List of PPDUs Supported in 802.11h
What is a PPDU in 802.11h?
PPDU stands for Physical Layer Protocol Data Unit, the basic unit of transmission at the physical layer in 802.11h networks.
How is the PPDU structured in 802.11h?
The PPDU includes a preamble, header, and data payload, similar to 802.11a, with no major changes in structure for 802.11h.
Does 802.11h change the PPDU format from 802.11a?
No, 802.11h maintains the 802.11a PPDU format but adds regulatory features like DFS and TPC at the MAC/PHY level.
What is the role of the preamble in a PPDU?
The preamble helps with synchronization, channel estimation, and signal detection before data transmission.
What are the types of preambles in 802.11h PPDUs?
802.11h uses the same preamble types as 802.11a: short and long preambles.
How does the PPDU header help in 802.11h?
The header contains rate and length information essential for decoding the data payload.
Is the PPDU affected by Dynamic Frequency Selection (DFS)?
While DFS affects channel selection, it does not change the PPDU structure.
Does Transmit Power Control (TPC) affect PPDU?
TPC adjusts transmission power but does not alter the PPDU format or timing.
What is the typical duration of a PPDU symbol in 802.11h?
A PPDU OFDM symbol is typically 4 µs, including 3.2 µs data and 0.8 µs guard interval.
How is the data rate encoded in the PPDU header?
The header includes a RATE field indicating the modulation and coding scheme for the payload.
Are management and control frames sent as PPDUs in 802.11h?
Yes, all frame types (data, management, control) are transmitted as PPDUs.
How does PPDU timing affect QoS in 802.11h?
Precise timing and symbol durations help maintain QoS by ensuring predictable transmission slots.
Can PPDU formats vary with different modulation schemes in 802.11h?
The overall format is consistent, but the modulation affects the number of bits per symbol within the PPDU.
Does 802.11h support any special PPDU formats for radar detection?
No special PPDU formats; radar detection is handled by DFS mechanisms outside the PPDU.
How does the PPDU handle error detection?
The data payload includes CRC for error detection at the receiver.
Is there a difference in PPDU structure for different channel bandwidths?
802.11h typically uses 20 MHz channels, so PPDU structure aligns with this bandwidth.
How are PPDU transmissions impacted during DFS events?
Transmissions pause or switch channels during radar detection, but PPDU structure remains unchanged.
What role does the SIGNAL field play in the PPDU?
It specifies the rate and length of the following data, allowing proper decoding.
Are PPDUs encrypted in 802.11h?
Encryption is handled at higher layers; PPDU transmits encrypted or unencrypted payload transparently.
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