nrf9160 throughput

[Ben Li]

 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 for the proof of concept. However, I'm concerned on nRF91's data rate. I am afraid it leave the throughput on the cellular side lacking compared to what it receives from the BLE peripheral. Is there anyway to get around this? Or should I use a third party GSM like sim7600?

My idea is to connect two NRF9160 together to handle the throughput. Or I can connect nrf52840 with a LTE CAT4 module like Maduino Zero 4G LTE. Both options need to be battery backed and runs without connecting to PC eventually.

Would that work?

Best,

Ben Li

[Albrecht Markus Schellenberger]

Ben Li said:

My first approach is to use nRF52 that scans and initiate connections, and I will need another nrf52 as a peripheral to advertise 20 BLE signals in total using blood pressure profile, heart rate profile... etc. To send the data to the cloud, I will connect the central with another third party cellular module such as the madrino board via SPI or UART so that I can foward the data to the cloud via 4G/5G cellular

Thanks a lot for the detailed input, Ben Li! 

Ben Li said:

My second approach is just using two NRF9160 together. Since there are on board nrf52480 SOC and cellular modem.

In this case, you mean two nRF9160 DKs, right? Because the nRF9160 SiP itself has no nRF52840 SoC included. Please be advised, that on the nRF9160 DK the nRF52840 SoC is flashed with a firmware called the Board Controller. You can of course flash other firmware to it, but you will then loose some of the functionality that comes along with the DK. 

Ben Li said:

My concern is that I'm not sure if there is going to be latency issue 

I’m still not sure if I understand what you mean by 'latency issues'. Could you think of a specific example or use case here? 

Ben Li said:

since nRF9160 seems to be designed for low throughput use cases.

What gives you the impression that the nRF9160 'seems to be designed for low throughput use cases'? Could you point me to the source mentioning that? 

Ben Li said:

I am afraid the network core will runs out of memory.

The nRF9160 has no network core. It includes an application and a modem core which, except of a shared RAM memory area, are completely separated from each other. Along with the nRF5340, the nRF9160 is our most powerful product. Having the application core out of memory will require quite some coding. The modem core on the other hand is designed as a black box which cannot be accessed from the outside, except via the mentioned shared RAM memory area.

Regards,

Markus