List of PPDUs Supported in 802.11be ======================================== .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What is a PPDU in IEEE 802.11be?** A PPDU (Physical Protocol Data Unit) is the complete transmission unit at the physical layer that includes the preamble and data payload. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What types of PPDUs are defined in 802.11be?** 802.11be defines EHT PPDUs, which include EHT-SU, EHT-MU, EHT-TB, and EHT-Trigger-Based variants, tailored for various transmission modes. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What is an EHT PPDU?** An EHT (Extremely High Throughput) PPDU is the new format used in 802.11be, supporting high data rates and advanced features like 4096-QAM. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What is included in a PPDU preamble in 802.11be?** The preamble includes legacy, HE (if backward compatibility is needed), and EHT-specific fields for synchronization, channel estimation, and signaling. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What modulation types are supported in 802.11be PPDUs?** 802.11be supports modulation types up to 4096-QAM, which allows 12 bits per symbol and improves spectral efficiency. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **How does the PPDU format enable backward compatibility?** Legacy and HE preamble fields in the PPDU ensure that older Wi-Fi devices can detect the transmission and defer appropriately. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What is the role of EHT-SIG fields in the PPDU?** EHT-SIG fields carry critical signaling information like MCS, RU allocation, and user-specific parameters used in decoding the data. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What is the EHT-STF in the PPDU preamble?** The EHT-STF (Short Training Field) is used for signal detection, AGC convergence, and initial synchronization of the receiver. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What is the EHT-LTF used for in the PPDU?** The EHT-LTF (Long Training Field) provides channel estimation for accurate demodulation of the data portion in MU and SU PPDUs. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What is the typical structure of a PPDU in 802.11be?** Preamble → Header (L-SIG, RL-SIG, HE-SIG, EHT-SIG) → Data → Optional fields depending on the transmission type. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **How are different users supported in a multi-user PPDU?** The EHT-MU PPDU contains user-specific segments with independent MCS, spatial stream allocation, and resource units (RUs). .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **Does the PPDU support Multi-Link Operation (MLO)?** Yes, each link in an MLO session can transmit its own PPDU, potentially simultaneously, improving aggregate throughput. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **How are guard intervals handled in 802.11be PPDUs?** 802.11be supports shorter guard intervals (as low as 0.8 µs) to improve efficiency, especially in high-density or short-range deployments. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **Can PPDU formats vary by frequency band?** Yes, PPDU format and field length may vary between 2.4 GHz, 5 GHz, and 6 GHz bands, depending on bandwidth and modulation. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **How is channel sounding supported in 802.11be PPDUs?** EHT PPDUs include LTFs for channel sounding, supporting enhanced beamforming and MU-MIMO operations. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What is the maximum size of a PPDU in 802.11be?** The maximum PPDU duration is typically limited to 5.484 ms for a single transmission, but actual size depends on channel and MCS. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **Is there any change in CRC or FCS handling in PPDUs?** No major changes—PPDUs still include frame check sequences (FCS) for error detection at the MAC/PHY boundary. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **How are broadcast/multicast PPDUs transmitted?** They use the EHT-Broadcast PPDU format, typically with lower MCS and broader compatibility across devices. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **How do PPDUs interact with the MAC layer?** The MAC layer constructs MPDUs which are passed to the PHY layer and encapsulated into PPDUs for transmission over the air. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **Where can I find official PPDU format details for 802.11be?** In the IEEE 802.11be (EHT) standard draft/specification documents, especially sections related to PHY layer operations. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow Topics in this section, * :ref:`Reference links ` .. _ppdu_step17: .. tab-set:: .. tab-item:: Reference links * Reference links