IEEE 802.11d-2001 or 802.11d, is an amendment to the IEEE 802.11 specification that adds support for "additional regulatory domains". This support includes the addition of a country information element to beacons, probe requests, and probe responses. The country information elements simplifies the creation of 802.11 wireless access points and client devices that meet the different regulations enforced in various parts of the world. The amendment has been incorporated into the published IEEE 802.11-2007 standard.
802.11 is a set of IEEE standards that govern wireless networking transmission methods. They are commonly used today in their 802.11a, 802.11b, and 802.11g versions to provide wireless connectivity in the home, office and some commercial establishments.
802.11d is a wireless specification for operation in additional regulatory domains. This supplement to the 802.11 specifications defines the physical layer requirements: • Channelization • Hopping patterns • New values for current MIB attributes • Future requirements to extend the operation of 802.11 WLANs to new regulatory domains (countries).
The current 802.11 standard defines operation in only a few regulatory domains (countries). This supplement adds the requirements and definitions necessary to allow 802.11 WLAN equipment to operate in markets not served by the current standard. Enable the 802.11d feature/option if you are operating in one of these "additional regulatory domains
Thursday, May 21, 2009
Frame aggregation
Frame aggregation is a feature of the IEEE 802.11e and 802.11n wireless LAN standards that increases throughput by sending two or more data frames in a single transmission.
Every frame transmitted by an 802.11 device has a significant amount of overhead, including radio level headers, media access control (MAC) frame fields, interframe spacing, and acknowledgment of transmitted frames. At the highest data rates, this overhead can consume more bandwidth than the payload data frame.[1] To address this issue, the draft 802.11n standard defines two types of frame aggregation: Mac Service Data Unit (MSDU) aggregation and Message Protocol Data Unit (MPDU) aggregation. Both types group several data frames into one large frame. Because management information needs to be specified only once per frame, the ratio of payload data to the total volume of data is higher, allowing higher throughput.
Every frame transmitted by an 802.11 device has a significant amount of overhead, including radio level headers, media access control (MAC) frame fields, interframe spacing, and acknowledgment of transmitted frames. At the highest data rates, this overhead can consume more bandwidth than the payload data frame.[1] To address this issue, the draft 802.11n standard defines two types of frame aggregation: Mac Service Data Unit (MSDU) aggregation and Message Protocol Data Unit (MPDU) aggregation. Both types group several data frames into one large frame. Because management information needs to be specified only once per frame, the ratio of payload data to the total volume of data is higher, allowing higher throughput.
IEEE 802.11h
IEEE 802.11h-2003, or just 802.11h, refers to the amendment added to the IEEE 802.11 standard for Spectrum and Transmit Power Management Extensions. It solves problems like interference with satellites and radar using the same 5 GHz frequency band. It was originally designed to address European regulations but is now applicable in many other countries. The standard provides Dynamic Frequency Selection (DFS) and Transmit Power Control (TPC) to the 802.11a MAC. It has been integrated into the full IEEE 802.11-2007 standard.
IEEE 802.11 is a set of IEEE standards that govern wireless networking transmission methods. They are commonly used today in their 802.11a, 802.11b, and 802.11g versions to provide wireless connectivity in the home, office, and some commercial establishments
IEEE 802.11 is a set of IEEE standards that govern wireless networking transmission methods. They are commonly used today in their 802.11a, 802.11b, and 802.11g versions to provide wireless connectivity in the home, office, and some commercial establishments
IEEE 802.11i
IEEE 802.11i-2004 or 802.11i is an amendment to the original IEEE 802.11 standard specifying security mechanisms for wireless networks. It replaced the short Authentication and privacy clause of the original standard with a detailed Security clause, in the process deprecating the broken WEP. The amendment was later incorporated into the published IEEE 802.11-2007 standard.
The draft standard was ratified on 24 June 2004, and supersedes the previous security specification, Wired Equivalent Privacy (WEP), which was shown to have severe security weaknesses. Wi-Fi Protected Access (WPA) had previously been introduced by the Wi-Fi Alliance as an intermediate solution to WEP insecurities. WPA implemented a subset of 802.11i. The Wi-Fi Alliance refers to their approved, interoperable implementation of the full 802.11i as WPA2, also called RSN (Robust Security Network). 802.11i makes use of the Advanced Encryption Standard (AES) block cipher, whereas WEP and WPA use the RC4 stream cipher.
