WiFi IEEE 802.11协议精读：IEEE 802.11-2007，15，802.11b（1 Mb/s and 2 Mb/s ），18，802.11b(5.5 Mb/s and 11 Mb/s-优快云博客

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继续精读IEEE 802.11-2007

10，Layer management 层管理

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11，MLME，MAC sublayer management entity，MAC子层管理入口

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12，PHY service specification，物理层服务规范

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13，PHY management，物理层管理

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14，Frequency-Hopping spread spectrum (FHSS) PHY specification for the 2.4 GHz industrial, scientific, and medical (ISM) band，FHSS 跳频--已废弃

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15，DSSS PHY specification for the 2.4 GHz band designated for ISM applications，802.11b（2.4G 1 Mb/s and 2 Mb/s ）

15.1 Overview

The PHY for the DSSS system is described in this clause. The RF LAN system is aimed for the 2.4 GHz band designated for ISM applications.

The DSSS system provides a WLAN with both a 1 Mb/s and a 2 Mb/s data payload communication capability. The DSSS system uses baseband modulations of differential binary phase shift keying (DBPSK) and differential quadrature phase shift keying (DQPSK) to provide the 1 Mb/s and 2 Mb/s data rates, respectively

TX Spectrum Mask

16，Infrared (IR) PHY specification 红外--已废弃

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18，High Rate direct sequence spread spectrum (HR/DSSS) PHY specification，802.11b(2.4G CCK 5.5 Mb/s and 11 Mb/s)

18.1 Overview

This clause specifies the High Rate extension of the PHY for the DSSS system (see Clause 15), hereinafter known as the High Rate PHY for the 2.4 GHz band designated for ISM applications .

This extension of the DSSS system builds on the data rate capabilities, as described in Clause 15, to provide 5.5 Mb/s and 11 Mb/s payload data rates in addition to the 1 Mb/s and 2 Mb/s rates. To provide the higher rates, 8-chip complementary code keying (CCK) is employed as the modulation scheme. The chipping rate is 11 MHz, which is the same as the DSSS system described in Clause 15, thus providing the same occupied channel bandwidth. The basic new capability described in this clause is called HR/DSSS. The basic High Rate PHY uses the same PLCP preamble and header as the DSSS PHY, so both PHYs can co-exist in the same BSS and can use the rate switching mechanism as provided.