*Wi‑Fi 0, 1, 2, and 3 are named by retroactive inference. They do not exist in the official nomenclature.[6][7][8]
IEEE 802.11g-2003 or 802.11g is an amendment to the IEEE 802.11 specification that operates in the 2.4 GHz microwave band. The standard has extended link rate to up to 54 Mbit/s using the same 20 MHz bandwidth as 802.11b uses to achieve 11 Mbit/s. This specification, under the marketing name of Wi‑Fi, has been implemented all over the world. The 802.11g protocol is now Clause 19 of the published IEEE 802.11-2007 standard, and Clause 19 of the published IEEE 802.11-2012 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, 802.11g, 802.11n, 802.11ac and 802.11ax versions to provide wireless connectivity in the home, office and some commercial establishments.
802.11g is fully backward compatible with 802.11b, but coexistence of the two methods creates a significant performance penalty.
Descriptions
802.11g is the third modulation standard for wireless LANs. It works in the 2.4 GHz band (like 802.11b) but operates at a maximum raw data rate of 54 Mbit/s. Using the CSMA/CA transmission scheme, 31.4 Mbit/s[9] is the maximum net throughput possible for packets of 1500 bytes in size and a 54 Mbit/s wireless rate (identical to 802.11a core, except for some additional legacy overhead for backward compatibility). In practice, access points may not have an ideal implementation and may therefore not be able to achieve even 31.4 Mbit/s throughput with 1500 byte packets. 1500 bytes is the usual limit for packets on the Internet and therefore a relevant size to benchmark against. Smaller packets give even lower theoretical throughput, down to 3 Mbit/s using 54 Mbit/s rate and 64 byte packets.[9] Also, the available throughput is shared between all stations transmitting, including the AP so both downstream and upstream traffic is limited to a shared total of 31.4 Mbit/s using 1500 byte packets and 54 Mbit/s rate.
802.11g hardware is fully backward compatible with 802.11b hardware. Details of making b and g work well together occupied much of the lingering technical process. In an 802.11g network, however, the presence of a legacy 802.11b participant will significantly reduce the speed of the overall 802.11g network, as airtime needs to be managed by RTS/CTS transmissions and a "back off" mechanism.[10] Some 802.11g routers employ a back-compatible mode for 802.11b clients called 54g LRS (Limited Rate Support).[11]
The modulation scheme used in 802.11g is orthogonal frequency-division multiplexing (OFDM) copied from 802.11a with data rates of 6, 9, 12, 18, 24, 36, 48, and 54 Mbit/s, and reverts to CCK (like the 802.11b standard) for 5.5 and 11 Mbit/s and DBPSK/DQPSK+DSSS for 1 and 2 Mbit/s. Even though 802.11g operates in the same frequency band as 802.11b, it can achieve higher data rates because of its better modulation from 802.11a.
Technical description
Of the 52 OFDM subcarriers, 48 are for data and 4 are pilot subcarriers with a carrier separation of 0.3125 MHz (20 MHz/64). Each of these subcarriers can be a BPSK, QPSK, 16-QAM or 64-QAM. The total bandwidth is 22 MHz with an occupied bandwidth of 16.6 MHz. Symbol duration is 4 microseconds, which includes a guard interval of 0.8 microseconds. The actual generation and decoding of orthogonal components is done in baseband using DSP which is then upconverted to 2.4 GHz at the transmitter. Each of the subcarriers could be represented as a complex number. The time domain signal is generated by taking an Inverse Fast Fourier transform (IFFT). Correspondingly the receiver downconverts, samples at 20 MHz and does an FFT to retrieve the original coefficients. The advantages of using OFDM include reduced multipath effects in reception and increased spectral efficiency.[12]
The then-proposed 802.11g standard was rapidly adopted by consumers starting in January 2003, well before ratification, due to the desire for higher speeds and reductions in manufacturing costs. By mid-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. [citation needed]
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, baby monitors, and digital cordless telephones, which can lead to interference issues. Additionally, the success of the standard has caused usage/density problems related to crowding in urban areas. To prevent interference, there are only three non-overlapping usable channels in the U.S. and other countries with similar regulations (channels 1, 6, 11, with 25 MHz separation), and four in Europe (channels 1, 5, 9, 13, with only 20 MHz separation). Even with such separation, some interference due to side lobes exists, though it is considerably weaker.
Not all channels are legal to use in all countries. In particular, no countries in the world permit the use of channel 14 for 802.11g. Channels 12 and 13 are avoided in the United States due to a misinterpretation of regulations.
Overlaps noted with an asterisk (*) indicate overlap only in the 22 MHz width, while 802.11g only requires 20 MHz (the actual occupied bandwidth is even lower, 16.25 MHz). As a result, such overlaps have minimal performance implications.
^ abIEEE 802.11y-2008 extended operation of 802.11a to the licensed 3.7 GHz band. Increased power limits allow a range up to 5,000 m. As of 2009[update], it is only being licensed in the United States by the FCC.
^ abcdefghiBased on short guard interval; standard guard interval is ~10% slower. Rates vary widely based on distance, obstructions, and interference.