The 802.11i architecture contains the following components: 802.1X for authentication (entailing the use of EAP and an authentication server), RSN for keeping track of associations, and AES-based CCMP to provide confidentiality, integrity and origin authentication. Another important element of the authentication process is the four-way handshake, explained below
The draft standard was ratified on 24 June 2004, and supersedes the previous security specification, Wired Equivalent Privacy (WEP), which was shown to have severe security weaknesses. Wi-Fi Protected Access (WPA) had previously been introduced by the Wi-Fi Alliance as an intermediate solution to WEP insecurities. WPA implemented a subset of 802.11i. The Wi-Fi Alliance refers to their approved, interoperable implementation of the full 802.11i as WPA2, also called RSN (Robust Security Network). 802.11i makes use of the Advanced Encryption Standard (AES) block cipher, whereas WEP and WPA use the RC4 stream cipher.
The 802.11i architecture contains the following components: 802.1X for authentication (entailing the use of EAP and an authentication server), RSN for keeping track of associations, and AES-based CCMP to provide confidentiality, integrity and origin authentication. Another important element of the authentication process is the four-way handshake, explained below
IEEE 802.11k
IEEE 802.11k-2008 is an amendment to IEEE 802.11-2007 standard for radio resource management. It defines and exposes radio and network information to facilitate the management and maintenance of a mobile Wireless LAN.
IEEE 802.11k and 802.11r are the key industry standards now in development that will enable seamless Basic Service Set (BSS) transitions in the WLAN environment. The 802.11k standard provides information to discover the best available access point.
802.11k is intended to improve the way traffic is distributed within a network. In a wireless LAN, each device normally connects to the access point (AP) that provides the strongest signal. Depending on the number and geographic locations of the subscribers, this arrangement can sometimes lead to excessive demand on one AP and underutilization of others, resulting in degradation of overall network performance. In a network conforming to 802.11k, if the AP having the strongest signal is loaded to its full capacity, a wireless device is connected to one of the underutilized APs. Even though the signal may be weaker, the overall throughput is greater because more efficient use is made of the network resources
IEEE 802.11k and 802.11r are the key industry standards now in development that will enable seamless Basic Service Set (BSS) transitions in the WLAN environment. The 802.11k standard provides information to discover the best available access point.
802.11k is intended to improve the way traffic is distributed within a network. In a wireless LAN, each device normally connects to the access point (AP) that provides the strongest signal. Depending on the number and geographic locations of the subscribers, this arrangement can sometimes lead to excessive demand on one AP and underutilization of others, resulting in degradation of overall network performance. In a network conforming to 802.11k, if the AP having the strongest signal is loaded to its full capacity, a wireless device is connected to one of the underutilized APs. Even though the signal may be weaker, the overall throughput is greater because more efficient use is made of the network resources
IEEE 802.11j-2004
802.11j-2004 or 802.11j is an amendment to the IEEE 802.11 standard designed specially for Japanese market. It allows Wireless LAN operation in the 4.9 to 5 GHz band to conform to the Japanese rules for radio operation for indoor, outdoor and mobile applications. The amendment has been incorporated into the published IEEE 802.11-2007 standard.
802.11 is a set of IEEE standards that govern wireless networking transmission methods. They are commonly used today in their 802.11a, 802.11b, and 802.11g versions to provide wireless connectivity in the home, office and some commercial establishments.
802.11 is a set of IEEE standards that govern wireless networking transmission methods. They are commonly used today in their 802.11a, 802.11b, and 802.11g versions to provide wireless connectivity in the home, office and some commercial establishments.
IEEE 802.11w
IEEE 802.11w is a proposed amendment to the IEEE 802.11 standard to increase the security of its management frames.
802.11 is a set of IEEE standards that govern wireless networking transmission methods. They are commonly used today in their 802.11a, 802.11b, and 802.11g versions to provide wireless connectivity in the home, office and some commercial establishments.
Current 802.11x standards define "frame" types for use in management and control of wireless links. IEEE 802.11w is the Protected Management Frames standard for the IEEE 802.11 family of standards. TGw is working on improving the IEEE 802.11 Medium Access Control layer. The objective of this is to increase the security by providing data confidentiality of management frames, mechanisms that enable data integrity, data origin authenticity, and replay protection. These extensions will have interactions with IEEE 802.11r and IEEE 802.11u
Wireless LANs send system management information in unprotected frames, which makes them vulnerable. This standard will protect against network disruption caused by malicious systems that forge disassociation requests that appear to be sent by valid equipment
802.11 is a set of IEEE standards that govern wireless networking transmission methods. They are commonly used today in their 802.11a, 802.11b, and 802.11g versions to provide wireless connectivity in the home, office and some commercial establishments.
Current 802.11x standards define "frame" types for use in management and control of wireless links. IEEE 802.11w is the Protected Management Frames standard for the IEEE 802.11 family of standards. TGw is working on improving the IEEE 802.11 Medium Access Control layer. The objective of this is to increase the security by providing data confidentiality of management frames, mechanisms that enable data integrity, data origin authenticity, and replay protection. These extensions will have interactions with IEEE 802.11r and IEEE 802.11u
Wireless LANs send system management information in unprotected frames, which makes them vulnerable. This standard will protect against network disruption caused by malicious systems that forge disassociation requests that appear to be sent by valid equipment
Wi-Fi
Wi-Fi (pronounced /ˈwaɪfaɪ/) is a trademark of the Wi-Fi Alliance for certified products based on the IEEE 802.11 standards. This certification warrants interoperability between different wireless devices.
