802.11ak PHYs
What does PHY stand for in 802.11ak?
PHY stands for Physical Layer, the part of the network responsible for transmitting and receiving data over the air.
How many PHY types are defined in 802.11ak?
802.11ak defines three PHY types: Single Carrier (SC), OFDM, and a new Narrowband OFDM.
What is the purpose of the Narrowband OFDM PHY?
It supports narrower bandwidth channels (5 MHz and 10 MHz) for extended range and robustness.
Does 802.11ak use the same modulation schemes as 802.11ac?
Yes, it supports BPSK, QPSK, 16-QAM, 64-QAM, and 256-QAM, similar to 802.11ac but adapted for narrower bandwidths.
What FFT sizes are used in 802.11ak OFDM PHY?
802.11ak uses 64-point FFT for 5 and 10 MHz channels and 256-point FFT for 20 MHz channels.
What symbol durations are used in 802.11ak PHY?
Symbol durations vary: 16 µs for 5 MHz and 10 MHz channels and 16 µs for 20 MHz with appropriate guard intervals.
Does 802.11ak support legacy PHYs?
Yes, 802.11ak devices are backward compatible with legacy 802.11 PHYs.
What is the coding rate range in 802.11ak PHY?
Coding rates supported include 1/2, 2/3, 3/4, and 5/6, similar to previous 802.11 standards.
What are the data rates supported by 802.11ak PHY?
Data rates range from 1.5 Mbps (BPSK 5 MHz) up to 90 Mbps (256-QAM 20 MHz).
How does 802.11ak achieve extended range?
By using narrower bandwidths, longer symbol durations, and robust modulation coding schemes.
What guard intervals are used in 802.11ak PHY?
Guard intervals are typically one quarter of the symbol duration (e.g., 3.2 µs for 20 MHz).
Does 802.11ak use MIMO technology?
802.11ak primarily focuses on single-stream PHY but can be integrated with MIMO in higher layers.
What is the FFT subcarrier spacing in 802.11ak?
The subcarrier spacing is 78.125 kHz for 20 MHz channels and proportionally smaller for narrower bandwidths.
How does 802.11ak PHY handle interference?
By using narrow channels and robust modulation schemes, it reduces interference impact.
What modulation is used for the highest data rates in 802.11ak?
256-QAM with 5/6 coding rate at 20 MHz bandwidth.
Is the PHY in 802.11ak optimized for any specific environment?
Yes, it is optimized for industrial and extended range indoor environments.
Does 802.11ak support OFDM pilot subcarriers?
Yes, pilot subcarriers are used for channel estimation and synchronization.
Where can I find detailed technical specs of 802.11ak PHY?
The IEEE 802.11ak amendment document provides comprehensive PHY details.
Topics in this section,
Reference links