nRF9151-DK - Slow TCP communication, high latency

[iotdeveloper]

Hello,

I would like to ask about LTE-M communication latency when using nRF9151-DK. I am using a TCP connection to transfer data read from another device via UART (MTU=1500 B), but communication is significantly slower than Wi-Fi, with high latency. The ping on the nRF9151-DK is around 150-300 ms when using a Vodafone EasyConnect NB-IoT/LTE-M SIM card. I have explicit LTE-M usage set in the program. Is this normal and is it a feature of LTE-M, meaning that it cannot be sped up in any way?

Thank you

[Samruddhi Jadhav]

Hi,

What you are observing seems reasonable. According to the LTE Technology documentation, the LTE-M latency is about 50-100ms and LTE-M isn't designed for very low latency like Wi-Fi. For NB-IoT it is 1.5-10s. The reason for the additional delay is that LTE-M passes through a mobile core network. So, LTE-M doesn't behave like Wi-Fi and therefore, it will be slower.

Hope this helps.