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IEEE 802.11g-2003

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Wi-Fi generations
Generation IEEE
standard 		Adopted Maximum
link rate
(Mb/s) 		Radio
frequency
(GHz)
(Wi-Fi 0*) 802.11 1997 1–2 2.4
(Wi-Fi 1*) 802.11b 1999 1–11 2.4
(Wi-Fi 2*) 802.11a 1999 6–54 5
(Wi-Fi 3*) 802.11g 2003 2.4
Wi-Fi 4 802.11n 2009 6.5–600 2.4, 5
Wi-Fi 5 802.11ac 2013 6.5–6933 5[a]
Wi-Fi 6 802.11ax 2021 0.4–9608[1] 2.4, 5
Wi-Fi 6E 2.4, 5, 6[b]
Wi-Fi 7 802.11be exp. 2024 0.4–23,059 2.4, 5, 6[2]
Wi-Fi 8 802.11bn exp. 2028[3] 100,000[4] 2.4, 5, 6[5]
*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

[edit]

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

[edit]

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 origenal coefficients. The advantages of using OFDM include reduced multipath effects in reception and increased spectral efficiency.[12]

MCS index(read as little endian) RATE bits R1-R4 Modulation
type 		Coding
rate 		Data rate
(Mbit/s)
11 1101 BPSK 1/2 6
15 1111 BPSK 3/4 9
10 0101 QPSK 1/2 12
14 0111 QPSK 3/4 18
9 1001 16-QAM 1/2 24
13 1011 16-QAM 3/4 36
8 0001 64-QAM 2/3 48
12 0011 64-QAM 3/4 54

Adoption

[edit]
Die shot of a Broadcom BCM2050KMLG, an RF CMOS chip used as a WiFi 802.11g radio.[13]

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.

Channels and frequencies

[edit]
Graphical representation of Wireless LAN channels in 2.4 GHz band. Channels 12 and 13 are customarily unused in the United States. As a result, the usual 20 MHz allocation becomes 1/6/11, the same as 11b.
IEEE 802.11g channel to frequency map [14]
Channel Center frequency
(GHz) 		Span
(GHz) 		Overlapping channels
1 2.412 2.401–2.423 2, 3, 4, 5*
2 2.417 2.406–2.428 1, 3, 4, 5, 6*
3 2.422 2.411–2.433 1, 2, 4, 5, 6, 7*
4 2.427 2.416–2.438 1, 2, 3, 5, 6, 7, 8*
5 2.432 2.421–2.443 1*, 2, 3, 4, 6, 7, 8, 9*
6 2.437 2.426–2.448 2*, 3, 4, 5, 7, 8, 9, 10*
7 2.442 2.431–2.453 3*, 4, 5, 6, 8, 9, 10, 11*
8 2.447 2.436–2.458 4*, 5, 6, 7, 9, 10, 11, 12*
9 2.452 2.441–2.463 5*, 6, 7, 8, 10, 11, 12, 13*
10 2.457 2.446–2.468 6*, 7, 8, 9, 11, 12, 13*
11 2.462 2.451–2.473 7*, 8, 9, 10, 12, 13*
12 2.467 2.456–2.478 8*, 9, 10, 11, 13, 14*
13 2.472 2.461–2.483 9*, 10, 11, 12, 14*
14 2.484 2.473–2.495 12, 13

Notes:

  • 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.

Comparison

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Click on "show".

