Mobile hotspot keeps dropping

I’m currently tethering my connection through a mobile hotspot using my Apple phone, and I'm running Tomato on my router. The issue is that the connection drops out almost constantly; it stays active for about a minute and then cuts out for another minute before coming back online. It’s this rhythmic, one-minute-on, one-minute-off cycle that’s driving me a bit crazy. Does anyone have any idea what might be causing this kind of instability or how I might go about fixing it?

E: I ended up doing a full factory reset on my phone, and honestly, it's running like a dream again. It looks like I might have picked up some kind of malware along the way, but 😕