Smartphone controlled home security systems?
 

I'm not interested in systems requiring an external monitoring service and contract. Rather, I want all control and alerts to be via a smartphone operating through the cellular network, not by WiFi (which can be compromised, or go down during a power outage). Does anyone have any experience here, or can recommend a consultant or such in this area?

I can open my garage door with my smart phone haven't tried yet but it was a feature