Broadband W-LAN

So What Is 802.11 about?

At 50 Mbps, they meet the needs of today’s bandwidth-hungry applications.

Highlights

l 802.11b offers a speed of 11 Mbps operating at 2.4 GHz

l 802.11a is expected to provide an impressive 20-50 Mbps rate

The key drivers of demand for broadband wireless access networks are rapid growth in wireless and mobile communications, the emergence of multimedia applications, and the need for high-speed Internet access, led by the telecom deregulation.

Today’s primarily narrowband wireless services are mostly used for circuit-switched voice services. The evolution of second-generation and the development of third-generation mobile wireless systems aims to enable networks to provide instantaneous user bit rates of up to 2 Mbps per radio channel. This capacity will significantly improve packet-data and mobile multimedia applications. In addition, even higher data rates could be obtained for local area networks (LANs) using novel short-range wireless technologies. Typical applications are bandwidth-hungry, real-time and interactive multimedia services such as high-quality video distribution, client/server applications, and data-bank access.

LANs have ubiquitous presence in most networked offices. Only problem is that they have traditionally been tied to wires, thus restricting user freedom. Wireless, which offers that freedom, is now entering the realm of LAN. However, till now, wireless-LAN has been at an embryonic stage.

Different Options, Different Speeds

802.11—the first IEEE wireless LAN standard/protocol to emerge—offered a data speed of 1–2 Mbps, not enough to meet the needs of today’s broadband applications.

The two latest versions of 802.11, denoted by suffixes ‘a’ and ‘b’, promise vastly improved speeds.

802.11b offers a speed of 11 Mbps operating at 2.4GHz. It has seen market penetration mainly in niche applications such as buildings where the new cabling presents a problem. 802.11b offers benefit of a 100-m range, but requires ten times more power support than Bluetooth. The high power draw may make it a less attractive proposition for mobile communication devices such as PDAs and notebooks, but the range makes it ideal for LAN applications. It operates on a ‘hopping’ basis, switching frequencies every 2.5 seconds. By wireless standards, this is a relatively slow switching sequence, making it somewhat susceptible to interference. For comparison, Bluetooth shifts frequencies 1,600 times per second.

802.11a offers broadband connectivity to the Internet in a LAN. Currently under development, it is expected to provide an impressive 20–50 Mbps speed while operating at 5.1GHz.

Applications Galore

The advantage that the wireless connectivity offers over other wired Internet connectivity alternatives like fiber is that it adds the mobility dimension to devices. It makes rollouts faster, rapidly increasing new subscribers. Not only it is convenient for the mobile user, it is also the easier way to connect home networks. The spectrum used for connectivity is likely to be cheaper and unregulated.

Traditionally, W-LANs have seen applications in markets such as healthcare and warehousing, where companies can justify high equipment and integration costs. But recently, the applications have grown into mainstream businesses, homes and educational environments as well. With the number of devices in a home multiplying, there is a need to connect them. Wireless LAN offers the best solution for the purpose.

By Niraj K. Gupta, "from my cell", Voice & Data, January 2002