Mdium-range wireless networks are the familiar wireless local area networks (WLANs). The most common type of medium-range wireless network is Wireless Fidelity, or Wi-Fi

Wireless Fidelity (Wi-Fi)

Wireless fidelity (Wi-Fi) is a medium-range WLAN, which is a wired LAN but without the cables. In a typical configuration, a transmitter with an antenna, called a wireless access point, connects to a wired LAN or to satellite dishes that provide an Internet connection.

A wireless access point provides service to a number of users within a small geographical perimeter (up to a couple of hundred feet), known as a hotspot.

Multiple wireless access points are needed to support a larger number of users across a larger geographical area. To communicate wirelessly, mobile devices, such as laptop PCs, typically have a built-in wireless network interface capability.

Wi-Fi provides fast and easy Internet or intranet broadband access from public hotspots located at airports, hotels, Internet cafés, universities, conference centers, offices, and homes.

The Institute of Electrical and Electronics Engineers (IEEE) has established a set of standards for wireless computer networks.

The IEEE standard for Wi-Fi is the 802.11 family. As of mid-2013, there were five standards in this family:

802.11a: supports wireless bandwidth up to 54 Mbps; high cost; short range; difficulty penetrating walls.

802.11b: supports wireless bandwidth up to 11 Mbps; low cost; longer range.

802.11g: supports wireless bandwidth up to 54 Mbps; high cost; longer range.

802.11n: supports wireless bandwidth exceeding 600 Mbps; higher cost than 802.11g; longer range than 802.11g.

802.11ac: a standard finalized in late 2012 that will support wireless bandwidth of 1 Gbps (1 billion bits per second); expected to reach the general market by early 2014.

The major benefits of Wi-Fi are its low cost and its ability to provide simple Internet access. It is the greatest facilitator of the wireless Internet-that is, the ability to connect to the Internet wirelessly.

Corporations are integrating Wi-Fi into their strategies. For example, Starbucks, McDonald’s, Panera, and Barnes & Noble offer customers Wi-Fi in many of their stores, primarily for Internet access.

Although Wi-Fi has become extremely popular, it is not without problems. Three factors are preventing the commercial Wi-Fi market from expanding even further: roaming, security, and cost.

• At this time, users cannot roam from hotspot to hotspot if the hotspots use different Wi-Fi network services. Unless the service is free, users have to log on to separate accounts and, where required, pay a separate fee for each service. (Some Wi-Fi hotspots offer free service, while others charge a fee.)
• Security is the second barrier to greater acceptance of Wi-Fi. Because Wi-Fi uses radio waves, it is difficult to shield from intruders.
• The final limitation to greater Wi-Fi expansion is cost. Even though Wi-Fi services are relatively inexpensive, many experts question whether commercial Wi-Fi services can survive when so many free hotspots are available to users.

Wireless Mesh Networks

Mesh networks use multiple Wi-Fi access points to create a wide area network that can be quite large. Mesh networks could have been included in the long-range wireless section, but you see them here because they are essentially a series of interconnected local area networks.

Around the United States, public wireless mesh programs have stalled and failed. Service providers that partnered with cities to maintain the systems are dropping out, largely because the projects’ costs are escalating and the revenue models are unclear.