Of all connectivity issues, channel congestion is the most common. While there's no guarantee, I'd recommend you install WiFi Analyzer for Android or something similar for iPhone. Once installed, open the app and take note of the channel graph which will show how many others are using the same channel. The circular icon to the right provides the SSID and channels being used by those it detects and the star icon rates the best to worst in the area. Then log into the router and see if the default 'auto' feature for channels is set and if so, disable and manually select a channel with less congestion..Hope that helps