There is a bug in some hardware where the device never wakes back up.
You may try disabling the power management by putting a file
# Disable power management in the 8192cu driver. This works around a bug in
# some hardware where the device never wakes back up.
# Credit goes to Saqib Razaq (https://github.com/s-razaq) for the fix.
# rtw_power_mgnt=0 disables power saving
# rtw_enusbss=0 disables USB autosuspend
options 8192cu rtw_power_mgnt=0 rtw_enusbss=0