Broad sorting of wireless network protocol standards

When we configure hardware devices, we often see some wireless network protocol standards. The protocol standards vary with hardware. The wireless network card of the notebook is often labeled as 802.11a/B/g or 802.11a/g/n. In fact, it refers to the wireless network protocol, it can be divided into 802.11a, 802.11b, 802.11g, and 802.11n. these different wireless protocols have evolved from 802.11. 802.11 is a wireless LAN Standard originally developed by IEEE, it is mainly used to solve the wireless access between users and user terminals in the office LAN and campus network, 802.11a works in the 5.4G band, the maximum speed is 54 megabytes, and is mainly used for long-distance wireless connections, 802.11b works in the 2.4G band, the maximum speed is 11 Mbit/s, and the 802.11g is used in the 2.4G band, the maximum speed is 54 Mbit/s, and the latest 802.11n wireless standard. It is not mature yet, and the maximum speed can reach 300 Mbit/s.

Protocol	Frequency	Signal	Maximum data transmission rate
Traditional 802.11	2.4 GHz	FHSS or DSSS	2 Mbps
802.11a	5 GHz	OFDM	54 Mbps
802.11b	2.4 GHz	HR-DSSS	11 Mbps
802.11 GB	2.4 GHz	OFDM	54 Mbps
802.11n	2.4 or 5 GHz	OFDM	540 Mbps theoretical value)

Wireless Network Protocol 1. Traditional 802.11

1997 release

Two Original data rates: 1 Mbps and 2 Mbps

Frequency Hopping FHSS) or direct sequence frequency spreading DSSS)

The three 2.4 GHz frequencies in the industrial, technological, and medical ISM fields do not overlap.

Initial definition of carrier listen Multi-Point Access/avoid collision with CSMA-CA)

Wireless Network Protocol 2. 802.11a

1999 release

Data transmission rates for various modulation types: 6, 9, 12, 18, 24, 36, 48, and 54 Mbps

Orthogonal Frequency Division Multiplexing (OFDM) technology with 52 sub-carrier channels

The 12 5 GHz frequencies in the National Information Infrastructure (UNII) channel that do not require licenses do not overlap

Wireless Network Protocol 3. 802.11b

1999 release

Data transmission rates for various modulation types: 1, 2, 5.5, and 11 Mbps

High speed direct serial frequency HR-DSSS)

The three 2.4 GHz frequencies in the industrial, technological, and medical ISM fields do not overlap.

Wireless network protocol 802.11g

2003 release

Data transmission rates of various modulation types: 6, 9, 12, 18, 24, 36, 48, and 54 Mbps;

You can use DSSS and kipks to further convert them to 1, 2, 5.5, and 11 Mbps.

Orthogonal Frequency Division Multiplexing (OFDM) technology with 52 sub-carrier channels; downward compatibility with 802.11b using DSSS and si-

The three 2.4 GHz frequencies in the industrial, technological, and medical ISM fields do not overlap.

Wireless Network Protocol 5. 802.11n

It is planned to perform IEEE authentication in second quarter of 2008, but now there are Access Points AP earlier than 11n) and wireless network interfaces.

Data transmission rates for various modulation types: 1, 2, 5.5, 6, 9, 11, 12, 18, 24, 36, 48, and 54 Mbps

Orthogonal Frequency Division Multiplexing (OFDM) technology using multi-input, multi-output MIMO) and channel binding CB)

The three 2.4 GHz frequencies in the industrial, technological, and medical ISM fields do not overlap.

The 12 5 GHz frequencies in the channel do not overlap with each other, regardless of whether CB exists.

Wireless Network Protocols: 802.11a, 802.11b, and 802.11g

802.11a 54 M bps does not overlap 8) 5.8G is small, relatively short

802.11b 11 M bps sharing 3) more than 2.4G smaller far and stronger

802.11g 22 M bps sharing 3) 2.4G multi-medium

In addition:

1. There are only a handful of 802.11a application cases because China has just opened the G frequency band this year!

2. Due to the number of channels, in an open environment, 802.11b can only have up to three APs at the same time.

3. 802.11g and 802.11a use the OFDM modulation method, while 802.11b uses the complement key technology with lower energy consumption)

4. The communication rate and distance of 802.11b in an open environment are as follows:

160 m -- 11 Mbps

270 meters -- 5.5 Mbps

400 meters -- 2 Mbps

550 meters -- 1 Mbps

5. Wireless 802.11g is a controversial standard!

In summary, 802.11b is the first choice for wireless connection!

Some vendors have recently released their own 22 Mbps solutions, but they all use TI chips in essence.

SMC is called 802.11b Turbo model: SMC2435W

D-Link is known as 802.11b Plus.

Originally TI wanted to use this scheme as the standard of 802.11g and adopt the PBCC 22M modulation method. However, the 802 committee did not adopt this standard and decided to use OFDM. In this way, the 802.11g can reach 54M. therefore, this chip will not become the 802.11g standard, but because it is backward compatible with 802.11b and also runs in the 2.4G band, some manufacturers have launched related products.

In addition, China's 2.4 GHz band is the same as that of other countries, which is 2.4835-5.725 GHz, while the 5 GHz band is different, which is 5.850-GHz,

For more information about frequency and transmit power limits, see the home page of China Radio Management Board: http://www.srrc.gov.cn.

About 5 GHz band: http://www.srrc.gov.cn/fg29.htm

About GHz band: http://www.srrc.gov.cn/fg38.htm