Network issue

Hi Guys,

I'm from India and using a Vodafone Operator for my iphone5 device, since last few days i m facing a network issue my device keep on "Searching" for network with sim or without sim. I have reset the Network setting further reset the whole device even replaced the sim but nothing help .

Gone through the blog and tried to "Update & Restore" via iTune, luckily it starred showing the network bar, however after 24 hours the same issue persist "Searching" for network with sim or no sim, again repeated the same procedure restore & updated via itune issue resolved but after some time again gone back to old process.

Kindly help me to understand the solution whether its hardware or some software issue or i have to live with it.