How Does WiFi Work on a Desktop?

Wi-Fi, or wireless fidelity, refers to a family of radio frequency technologies -- otherwise known as Institute of Electrical and Electronics Engineers (IEEE) 802.11 -- which allow electronic devices to connect to each other quickly, reliably and securely without wires. Desktop computers are typically larger, heavier and less mobile than their laptop counterparts, but, that fact aside, Wi-Fi in desktop computers essentially works in the same way as it does in any Wi-Fi enabled device.

Wi-Fi Radio

Desktop computers are less likely to have Wi-Fi radio built-in than laptop computers, although some do. Similarly, desktop computers don't have PCMCIA slots, so a wireless PCMCIA card, or PC card, is not an option. The easiest solution for adding Wi-Fi to a desktop computer is often via an external Universal Serial Bus (USB) wireless network adapter, which simply plugs into any available USB port.

Internet Connectivity

Whether it is connected to a desktop computer internally or externally, the Wi-Fi radio sends and receives radio signals -- at 2.4 gigahertz, 5 gigahertz, or both, depending upon the specification -- to and from other Wi-Fi enabled devices within range. Typically, one such device is a wireless access point, or router, which is also physically wired to an active broadband Internet connection. This way, any desktop computer that can connect to the access point can also connect seamlessly to the Internet.

802.11n

Desktop computers can also connect to a wired router using regular Ethernet cables, but Wi-Fi radios and routers that comply with the 802.11n standard not only do away with unsightly wires, they offer data transfer rates up to 450 megabits per second over a range of 600 feet or more. This means that 802.11n hardware can cover an entire home with a strong Wi-Fi signal, with data transfer rates that compare favorably with wired networks. 802.11n devices use reflection from walls and other structures to reinforce or strengthen radio signals and eliminate weak spots from their coverage.

Compatibility

The 2.4 gigahertz and 5 gigahertz frequency bands of the radio spectrum are unlicensed and can therefore be used by other devices, such as remote control toys. However, Wi-Fi devices need to undergo rigorous certification testing to ensure that they interoperate with other devices without interference. Interoperability also means that certified products (including desktop wireless network interface cards) from more than 350 members of the Wi-Fi Alliance can be used side-by-side without concern over compatibility.

References

• Wi-Fi Alliance: Discover and Learn
• "Introduction to Information Systems: Enabling and Transforming Business"; R. Kelly Rainer, Casey G. Cegielski; 2009
• "Wireless Home Networking For Dummies"; Danny Briere, Pat Hurley, Edward Ferris; 2008