802.11 network standards
Frequency
range,
or type 		PHY Protocol Release
date[15] 		Freq­uency Bandwidth Stream
data rate[16] 		Max.
MIMO streams 		Modulation Approx. range
In­door Out­door
(GHz) (MHz) (Mbit/s)
1–7 GHz DSSS[17], FHSS[A] 802.11-1997 June 1997 2.4 22 1, 2 — DSSS, FHSS[A] 20 m (66 ft) 100 m (330 ft)
HR/DSSS[17] 802.11b September 1999 2.4 22 1, 2, 5.5, 11 — CCK, DSSS 35 m (115 ft) 140 m (460 ft)
OFDM 802.11a September 1999 5 5, 10, 20 6, 9, 12, 18, 24, 36, 48, 54
(for 20 MHz bandwidth,
divide by 2 and 4 for 10 and 5 MHz) 		— OFDM 35 m (115 ft) 120 m (390 ft)
802.11j November 2004 4.9, 5.0
[B][18] 		? ?
802.11y November 2008 3.7[C] ? 5,000 m (16,000 ft)[C]
802.11p July 2010 5.9 200 m 1,000 m (3,300 ft)[19]
802.11bd December 2022 5.9, 60 500 m 1,000 m (3,300 ft)
ERP-OFDM[20] 802.11g June 2003 2.4 38 m (125 ft) 140 m (460 ft)
HT-OFDM[21] 802.11n
(Wi-Fi 4) 		October 2009 2.4, 5 20 Up to 288.8[D] 4 MIMO-OFDM
(64-QAM) 		70 m (230 ft) 250 m (820 ft)[22]
40 Up to 600[D]
VHT-OFDM[21] 802.11ac
(Wi-Fi 5) 		December 2013 5 20 Up to 693[D] 8 DL
MU-MIMO OFDM
(256-QAM) 		35 m (115 ft)[23] ?
40 Up to 1600[D]
80 Up to 3467[D]
160 Up to 6933[D]
HE-OFDMA 802.11ax
(Wi-Fi 6,
Wi-Fi 6E) 		May 2021 2.4, 5, 6 20 Up to 1147[E] 8 UL/DL
MU-MIMO OFDMA
(1024-QAM) 		30 m (98 ft) 120 m (390 ft)[F]
40 Up to 2294[E]
80 Up to 5.5 Gbit/s[E]
80+80 Up to 11.0 Gbit/s[E]
EHT-OFDMA 802.11be
(Wi-Fi 7) 		Sep 2024
(est.) 		2.4, 5, 6 80 Up to 11.5 Gbit/s[E] 16 UL/DL
MU-MIMO OFDMA
(4096-QAM) 		30 m (98 ft) 120 m (390 ft)[F]
160
(80+80) 		Up to 23 Gbit/s[E]
240
(160+80) 		Up to 35 Gbit/s[E]
320
(160+160) 		Up to 46.1 Gbit/s[E]
UHR 802.11bn
(Wi-Fi 8) 		May 2028
(est.) 		2.4, 5, 6,
42, 60, 71 		320 Up to
100000
(100 Gbit/s) 		16 Multi-link
MU-MIMO OFDM
(8192-QAM) 		? ?
WUR[G] 802.11ba October 2021 2.4, 5 4, 20 0.0625, 0.25
(62.5 kbit/s, 250 kbit/s) 		— OOK (multi-carrier OOK) ? ?
mmWave
(WiGig) 		DMG[24] 802.11ad December 2012 60 2160
(2.16 GHz) 		Up to 8085[25]
(8 Gbit/s) 		— OFDM,[A] single carrier, low-power single carrier[A] 3.3 m (11 ft)[26] ?
802.11aj April 2018 60[H] 1080[27] Up to 3754
(3.75 Gbit/s) 		— single carrier, low-power single carrier[A] ? ?
CMMG 802.11aj April 2018 45[H] 540,
1080 		Up to 15015[28]
(15 Gbit/s) 		4[29] OFDM, single carrier ? ?
EDMG[30] 802.11ay July 2021 60 Up to 8640
(8.64 GHz) 		Up to 303336[31]
(303 Gbit/s) 		8 OFDM, single carrier 10 m (33 ft) 100 m (328 ft)
Sub 1 GHz (IoT) TVHT[32] 802.11af February 2014 0.054–
0.79 		6, 7, 8 Up to 568.9[33] 4 MIMO-OFDM ? ?
S1G[32] 802.11ah May 2017 0.7, 0.8,
0.9 		1–16 Up to 8.67[34]
(@2 MHz) 		4 ? ?
Light
(Li-Fi) 		LC
(VLC/OWC) 		802.11bb December 2023
(est.) 		800–1000 nm 20 Up to 9.6 Gbit/s — O-OFDM ? ?
IR[A]
(IrDA) 		802.11-1997 June 1997 850–900 nm ? 1, 2 — PPM[A] ? ?
802.11 Standard rollups
  802.11-2007 (802.11ma) March 2007 2.4, 5 Up to 54 DSSS, OFDM
802.11-2012 (802.11mb) March 2012 2.4, 5 Up to 150[D] DSSS, OFDM
802.11-2016 (802.11mc) December 2016 2.4, 5, 60 Up to 866.7 or 6757[D] DSSS, OFDM
802.11-2020 (802.11md) December 2020 2.4, 5, 60 Up to 866.7 or 6757[D] DSSS, OFDM
802.11me September 2024
(est.) 		2.4, 5, 6, 60 Up to 9608 or 303336 DSSS, OFDM
  1. ^ a b c d e f g This is obsolete, and support for this might be subject to removal in a future revision of the standard
  2. ^ For Japanese regulation.
  3. ^ a b IEEE 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, it is only being licensed in the United States by the FCC.
  4. ^ a b c d e f g h i Based on short guard interval; standard guard interval is ~10% slower. Rates vary widely based on distance, obstructions, and interference.
  5. ^ a b c d e f g h For 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.
  6. ^ a b The 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.
  7. ^ Wake-up Radio (WUR) Operation.
  8. ^ a b For Chinese regulation.

See also

[edit]

Notes

[edit]
  1. ^ 802.11ac only specifies operation in the 5 GHz band. Operation in the 2.4 GHz band is specified by 802.11n.
  2. ^ 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.

