First find out what your wireless kernel driver you use:

Run

sudo lshw -class network

Then look for "driver=xxxxx" e.g.

Now create a text-file called "reset_wireless.sh" with the following:

#!/bin/sh

service network-manager stop

modprobe -r brcm80211

modprobe brcm80211

service network-manager start

obviously change "brcm80211" with your driver.

Give it execute rights i.e.

chmod +x reset_wireless.sh

Now right-click and create a launcher on your desktop with the command:

gksudo reset_wireless.sh

Now when you awaken you can reset your wireless by double-clicking on the new launcher.

Automating

You can try the following to automate the above script on resume:

Move the file to a known location e.g.

sudo mv ~/resume_wireless.sh /var/local

Now create a new script:

#!/bin/sh

case "$1" in

        thaw|resume)

    /var/local/resume_wireless.sh

    /var/local/resume_wireless.sh

        ;;

        *)

        ;;

        esac

exit $?

save this script in the folder /etc/pm/sleep.d called 99wireless-resume and give it execute rights.

_{technique borrowed from here and here}