In my previous web exclusive, I explained how fiber was essential to cellular wireless networks. This time, we are going to discuss the “other wireless,” Wi-Fi. Our focus is not on the Wi-Fi found in every office and coffee shop, but Wi-Fi used outdoors in metropolitan or rural areas to make connections instead of a landline, either fiber or copper.

 Since the dawn of wireless communications with Marconi in 1897, wireless has been used to create communications links where communications over cable is difficult or expensive, or both. One of Marconi’s first stations was on the Isle of Wight to allow Queen Victoria to send messages to the Royal Yacht.

When telephone network traffic grew too much for copper cables, microwave networks were used on land and satellites between the continents. Once fiber optics was developed, wireless networks were rapidly replaced by fiber optic cables, except in areas on land where wireless made more sense, such as rugged mountain terrain.

Hilltop towers are part of large microwave networks.

The internet caused immense growth in communications traffic and the smartphone accelerated its growth, plus demanded mobility. Over a decade, wireless communications became a necessity. Technology for both cellular wireless and Wi-Fi were developed to provide more bandwidth. Today we have 5G and Wi-Fi 6, both offering nearly gigabit speeds, using almost identical technology.

The biggest difference between the two is a difference in protocols. Cellular networks like 5G assume the user is mobile and have protocols to seamlessly handoff a user from one cell tower to another as they move. Wi-Fi assumes the user is stationery, so a moving user would have to manually log into a new network because it probably has a different owner. The extra overhead of seamless handoffs makes cellular less efficient than wireless—part of the reason that smartphones are programmed to prefer Wi-Fi connections.

Many cities have open Wi-Fi networks for public use. Sitting on a park bench or waiting for a bus or tram, you can often log into the free city Wi-Fi and use your smartphone, tablet or laptop just like in a coffee shop. It’s essentially the same Wi-Fi, although sometimes it may be a bit more powerful and have more channels than the coffee shop to accommodate more users. Access points like those pictured below are connected with fiber to city networks to provide the internet connection.

Santa Monica, Calif., offers free Wi-Fi to everybody and private Wi-Fi for city employees.

You can access metro Wi-Fi in most cities around the world, like Istanbul.

There is another type of Wi-Fi that creates line-of-sight links. Rather than using antennas that work in all directions (omnidirectional) like premises or metro access points, Wi-Fi can be configured to transmit with directional antennas to create private links. Suppose you have two buildings separated by a highway or a river that need connection. Put antennas on the roof of both buildings, connect the users and you have a private communications link.

What if you live in or near a small rural town and need fast internet access? The local phone company might offer slow DSL, but you probably can’t get CATV cable modem service, and fiber is out of the question. But there is probably fiber along the road that runs through the town. A wireless internet service provider (WISP) can set up a head end in town, connect to the fiber along the road to get an internet service connection, build an antenna at the head end and one at your location, and then connect you to high speed internet.

Rooftop line-of-sight Wi-Fi link. Above and below photos courtesy of San Diego Broadband.

Many rural towns have WISPs because of the simplicity of setting up line-of-sight Wi-Fi and the lower cost compared to running fiber to every user. The setup cost is relatively low, so these systems are often locally owned and operated. A WISP works in both flat and mountainous terrain, just requiring some site surveys to find locations for antennas with clear line-of-sight. It is easier to get connectivity with a private Wi-Fi link than with cellular, which is a broadcast network designed for many users, not just one, and is not easy to adapt to the rugged rural terrain or long distances involved. 

What all these Wi-Fi networks have in common is they are connected to the ubiquitous fiber optic backbones that provide worldwide communications.

Remember what AT&T’s CEO John Stankey said: “There’s a fallacy to say there’s fixed networks and wireless networks. There are only fiber networks with different access technologies on the end of them. That’s where this is all going.”