Help GSM Signal loss

[ithinkunome]

My mobile loss gsm signal when left ideal, Im not able to make/receive call neither able to send/receive sms.

If I restart my mobile Im able to receive call/sms, but than after some time again signal are loss but strange
thing is that My phone showing full bar all the time.

The sim Im using is working perfectly fine on other mobiles. I also tried re-inseting SIM

I tried restoring my mobile but it didn't work.

Anyone please help me fixing this problem

Thanks

Mobile Details

Samsung -sgh -I747

Android Version 4.3

Baseband version
I747UCUEMJB


Kernal version
3.0.31-2024954
se.infra@ro210-11#1

build number
JSS15J.1747UCUEMJB