Reg Apple 4s ios 6

My iPhone automatically locked when i updated with apple 4s ios 6 and on the screen it said 'Activation Required'. SIM from the carrier to which your phone is locked in order to activate your phone. I switched of the phone once again same problem. what i have to do. i dont have the carreier SIM to get it activated. i am in india. my relative brought it from us. but earlier it was working and un locked phone.