A correctly functioning wireless connection should not add any increase in latency to the AH servers. Your slowest link is still the Telco itself, not any home networking gear you have. Most likely your 20ms ping time increase is a result of your moving to a "new place", unless you mean you tested it with a cable first.
That all said, if you enable certain features on most "wireless routers" such as firewall (as an example), it would increase your latency as the device is taking longer to inspect the network traffic.
Having a "N", "G", or even "B" type wireless connection is not going to impact your ping times in AH.