Wireless Network Technologies

The most common wireless network technologies fall under the Institute of Electrical and Electronics Engineers (IEEE) 802.11 specification. Although other wireless technologies exist, they are not as prevalent as 802.11 (Wi-Fi) networks. Wi-Fi networks transmit radio waves between devices to allow network communications. Wi-Fi uses the 2.4 GHz and 5 GHz spectrums. There are three major standards within the Wi-Fi designation. See Table 17-4 for a listing of the major standards and their specifications.

Table 17-4. Common wireless networking technologies

Version

Transmission frequency

Transmission rate

802.11a

5 GHz

Up to 54 Mbps

802.11b

2.4 GHz

Up to 11 Mbps

802.11g

2.4 GHz

Up to 54 Mbps

802.11n

2.4 GHz, 5 GHz, or both

Up to 540 Mbps

The 802.11b specification was the first Wi-Fi technology introduced to the market. It uses the 2.4 GHz spectrum to transmit data at 11 Mbps. The 802.11b specification uses Complimentary Code Keying (CCK) coding to transmit data. While 802.11b has enjoyed the most widespread use, the lowering costs of faster technologies are rapidly replacing it with newer technologies.

The 802.11a specification transmits in the 5 GHz spectrum at a transmission rate of 54 Mbps. This specification uses Orthogonal Frequency-Division Multiplexing (OFDM) to transmit data, which is considerably better than the CCK coding standard. Additionally, 802.11a has more usable channels than 802.11b. This, plus the fact that the 5 GHz spectrum typically has less interference than 2.4 GHz, gives 802.11a a considerably faster transmission rate.

The 802.11g specification transmits in the 2.4 GHz spectrum at a transmission rate of 54 Mbps. This specification also uses OFDM to transmit data, and it enjoys the most widespread use of the newer technologies.

The 802.11n specification transmits in the 2.4 GHz, 5 GHz, or both spectrums. 802.11n offers up to 540 Mbps while using Multiple-Input-Multiple-Output (MIMO) technology. Essentially this means that the client computer and the wireless access point will use multiple receivers and multiple transmitters to achieve improved performance. Although multiple data streams can help your computer achieve higher throughput, many standard 802.11n devices combine strong, weak, and reflected signals into one data stream to maximize the range.

These technologies fall under the Wi-Fi designation, since devices that use the 802.11 family of standards are typically certified for interoperability by the Wi-Fi Alliance. Windows 7 supports each of these wireless technologies and the devices used to make connections to these types of networks.

New networking standards are also in the marketplace today. It bears noting that early adoption of new technologies does not always favor the consumer, because some products in the market may support early adoption of a standard that is not yet finalized. Therefore, if you purchase products too early, you may have to purchase additional hardware to support the additional features defined in the final version of the standard. Though this is not always true, be wary of purchasing the latest and greatest wireless products. Take some time to research the technology before buying equipment on impulse.

Not all 802.11 specifications are about transmission speed and rate, however. The 802.11i specification offers enhanced security. The 802.11h specification offers frequency and power control management. The 802.11e specification offers quality of service enhancements.

Another emerging wireless technology is Worldwide Interoperability for Microwave Access (WiMax). WiMax is not really a technology, but a stamp of approval for use with the 802.16 specification in broadband wireless deployments in metropolitan areas. WiMax-certified equipment usually uses the 2.5 GHz spectrum, but the 3.5 GHz, 2.3 GHz, and 5 GHz spectrums are available in some regions. Currently, a movement exists to use the 700 MHz spectrum for future WiMax deployments.

Wireless devices come in different shapes and sizes. A wireless device is the network adapter used to make the connection to wireless networks. A wireless network adapter is the actual hardware device you install into a slot or port in your computer. You must

The 802.1x specification is not part of the 802.11 family of protocols. It works with wireless and wired network protocols and provides a framework for authenticating users and controlling their access to a protected network.

Was this article helpful?

0 0

Post a comment