The term Wi-Fi is often used by the public as a synonym for wireless LAN (WLAN); but not every wireless LAN product has a Wi-Fi certification, which may be because of certification costs that must be paid for each certified device type.
Wi-Fi is supported by most personal computer operating systems, many game consoles, laptops, smartphones, printers, and other peripherals.
Spectrum assignments and operational limitations are not consistent worldwide. Most of Europe allows for an additional 2 channels beyond those permitted in the U.S. for the 2.4 GHz band. (1–13 vs. 1–11); Japan has one more on top of that (1–14). Europe, as of 2007, was essentially homogeneous in this respect. A very confusing aspect is the fact that a Wi-Fi signal actually occupies five channels in the 2.4 GHz band resulting in only three non-overlapped channels in the U.S.: 1, 6, 11, and three or four in Europe: 1, 5, 9, 13 can be used if all the equipment on a specific area can be guaranteed not to use 802.11b at all, even as fallback or beacon. Equivalent isotropically radiated power (EIRP) in the EU is limited to 20 dBm
The term Wi-Fi is often used by the public as a synonym for wireless LAN (WLAN); but not every wireless LAN product has a Wi-Fi certification, which may be because of certification costs that must be paid for each certified device type.
Wi-Fi is supported by most personal computer operating systems, many game consoles, laptops, smartphones, printers, and other peripherals.
Spectrum assignments and operational limitations are not consistent worldwide. Most of Europe allows for an additional 2 channels beyond those permitted in the U.S. for the 2.4 GHz band. (1–13 vs. 1–11); Japan has one more on top of that (1–14). Europe, as of 2007, was essentially homogeneous in this respect. A very confusing aspect is the fact that a Wi-Fi signal actually occupies five channels in the 2.4 GHz band resulting in only three non-overlapped channels in the U.S.: 1, 6, 11, and three or four in Europe: 1, 5, 9, 13 can be used if all the equipment on a specific area can be guaranteed not to use 802.11b at all, even as fallback or beacon. Equivalent isotropically radiated power (EIRP) in the EU is limited to 20 dBm
IEEE 802.11r
IEEE 802.11r-2008 or fast BSS transition (FT) is an amendment to the IEEE 802.11 standard to permit continuous connectivity aboard wireless devices in motion, with fast and secure handoffs from one base station to another managed in a seamless manner.
802.11, commonly referred to as Wi-Fi, is widely used for wireless communications. Many deployed implementations have effective ranges of only a few hundred meters, so to maintain communications devices in motion that use it will need to handoff from one access point to another. In an automotive environment, this could easily result in a handoff every five to ten seconds.
Handoffs are already supported under the preexisting standard. The fundamental architecture for handoffs is identical for 802.11 with and without 802.11r: the mobile device is entirely in charge of deciding when to hand off and to which access point it wishes to hand off. In the early days of 802.11, handoff was a much simpler task for the mobile device. Only four messages were required for the device to establish a connection with a new access point (five if you count the optional message the client could send to the old access point to inform it that it had left). However, as additional features were added to the standard, including 802.11i with 802.1X authentication and 802.11e or WMM with admission control requests, the number of messages required went up dramatically. During the time these additional messages are being exchanged, the mobile device's traffic, including that from voice calls, cannot proceed, and the user will hear loss approaching that of seconds.[1] Generally, the highest amount of delay or loss that the edge network should introduce into a voice call is 50 msec.
802.11r was launched to attempt to undo the added burden that security and quality of service added to the handoff process, and restore it back to the original four-message exchange. In this way, handoff problems are not eliminated, but at least are returned to the status quo.
The primary application currently envisioned for the 802.11r standard is VOIP ("voice over IP", or Internet-based telephony) via mobile phones designed to work with wireless Internet networks, instead of (or in addition to) standard cellular networks.
802.11, commonly referred to as Wi-Fi, is widely used for wireless communications. Many deployed implementations have effective ranges of only a few hundred meters, so to maintain communications devices in motion that use it will need to handoff from one access point to another. In an automotive environment, this could easily result in a handoff every five to ten seconds.