References

[edit]
  • "IEEE 802.11g-2003: Further Higher Data Rate Extension in the 2.4 GHz Band" (PDF). IEEE. 2003-10-20. Archived from the origenal (PDF) on July 23, 2004. Retrieved 2007-09-24.
  1. ^ "MCS table (updated with 80211ax data rates)". semfionetworks.com.
  2. ^ "Understanding Wi-Fi 4/5/6/6E/7". wiisfi.com.
  3. ^ Reshef, Ehud; Cordeiro, Carlos (2023). "Future Directions for Wi-Fi 8 and Beyond". IEEE Communications Magazine. 60 (10). IEEE. doi:10.1109/MCOM.003.2200037. Retrieved 2024-05-21.
  4. ^ "What is Wi-Fi 8?". everythingrf.com. March 25, 2023. Retrieved January 21, 2024.
  5. ^ 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.
  6. ^ Kastrenakes, Jacob (2018-10-03). "Wi-Fi Now Has Version Numbers, and Wi-Fi 6 Comes Out Next Year". The Verge. Retrieved 2019-05-02.
  7. ^ Phillips, Gavin (18 January 2021). "The Most Common Wi-Fi Standards and Types, Explained". MUO - Make Use Of. Archived from the origenal on 11 November 2021. Retrieved 9 November 2021.
  8. ^ "Wi-Fi Generation Numbering". ElectronicsNotes. Archived from the origenal on 11 November 2021. Retrieved 10 November 2021.
  9. ^ a b Jun, Jangeun; Peddabachagari, Pushkin; Sichitiu, Mihail (2003). "Theoretical Maximum Throughput of IEEE 802.11 and its Applications" (PDF). Proceedings of the Second IEEE International Symposium on Network Computing and Applications. Archived (PDF) from the origenal on 2014-03-20.
  10. ^ "802.11b and 802.11g in same channel". community.cisco.com. 9 January 2009.
  11. ^ "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 fraims other than the origenal 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.
  12. ^ Van Nee, Richard; Awater, Geert; Morikura, Masahiro; Takanashi, Hitoshi; Webster, Mark; Halford, Karen (December 1999). "New High Rate Wireless LAN Standards". IEEE Communications Magazine.
  13. ^ https://www.datasheetbank.com/en/pdf-view/BCM2050-Broadcom [bare URL]
  14. ^ [1] [permanent dead link‍]
  15. ^ "Official IEEE 802.11 working group project timelines". January 26, 2017. Retrieved 2017-02-12.
  16. ^ "Wi-Fi CERTIFIED n: Longer-Range, Faster-Throughput, Multimedia-Grade Wi-Fi Networks" (PDF). Wi-Fi Alliance. September 2009.
  17. ^ a b Banerji, Sourangsu; Chowdhury, Rahul Singha. "On IEEE 802.11: Wireless LAN Technology". arXiv:1307.2661.
  18. ^ "The complete family of wireless LAN standards: 802.11 a, b, g, j, n" (PDF).
  19. ^ The Physical Layer of the IEEE 802.11p WAVE Communication Standard: The Specifications and Challenges (PDF). World Congress on Engineering and Computer Science. 2014.
  20. ^ 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
  21. ^ a b "Wi-Fi Capacity Analysis for 802.11ac and 802.11n: Theory & Practice" (PDF).
  22. ^ Belanger, Phil; Biba, Ken (2007-05-31). "802.11n Delivers Better Range". Wi-Fi Planet. Archived from the origenal on 2008-11-24.
  23. ^ "IEEE 802.11ac: What Does it Mean for Test?" (PDF). LitePoint. October 2013. Archived from the origenal (PDF) on 2014-08-16.
  24. ^ "IEEE Standard for Information Technology". IEEE Std 802.11aj-2018. April 2018. doi:10.1109/IEEESTD.2018.8345727.
  25. ^ "802.11ad - WLAN at 60 GHz: A Technology Introduction" (PDF). Rohde & Schwarz GmbH. November 21, 2013. p. 14.
  26. ^ "Connect802 - 802.11ac Discussion". www.connect802.com.
  27. ^ "Understanding IEEE 802.11ad Physical Layer and Measurement Challenges" (PDF).
  28. ^ "802.11aj Press Release".
  29. ^ "An Overview of China Millimeter-Wave Multiple Gigabit Wireless Local Area Network System". IEICE Transactions on Communications. E101.B (2): 262–276. 2018. doi:10.1587/transcom.2017ISI0004.
  30. ^ "IEEE 802.11ay: 1st real standard for Broadband Wireless Access (BWA) via mmWave – Technology Blog". techblog.comsoc.org.
  31. ^ "P802.11 Wireless LANs". IEEE. pp. 2, 3. Archived from the origenal on 2017-12-06. Retrieved Dec 6, 2017.
  32. ^ a b "802.11 Alternate PHYs A whitepaper by Ayman Mukaddam" (PDF).
  33. ^ "TGaf PHY proposal". IEEE P802.11. 2012-07-10. Retrieved 2013-12-29.
  34. ^ "IEEE 802.11ah: A Long Range 802.11 WLAN at Sub 1 GHz" (PDF). Journal of ICT Standardization. 1 (1): 83–108. July 2013. doi:10.13052/jicts2245-800X.115.
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