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Definition: WiFi Internet Access

WiFi actually began as wireless local area networks (WLANs). Many Information Technology (IT) professionals dreamed up WLANs to make administration of moving personnel around in corporate business environments easier. In addition, the technology allowed staff to stay connected to their corporate networks as they roamed from one meeting to the next, regardless of where they were located on corporate campus.

This was about the same time that cell phones were starting to make their way into the business world. For the first time, employees were beginning to understand the benefits of instantaneous communications.

It didn't take long before corporate executives longed to take their high-speed connections home with them. The only problem was that residential locations didnt have DSL or cable modems. The only thing available was ISDN or a T1 line, which usually ran in the $1,000 per month price range.

Originally designed as an indoor solution, some enterprising engineers began putting wireless radios in a weather proof box and putting them in an elevated position so that they could share their bandwidth and the cost of their T1 with neighbors. This was the beginning of the wireless industry as we know it today.

One major problem that affected the wireless industry in the beginning was the lack of wireless standards that ensured all wireless networking equipment could be used in any wireless network. Members of the IEEE created an organization called the Wi-Fi Alliance, which began marketing WiFi under a unified brand and set of industry standards. The Wi-Fi Alliance's work paved the way for wireless networks that now cover the entire world.

WiFi provides an amazing amount of wireless bandwidth, which can support voice, video and data applications.

Common uses for WiFi now include high-speed wirelesss Internet accesss, wireless VoIP phone calls, wireless gaming, wireless video surveillance and wireless network connectivity for a wide variety of consumer electronics such as televisions, DVD players, and digital cameras.

More than likely, WiFi and its newer cousin, WiMAX, will continue to permeate the world until the technology becomes more ubiquitous than wireless cell phones, which are limited to less than 100-200 Kbps of wireless bandwidth. New Internet access devices such as Apple's iPhone will demand more bandwidth (1-5Mbps) than 3G networks can deliver. The 3G wireless carriers will either embrace WiFi's higher speed connections or their networks will become about as useful as a network of payphones.

Locating a Public WiFi Hotspot with High-Speed Internet Access

There are more than 250,000 public Internet WiFi hotspots where users can get free or fee-based wireless Internet access. This does not include the nearly 10 million residential and business wireless access points and wireless routers that are attached to a DSL or cable modem broadband connection. Turn on a laptop in an airport, bus station, shopping mall, apartment complex, residential neighborhood, franchise restaurant, truck stop or hotel and you are almost guaranteed to find a WiFi Internet access point that will provide users with wireless high-speed Internet access.

If you are searching for a public WiFi hotspot or Internet access point, you can find one quickly by searching BWE's Directory of Public WiFi Internet Hotspots to find a high-speed wireless Internet connection near you.

WiFi Table of Contents

What is WiFi? How does it work?

Evolution of WiFi standards

WiFi technology has gone through numerous generations since its inception in 1997. Reviewing the standards is like alphabet soup and doesnt allows progress in logical order. Please review the standards below.

802.11

The original version of the standard IEEE 802.11 released in 1997 specifies two raw data rates of 1 and 2 megabits per second (Mbps) to be transmitted via infrared (IR) signals or by either frequency hopping or direct-sequence spread spectrum in the Industrial Scientific Medical frequency band at 2.4 GHz. IR remains a part of the standard but has no actual implementations.

802.11a.

The 802.11a amendment to the original standard was ratified in 1999. The 802.11a standard uses the same core protocol as the original standard and yields realistic throughput in the mid-20 Mbps. Since the 2.4 GHz band is heavily used, using the 5 GHz band gives 802.11a the advantage of less interference. However, this high carrier frequency also brings disadvantages. It restricts the use of 802.11a to almost line of sight, necessitating the use of more access points.

802.11b.

The 802.11b amendment to the original standard was ratified in 1999. 802.11b has a maximum raw data rate of 11 Mbps and uses the same CSMA/CA media access method defined in the original standard. The dramatic increase in throughput of 802.11b (compared to the original standard) along with substantial price reductions led to the rapid acceptance of 802.11b as the definitive wireless LAN technology.

802.11g.

In June 2003, a third standard was ratified: 802.11g. This works in the 2.4 GHz band (like 802.11b) but operates at a maximum raw data rate of 54 Mbps, or about 24.7 Mbps net throughputs (like 802.11a). Despite its major acceptance, 802.11g suffers from the same interference as 802.11b in the already crowded 2.4 GHz range. Devices operating in this range include microwave ovens, Bluetooth devices, and cordless telephones.