Handoffs are already supported under the preexisting standard. The fundamental architecture for handoffs is identical for 802.11 with and without 802.11r: the mobile device is entirely in charge of deciding when to hand off and to which access point it wishes to hand off. In the early days of 802.11, handoff was a much simpler task for the mobile device. Only four messages were required for the device to establish a connection with a new access point (five if you count the optional message the client could send to the old access point to inform it that it had left). However, as additional features were added to the standard, including 802.11i with 802.1X authentication and 802.11e or WMM with admission control requests, the number of messages required went up dramatically. During the time these additional messages are being exchanged, the mobile device's traffic, including that from voice calls, cannot proceed, and the user will hear loss approaching that of seconds.[1] Generally, the highest amount of delay or loss that the edge network should introduce into a voice call is 50 msec.
802.11r was launched to attempt to undo the added burden that security and quality of service added to the handoff process, and restore it back to the original four-message exchange. In this way, handoff problems are not eliminated, but at least are returned to the status quo.
The primary application currently envisioned for the 802.11r standard is VOIP ("voice over IP", or Internet-based telephony) via mobile phones designed to work with wireless Internet networks, instead of (or in addition to) standard cellular networks.
Inter-Access Point Protocol
IEEE 802.11F or Inter-Access Point Protocol is a recommendation that describes an optional extension to IEEE 802.11 that provides wireless access-point communications among multivendor systems . 802.11 is a set of IEEE standards that govern wireless networking transmission methods. They are commonly used today in their 802.11a, 802.11b, 802.11g and 802.11n versions to provide wireless connectivity in the home, office and some commercial establishments.
The IEEE 802.11 standard doesn't specify the communications between access points in order to support users roaming from one access point to another and load balancing. The 802.11 WG purposely didn't define this element in order to provide flexibility in working with different wired and wireless distribution systems (i.e., wired backbones that interconnect access points).
The IEEE 802.11 standard doesn't specify the communications between access points in order to support users roaming from one access point to another and load balancing. The 802.11 WG purposely didn't define this element in order to provide flexibility in working with different wired and wireless distribution systems (i.e., wired backbones that interconnect access points).
Channels and international compatibility
802.11 divides each of the above-described bands into channels, analogously to how radio and TV broadcast bands are carved up but with greater channel width and overlap. For example the 2.4000–2.4835 GHz band is divided into 13 channels each of width 22 MHz but spaced only 5 MHz apart, with channel 1 centred on 2.412 GHz and 13 on 2.472 GHz to which Japan adds a 14th channel 12 MHz above channel 13.
Availability of channels is regulated by country, constrained in part by how each country allocates radio spectrum to various services. At one extreme Japan permits the use of all 14 channels (with the exclusion of 802.11g/n from channel 14), while at the other Spain allowed only channels 10 and 11 (later all of the 14 channels have been allowed,and France that allowed only 10, 11, 12 and 13 (now channels 1 to 13 are allowed). Most other European countries are almost as liberal as Japan, disallowing only channel 14, while North America and some Central and South American countries further disallow 12 and 13. For more details on this topic, see List of WLAN channels.
Besides specifying the centre frequency of each channel, 802.11 also specifies (in Clause 17) a spectral mask defining the permitted distribution of power across each channel. The mask requires that the signal be attenuated by at least 30 dB from its peak energy at ±11 MHz from the centre frequency, the sense in which channels are effectively 22 MHz wide. One consequence is that stations can only use every fourth or fifth channel without overlap, typically 1, 6 and 11 in the Americas, 1, 5, 9 and 13 in Europe, etc. Another is that channels 1-13 effectively require the band 2.401–2.483 GHz, the actual allocations being, for example, 2.400–2.4835 GHz in the UK, 2.402–2.4835 GHz in the US, etc.
Since the spectral mask only defines power output restrictions up to ±22 MHz from the center frequency to be attenuated by 50 dB, it is often assumed that the energy of the channel extends no further than these limits. It is more correct to say that, given the separation between channels 1, 6, and 11, the signal on any channel should be sufficiently attenuated to minimally interfere with a transmitter on any other channel. Due to the near-far problem a transmitter can impact a receiver on a "non-overlapping" channel, but only if it is close to the victim receiver (within a meter) or operating above allowed power levels.
Although the statement that channels 1, 6, and 11 are "non-overlapping" is limited to spacing or product density, the 1–6–11 guideline has merit. If transmitters are closer together than channels 1, 6, and 11 (for example, 1, 4, 7, and 10), overlap between the channels may cause unacceptable degradation of signal quality and throughput.[11] However, overlapping channels may be used under certain circumstances. This way, more channels are available
Availability of channels is regulated by country, constrained in part by how each country allocates radio spectrum to various services. At one extreme Japan permits the use of all 14 channels (with the exclusion of 802.11g/n from channel 14), while at the other Spain allowed only channels 10 and 11 (later all of the 14 channels have been allowed,and France that allowed only 10, 11, 12 and 13 (now channels 1 to 13 are allowed). Most other European countries are almost as liberal as Japan, disallowing only channel 14, while North America and some Central and South American countries further disallow 12 and 13. For more details on this topic, see List of WLAN channels.
