Micromax Canvas Nitro A311 – Network Issue

Smartphone: Micromax Canvas Nitro A311
Problem: Problem in Network, Network not Coming
Description: I have Micromax A311 Nitro and I have a problem with the network signals in sim 1 port. In sim1 port 3g signals very weak sometimes no network showing. And sometime the 2g networks are shown full but while calling it says that the mobile is out of coverage area. Please solve the problem.