802.11n.

802.11n builds upon previous standards by adding MIMO (multiple-input multiple-output). MIMO uses multiple transmitter and receiver antennas to allow for increased data throughput through spatial multiplexing and increased range by exploiting the spatial diversity, through coding. On January 19, 2007, the IEEE 802.11 Working Group unanimously approved 802.11n to issue a new Draft 2.0 of the proposed standard.

WiFi: How it Works

WiFi networks use radio technologies called IEEE 802.11 to provide secure, reliable, fast wireless connectivity. A typical WiFi setup contains one or more Access Points (APs) and one or more clients. An AP broadcasts its SSID (Service Set Identifier, "Network name") via packets that are called beacons, which are usually broadcast every 100 ms. The beacons are transmitted at 1 Mbit/s, and are of relatively short duration and therefore do not have a significant effect on performance. Since 1 Mbit/s is the lowest rate of WiFi it assures that the client that receives the beacon can communicate at at least 1 Mbit/s. Based on the settings (e.g. the SSID), the client may decide whether to connect to an AP. If two APs of the same SSID are in range of the client, the client firmware might use signal strength to decide with which of the two APs to make a connection.

The WiFi standard leaves connection criteria and roaming totally open to the client. This is a strength of WiFi, but also means that one wireless adapter may perform substantially better than another. Since WiFi transmits in the air, it has the same properties as a non-switched wired Ethernet network, and therefore collisions can occur. Unlike a wired Ethernet, and like most packet radios, WiFi cannot do collision detection, and instead uses an acknowledgment packet for every data packet sent. If no acknowledgement is received within a certain time a retransmission occurs. Also, a medium reservation protocol can be used when excessive collisions are experienced or expected (RequestToSend/ClearToSend used for Collision Avoidance or CA) in an attempt to try to avoid collisions.

A WiFi network can be used to connect computers to each other to the internet and to wired networks (which use IEEE 802.3 or Ethernet). WiFi networks operate in the unlicensed 2.4 (802.11b/g) and 5 GHz (802.11a/h) radio bands, with an 11 Mbit/s (802.11b) or 54 Mbit/s (802.11a or g) data rate or with products that contain both bands (dual band). They can provide real world performance similar to the basic 10BaseT wired Ethernet networks.

WiFi's Wireless Sub-Channels

Except for 802.11a/h, which operates at 5 GHz, WiFi devices historically primarily use the spectrum in 2.4 GHz, which is standardized and unlicensed by international agreement, although the exact frequency allocations and maximum permitted power vary slightly in different parts of the world. Channel numbers, however, are standardized by frequency throughout the world, so authorized frequencies can be identified by channel numbers. The 2.4 GHz band is also used by microwave ovens, cordless phones, baby monitors and Bluetooth devices.

The maximum number of available channels for WiFi enabled devices are:

  • 13 for Europe. A typical channel layout for 802.11b would be 1/7/13 (or 1/6/11 for compatibility to devices bought in North America). For traffic that is predominantly 802.11g, 1/5/9/13 provides a fourth frequency enabling a much better frequency plan.
  • 11 for North America. Only channels 1, 6, and 11 are recommended for 802.11b/g to minimize interference from adjacent channels.[1]
  • 14 for Japan [2]

WiFi Uses

A person with a WiFi enabled device such as a PC, cell phone or PDA can connect to the Internet when in proximity of an access point. The region covered by one or several access points is called a hotspot. Hotspots can range from a single room to many square miles of overlapping hotspots. WiFi can also be used to create a mesh network. Both architectures are used in community networks.[citation needed]

WiFi also allows connectivity in peer-to-peer (wireless ad-hoc network) mode, which enables devices to connect directly with each other. This connectivity mode is useful in consumer electronics and gaming applications.

When the technology was first commercialized there were many problems because consumers could not be sure that products from different vendors would work together. The WiFi Alliance began as a community to solve this issue so as to address the needs of the end user and allow the technology to mature. The Alliance created the branding WiFi CERTIFIED to show consumers that products are interoperable with other products displaying the same branding.

WiFi at home

Home WiFi clients come in many shapes and sizes, from stationary PCs to digital cameras. The trend today is to incorporate wireless into every electronic where mobility is desired.