Besides specifying the centre frequency of each channel, 802.11 also specifies (in Clause 17) a spectral mask defining the permitted distribution of power across each channel. The mask requires that the signal be attenuated by at least 30 dB from its peak energy at ±11 MHz from the centre frequency, the sense in which channels are effectively 22 MHz wide. One consequence is that stations can only use every fourth or fifth channel without overlap, typically 1, 6 and 11 in the Americas, 1, 5, 9 and 13 in Europe, etc. Another is that channels 1-13 effectively require the band 2.401–2.483 GHz, the actual allocations being, for example, 2.400–2.4835 GHz in the UK, 2.402–2.4835 GHz in the US, etc.
Since the spectral mask only defines power output restrictions up to ±22 MHz from the center frequency to be attenuated by 50 dB, it is often assumed that the energy of the channel extends no further than these limits. It is more correct to say that, given the separation between channels 1, 6, and 11, the signal on any channel should be sufficiently attenuated to minimally interfere with a transmitter on any other channel. Due to the near-far problem a transmitter can impact a receiver on a "non-overlapping" channel, but only if it is close to the victim receiver (within a meter) or operating above allowed power levels.
Although the statement that channels 1, 6, and 11 are "non-overlapping" is limited to spacing or product density, the 1–6–11 guideline has merit. If transmitters are closer together than channels 1, 6, and 11 (for example, 1, 4, 7, and 10), overlap between the channels may cause unacceptable degradation of signal quality and throughput.[11] However, overlapping channels may be used under certain circumstances. This way, more channels are available
IEEE 802.11y
IEEE 802.11y-2008 is an amendment to the IEEE 802.11-2007 standard that will enable high powered Wi-Fi equipment to operate on a co-primary basis in the 3650 to 3700 MHz band in the United States, except when near a grandfathered satellite earth station. It was approved for publication by the IEEE on September 26, 2008.
The US 3650 MHz rules allow for registered stations to operate at much higher power than traditional Wi-Fi gear (Up to 20 watts equivalent isotropically radiated power). The combination of higher power limits and enhancements made to the MAC timing in 802.11-2007, will allow for the development of standards based 802.11 devices that could operate at distances of 5 kilometres (3 mi) or more.
IEEE 802.11y adds three new concepts to 802.11-2007 base Standard:
Contention based protocol (CBP)- enhancements have been made to the carrier sensing and energy detection mechanisms of 802.11 in order to meet the FCC's requirements for a contention based protocol.
Extended channel switch announcement (ECSA)- provides a mechanism for an access point to notify the stations connected to it of its intention to change channels or to change channel bandwidth. This mechanism will allow for the WLAN to continuously choose the channel that is the least noisy and the least likely to cause interference. ECSA also provides for other functionalities besides dynamic channel selection based on quality & noise characteristics.
For instance, in 802.11y Amendment, the licensed operator can send ECSA commands to any stations operating under their control, registered or unregistered. ECSA is also used in 802.11n. In the 802.11n D2.0 implementation (which is shipping & undergoes Wi-Fi Alliance testing) 20MHz & 40MHz channel switching is provided for by the 11n PHY's ECSA implementation. Note that 802.11n is specified for operation in the 2.4GHz and 5GHz license exempt bands--but future amendments could permit 11n's PHY to operate in other bands as well.
Dependent station enablement (DSE)- is the mechanism by which an operator extends and retracts permission to license exempt devices (referred to as dependent STAs in .11y) to use licensed radio spectrum. Fundamentally, this process satisfies a regulatory requirement that dictates that a dependent STAs operation is contingent upon its ability to receive periodic messages from a licensees base station, but DSE is extensible to other purposes in regards to channel management and coordination.
The US 3650 MHz rules allow for registered stations to operate at much higher power than traditional Wi-Fi gear (Up to 20 watts equivalent isotropically radiated power). The combination of higher power limits and enhancements made to the MAC timing in 802.11-2007, will allow for the development of standards based 802.11 devices that could operate at distances of 5 kilometres (3 mi) or more.
IEEE 802.11y adds three new concepts to 802.11-2007 base Standard:
Contention based protocol (CBP)- enhancements have been made to the carrier sensing and energy detection mechanisms of 802.11 in order to meet the FCC's requirements for a contention based protocol.
Extended channel switch announcement (ECSA)- provides a mechanism for an access point to notify the stations connected to it of its intention to change channels or to change channel bandwidth. This mechanism will allow for the WLAN to continuously choose the channel that is the least noisy and the least likely to cause interference. ECSA also provides for other functionalities besides dynamic channel selection based on quality & noise characteristics.
