802.11s PHYs
==============


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        **What is the PHY layer in 802.11s?**

        The PHY (Physical) layer in 802.11s defines how data is transmitted over the wireless medium using radio signals.

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        **Which base PHY standards does 802.11s use?**

        It uses PHYs defined in standards like 802.11a, 802.11b, 802.11g, 802.11n, and newer ones as supported.

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        **Does 802.11s define a new PHY?**

        No, 802.11s builds on existing 802.11 PHYs and adds mesh-specific MAC and management features.

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        **How does PHY choice affect 802.11s performance?**

        Different PHYs offer varying data rates, range, and robustness, impacting mesh throughput and coverage.

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        **Can 802.11s mesh nodes use different PHYs simultaneously?**

        Yes, nodes can operate with different PHY capabilities but interoperability depends on supported features.

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        **What modulation schemes are used in 802.11s PHYs?**

        Common schemes include DSSS, OFDM, and MIMO techniques depending on the base PHY (e.g., BPSK, QPSK, QAM).

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        **Does 802.11s support MIMO PHYs?**

        Yes, PHYs like 802.11n/ac with MIMO are supported to enhance mesh network capacity.

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        **How is channel bonding used in 802.11s PHYs?**

        Channel bonding combines adjacent channels to increase throughput on mesh links when supported by the PHY.

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        **What is the role of the PHY preamble in 802.11s?**

        The preamble synchronizes the receiver with the incoming signal and carries PHY-layer signaling.

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        **Are there PHY-layer changes specific to mesh in 802.11s?**

        No major changes; 802.11s relies on standard PHY operations, focusing enhancements at MAC and higher layers.

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        **How does PHY rate adaptation work in 802.11s?**

        Nodes adjust PHY data rates dynamically based on link quality to optimize throughput and reliability.

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        **What frequency bands are supported by 802.11s PHYs?**

        Both 2.4 GHz and 5 GHz bands are commonly supported, with newer PHYs possibly extending to 6 GHz.

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        **Can 802.11s PHYs use DFS channels?**

        Yes, if the underlying PHY and regulatory domain allow, DFS channels can be used for mesh communication.

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        **How does PHY affect mesh network latency?**

        Higher PHY rates generally reduce transmission time, lowering latency in mesh packet forwarding.

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        **Is power control handled at the PHY layer in 802.11s?**

        Power control mechanisms exist and can be managed to optimize signal strength and reduce interference.

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        **How do PHY characteristics influence mesh routing?**

        PHY conditions like link quality and rate influence route selection and path stability in mesh networks.

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        **Does 802.11s support multiple PHYs on the same device?**

        Some devices support multiple PHY interfaces or radios for enhanced mesh capabilities.

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        **Where can I find detailed PHY specifications for 802.11s?**

        PHY details are in the base 802.11 standards; 802.11s focuses on mesh MAC and management enhancements.


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        Topics in this section,

                * :ref:`Reference links <phy_s_step17>`


.. _phy_s_step17:

.. tab-set::

    .. tab-item:: Reference links

       * Reference links