List of PPDUs Supported in 802.11aj
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.
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.
What are the main fields of an 802.11aj PPDU?
Fields include the preamble, header, data payload, and optional beamforming training sequences.
What is the purpose of the preamble in the PPDU?
The preamble enables synchronization, channel estimation, and timing acquisition for the receiver.
Does 802.11aj use OFDM-based PPDU?
Yes, 802.11aj uses OFDM PPDUs similar to 802.11ad for robust communication in mmWave bands.
What symbol durations are used in 802.11aj PPDU?
802.11aj uses a symbol duration of 3.6 microseconds in its OFDM PPDU format.
How are beamforming training sequences incorporated in 802.11aj PPDU?
Special training fields within the PPDU allow devices to perform beamforming alignment and refinement.
What types of frames can be encapsulated in the PPDU?
Control, management, and data frames can all be transmitted inside PPDUs.
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.
How is error detection handled in the PPDU?
The PPDU includes CRC and FEC fields for error detection and correction.
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.
How does 802.11aj handle preamble detection?
The preamble is designed for rapid and reliable detection to support fast link establishment.
Are there special PPDU formats for control signaling in 802.11aj?
Yes, control PPDUs have tailored formats for efficient low-latency signaling.
Does the PPDU structure support beam tracking?
Yes, beam tracking sequences can be embedded for dynamic beam adaptation.
What is the role of the SIGNAL field in the PPDU?
The SIGNAL field carries essential transmission parameters such as rate and length.
Are PPDU formats in 802.11aj backward compatible with 802.11ad?
Yes, they are designed for compatibility while supporting new band operations.
How does 802.11aj PPDU support low latency applications?
By enabling scheduled service periods and efficient frame aggregation.
Is there any security feature embedded in the PPDU?
While PPDU itself does not contain encryption, it supports secure MAC frames with encryption.
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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