Wireless communications have enjoyed a steady growth over the last couple of decades. From television remote control to satellite−based communication systems, wireless communications have changed the way we live.
Devices connected through wireless technology provide increased mobility and require less infrastructure than traditional wired networks.
Computer networks have lagged behind in the wireless race because of intrinsic needs for higher bandwidth for data transmission compared to that of existing wireless devices (for example, television remote control or cordless phones).
However, in recent years, breakthroughs in silicon−chip technology have increased data throughput over the wireless connections, making wireless computer networks a reality.
Using electromagnetic waves, wireless LANs transmit and receive data over the air, minimizing the need for wired connections. With today's technology, wireless LANs are highly scalable, reliable, and easy to implement.
Wireless LANs have gained significant popularity among mobile users and those who work in small groups. Wireless LANs enable mobile users to gain access to real−time information.
A wireless LAN can be implemented as a standalone network (that is, a LAN with computers connected only using wireless links), with a handful of computers, as an enterprise−scale network with thousands of computers, as an extension to an existing wired network, or as a replacement to an existing wired network.
The U.S. Army first used radio signals for data transmission during Word War II more than 50 years ago. The army developed a radio data transmission technology, SIGSALY, which was heavily encrypted.
The mere existence of the capabilities to conduct secure wireless communications was kept classified until 1976. The army filed close to 80 patents, but these were also kept secret.
These were used quite extensively throughout the campaign by the United States and its allies. As the 1970s approached, computer capabilities were becoming cheaper and spreading rapidly in academic institutions.
The scientists working with these computers saw that, to enable them to share their research data, their computers needed to be able to communicate with each other. Around this same time ARPANET was slowly adding more nodes to its network.
This technology inspired a group of researchers in 1971 at the University of Hawaii to connect with ARPANET; unfortunately or fortunately the geography of Hawaiian Islands presented a challenge for connecting the computers, since this networking required wired connections, which was a monumental task considering that some of these nodes were on different islands.
To overcome this challenge, they created the first packet−based radio communications network. ALOHAnet, as it was named, was essentially the very first wireless LAN. With this, wireless networking was born.
This first wireless LAN consisted of seven computers on four islands communicating with the central computer on the Oahu Island in a bidirectional star topology.
A bidirectional star topology configuration consists of systems that are connected to a central system known as a hub, and they can send and receive data at the same time.
In Europe, a Swedish scientist named Östen Mäkitalo, also known as "Mr. Mobile," is considered the brain behind the first wireless network.
Östen was working as the research and development director of Sweden's national telephone company, Televerket (Telia), when he was asked to develop a common system for connecting the mobile phones in all of the Scandinavian countries.
He brought in research teams from Denmark, Norway, and Finland and created the Nordic Mobile Telephone (NMT) system, which was launched in 1981. As personal computers became more pervasive during the 1980s and 1990s, the demand to connect them wirelessly grew.
Initially, vendors such as IBM, Digital Equipment Corporation (DEC), and Symbol Technologies offered proprietary solutions to their customers. Almost all the vendors were under pressure to create more interoperable technologies.
In 1997, the Institute of Electrical and Electronics Engineers (IEEE) drafted the 802.11 standard for wireless local area networking. The basic concepts of 802.11 were based upon Ethernet, which by this time had become the de facto standard for wired LANs.
The initial 802.11 standard had left several key questions such as the encoding schemes up to each vendor's discretion, which resulted in the development of incompatible equipment. 802.11 was also limited to a 2−megabits−per−second transmission rate.
During this time several advances in direct−sequence spread spectrum (DSSS) technology and relaxation of FCC rules allowed the IEEE to draft the 802.11b standard in 1999, which was accepted by the networking industry, and products for wireless networking over the 2.4−GHz frequency entered the market.
Initially, 802.11 standard−based wireless LANs operated at 1 megabit per second (Mbps). Eventually, 802.11b—also known as wireless fidelity, or Wi-Fi, or 802.11 high rate, which is a modified version of the 802.11 standard—operated at 11 Mbps.
Today, higher speeds are being achieved through newer standards, optimized usage of wireless communication methods, and improvement in computer hardware.
Fortunately, the wireless LAN industry has matured enough to accept the need of standards, and IEEE is doing a great job of establishing standards in the wireless arena.