For instance, in 802.11y Amendment, the licensed operator can send ECSA commands to any stations operating under their control, registered or unregistered. ECSA is also used in 802.11n. In the 802.11n D2.0 implementation (which is shipping & undergoes Wi-Fi Alliance testing) 20MHz & 40MHz channel switching is provided for by the 11n PHY's ECSA implementation. Note that 802.11n is specified for operation in the 2.4GHz and 5GHz license exempt bands--but future amendments could permit 11n's PHY to operate in other bands as well.
Dependent station enablement (DSE)- is the mechanism by which an operator extends and retracts permission to license exempt devices (referred to as dependent STAs in .11y) to use licensed radio spectrum. Fundamentally, this process satisfies a regulatory requirement that dictates that a dependent STAs operation is contingent upon its ability to receive periodic messages from a licensees base station, but DSE is extensible to other purposes in regards to channel management and coordination.
IEEE 802.11k-2008
IEEE 802.11k-2008 is an amendment to IEEE 802.11-2007 standard for radio resource management. It defines and exposes radio and network information to facilitate the management and maintenance of a mobile Wireless LAN.
IEEE 802.11k and 802.11r are the key industry standards now in development that will enable seamless Basic Service Set (BSS) transitions in the WLAN environment. The 802.11k standard provides information to discover the best available access point.
802.11k is intended to improve the way traffic is distributed within a network. In a wireless LAN, each device normally connects to the access point (AP) that provides the strongest signal. Depending on the number and geographic locations of the subscribers, this arrangement can sometimes lead to excessive demand on one AP and underutilization of others, resulting in degradation of overall network performance. In a network conforming to 802.11k, if the AP having the strongest signal is loaded to its full capacity, a wireless device is connected to one of the underutilized APs. Even though the signal may be weaker, the overall throughput is greater because more efficient use is made of the network resources.
IEEE 802.11k and 802.11r are the key industry standards now in development that will enable seamless Basic Service Set (BSS) transitions in the WLAN environment. The 802.11k standard provides information to discover the best available access point.
802.11k is intended to improve the way traffic is distributed within a network. In a wireless LAN, each device normally connects to the access point (AP) that provides the strongest signal. Depending on the number and geographic locations of the subscribers, this arrangement can sometimes lead to excessive demand on one AP and underutilization of others, resulting in degradation of overall network performance. In a network conforming to 802.11k, if the AP having the strongest signal is loaded to its full capacity, a wireless device is connected to one of the underutilized APs. Even though the signal may be weaker, the overall throughput is greater because more efficient use is made of the network resources.
IEEE 802.11v
802.11v is the Wireless Network Management standard for the IEEE 802.11 family of standards. TGv is working on an amendment to the 802.11 standard to allow configuration of client devices while connected to IEEE 802.11 networks. The standard may include cellular-like management paradigms
IEEE 802.11p
IEEE 802.11p is a draft amendment to the IEEE 802.11 standard to add wireless access in vehicular environments (WAVE). It defines enhancements to 802.11 required to support Intelligent Transportation Systems (ITS) applications. This includes data exchange between high-speed vehicles and between the vehicles and the roadside infrastructure in the licensed ITS band of 5.9 GHz (5.85-5.925 GHz). IEEE 1609 is a higher layer standard on which IEEE 802.11p is based.
802.11p will be used as the groundwork for Dedicated Short Range Communications (DSRC), a U.S. Department of Transportation project based on the ISO Communications, Air-interface, Long and Medium range (CALM) architecture standard looking at vehicle-based communication networks, particularly for applications such as toll collection, vehicle safety services, and commerce transactions via cars. The ultimate vision is a nationwide network that enables communications between vehicles and roadside access points or other vehicles. This work builds on its predecessor ASTM E2213-03.
802.11p will be used as the groundwork for Dedicated Short Range Communications (DSRC), a U.S. Department of Transportation project based on the ISO Communications, Air-interface, Long and Medium range (CALM) architecture standard looking at vehicle-based communication networks, particularly for applications such as toll collection, vehicle safety services, and commerce transactions via cars. The ultimate vision is a nationwide network that enables communications between vehicles and roadside access points or other vehicles. This work builds on its predecessor ASTM E2213-03.
IEEE 802.11u
IEEE 802.11u is a proposed amendment to the IEEE 802.11-2007 standard to add features that improve interworking with external networks.
802.11 is an IEEE standard that allows devices such as laptop computers or cellular phones to join a wireless LAN widely used in the home, office and some commercial establishments.
IEEE 802.11 currently makes an assumption that a user is pre-authorised to use the network. IEEE 802.11u covers the cases where user is not pre-authorised. A network will be able to allow access based on the user's relationship with an external network (e.g. hotspot roaming agreements), or indicate that online enrollment is possible, or allow access to a strictly limited set of services such as emergency services (client to authority and authority to client.)