WiFi devices in home or consumer-type environments connect in the following ways:

Via a broadband Internet connection into a single router which can serve both wired and wireless clients Ad-hoc mode for client to client connections Built into non-computer devices to enable wireless connectivity to other devices or the Internet

WiFi in Business

Business and industrial WiFi has taken off, with the trends in implementation varying greatly over the years. Current technology trends in the corporate wireless world are:

Dramatically increasing the number of WiFi Access Points in an environment, in order to provide redundancy,support fast roaming and increasing overall network capacity by using more channels and/or creating smaller cells

Designing for wireless voice applications (VoWLAN or WVOIP)

Moving toward 'thin' Access Points, with more of the network intelligence housed in a centralized network appliance; relegating individual Access Points to be simply 'dumb' radios

Outdoor applications utilizing true mesh topologies

A proactive, self-managed network that functions as a security gateway, firewall, DHCP server, intrusion detection system, and a myriad of other features not previously considered relevant to a wireless network.

WiFi at Hotspots

The most publicly visible use of WiFi is at hotspots. These trends include:

Free WiFi at venues like Panera Bread, It's a Grind Coffee House, and over 100,000 locations in the USA has been growing in popularity. According to a door-to-door survey in San Jose, CA, the number of venues and users is growing fast. Paid WiFi at venues like Starbucks, McDonalds, and at hotels. This trend is growing rapidly at venues that require a higher rate of customer churn, such as sit-down restaurants.[citation needed] According to Muni Wireless, metropolitan-wide WiFi (Mu-Fi) already has more than 300 projects in process.

WiFi Advantages

Wireless Internet on the beach, Taba, EgyptAllows LANs to be deployed without cabling for client devices, typically reducing the costs of network deployment and expansion.

Spaces where cables cannot be run, such as outdoor areas and historical buildings, can host wireless LANs.

Built into most modern laptops, getting a laptop without a built in WiFi has become an exception.

WiFi chipset pricing continues to come down, making WiFi a very economical networking option and driving inclusion of WiFi in an ever-widening array of devices.

WiFi products are widely available in the market. Different competitive brands of access points and client network interfaces are inter-operable at a basic level of service. Products designated as WiFi CERTIFIED by the WiFi Alliance are backwards inter-operable.

WiFi is a global set of standards. Unlike cellular carriers, the same WiFi client works in different countries around the world.

Widely available in more than 250,000 public hot spots and tens of millions of homes and corporate and university campuses worldwide.

As of 2007, WPA is not easily cracked if strong passwords are used and WPA2 encryption has no known weaknesses.

New protocols for Quality of Service (WMM) and power saving mechanisms (WMM Power Save) make WiFi even more suitable for latency-sensitive applications (such as voice and video) and small Form-Factor

WiFi Disadvantages of WiFi

Spectrum assignments and operational limitations are not consistent worldwide; most of Europe allows for an additional 2 channels beyond those permitted in the US (1-13 vs 1-11); Japan has one more on top of that (1-14) - and some countries, like Spain, prohibited use of the lower-numbered channels (note that Europe, as of 2007, is now essentially homogeneous in this respect). Furthermore some countries, such as Italy, used to require a 'general authorization' for any WiFi used outside an operator's own premises, or require something akin to an operator registration.[citation needed]

Equivalent isotropically radiated power (EIRP) in the EU is limited to 20 dBm (0.1 W).

Power consumption is fairly high compared to some other low bandwidth standards (Zigbee and Bluetooth), making battery life a concern.

The most common wireless encryption standard, Wired Equivalent Privacy or WEP, has been shown to be easily breakable even when correctly configured. WiFi Protected Access (WPA and WPA2) which began shipping in 2003 aims to solve this problem and is now available on most products. WiFi Access Points typically default to an open (encryption-free) mode. Novice users benefit from a zero configuration device that works out of the box but without security enabled providing open wireless access to their LAN. To turn security on requires the user to configure the device, usually via a software GUI. Many 2.4 GHz 802.11b and 802.11g Access points default to the same channel on initial start up, contributing to congestion on certain channels. To change the channel of operation for an access point requires the user to configure the device. WiFi networks have limited range. A typical WiFi home router using 802.11b or 802.11g with a stock antenna might have a range of 45 m (150 ft) indoors and 90 m (300 ft) outdoors. Range also varies with frequency band. WiFi in the 2.4 GHz frequency block has slightly better range than WiFi in the 5 GHz frequency block. Outdoor range with improved antennas can be several kilometres or more with line-of-sight. WiFi pollution, of an excessive number of an access point with other access points in the area, especially on the same or neighboring channel, can prevent access and interfere with the use of other access points by others caused by overlapping channels in the 802.11g/b spectrum as well as with decreased signal-to-noise ratio (SNR) between access points. This can be a problem in high-density areas such as large apartment complexes or office buildings with many WiFi access points. Additionally, other devices use the 2.4 GHz band: microwave ovens, cordless phones, baby monitors, security cameras, and Bluetooth devices can cause significant additional interference. It is also an issue when municipalities[3] or other large entities such as universities seek to provide large area coverage. Everyone is considered equal for the base standard without 802.11e/WMM when they use the band. This openness is also important to the success and widespread use of 2.4 GHz WiFi, but makes it unsuitable for "must have" public service functions or where reliability is required. Users sometimes suffer network "frustrations" or a total network breakdown if gaming because a neighbour microwaves some pop corn. Interoperability issues between brands or proprietary deviations from the standard can disrupt connections or lower throughput speeds on other user's devices that are within range. And, WiFi devices do not presently pick channels to avoid interference. WiFi networks that are open (unencrypted) can be monitored and used to read and copy data (including personal information) transmitted over the network unless another security method is used to secure the data like a VPN or a secure web page. (HTTPS/Secure Socket Layer)

