I can give you some basic info to help eliminate possible issues.
Firstly playing games with WiFi will always be less efficient than wired.
I assume you have a general knowledge of drivers and other software configurations for your PC.
If you haven't already uninstall the current drivers and install the latest drivers for your Wireless Adapter, (download the correct drivers prior to uninstalling) see if that improves it. Corrupted drivers have been known to cause strange behavior such as packet loss, signal loss, disconnections, etc.
Next disable your Firewall/Antivirus software, these can have serious negative impacts on networking if misconfigured and see if that helps.
Disable automatic updates - as windows and other software can check and download updates that will cause ping fluctuations while they perform the task.
Ensure no other software/malware is running on your PC, use malwarebytes and kaspersky rootkit detector or similar scanners to scan your PC for malware as these can eat up CPU cycles and clog up your network.
http://www.malwarebytes.org/ (skip free trial if you like which enables realtime detection)
Disable running applications, use msconfig to disable startup programs and non-microsoft services.
Another random factor is hard drive fragmentation, this usually causes FPS loss, but none-the-less could also affect network throughput as your PC is thrashing your hard drive to load game files. Try to defragment your hard drive.
Another option to the above format and reinstall windows/games and test systematically.
You can also try to disable the detection of networks and specify the SSID of your router to connect to.
Another option if you have a desktop is try changing the port your wireless adapter cards is plugged into, open the chassis, find the wireless adapter card, and switch to another open port on the motherboard.
If you've checked all the software/hardware of your PC and you're still having issues we can try and troubleshoot your network connection.
Wire your PC up to the router, and access the routers configuration, normally http://192.168.1.1, this differs per network/router, but you should have taken the same steps to secure your WiFi.
Next go to the advanced WiFi settings.
http://ui.linksys.com/files/WRT610N/1.00.00.17/en_help/... The settings and nomenclature will differ depending on your router's make and model.
You will see multiple options for RTS (Fragmentation Length), Transmit Rate (Beacon Interval), Transmit Power, etc.
Try lowering the numbers for your RTS and Rate settings. For example changing RTS from 2346 to 1000, and Rate from 100 to 50. This will cause smaller packets to be sent out twice as fast, this usually helps with interference issues. Keep in mind decreasing the interval will consume more power, so you may need to also adjust the Transmit Power, find the lowest setting possible for transmit power to preserve the life of the router.
You can also try changing the channel you operate on.
If your Router supports dual band try switching between 2.4ghz and 5ghz bands.
Keep in mind as a general rule 2.4ghz will have further range than 5ghz.
See if you notice any change and continue to manipulate the settings until you find optimal connectivity.
Power irregularities can also cause ping fluctuations, which is usually the case in old office buildings or homes that are not up to code. Installing an uninterruptible power supply/battery backup, can help to remove power irregularities.
If none of the above seems to help you may have hardware or Internet Service issues.