943 (thingy 91) or nRF9160 DK for testing my proof of concept. Or is there any other board that can also serves as a BLE gateway that can connect up to 20 concurrent BLE connections. My next question will be, are that any other device or sensors that can advertise BLE signals for me to test the gateway? I was thinking about using nRF9160 as the gateway and thingy 91 as a peripheral that advertise signals to nRF9160DK since it has sensors on it. Is there a better solution?

Thank you

[Simonr]

Hi

As the gateway (which I assume won't have any sensors, just receive data and forward it to the cloud, the nRF9160 DK would be easiest to use as it is easier to program and debug than a Thingy:91. For the BLE peripheral that connects to the gateway and transmits sensor data I guess a Thingy:52 or Thingy:53 would be just as good, as you don't need the cellular features on that, correct? 

Best regards,

Simon

[Ben Li]

Hi Simon, thank you so much for your response. Yes, I don't need cellular on the BLE peripheral. However I do need cellular on my gateway. There's a problem that I run into. nRF9160DK uses LTE-M which offers a 1Mbps data rate (3G). If I'm using 20 concurrent connections, that will take too long for data trasmition. Is there any solution to this? One solution I've figured is to use a cellular module that offers a 4G LTE, but I'm not sure if there's any nordic dev board that support that. Or is there a way to compress BLE package size prior to transmission? 

Thank you 

Ben 

[Simonr]

Hi Ben

Not really, uploading data from 20 concurrent BLE connections will indeed leave the throughput on the cellular side lacking compared to what it receives from the BLE peripheral. The nRF9160 isn't really designed for high throughput use cases, but rather low power solutions. So if you'd rather use a cellular module that can handle higher throughputs you're free to do so. If so you probably only need nRF52/53 series for both peripheral and central.

Best regards,

Simon

[Ben Li]

Hi Simon,

What kind of third party cellular shield is nRF52/53 compatible with? I stumbled across airlink cellular routers, but I have not seen any use cases on combining the cellular routers and nRF52. Or is there any particular cellular shield you recommended that is compatible with nRF52 DK?

[Simonr]

Hi

We have no specific recommendations as far as I know, but the nRF52/53 series will be able to connect to any module that has SPI for example (TWI and UART is also fine, but I'd recommend using SPI for the best throughput.)

Any Arduino type shield will fit onto our DKs so if you find a shield with SPI and that form factor you should be good.

Best regards,

Simon