^ abcdefghFor single-user cases only, based on default guard interval which is 0.8 microseconds. Since multi-user via OFDMA has become available for 802.11ax, these may decrease. Also, these theoretical values depend on the link distance, whether the link is line-of-sight or not, interferences and the multi-path components in the environment.
^ abThe default guard interval is 0.8 microseconds. However, 802.11ax extended the maximum available guard interval to 3.2 microseconds, in order to support Outdoor communications, where the maximum possible propagation delay is larger compared to Indoor environments.
^802.11ac only specifies operation in the 5 GHz band. Operation in the 2.4 GHz band is specified by 802.11n.
^Wi-Fi 6E is the industry name that identifies Wi-Fi devices that operate in 6 GHz. Wi-Fi 6E offers the features and capabilities of Wi-Fi 6 extended into the 6 GHz band.
^"What is Wi-Fi 8?". everythingrf.com. March 25, 2023. Retrieved January 21, 2024.
^Giordano, Lorenzo; Geraci, Giovanni; Carrascosa, Marc; Bellalta, Boris (November 21, 2023). "What Will Wi-Fi 8 Be? A Primer on IEEE 802.11bn Ultra High Reliability". arXiv:2303.10442.
^"USRobotics Wireless ADSL2+ Router: User Guide". support.usr.com. 54g LRS (Limited Rate Support) is intended to support "legacy" (802.11b) clients that can't deal with access points which advertise supported rates in their beacon frames other than the original 802.11's 1 and 2 Mbps rates. [...] 54g™ protection: If you set this option as Automatic, the router will use RTS/CTS to improve the 802.11g performance in 802.11 mixed environments.
^Van Nee, Richard; Awater, Geert; Morikura, Masahiro; Takanashi, Hitoshi; Webster, Mark; Halford, Karen (December 1999). "New High Rate Wireless LAN Standards". IEEE Communications Magazine.
^IEEE Standard for Information Technology- Telecommunications and Information Exchange Between Systems- Local and Metropolitan Area Networks- Specific Requirements Part Ii: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications. (n.d.). doi:10.1109/ieeestd.2003.94282
1894 adventure novel by Anthony Hope This article is about the 1894 novel by Anthony Hope Hawkins. For other uses, see The Prisoner of Zenda (disambiguation). This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed.Find sources: The Prisoner of Zenda – news · newspapers · books · scholar · JSTOR (June 2014) (Learn how and when to...
De neutraliteit van dit artikel wordt betwist.Zie de bijbehorende overlegpagina voor meer informatie. Patoch Sjodijev Patoch Kajoemovitsj Sjodijev (Jizzax, 15 april 1953), ook wel Patokh Chodiev (Russisch: Фаттох Каюмович Шодиев), is een omstreden, in Londen wonende Oezbeekse zakenman en oligarch met de Belgische nationaliteit. Samen met Alexander Masjkevitsj en Alijan Ibragimov vormt hij het zogenaamde 'Kazachse trio'[1], een groep van Centraal-Aziatische zakenlui...
Este artículo o sección necesita referencias que aparezcan en una publicación acreditada.Este aviso fue puesto el 28 de junio de 2019. Para la carretera federal de Rusia, véase Autopista M29 Cáucaso. Cúmulo abierto M29 Datos de observación(Época J2000.0)Tipo Cúmulo abiertoAscensión recta 20 h 24 m 0 sDeclinación +38°120′0″Distancia 4.0 kalMagnitud aparente (V) 7.1Tamaño aparente (V) 7'Constelación CygnusCaracterísticas físicasEdad estimada 10 millo...
Bupati MimikaLambang Kabupaten MimikaPetahanaEltinus Omalengsejak 9 September 2023Masa jabatan5 tahun (definitif)Dibentuk1996 (sebagai kabupaten administrasi) 2001 (sebagai kabupaten)Pejabat pertamaDrs. Titus Octovianus PotereyauwSitus webSitus Resmi Kabupaten Mimika Kabupaten Mimika dari awal berdirinya pada tahun - hingga saat ini sudah pernah dipimpin oleh beberapa bupati. Saat ini Bupati Mimika dijabat oleh Eltinus Omaleng. Daftar Bupati Berikut ini adalah Bupati Mimika dari masa ke ...
Este artigo não cita fontes confiáveis. Ajude a inserir referências. Conteúdo não verificável pode ser removido.—Encontre fontes: ABW • CAPES • Google (N • L • A) (Junho de 2020) Castillo de San Juan BautistaApresentaçãoTipo castelomonumentoFundação 1641Estatuto patrimonial Bem de Interesse Cultural (1993)LocalizaçãoLocalização Santa Cruz de Tenerife EspanhaAltitude 6 mCoordenadas 28° 27′ 20″ N, 16...
This article relies excessively on references to primary sources. Please improve this article by adding secondary or tertiary sources. Find sources: University of Texas at Austin College of Natural Sciences – news · newspapers · books · scholar · JSTOR (October 2015) (Learn how and when to remove this template message) The Physics, Math, and Astronomy Building (left), the Molecular Biology Building (middle), and the Neuromolecular Sciences Building (ri...
