Dear george, thx,
When I leave my computer (sometimes I lock the screen others not) and I'm back i notice that the connection is down (I found this by seeing my torrent client at 0 kb/s)
I don't close the lid.
computer is not hibernating, I quickly enter the pass and I'm on, no delay time or HD activity.
No problem with my wireless, just to note that one day I lost my wireless card when upgrading kernel, following some forums I downloaded the linux drivers (Wireless-bluetooth-linux-STA-driver) from broadcom site and I 'make' the driver and install it again.
I often repeated this operation.

perhaps the problem is from here ????
I'll try to remove it and check again.
gsettings list-recursively | grep -i plugins.power
gave :
org.gnome.settings-daemon.plugins.power active true
org.gnome.settings-daemon.plugins.power button-hibernate 'hibernate'
org.gnome.settings-daemon.plugins.power button-power 'suspend'
org.gnome.settings-daemon.plugins.power button-sleep 'hibernate'
org.gnome.settings-daemon.plugins.power button-suspend 'suspend'
org.gnome.settings-daemon.plugins.power critical-battery-action 'hibernate'
org.gnome.settings-daemon.plugins.power idle-brightness 30
org.gnome.settings-daemon.plugins.power idle-dim-ac false
org.gnome.settings-daemon.plugins.power idle-dim-battery true
org.gnome.settings-daemon.plugins.power idle-dim-time 90
org.gnome.settings-daemon.plugins.power lid-close-ac-action 'suspend'
org.gnome.settings-daemon.plugins.power lid-close-battery-action 'suspend'
org.gnome.settings-daemon.plugins.power notify-perhaps-recall true
org.gnome.settings-daemon.plugins.power percentage-action 2
org.gnome.settings-daemon.plugins.power percentage-critical 3
org.gnome.settings-daemon.plugins.power percentage-low 10
org.gnome.settings-daemon.plugins.power priority 1
org.gnome.settings-daemon.plugins.power sleep-display-ac 600
org.gnome.settings-daemon.plugins.power sleep-display-battery 600
org.gnome.settings-daemon.plugins.power sleep-inactive-ac-timeout 0
org.gnome.settings-daemon.plugins.power sleep-inactive-ac-type 'suspend'
org.gnome.settings-daemon.plugins.power sleep-inactive-battery-timeout 0
org.gnome.settings-daemon.plugins.power sleep-inactive-battery-type 'suspend'
org.gnome.settings-daemon.plugins.power time-action 120
org.gnome.settings-daemon.plugins.power time-critical 300
org.gnome.settings-daemon.plugins.power time-low 1200
org.gnome.settings-daemon.plugins.power use-time-for-policy true
Thx