Have you come up with iPhone no service iOS 7 issue? Here are some steps that could be of much help to a lot of iPhone 5 / 4S / 4 users who have upgraded to iOS 7 and wish to solve the problems as soon as possible to enjoy all the new benefits that are included in the latest firmware release from Apple. 
Note that these solutions might not help you if the problem is related to hardware. In such case, you will have to take your iPhone to Apple service to have it repaired or replaced. 
Method 1. 
Some people assure that when you get into the place with no signal you should place your gadget in the empty glass. Don’t laugh. They assure that this way you can avoid iPhone no service issue. Try it and share your impressions whether this method has helped you or just made everyone around you joking about the stranger who places his iDevice into the glass. 
Method 2. 
 The problem could be caused by your SIM card tray. If the SIM’s metal part hasn’t been centered you might experience service drop off issues. You can take the card out and look closely whether its metal touches the tray or not.
Method 3. 
Another thing that could lead to iPhone no service on iOS 7 is the antenna tower. You can contact your carrier to make sure the signal is strong in your area. Remember that you can always unlock the gadget and switch to another network if you are tired of dropped connections with your original carrier. 
Method 4. 
Apple has designed its iPhone 4S / 4 models in such a way that users often get service drop out problems because of the device’s antenna. Use an iPhone case to not touch the antenna with your hand and maintain the signal. 
Method 5. 
Sometimes the strength of the signal depends on the cases you are using. Experiment with different accessories and find the one that doesn’t cause problems. 
Method 6. 
iPhone users can also restart their device when they get iPhone no service problem. Your device might be mistaking believing you are in the dead area while you are no longer are. The signal will be updated after restart.