WiFi Standard Devices

WiFi Wireless Access Point (WAP)

Main article: Wireless access point

A wireless access point connects a group of wireless devices to an adjacent wired LAN. An access point is similar to an ethernet hub, relaying data between connected wireless devices in addition to a (usually) single connected wired device, most often an ethernet hub or switch, allowing wireless devices to communicate with other wired devices.

WiFi Wireless Adapter

A wireless adapter allows a device to connect to a wireless network. These adapters connect to devices using various external or internal interconnects such as PCI, miniPCI, USB, ExpressCard, Cardbus and PC card. Most newer laptop computers are equipped with internal adapters. Internal cards are generally more difficult to install.

WiFi Wireless Router

A wireless router integrates a WAP, ethernet switch, and internal Router firmware application that provides IP Routing, NAT, and DNS forwarding through an integrated WAN interface. A wireless router allows wired and wireless ethernet LAN devices to connect to a (usually) single WAN device such as cable modem or DSL modem. A wireless router allows all three devices (mainly the access point and router) to be configured through one central utility. This utility is most usually an integrated web server which serves web pages to wired and wireless LAN clients and often optionally to WAN clients. This utility may also be an application that is run on a desktop computer such as Apple's AirPort.

WiFi Wireless Ethernet Bridge

A wireless Ethernet bridge connects a wired network to a wireless network. This is different from an access point in the sense that an access point connects wireless devices to a wired network at the data-link layer. Two wireless bridges may be used to connect two wired networks over a wireless link, useful in situations where a wired connection may be unavailable, such as between two separate homes.

WiFi Repeater for Extended Range

A wireless range extender or wireless repeater can extend the range of an existing wireless network. Range extenders can be strategically placed to elongate a signal area or allow for the signal area to reach around barriers such as those created in L-shaped corridors. Wireless devices connected through repeaters will suffer from an increased latency for each hop. Additionally, a wireless device at the end of chain of wireless repeaters will have a throughput that is limited by the weakest link within the repeater chain.

WiFi Antenna connectors

Most commercial devices (routers, access points, bridges, repeaters) designed for home or business environments use either RP-SMA or RP-TNC antenna connectors. PCI wireless adapters also mainly use RP-SMA connectors.

Most PC card and USB wireless only have internal antennas etched on their printed circuit board while some have MMCX connector or MC-Card external connections in addition to an internal antenna. A few USB cards have a RP-SMA connector.

Most Mini PCI wireless cards utilize Hirose U.FL connectors, but cards found in various wireless appliances contain all of the connectors listed.

Many high-gain (and homebuilt antennas) utilize the Type N connector more commonly used by other radio communications methods.

WiFi Non-Standard Devices

WiFi DIY Range Optimizations

USB-WiFi adapters, food container "Cantennas", parabolic reflectors, and many other types of self-built antennae are increasingly made by do-it-yourselvers. For minimal budgets, as low as a few dollars, signal strength and range can be improved dramatically. There is also a type of optimization by polarizing the signal to achieve a planar coverage like a plate. Many of these high-gain aftermarket modifications are technically illegal under FCC and other regulatory guidelines.

