I pad 2 disconnect frequently from wi fi

I have i pad 2 with latest iOs installed. It disconnect frequently from wi fi connection. Sometimes reconnect automatically. sometimes I have to disconnect wi fi & reconnect it.
Note that internate connection or router has no problem as same wi fi I use in Smart phone samsung & Dell lap top.

I have no problem with mobile & lap top it happens in i pad 2 only.
It started after new latest iOS is updated.

It was problem with you tube video also but somehow the situation is better in you tube video.

So give me a guidance how to avoid frequent disconnection from intern ate wi fi.

KULIN DESAI