This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed.Find sources: Bill Walsh College Football – news · newspapers · books · scholar · JSTOR (October 2017) (Learn how and when to remove this template message) 1993 video gameBill Walsh College FootballCover artDeveloper(s)High Score Productions (Sega Genesis & Sega CD) Visu...
Sports season2006 FINA Men's Water Polo World LeagueLeagueFINA Water Polo World LeagueSportWater PoloFINA Men's Water Polo World League seasons← 20052007 → The 2006 FINA Men's Water Polo World League was the fifth edition of the annual event, organised by the world's governing body in aquatics, the FINA. After a preliminary round and a semifinal round, the Super Final was held in Athens, Greece.[1] Preliminary round Three teams from each pool advanced to the semifinal ro...
Science museum in London, England For other uses, see Geological Museum (disambiguation). 51°29′47″N 0°10′36″W / 51.49639°N 0.17667°W / 51.49639; -0.17667 The building of the Geological Museum from 1935, designed by Sir Richard Allison and John Hatton Markham The atrium of the Geological Museum as it appeared until 2014 The Geological Museum (originally the Museum of Economic Geology then the Museum of Practical Geology), started in 1835[1][2 ...
يفتقر محتوى هذه المقالة إلى الاستشهاد بمصادر. فضلاً، ساهم في تطوير هذه المقالة من خلال إضافة مصادر موثوق بها. أي معلومات غير موثقة يمكن التشكيك بها وإزالتها. (ديسمبر 2018) شعب السميع - قرية - تقسيم إداري البلد اليمن المحافظة محافظة تعز المديرية مديرية ماوية السك...
Residential House and Museum in Tagbilaran City, PhilippinesPresident Carlos P. Garcia Heritage HouseMarker of the President Carlos P. Garcia Heritage House in Tagbilaran City, BoholGeneral informationTypeResidential House and MuseumArchitectural stylemodern domesticAddressA. Hontanosas corner F. Rocha St.Town or cityTagbilaran CityCountryPhilippinesCoordinates9°38′29″N 123°51′29″E / 9.6414°N 123.8581°E / 9.6414; 123.8581OwnerGarcia FamilyTechnical detailsM...
Postal codes in Malaysia, usually referred to as postcodes (Malay: poskod), are five digit numeric. The first two digits of the postcode denote the state or federal territory (e.g. 42000 Port Klang, Selangor). However, postcode area boundaries may cross state borders, as areas near to state borders may be served by post offices located in another state, and therefore use postcodes of the assigned post offices. History Malaysia's current postcode system was initiated by M. Rajasingam, director...
Anna Kožnikova Nazionalità Russia Altezza 176 cm Peso 65 kg Calcio Ruolo Difensore Squadra Lokomotiv Mosca Carriera Squadre di club1 2001-2004 Ėnergija Voronež? (?)2005 Prialit? (?)2005-2016 Rossijanka? (?)2017 CSKA Mosca14 (2)2018- Lokomotiv Mosca46 (10) Nazionale 2005-200? Russia U-19? (?)2006 Russia U-205 (2)2006- Russia105 (8) 1 I due numeri indicano le presenze e le reti segnate, per le sole partite di campionato.Il simbolo → indica un trasferimento ...
2004 young adult novel by Pete Hautman Godless AuthorPete HautmanCountryUnited StatesLanguageEnglishPublisherSimon & Schuster Children's PublishingPublication date2004Media typePrintPages208ISBN0-689-86278-4OCLC52386196LC ClassPZ7.H2887 Go 2004 Godless, a young adult novel by Pete Hautman, was published in 2004 by Simon & Schuster. It won the annual U.S. National Book Award for Young People's Literature.[1] Godless tells the story of Jason Bock, a fifteen-year-old bo...
Купрес серб. Општина Купрес — Громада — Країна Боснія і Герцеговина Автономна одиниця Республіка Сербська Адміністративний центр Ново-Село Площа - Повна 89 км² Населення (2013[1]) - Усього 320 - Густота 3,6/км² Вебсайт: www.opcinakupres.ba Розт...
Sickle parang (knife) Parang Ginah A Parang Ginah, 18th–19th century.TypeSickle parang (knife)Place of origin Malaysia (Northern Malay Peninsula)Service historyUsed byKelantanese Malay people, Terengganuan MalaysSpecificationsLengthApproximately 58 cm (23 in)Blade typeSingle edgeHilt typeWoodScabbard/sheathNo scabbard The Parang Ginah is a sickle shaped Malay cutting implement,[1] whether a sword or a sickle is uncertain, most likely the latte...
ريزدنت إيفل 6 المطور كابكوم الناشر كابكوم الموزع كابكوم المنتج هيرويوكي كوباياشي سلسلة اللعبة ريزدنت إيفل محرك اللعبة إم تي فريمورك النسخة الحالية 6 النظام بلاي ستيشن 4 بلاي ستيشن 3 إكس بوكس ون اكس بوكس 360 مايكروسوفت ويندوز تاریخ الإصدار 1 أكتوبر، 2012 نوع اللعبة تصويب منظ...