History and Types of Wi-Fi
In the 1980s, a technology designed for wireless cash registers called WaveLAN was developed and shared with the Institute of Electrical and Electronics Engineers group responsible for networking standards, known as Committee 802. This technology was further developed during the 1990s until the committee published standard 802.11 in 1997. The initial form of Wi-Fi from that 1997 standard supported only 2 Mbps connections. This technology was not officially known as Wi-Fi from the beginning, either; that term was coined a few years later as its popularity increased. An industry standards group has continued to evolve the standard ever since, generating a family of new versions of Wi-Fi called successively 802.11b, 802.11g, 802.11n, 802.11ac, and so on. Each of these related standards can communicate with each other, although newer versions offer better performance and more features.
Wi-Fi Hardware
Wireless broadband routers commonly used in home networks serve as Wi-Fi access points (along with other functions). Similarly, public Wi-Fi hotspots use one or more access points installed inside the coverage area. Small Wi-Fi radios and antennas are embedded inside smartphones, laptops, printers, and many consumer gadgets enabling these devices to function as network clients. Access points are configured with network names that clients can discover when scanning the area for available networks.
Wi-Fi Hotspots
Hotspots are a kind of infrastructure mode network designed for public or metered access to the internet. Many wireless hotspots use special software packages to manage user subscriptions and limit internet access accordingly.
Wi-Fi Network Protocols
Wi-Fi consists of a data link layer protocol that runs over any of several physical layer links. The data layer supports a special Media Access Control protocol that uses collision avoidance techniques (technically called Carrier Sense Multiple Access with Collision Avoidance) to help handle many clients on the network communicating at once. Wi-Fi supports the concept of channels similar to those of televisions. Each Wi-Fi channel employs a specific frequency range within the larger signal bands (2.4 GHz or 5 GHz). This architecture allows local networks in close physical proximity to communicate without interfering with each other. Wi-Fi protocols additionally test the quality of the signal between two devices and adjust the connection’s data rate down if needed to increase reliability. The necessary protocol logic is embedded in specialized device firmware installed by the manufacturer.
Common Problems With Wi-Fi Networks
No technology is perfect, and Wi-Fi possesses its share of limitations. Common issues with Wi-Fi networks include:
Security: Network traffic sent across Wi-Fi networks passes through open air, making it prone to snooping. Several kinds of Wi-Fi security technologies have been added to Wi-Fi over the years to help address this problem, although some work better than others. Signal range: A basic Wi-Fi network with one wireless access point reaches at most only a few hundred feet (100m or less) in any direction. Expanding the range of a Wi-Fi network requires installing additional access points configured to communicate with each other, which becomes expensive and difficult to support, especially outdoors. As with other wireless protocols, signal interference (from other wireless devices, or from physical obstructions such as walls) can lower the effective range of Wi-Fi and its overall reliability.
