I'm trying to drive my simcom A7672s help me to design clt

Hi team,
I want to drive simcom A7672s using LM317 i got the desired output voltage 3.9v but still i think i'm not able to drive my simcom, sometime network comes , but mostly simcom get restarted , i think, due to current issue,
here is circuit
now let me know how i can run this and what i should do
1 i have tried simcom able to run with 700mA supply
2 if its required more peak current then which is other linear voltage regulator cost effective i should use
resistor pairs i used of R30, R33 is 4.7k and 10k.