List of PPDUs Supported in 802.11ak
What is 802.11ak?
802.11ak is an amendment to the IEEE 802.11 standard introducing physical layer enhancements for extended range and robustness in WLANs.
What does PPDU stand for?
PPDU stands for Physical Protocol Data Unit, the fundamental data transmission unit at the physical layer.
How is 802.11ak PPDU different from previous standards?
802.11ak PPDU features longer symbol durations, larger FFT sizes (256-point), and longer guard intervals for better performance in challenging environments.
Which bandwidths does 802.11ak support?
802.11ak supports 5 MHz, 10 MHz, and 20 MHz channel bandwidths.
What FFT size is used in 802.11ak?
A 256-point FFT is used, increasing subcarrier granularity compared to the 64-point FFT in 802.11ac/ax.
Why is a larger FFT size beneficial?
It improves performance in multipath and long-delay environments by offering finer frequency resolution.
What is the symbol duration in 802.11ak?
The symbol duration is 16 microseconds, composed of a 12.8 µs data period plus a 3.2 µs guard interval.
How does the guard interval compare to earlier standards?
The guard interval is longer to reduce inter-symbol interference, especially in extended-range scenarios.
What modulation schemes are supported?
BPSK, QPSK, 16-QAM, 64-QAM, and 256-QAM are supported.
What code rates are available?
Code rates include 1/2, 2/3, 3/4, and 5/6 depending on the modulation.
How many usable subcarriers are there for 20 MHz bandwidth?
There are 234 usable subcarriers at 20 MHz.
What data rates does 802.11ak support at 20 MHz?
Rates range from 6 Mbps (BPSK 1/2) to 90 Mbps (256-QAM 5/6).
How does 802.11ak improve coverage?
Longer symbols and guard intervals mitigate multipath effects, improving signal robustness over longer distances.
Is 802.11ak backward compatible?
Yes, it is designed to coexist with legacy 802.11 devices using appropriate detection and coexistence methods.
Does 802.11ak support OFDMA?
No, 802.11ak focuses on extended coverage and does not implement OFDMA.
What is the role of PPDU in 802.11ak?
PPDU defines the physical layer framing and transmission format for data sent over the air.
How is timing synchronization achieved with longer symbols?
Advanced synchronization techniques and longer preambles tailored for 16 µs symbols are used.
What applications benefit from 802.11ak?
Industrial, extended-range, and harsh multipath wireless environments benefit most.
Where to find the official 802.11ak standard?
The IEEE Standards Association website hosts the official amendment document.
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