11ad DMG

802.11ad

The IEEE 802.11ad, which is also called DMG (Directional Multi-Gigabit in IEEE 802.11 standard), provides data throughput speeds of up to 8 Gbps with low latency, using the 60 GHz ISM band to achieve the required levels of bandwidth and ensure reduced interference levels. Wi-Fi Alliance has introduced Wi-Fi CERTIFIED WiGig to accelerate the commercial availability of devices, whose MAC/PHY specification aligns exactly with the 802.11ad standard. WiGig complements Wi-Fi CERTIFIED ac and increases network performance, resulting in better use of network resources and rivaling wired connections.

At unlicensed 60 GHz band, each channel for WiGig is 2.16 GHz wide. The 802.11ad PHY supports following three main signals with different modulation:

  • Control PHY, CPHY: This signal provides control and has high levels of error correction and detection. However, it has a relatively low throughput and exclusively carriers control channel messages. The CPHY uses differential encoding, code spreading and BPSK modulation.

  • Single Carrier (SC) PHY: It supports two types of modulation and coding schemes, which provide different benefits:

    • Single Carrier mode supports the highest available data rates up to 8 Gbps

    • Low-power Single Carrier mode provides lowest possible power consumption, targeting mobile devices such as smartphones, up to 2.5 Gbps

      The two types of schemes share common elements such as preamble and channel coding. This reduces implementation complexity for manufacturers of WiGig devices.

  • Orthogonal Frequency Division Multiplex PHY, OFDMPHY: The OFDMPHY uses multicarrier modulation to provide high modulation densities and higher data throughput levels than the single carrier modes.

The OFDM mode is defined in IEEE 802.11ad standard, but no commercial implementation yet.

LDPC encoding with codeword size of 672 bits is applied to DMG SC mode. The table below displays the SC mode modulation and coding (MCS) schemes. MCS 0 is used to identify the DMG control mode.

The figure below shows the SC PPDU format. A SC frame is composed of the Short Training field (STF), the channel estimation field (CE), the Header, SC blocks (BLK) and optional training fields.

以上原文地址为:https://rfmw.em.keysight.com/wireless/helpfiles/n7637/Content/Main/802.11ad%20Concepts.htm

就MAC层而言,DMG和传统的80211 (DCF, PCF)是一个并列关系,它是一个新的东西,并不像11a,11n,11ax这种持续兼容的东西,如下图

 

posted on 2023-12-06 14:34  sudochen  阅读(57)  评论(0编辑  收藏  举报

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