When a company completes migration to 802.11n, what can it do to avoid coexistence problems with neighboring businesses that still use 802.11g?
Not a lot. There are no government regulations or laws that can ‘force’ anyone to move to the more efficient newer 802.11 protocols. A good RF design, with accurate placement of access points, and perhaps even use of directional antennas can help. Just adding more access points usually just results in less efficient RF spectrum. The Wi-Fi protocol is a ‘shared medium’ protocol – unlike Ethernet Switches where each device has dedicated access to the media – Access Points are more like Hubs where all AP’s and Clients on the same frequency ‘share’ the media at the same time.
That is why we are moving as quickly as possible to the 5GHz frequencies where we have more channels and options to choose from. The 2.4GHz space only has enough spectrum to support three channels, 1, 6, and 11 at the same time.
Moving to all 5GHz capable devices would be a great start.