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What is WiFi?

WiFi is a popular term that is used referring to wireless communications between computers and other computer related devices. Regular radio waves are use to broadcast and receive just like a pair of walkie talkies, but on a much higher frequency.

These days you will find many areas around town that offer free WiFi internet access, but the most common use for WiFi is in the home. If you have high speed Internet (DSL, Cable, Satellite, etc) and have a piece of equipment that is called a wireless router, then you have WiFi.

Typical home WiFi setup

In the illustration above you will see what equipment is used in a typical home WiFi network. In some cases an Internet service provider will supply a wireless router/modem combination when you subscribe to their service.

The main benefit of WiFi is cordless internet access. Many electronic devices have WiFi built-in and can access the internet anywhere within range of your wireless router. This means that while using a WiFi laptop computer you can browse the internet from your couch. If you own a WiFi Internet Radio you can listen to over 14,000 stations in your bedroom, kitchen, or bathroom. Some cell phones have WiFi internet access also.

An electronic device cannot communicate with a WiFi router unless it has a WiFi receiver/transmitter (otherwise called a WiFi card or module) built-in. Most newer laptops have a built-in WiFi card which can communicate with nearby wireless routers. If your computer does not have built-in WiFi then you can purchase a USB WiFi Antenna for it. Modern USB WiFi antennas can be connected to almost any Windows computer to enable or improve WiFi communication.

WiFi works using two-way communication between devices. For example: When you type "CCrane" into the Google search bar and press "Go", you are sending a request from your computer to your router using WiFi. The router uses it's WiFi to receive your request and forward it over the internet to Google. When Google replies, they send you the results of your request back over the internet to your router. Your router then forwards the results via WiFi back to your laptop computer. In this scenario the use of WiFi communication takes place only between your computer and the router.

There are several different types of WiFi, but the end result is still the same, wireless communication. In the technical world WiFi is translated to 802.11, which is a group of standards created by the Institute of Electrical and Electronics Engineers (IEEE). Listed below are several different types of WiFi.

802.11a - Referred to as "Wireless A" was the first popular version of WiFi that was developed in 1999. It uses the 5 Gigahertz (GHz) radio band and can communicate at a data rate of 54 Megabits per second (Mbps). 802.11a was initially plagued with problems such as high cost for components, low reliability, and moderate range. This fueled the market to adopt the more reliable and affordable 802.11b and 802.11g technologies.

Today 802.11a is much more reliable and has increased range equaling that of 802.11b. Typical indoor range is about 100 feet. Typical outdoor range is about 300 feet.

802.11b - Referred to as "Wireless B" was also developed in 1999, began to gain popularity in late 2000. Using the 2.4 GHz radio band it can communicate at a maximum data rate of 11 Mbps although the typical throughput fluctuates between 6 and 7 Mbps. 802.11b gained much momentum as the WiFi leader because of the low cost of parts and good reliability. Because of this reliability 802.11b is typically used in point-to-point and point-to-multi-point long distance applications.

Many other devices such as cordless phones, bluetooth modules, and microwave ovens share the 2.4 GHz radio band. These devices can cause interference and WiFi "drop out", especially when multiple 2.4 GHz items are used simultaneously. Typical indoor range is about 100 feet. Typical outdoor range is about 400 feet.

802.11g - Referred to as "Wireless G" it was developed in 2003. It uses many of the same modulation techniques as 802.11a but operates in the 2.4 GHz radio band. The maximum data rate is 54 Mbps but typical throughput is closer to 19 Mbps. 802.11g is often used simultaneously with 802.11b to give the client user better reliability in different environments and backwards compatibility with older technology. Considerably higher data throughput can be achieved when using 802.11g only.

802.11g is susceptible to interference caused by other devices using the congested 2.4 GHz radio band. Typical indoor range is about 100 feet. Typical outdoor range is about 400 feet.

802.11n - Referred to as "Wireless N" it is the newest type of WiFi that is expected to be finalized in November 2009. Currently several companies are selling "Draft N" WiFi equipment based on the latest developments and approvals with this technology. 802.11n is faster and can broadcast further then previous WiFi standards.

It can use both the 2.4 GHz and the 5 GHz radio bands and can pass data at a maximum speed of 600 Mbps. Maximum speed is better achieved by using the 5 GHz band only. Typical data throughput is 75 Mbps depending on the signal quality. Many 802.11n routers can simultaneously broadcast 802.11b, 802.11g, and 802.11n giving the client WiFi user more compatibility with older technology.

Because 802.11n uses multiple channels to send and receive data, the equipment requires multiple radios which raises the cost for the consumer. Wireless "N" routers can have up to four antennas to send and receive faster, but this speed is "bottle necked" by the number of antennas that the client WiFi device is equipped with. Typical indoor range is about 200 feet. Typical outdoor range is about 800 feet.