List of PPDUs Supported in 802.11aj
========================================


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

        PPDU (Physical Layer Protocol Data Unit) is the data packet format used at the PHY layer for transmission in 802.11aj.

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        **How does 802.11aj PPDU differ from 802.11ad PPDU?**

        802.11aj PPDU is similar to 802.11ad but adapted for 45 GHz and 60 GHz bands with specific timing and channel usage enhancements.

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        **What are the main fields of an 802.11aj PPDU?**

        Fields include the preamble, header, data payload, and optional beamforming training sequences.

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

        The preamble enables synchronization, channel estimation, and timing acquisition for the receiver.

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        **Does 802.11aj use OFDM-based PPDU?**

        Yes, 802.11aj uses OFDM PPDUs similar to 802.11ad for robust communication in mmWave bands.

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        **What symbol durations are used in 802.11aj PPDU?**

        802.11aj uses a symbol duration of 3.6 microseconds in its OFDM PPDU format.

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        **How are beamforming training sequences incorporated in 802.11aj PPDU?**

        Special training fields within the PPDU allow devices to perform beamforming alignment and refinement.

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        **What types of frames can be encapsulated in the PPDU?**

        Control, management, and data frames can all be transmitted inside PPDUs.

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        **Is there any difference in PPDU structure for single-user vs multi-user transmission?**

        802.11aj supports both, with multi-user PPDUs having additional headers to coordinate transmissions.

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        **How is error detection handled in the PPDU?**

        The PPDU includes CRC and FEC fields for error detection and correction.

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        **What is the maximum PPDU duration allowed in 802.11aj?**

        The standard specifies maximum durations to manage latency and fairness, typically up to several milliseconds.

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        **How does 802.11aj handle preamble detection?**

        The preamble is designed for rapid and reliable detection to support fast link establishment.

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        **Are there special PPDU formats for control signaling in 802.11aj?**

        Yes, control PPDUs have tailored formats for efficient low-latency signaling.

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        **Does the PPDU structure support beam tracking?**

        Yes, beam tracking sequences can be embedded for dynamic beam adaptation.

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        **What is the role of the SIGNAL field in the PPDU?**

        The SIGNAL field carries essential transmission parameters such as rate and length.

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        **Are PPDU formats in 802.11aj backward compatible with 802.11ad?**

        Yes, they are designed for compatibility while supporting new band operations.

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        **How does 802.11aj PPDU support low latency applications?**

        By enabling scheduled service periods and efficient frame aggregation.

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        **Is there any security feature embedded in the PPDU?**

        While PPDU itself does not contain encryption, it supports secure MAC frames with encryption.

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        **How does the MAC layer interact with the PPDU in 802.11aj?**

        The MAC layer controls the assembly and scheduling of PPDUs for transmission and reception.


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        Topics in this section,

                * :ref:`Reference links <ppdu_aj_step17>`


.. _ppdu_aj_step17:

.. tab-set::

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