WiFi Long Range WiFi

For more details on this topic, see Long Range WiFi. Recently, long range WiFi kits have begun to enter the market. Companies like RadioLabs and BroadbandXpress offer long range, inexpensive kits that can be setup with limited knowledge. These kits utilize specialized antennas which increase the range of WiFi dramatically, in the case of the world record 137.2 miles (220 km). These kits are commonly used to get Broadband internet to a place that cannot access the service itself.[4]

The longest link ever achieved was by the Swedish space agency. They attained 310 km, but used 6 watt amplifiers to reach an overhead stratospheric balloon.

The longest link without amplification was 279 km in Venezuela, 2006 Read PDF by www.eslared.org

WiFi Manufacturers

There are many vendors now manufacturing and selling 802.11n products. They include:

  • Acer
  • Airgo Networks
  • Apple
  • Asus
  • Atheros
  • Broadcom
  • Buffalo Technology
  • Dell
  • Intel
  • Linksys
  • Netgear
  • U.S. Robotics
  • Valuepoint

WiFi Embedded systems

WiFi availability in the home is on the increase. This extension of the Internet into the home space will increasingly be used for remote monitoring. Examples of remote monitoring include security systems and tele-medicine. In all these kinds of implementation, if the WiFi provision is provided using a system running one of operating systems mentioned above, then it becomes unfeasible due to weight, power consumption and cost issues.

Increasingly in the last few years (particularly as of early 2007), embedded WiFi modules have become available which come with a real-time operating system and provide a simple means of wireless enabling any device which has and communicates via a serial port.

This allows simple monitoring devices, for example a portable ecg monitor hooked up to a patient in the home, to be created. This WiFi enabled device effectively becomes part of the internet cloud and can communicate with any other node on the internet. The data collected can hop via the home's WiFi access point to anywhere on the internet.

These WiFi modules are designed so that minimal WiFi knowledge is required by designers to wireless enable their product.

WiFi Media reports of health risks

The UK's Health Protection Agency considers there is no consistent evidence of harm from the low power transmissions of WiFi equipment, nevertheless their chairman, Sir William Stewart, stated that it is a sensible precaution to keep the situation under review.[7] Two media items (the latest in an episode of the current affairs television program Panorama in May 2007) reported that schools and families have been removing their WiFi systems as a result.[1] Individual anecdotes of deleterious effects which ceased upon removal of the systems have also been reported including headaches and lethargy.[1]. Consensus amongst scientists is that there is no evidence of harm, and the continuing calls for more research into the effects on human health remain limited. Thirty-seven studies have already been conducted that do not show a causal relationship.[1][2]

WiFi History

WiFi uses both single carrier direct-sequence spread spectrum radio technology (part of the larger family of spread spectrum systems) and multi-carrier OFDM (Orthogonal Frequency Division Multiplexing) radio technology. These regulations then enabled the development of WiFi, its onetime competitor HomeRF, and Bluetooth.

Unlicensed spread spectrum was first made available by the Federal Communications Commission in 1985 and these FCC regulations were later copied with some changes in many other countries enabling use of this technology in all major countries.[8] The FCC action was proposed by Michael Marcus of the FCC staff in 1980 and the subsequent controversial regulatory action took 5 more years. It was part of a broader proposal to allow civil use of spread spectrum technology and was opposed at the time by main stream equipment manufacturers and many radio system operators.

The precursor to WiFi was invented in 1991 by NCR Corporation/AT&T (later Lucent & Agere Systems) in Nieuwegein, the Netherlands. It was initially intended for cashier systems; the first wireless products were brought on the market under the name WaveLAN with speeds of 1 Mbit/s to 2 Mbit/s. Vic Hayes, who held the chair of IEEE 802.11 for 10 years and has been named the 'father of WiFi,' was involved in designing standards such as IEEE 802.11b, 802.11a and 802.11g.

WiFi Origin and meaning of the term 'WiFi'

Despite the similarity between the terms 'WiFi' and 'Hi-Fi', statements reportedly made by Phil Belanger of the WiFi Alliance contradict the popular conclusion that 'WiFi' stands for 'Wireless Fidelity.'[9] According to Mr. Belanger, the Interbrand Corporation developed the brand 'WiFi' for the WiFi Alliance to use to describe WLAN products that are based on the IEEE 802.11 standards. In Mr. Belanger's words, "WiFi and the yin yang style logo were invented by Interbrand. We [the founding members of the Wireless Ethernet Compatibility Alliance, now called the WiFi Alliance] hired Interbrand to come up with the name and logo that we could use for our interoperability seal and marketing efforts. We needed something that was a little catchier than 'IEEE 802.11b Direct Sequence'."


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