SIM7080G Module speed and stability

alan-zhang

I have the SIM7080G module: https://shop.m5stack.com/products/sim7080g-cat-m-nb-iot-unit

I'm using the TinyGSM lib to interface with the module. There are a couple of issues I've encountered:

Speed: downloading the google logo (~4KB) over https take 7 - 12 seconds. I've tested the SIM card from a phone and it's 1MB/s download and upload. Downloading from http was equally slow, so doesn't look like to be encryption/compute bound. What can I do to make this a bit faster?
When I make repeated HTTP calls in a loop for testing, the device would freeze or stop responding after a random amount of time (minutes). When I reboot the CPU (ESP32) sometime it would recover, sometimes not. Also when power is unplugged, sometimes the module would go into a state where it would not respond AT commands at all. I would have to power cycle the module, sometimes more than once, to get it to accept AT commands again. Is this expected and is there a reliable way to recover from this?

Thank you!

felmue

Hello @alan-zhang

Are you connecting with NB-IoT or Cat-M? According to the documentation the speed are:
Cat-M: Up: 1119Kbps (= 140KB/s) Down: 589Kbps (= 74KB/s)
NB-Iot: Up: 150Kbps (= 19KB/s) Down: 136Kbps (= 17KB/s)
In other words far away from 1MB/s.
Maybe increasing the Baudrate might help?
Freezing could be a power issue. Make sure you use a good power source for your M5Stack and modem. Maybe consider to power the modem separately using one of these? (Please note: I cannot guarantee that this fixes the issue though. It's just an idea.)

Thanks
Felix

mtylerjr

@alan-zhang said in SIM7080G Module speed and stability:

I've tested the SIM card from a phone and it's 1MB/s download and upload.

Your phone might be using 3g/4g/5g/LTE and not NB-Iot or Cat-M. In fact Ive never seen a phone that uses NB-Iot or Cat-M (Doesn't mean they might not exist though)

M5Stack does sell an LTE module if you want LTE speeds though.