List of PPDUs Supported in 802.11ax 6E
What is a PPDU in the context of IEEE 802.11ax 6E?
PPDU stands for Physical Protocol Data Unit, the complete unit of data that is transmitted over the wireless medium, including preamble and payload.
How many types of PPDUs are supported in 802.11ax 6E?
There are five types: HE SU PPDU, HE MU PPDU, HE ER SU PPDU, HE TB PPDU, and HE Extended Range PPDU.
What is an HE SU PPDU?
HE SU (High Efficiency Single User) PPDU is used for single-user transmission and is backward compatible with 802.11a/n/ac devices.
What is HE MU PPDU used for?
HE MU (Multi-User) PPDU is used for simultaneous transmission to multiple users using OFDMA and/or MU-MIMO techniques.
What is the purpose of HE TB PPDU?
HE TB (Trigger-Based) PPDU supports uplink transmissions that are initiated by the AP using trigger frames, enabling scheduled access.
What is HE ER SU PPDU?
HE ER SU (Extended Range Single User) PPDU is designed for longer-range communication in the 2.4 GHz and 5 GHz bands, especially useful for IoT.
Which PPDU types support uplink transmissions?
HE TB PPDU and HE MU PPDU support uplink transmissions from clients to the AP.
Which PPDU types are exclusive to 802.11ax (Wi-Fi 6/6E)?
All five PPDU types—HE SU, HE MU, HE TB, HE ER SU, and HE Extended Range—are new in 802.11ax and not available in legacy standards.
Can legacy devices interpret HE PPDUs?
No. Legacy devices cannot decode HE-specific PPDUs, but 802.11ax APs maintain interoperability through compatible preambles and fallbacks.
Do 6 GHz transmissions use a different PPDU format?
No new PPDU type is introduced for 6 GHz, but HE PPDUs are optimized for the cleaner, wider channels available in this band.
Is there a difference in preamble structure between HE PPDUs?
Yes, each PPDU type has a slightly different preamble tailored to its use case (e.g., SU, MU, TB), though all start with an L-STF/L-LTF for legacy compatibility.
What is the benefit of using HE MU PPDU over HE SU PPDU?
HE MU PPDU allows efficient utilization of the spectrum by serving multiple users simultaneously, improving throughput and efficiency.
What are the key enhancements in HE TB PPDU for uplink efficiency?
It enables scheduled access, reduces collisions, and supports low-latency, high-efficiency transmission for uplink traffic.
Are HE PPDUs compatible across 2.4 GHz, 5 GHz, and 6 GHz bands?
Yes, HE PPDUs are designed to be band-agnostic and operate across all three frequency bands supported by Wi-Fi 6E.
What’s the role of L-SIG in HE PPDU formats?
The L-SIG (Legacy Signal field) is included for compatibility with older devices and to allow carrier sensing.
How are PPDU durations calculated in 802.11ax?
PPDU duration depends on modulation, coding scheme (MCS), guard interval (GI), and number of spatial streams, among other factors.
Do all PPDU types support the same Modulation and Coding Schemes (MCS)?
Most HE PPDUs support up to MCS 11, but support may vary by device and band.
What is the maximum channel width supported by HE PPDUs in Wi-Fi 6E?
In the 6 GHz band, HE PPDUs can operate over channel widths up to 160 MHz, or 320 MHz with Wi-Fi 7 (not in 802.11ax).
How do PPDU formats influence power consumption?
Shorter, more efficient PPDUs like those in trigger-based transmissions reduce airtime and power usage for battery-powered devices.
Are custom or vendor-specific PPDUs allowed?
No, all PPDU formats must conform to the IEEE 802.11ax standard to ensure interoperability across devices and vendors.
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