sm5100b shield problem

my shield keeps rebooting when i receive SMS, i think it might be cause i run it through USB.

cause it might take a lot of current (more then the 500mA usb can provide)

Does anyone have any experience with this type of problem ?

if i buy 9V 1.5A wall wart, will it work well with the arduino and supply enough current if needed ?

any tips and suggestion will be welcome, thanks

Yes, I had a similar problem. If you buy that wallwart it should work better.