Here is a technique that often works. Find out your wireless driver:
sudo lshw -C network
Included in the details for your wireless device will be 'driver=some_driver' Here is an example:
*-network
description: Wireless interface
product: Centrino Advanced-N 6200
vendor: Intel Corporation
logical name: wlan0
version: 35
serial: xx:94:6b:99:55:yy
width: 64 bits
clock: 33MHz
capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless
configuration: broadcast=yes driver=iwlwifi driverversion=3.8.0-26
Next, write a configuration file:
gksudo gedit /etc/pm/config.d/config
Add a single line:
SUSPEND_MODULES="iwlwifi"
Of course, substitute your wireless driver in place of iwlwifi in my example. Proofread, save and close gedit.
Alt+F2
then typenm-applet
and ENTER. It's always do the trick for me. – Shaharil Ahmad Jul 08 '13 at 16:29