ps3 game network a complete crapstorm!

I have excellent Internet signal, my Netflix on the console works without a hitch, but I'm spending 90% on my time on gta5 getting kicked off the network and having to sigh back in. It's worse with the heist missions. The game has minor issues with load failure but that's menial in comparison to the ps network constantly crashing on me.
I've reset modem/router numerous times. Re-entered email/password info. Change network password several times. Reset the console several times.
Nothing has made any significant difference.
What is the problem and what can I do, if anything, to resolve this from my end?