Devices intermittently drop contact when idle

I'v had comcast business internet in my home office. Devices (all my devices are Apple) that connect through WIFi will intermittently lose connection. It NEVER happens while using the device- only when a device is idle or asleep and I try to reconnect. I'll then have to turn off wifi and turn it on again. This happens with no pattern- it might happen 5 times a day...or every couple days. I had this issue years ago with ATT, but don't remeber that solution. Ideas?