Take Wi-Fi, the popular wireless-networking technology that's taken the computer and consumer electronics industries by storm. The term specifically refers to a handful of standards approved by industry groups that has made wireless networking inexpensive and nearly unbiquitous in the latest gadgets and computers. The Wi-Fi standards use unlicensed radio spectrum to transfer data between devices, such as a laptop and a wireless-networking router.
802.11b was the first of the Wi-Fi standards to become popular about five years ago. Two other standards, 802.11a and 802.11g, have joined it as Wi-Fi standards, and still another, 802.11n, is on the way, although still a way off. Some of these work together, but some don't. Each offers slightly different advantages and disadvantages. All are available in commercial products you can buy now.
Sorting out the alphabet soup can be as frustrating as untangling the ball of wires behind your PC that the standards are supposed to help replace. For example, 802.11n is still in development but manufacturers are trying to get a jump on the demand for it by developing products using a technology that 802.11n will be based on. Called MIMO, it's getting lots of buzz as some wireless-router makers tout it as the most powerful flavour of Wi-Fi to date.
Here are the basics to begin cutting through the knot.
What are the different flavours of Wi-Fi?
Wi-Fi standards are set by the Institute of Electrical and Electronics Engineers, or IEEE, and the Wi-Fi Alliance, an industry group responsible for interoperability testing. So far they have finalised and approved three standards: 802.11a, 802.11b and 802.11g.
802.11n is a proposed specification that will become a Wi-Fi standard once it's finalised by the IEEE and the Wi-Fi Alliance completes its interoperability testing. Groups have submitted various 802.11n proposals to the IEEE, but are still debating what to include in the standard. It isn't expected to be completed until late 2006, with products based on the standard coming out in early 2007.
Some companies are also touting a wireless-networking technology known as MIMO. This is not technically a variety of Wi-Fi, or even an industry standard. Rather, it is the technology that's expected to form the basis of 802.11n.
What is MIMO and what does it do?
MIMO (pronounced my-mo) stands for multiple input, multiple output and refers to the use of more than one antenna to send and receive two or more unique data streams over the same channel simultaneously in wireless devices, resulting in networks with long ranges and high throughputs. It is currently the primary basis for the proposed 802.11n standard.
In addition to multiple antennas, MIMO products use specialised software, allowing data sent from access points in multiple streams to be received and deciphered by clients. In combination, the multiple antennas and software allow data to be reliably sent and received in environments with considerable interference over relatively long distances.
MIMO products create wireless networks that can reach significantly farther than current Wi-Fi networks and still provide high data throughputs. In some cases, wireless networks using MIMO technology can reach over 300 feet and still send and receive data at 30mbps.
However, Pre-N products offer higher throughputs at the outer edges of its range, according to reviewers.
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