List of PPDUs Supported in 802.11ad
What does PPDU stand for in 802.11ad?
PPDU stands for Physical Protocol Data Unit, which is the format of data frames sent over the physical layer.
How many types of PPDUs are defined in 802.11ad?
IEEE 802.11ad defines three main PPDU types: Control PHY, Single Carrier (SC) PHY, and Orthogonal Frequency Division Multiplexing (OFDM) PHY.
What is the Control PHY PPDU used for?
Control PHY is used for low-rate control messages and management frames to ensure robust communication.
What are Single Carrier (SC) PPDUs?
SC PPDUs use single carrier modulation schemes for data transmission, offering lower complexity and power consumption.
What is the purpose of OFDM PPDUs in 802.11ad?
OFDM PPDUs enable high data rates by dividing the channel into multiple subcarriers, providing robustness to multipath interference.
Are all PPDU types compatible with each other?
Yes, 802.11ad devices support multiple PPDU types and can switch between them based on data rate and channel conditions.
What data rates are supported by Control PHY PPDUs?
Control PHY supports data rates up to 27.5 Mbps.
What is the maximum data rate achievable using OFDM PPDUs in 802.11ad?
OFDM PPDUs support data rates up to 6.7 Gbps.
How does Single Carrier PHY compare to OFDM in 802.11ad?
SC PHY offers lower power and complexity but lower maximum data rates compared to OFDM PHY.
What modulation schemes are used in Single Carrier PPDUs?
SC PPDUs use BPSK, QPSK, 16-QAM, and 64-QAM modulation depending on link conditions.
How are PPDUs selected during communication?
Devices negotiate PPDU type during association and adapt dynamically based on channel quality and throughput requirements.
What is the role of the preamble in 802.11ad PPDUs?
The preamble helps in synchronization, channel estimation, and timing acquisition at the receiver.
Are there different preamble formats for different PPDU types?
Yes, each PPDU type has a specific preamble structure optimized for its modulation scheme.
Can 802.11ad devices switch between PPDUs mid-session?
Yes, devices can adapt PPDU types dynamically to optimize performance and reliability.
What coding techniques are used in 802.11ad PPDUs?
LDPC (Low-Density Parity-Check) codes are used for error correction in most PPDU types.
What is the shortest PPDU duration supported in 802.11ad?
The Control PHY allows very short PPDUs for control messages, often just a few microseconds.
How does beamforming interact with PPDU types in 802.11ad?
Beamforming training and feedback are coordinated using Control PHY PPDUs, while data transmission uses SC or OFDM PPDUs.
Are PPDU formats backward compatible with earlier 802.11 standards?
No, 802.11ad operates at 60 GHz with different PPDU formats and is not backward compatible with 2.4 or 5 GHz standards.
Where can I find detailed specifications of 802.11ad PPDU formats?
Detailed formats are defined in the IEEE 802.11ad standard document (IEEE Std 802.11-2012 and amendments).
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