These days I've been noticed that my iPhone 4S with iOS 9.2.1 has a lot of usage in the phone app, arround 80%-85% so I've to charge the battery 2-3 times a day. 
In the battery usage section it shows that Phone App has "low signal" and the Whatsapp too... is there any problem with that? How could I fix this?
	
		
			
		
		
	
				
			In the battery usage section it shows that Phone App has "low signal" and the Whatsapp too... is there any problem with that? How could I fix this?
 
 
		 
 
		 
 
		 
 
		 
 
		