From a user perspective, the aim is to improve the experience of a traveling user who turns on a laptop in a hotel many miles from home. Instead of being presented with a long list of largely meaningless SSIDs the user could be presented with a list of networks, the services they provide, and the conditions under which the user could access them.
The IEEE 802.11u Proposal Requirements Specification contains requirements in the areas of enrollment, network selection, emergency call support, emergency alert notification, user traffic segmentation, and service advertisement.
802.11 is an IEEE standard that allows devices such as laptop computers or cellular phones to join a wireless LAN widely used in the home, office and some commercial establishments.
IEEE 802.11 currently makes an assumption that a user is pre-authorised to use the network. IEEE 802.11u covers the cases where user is not pre-authorised. A network will be able to allow access based on the user's relationship with an external network (e.g. hotspot roaming agreements), or indicate that online enrollment is possible, or allow access to a strictly limited set of services such as emergency services (client to authority and authority to client.)
From a user perspective, the aim is to improve the experience of a traveling user who turns on a laptop in a hotel many miles from home. Instead of being presented with a long list of largely meaningless SSIDs the user could be presented with a list of networks, the services they provide, and the conditions under which the user could access them.
The IEEE 802.11u Proposal Requirements Specification contains requirements in the areas of enrollment, network selection, emergency call support, emergency alert notification, user traffic segmentation, and service advertisement.
802.11T puts WLANs to the test
Buyers of Wi-Fi equipment and systems must be assured that all products have the performance and stability to carry mission-critical applications and data. However, testing of Wi-Fi, or 802.11, devices and systems for performance and stability is a challenge for the industry because of the complexity of the 802.11 protocol. That is compounded by the inherent mobility of the wireless devices and the prevalence of radio frequency interference
802.11n
802.11n is a proposed amendment which improves upon the previous 802.11 standards by adding multiple-input multiple-output (MIMO) and many other newer features. The TGn workgroup is not expected to finalize the amendment until December 2009.[6] Enterprises, however, have already begun migrating to 802.11n networks based on Draft 2 of the 802.11n proposal. A common strategy for many businesses is to set up 802.11b and 802.11g client devices while gradually moving to 802.11n clients as part of new equipment purchases
802.11g
In June 2003, a third modulation standard was ratified: 802.11g. This works in the 2.4 GHz band (like 802.11b), but uses the same OFDM based transmission scheme as 802.11a. It operates at a maximum physical layer bit rate of 54 Mbit/s exclusive of forward error correction codes, or about 19 Mbit/s average throughput[citation needed]. 802.11g hardware is fully backwards compatible with 802.11b hardware and therefore is encumbered with legacy issues that reduce throughput when compared to 802.11a by ~21%.
The then-proposed 802.11g standard was rapidly adopted by consumers starting in January 2003, well before ratification, due to the desire for higher data rates, and reductions in manufacturing costs. By summer 2003, most dual-band 802.11a/b products became dual-band/tri-mode, supporting a and b/g in a single mobile adapter card or access point. Details of making b and g work well together occupied much of the lingering technical process; in an 802.11g network, however, activity by a 802.11b participant will reduce the data rate of the overall 802.11g network.
Like 802.11b, 802.11g devices suffer interference from other products operating in the 2.4 GHz band
The then-proposed 802.11g standard was rapidly adopted by consumers starting in January 2003, well before ratification, due to the desire for higher data rates, and reductions in manufacturing costs. By summer 2003, most dual-band 802.11a/b products became dual-band/tri-mode, supporting a and b/g in a single mobile adapter card or access point. Details of making b and g work well together occupied much of the lingering technical process; in an 802.11g network, however, activity by a 802.11b participant will reduce the data rate of the overall 802.11g network.
Like 802.11b, 802.11g devices suffer interference from other products operating in the 2.4 GHz band
802.11b
Release date Frequency band Throughput (typ.) Net bit rate (max.) Range (indoor)
October 1999 2.4 GHz ~5 Mbit/s[4] 11 Mbit/s ~30 m[citation needed]
Main article: IEEE 802.11b-1999
802.11b has a maximum raw data rate of 11 Mbit/s and uses the same media access method defined in the original standard. 802.11b products appeared on the market in early 2000, since 802.11b is a direct extension of the modulation technique defined in the original standard. The dramatic increase in throughput of 802.11b (compared to the original standard) along with simultaneous substantial price reductions led to the rapid acceptance of 802.11b as the definitive wireless LAN technology.
802.11b devices suffer interference from other products operating in the 2.4 GHz band. Devices operating in the 2.4 GHz range include: microwave ovens, Bluetooth devices, baby monitors and cordless telephones.
