List of PPDUs Supported in 802.11h
========================================


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        **What is a PPDU in 802.11h?**

        PPDU stands for Physical Layer Protocol Data Unit, the basic unit of transmission at the physical layer in 802.11h networks.

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        **How is the PPDU structured in 802.11h?**

        The PPDU includes a preamble, header, and data payload, similar to 802.11a, with no major changes in structure for 802.11h.

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        **Does 802.11h change the PPDU format from 802.11a?**

        No, 802.11h maintains the 802.11a PPDU format but adds regulatory features like DFS and TPC at the MAC/PHY level.

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        **What is the role of the preamble in a PPDU?**

        The preamble helps with synchronization, channel estimation, and signal detection before data transmission.

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        **What are the types of preambles in 802.11h PPDUs?**

        802.11h uses the same preamble types as 802.11a: short and long preambles.

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        **How does the PPDU header help in 802.11h?**

        The header contains rate and length information essential for decoding the data payload.

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        **Is the PPDU affected by Dynamic Frequency Selection (DFS)?**

        While DFS affects channel selection, it does not change the PPDU structure.

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        **Does Transmit Power Control (TPC) affect PPDU?**

        TPC adjusts transmission power but does not alter the PPDU format or timing.

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        **What is the typical duration of a PPDU symbol in 802.11h?**

        A PPDU OFDM symbol is typically 4 µs, including 3.2 µs data and 0.8 µs guard interval.

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        **How is the data rate encoded in the PPDU header?**

        The header includes a RATE field indicating the modulation and coding scheme for the payload.

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        **Are management and control frames sent as PPDUs in 802.11h?**

        Yes, all frame types (data, management, control) are transmitted as PPDUs.

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        **How does PPDU timing affect QoS in 802.11h?**

        Precise timing and symbol durations help maintain QoS by ensuring predictable transmission slots.

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        **Can PPDU formats vary with different modulation schemes in 802.11h?**

        The overall format is consistent, but the modulation affects the number of bits per symbol within the PPDU.

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        **Does 802.11h support any special PPDU formats for radar detection?**

        No special PPDU formats; radar detection is handled by DFS mechanisms outside the PPDU.

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        **How does the PPDU handle error detection?**

        The data payload includes CRC for error detection at the receiver.

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        **Is there a difference in PPDU structure for different channel bandwidths?**

        802.11h typically uses 20 MHz channels, so PPDU structure aligns with this bandwidth.

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        **How are PPDU transmissions impacted during DFS events?**

        Transmissions pause or switch channels during radar detection, but PPDU structure remains unchanged.

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        **What role does the SIGNAL field play in the PPDU?**

        It specifies the rate and length of the following data, allowing proper decoding.

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        **Are PPDUs encrypted in 802.11h?**

        Encryption is handled at higher layers; PPDU transmits encrypted or unencrypted payload transparently.

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        Topics in this section,

                * :ref:`Reference links <ppdu_80211h_step17>`


.. _ppdu_80211h_step17:

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    .. tab-item:: Reference links

       * Reference links