List of PPDUs Supported in 802.11u
========================================


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        **What is a PPDU in IEEE 802.11u?**

        PPDU stands for Physical Protocol Data Unit, which is the format of the data sent over the wireless medium at the physical layer.

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

        No, 802.11u builds upon existing 802.11 PHY layers and uses the PPDU formats defined in base standards like 802.11a/g/n/ac.

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        **How is PPDU related to MAC frames in 802.11u?**

        The MAC frames are encapsulated inside the PPDU payload for transmission over the physical medium.

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        **What components make up a PPDU?**

        Typical components include the preamble, header (SIGNAL field), and payload (data).

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

        The preamble is used for synchronization, channel estimation, and signaling between sender and receiver.

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        **Does 802.11u impact modulation or coding schemes in the PPDU?**

        No, modulation and coding are defined by the underlying PHY standard, not directly modified by 802.11u.

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        **How does 802.11u affect PPDU transmission timing?**

        802.11u does not alter timing parameters; it focuses on network interworking at higher layers.

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        **Are there specific PPDU types used in 802.11u?**

        No new PPDU types; standard data, management, and control PPDU types are used.

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        **Does 802.11u specify any additional fields within the PPDU?**

        No additional physical layer fields; enhancements occur at MAC and higher layers.

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        **Can 802.11u affect PPDU size?**

        Indirectly, network selection and roaming behaviors may affect packet sizes, but PPDU format remains consistent.

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        **How does 802.11u improve reliability at the PPDU level?**

        Reliability is managed by underlying PHY and MAC mechanisms; 802.11u supports seamless network transitions to maintain connection quality.

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        **Does 802.11u support multi-band PPDU transmissions?**

        802.11u supports network selection across bands but relies on PHY layers for actual PPDU transmissions.

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        **Is PPDU encryption affected by 802.11u?**

        Encryption is handled by security protocols like WPA2/3 at higher layers, not by 802.11u at the PPDU level.

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

        It communicates data rate and length information needed for decoding the payload.

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        **Does 802.11u introduce changes in PPDU error detection?**

        No, error detection is handled by CRC at the PHY and MAC layers unchanged by 802.11u.

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        **How does PPDU relate to 802.11u’s interworking functions?**

        PPDU serves as the physical transmission unit, carrying frames that contain interworking info defined by 802.11u.

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        **Are there specific PPDU requirements for 802.11u network discovery?**

        No, discovery uses standard beacon and probe frames transmitted via conventional PPDUs.

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        **Can 802.11u facilitate PPDU aggregation or fragmentation?**

        Aggregation/fragmentation occurs at MAC layer; 802.11u does not modify PPDU structure for these purposes.

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        **Where can I learn more about PPDU formats used with 802.11u?**

        Consult the base 802.11 standards (a/g/n/ac) for PHY details since 802.11u builds on these without modifying PPDU structure.


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        Topics in this section,

                * :ref:`Reference links <ppdu_u_step17>`


.. _ppdu_u_step17:

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    .. tab-item:: Reference links
     
       * Reference links