October 1999 2.4 GHz ~5 Mbit/s[4] 11 Mbit/s ~30 m[citation needed]
Main article: IEEE 802.11b-1999
802.11b has a maximum raw data rate of 11 Mbit/s and uses the same media access method defined in the original standard. 802.11b products appeared on the market in early 2000, since 802.11b is a direct extension of the modulation technique defined in the original standard. The dramatic increase in throughput of 802.11b (compared to the original standard) along with simultaneous substantial price reductions led to the rapid acceptance of 802.11b as the definitive wireless LAN technology.
802.11b devices suffer interference from other products operating in the 2.4 GHz band. Devices operating in the 2.4 GHz range include: microwave ovens, Bluetooth devices, baby monitors and cordless telephones.
802.11a
Release date Op. Frequency Throughput (typ.) Net bit rate (max.) Gross bit rate (max.) Range (indoor)
October 1999 5 GHz 27 Mbit/s[4] 54 Mbit/s 72 Mbit/s ~35 m[citation needed]
Main article: IEEE 802.11a-1999
The 802.11a standard uses the same data link layer protocol and frame format as the original standard, but an OFDM based air interface (physical layer). It operates in the 5 GHz band with a maximum net data rate of 54 Mbit/s, plus error correction code, which yields realistic net achievable throughput in the mid-20 Mbit/s[citation needed].
Since the 2.4 GHz band is heavily used to the point of being crowded, using the relatively un-used 5 GHz band gives 802.11a a significant advantage. However, this high carrier frequency also brings a disadvantage: The effective overall range of 802.11a is less than that of 802.11b/g; and in theory 802.11a signals cannot penetrate as far as those for 802.11b because they are absorbed more readily by walls and other solid objects in their path due to their smaller wavelength. In practice 802.11b typically has a higher distance range at low speeds (802.11b will reduce speed to 5 Mbit/s or even 1 Mbit/s at low signal strengths). However, at higher speeds, 802.11a typically has the same or higher range due to less interference
October 1999 5 GHz 27 Mbit/s[4] 54 Mbit/s 72 Mbit/s ~35 m[citation needed]
Main article: IEEE 802.11a-1999
The 802.11a standard uses the same data link layer protocol and frame format as the original standard, but an OFDM based air interface (physical layer). It operates in the 5 GHz band with a maximum net data rate of 54 Mbit/s, plus error correction code, which yields realistic net achievable throughput in the mid-20 Mbit/s[citation needed].
Since the 2.4 GHz band is heavily used to the point of being crowded, using the relatively un-used 5 GHz band gives 802.11a a significant advantage. However, this high carrier frequency also brings a disadvantage: The effective overall range of 802.11a is less than that of 802.11b/g; and in theory 802.11a signals cannot penetrate as far as those for 802.11b because they are absorbed more readily by walls and other solid objects in their path due to their smaller wavelength. In practice 802.11b typically has a higher distance range at low speeds (802.11b will reduce speed to 5 Mbit/s or even 1 Mbit/s at low signal strengths). However, at higher speeds, 802.11a typically has the same or higher range due to less interference
IEEE 802.11
IEEE 802.11 is a set of standards carrying out wireless local area network (WLAN) computer communication in the 2.4, 3.6 and 5 GHz frequency bands. They are implemented by the IEEE LAN/MAN Standards Committee (IEEE 802).
The original version of the standard IEEE 802.11 was released in 1997 and clarified in 1999, but is today obsolete. It specified two net bit rates of 1 or 2 megabits per second (Mbit/s), plus forward error correction code. It specifed three alternative physical layer technologies: diffuse infrared operating at 1 Mbit/s; frequency-hopping spread spectrum operating at 1 Mbit/s or 2 Mbit/s; and direct-sequence spread spectrum operating at 1 Mbit/s or 2 Mbit/s. The latter two radio technologies used microwave transmission over the Industrial Scientific Medical frequency band at 2.4 GHz. Some earlier WLAN technologies used lower frequencies, such as the U.S. 900 MHz ISM band.
Legacy 802.11 with direct-sequence spread spectrum was rapidly supplemented and popularized by 802.11b.
The original version of the standard IEEE 802.11 was released in 1997 and clarified in 1999, but is today obsolete. It specified two net bit rates of 1 or 2 megabits per second (Mbit/s), plus forward error correction code. It specifed three alternative physical layer technologies: diffuse infrared operating at 1 Mbit/s; frequency-hopping spread spectrum operating at 1 Mbit/s or 2 Mbit/s; and direct-sequence spread spectrum operating at 1 Mbit/s or 2 Mbit/s. The latter two radio technologies used microwave transmission over the Industrial Scientific Medical frequency band at 2.4 GHz. Some earlier WLAN technologies used lower frequencies, such as the U.S. 900 MHz ISM band.
Legacy 802.11 with direct-sequence spread spectrum was rapidly supplemented and popularized by 802.11b.
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