IEEE 802.11b-1999

Not to be confused with IEEE 802.11be.

IEEE 802.11b-1999 or 802.11b is an amendment to the IEEE 802.11 wireless networking specification that extends throughout up to 11 Mbit/s using the same 2.4 GHz band. A related amendment was incorporated into the IEEE 802.11-2007 standard.

Wi-Fi generations

• v
• t
• e

Gen.[1]	Vi- sual	IEEE standard	Adopt.	Link rate (Mbit/s)	RF (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	6–54	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	2.4, 5
Wi-Fi 6E[b]					6
Wi-Fi 7		802.11be	2024[c]	0.4–23 059	2.4, 5, 6
Wi-Fi 8[2][3]	—	802.11bn		100 000	2.4, 5, 6

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.

Description

802.11b has a maximum raw data rate of 11 Mbit/s and uses the same CSMA/CA media access method defined in the original standard. Due to the CSMA/CA protocol overhead, in practice the maximum 802.11b throughput that an application can achieve is about 5.9 Mbit/s using TCP and 7.1 Mbit/s using UDP.

802.11b products appeared on the market in mid-1999, since 802.11b is a direct extension of the DSSS (Direct-sequence spread spectrum) modulation technique defined in the original standard. The Apple iBook was the first mainstream computer sold with optional 802.11b networking. Technically, the 802.11b standard uses complementary code keying (CCK) as its modulation technique, which uses a specific set of length 8 complementary codes that was originally designed for OFDM ^[4] but was also suitable for use in 802.11b because of its low autocorrelation properties.^[5] 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 as well as to the formation of the Wi-Fi Alliance.

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. Interference issues and user density problems within the 2.4 GHz band have become a major concern and frustration for users.

Code Length bits	Modulation type	Symbol Rate	Bit per Symbol	Data rate (Mbit/s)
11-bit Barker code	DBPSK	11/11 = 1	1	1
11-bit Barker code	DQPSK	11/11 = 1	2	2
8-bit CCK	QPSK	11/8 = 1.375	4	5.5
8-bit CCK	QPSK	11/8 = 1.375	8	11

Range

802.11b is used in a point-to-multipoint configuration, wherein an access point communicates via an omnidirectional antenna with mobile clients within the range of the access point. Typical range depends on the radio frequency environment, output power and sensitivity of the receiver. Allowable bandwidth is shared across clients in discrete channels. A directional antenna focuses transmit and receive power into a smaller field which reduces interference and increases point-to-point range. Designers of such installations who wish to remain within the law must however be careful about legal limitations on effective radiated power.^[6]

Some 802.11b cards operate at 11 Mbit/s, but scale back to 5.5, then to 2, then to 1 Mbit/s (also known as Adaptive Rate Selection) in order to decrease the rate of re-broadcasts that result from errors.

Channels and frequencies

802.11b/g channels in 2.4 GHz band

channel to frequency map ^[7]

Channel	Center frequency	Frequency delta	Channel width	Overlaps channels
1	2.412 GHz	5 MHz	2.401–2.423 GHz	2-5
2	2.417 GHz	5 MHz	2.406–2.428 GHz	1,3-6
3	2.422 GHz	5 MHz	2.411–2.433 GHz	1–2,4-7
4	2.427 GHz	5 MHz	2.416–2.438 GHz	1–3,5-8
5	2.432 GHz	5 MHz	2.421–2.443 GHz	1–4,6-9
6	2.437 GHz	5 MHz	2.426–2.448 GHz	2–5,7-10
7	2.442 GHz	5 MHz	2.431–2.453 GHz	3–6,8-11
8	2.447 GHz	5 MHz	2.436–2.458 GHz	4–7,9-12
9	2.452 GHz	5 MHz	2.441–2.463 GHz	5–8,10-13
10	2.457 GHz	5 MHz	2.446–2.468 GHz	6–9,11-13
11	2.462 GHz	5 MHz	2.451–2.473 GHz	7-10,12-13
12	2.467 GHz	5 MHz	2.456–2.478 GHz	8-11,13-14
13	2.472 GHz	5 MHz	2.461–2.483 GHz	9-12, 14
14	2.484 GHz	12 MHz	2.473–2.495 GHz	12-13

Note: Channel 14 is only allowed in Japan, Channels 12 & 13 are allowed in most parts of the world. More information can be found in the List of WLAN channels.

Comparison

v t e 802.11 network standards
Frequency range, or type	PHY	Protocol	Release date[8]	Freq­uency	Bandwidth	Stream data rate[9]	Max. MIMO streams	Modulation	Approx. range
									In­door	Out­door
				(GHz)	(MHz)	(Mbit/s)
1–7 GHz	DSSS[10], 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[10]	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][11]					?	?
		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)[12]
		802.11bd	December 2022	5.9, 60					500 m	1,000 m (3,300 ft)
	ERP-OFDM[13]	802.11g	June 2003	2.4					38 m (125 ft)	140 m (460 ft)
	HT-OFDM[14]	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)[15]
					40	Up to 600[D]
	VHT-OFDM[14]	802.11ac (Wi-Fi 5)	December 2013	5	20	Up to 693[D]	8	DL MU-MIMO OFDM (256-QAM)	35 m (115 ft)[16]	?
					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 5500[E]
					80+80	Up to 11 000[E]
	EHT-OFDMA	802.11be (Wi-Fi 7)	Sep 2024 (est.)	2.4, 5, 6	80	Up to 5764[E]	8	UL/DL MU-MIMO OFDMA (4096-QAM)	30 m (98 ft)	120 m (390 ft)[F]
					160 (80+80)	Up to 11 500[E]
					240 (160+80)	Up to 14 282[E]
					320 (160+160)	Up to 23 059[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[17]	802.11ad	December 2012	60	2160 (2.16 GHz)	Up to 8085[18] (8 Gbit/s)	—	OFDM,[A] single carrier, low-power single carrier[A]	3.3 m (11 ft)[19]	?
		802.11aj	April 2018	60[H]	1080[20]	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[21] (15 Gbit/s)	4[22]	OFDM, single carrier	?	?
	EDMG[23]	802.11ay	July 2021	60	Up to 8640 (8.64 GHz)	Up to 303336[24] (303 Gbit/s)	8	OFDM, single carrier	10 m (33 ft)	100 m (328 ft)
Sub 1 GHz (IoT)	TVHT[25]	802.11af	February 2014	0.054– 0.79	6, 7, 8	Up to 568.9[26]	4	MIMO-OFDM	?	?
	S1G[25]	802.11ah	May 2017	0.7, 0.8, 0.9	1–16	Up to 8.67[27] (@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
This is obsolete, and support for this might be subject to removal in a future revision of the standard For Japanese regulation. 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[update], it is only being licensed in the United States by the FCC. Based on short guard interval; standard guard interval is ~10% slower. Rates vary widely based on distance, obstructions, and interference. 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. 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. Wake-up Radio (WUR) Operation. For Chinese regulation.

See also

• IEEE 802.11
• IEEE 802.11g-2003
• Wi-Fi
• List of WLAN channels

Notes

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.
3. The Wi-Fi Alliance began certifying Wi-Fi 7 devices in 2024, but as of January 2025^[update] the IEEE standard 802.11be is yet to be ratified.