List of PPDUs Supported in 802.11s
========================================


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

        PPDU stands for Physical Layer Protocol Data Unit, the basic frame structure used for transmitting data over the wireless physical layer.

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        **How does 802.11s use the PPDU?**

        802.11s uses the standard PPDU format from base 802.11 PHYs to carry mesh management and data frames without modifying the PPDU structure.

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        **Does 802.11s define a new PPDU format?**

        No, 802.11s reuses the existing PPDU formats defined in 802.11a/b/g/n standards.

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        **What types of frames does the PPDU carry in 802.11s?**

        It carries mesh data frames, mesh management frames, and control frames essential for mesh networking.

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        **What components make up the PPDU in 802.11s?**

        The PPDU consists of a physical layer preamble, header, and MAC frame payload.

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        **How does 802.11s ensure backward compatibility in PPDU?**

        By using the same PPDU structure as legacy 802.11 PHYs, it maintains compatibility with existing devices.

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

        The preamble enables synchronization, channel estimation, and signal detection for the receiver.

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        **Does 802.11s modify MAC headers inside the PPDU?**

        Yes, 802.11s defines additional mesh control information inside MAC headers but not at the PHY PPDU level.

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        **Are there special mesh measurement frames in the PPDU?**

        Yes, measurement frames for radio resource management can be transmitted within the PPDU payload.

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        **What PHY modulation schemes are used in 802.11s PPDUs?**

        Modulation schemes like OFDM and DSSS from underlying PHYs are used unchanged.

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        **How is the data rate decided for PPDUs in 802.11s?**

        It is dynamically selected based on link quality, channel conditions, and mesh routing metrics.

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        **Can 802.11s PPDUs support multiple bandwidths?**

        Yes, PPDUs support channel bandwidths inherited from the PHY layer (e.g., 20, 40 MHz).

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        **How does PPDU timing affect mesh performance?**

        Efficient PPDU timing helps reduce latency and improve throughput in mesh networks.

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        **Are control frames in 802.11s sent inside the PPDU?**

        Yes, control frames such as acknowledgments and mesh action frames are sent within PPDUs.

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        **What is the maximum size of a PPDU payload in 802.11s?**

        It follows the maximum PSDU size defined in the base 802.11 standards (usually up to 7935 bytes).

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        **Does 802.11s support aggregation in PPDU?**

        Yes, frame aggregation techniques like A-MPDU and A-MSDU can be used to improve efficiency.

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        **How are errors handled in 802.11s PPDUs?**

        Error detection and correction are managed by PHY layer mechanisms such as CRC and FEC.

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        **Can 802.11s mesh nodes decode all PPDUs?**

        Nodes can decode PPDUs addressed to them or broadcast/multicast frames relevant to mesh operations.

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        **Where can I learn more about 802.11s PPDU structure?**

        Refer to the IEEE 802.11s standard documentation and PHY layer specifications in base 802.11 standards.


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        Topics in this section,

                * :ref:`Reference links <ppdu_s_step17>`

.. _ppdu_s_step17:

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    .. tab-item:: Reference links

       * Reference links