List of PPDUs Supported in 802.11ac

What are PPDU types supported in IEEE 802.11ac?

IEEE 802.11ac primarily supports the Single User (SU) PPDU and Multi-User (MU) PPDU formats for data transmission.

What is a Single User PPDU in 802.11ac?

SU PPDU is used for communication between an access point and a single client device using one spatial stream or multiple streams.

What is a Multi-User PPDU (MU-PPDU)?

MU-PPDU allows simultaneous transmission to multiple clients using MU-MIMO technology, increasing throughput and efficiency.

What modulation and coding schemes (MCS) are used in 802.11ac PPDUs?

802.11ac supports MCS indices 0 through 9, using up to 256-QAM for high data rates.

What is the role of the preamble in 802.11ac PPDU?

The preamble contains synchronization, channel estimation, and signaling information needed for proper decoding.

How does 802.11ac PPDU differ from 802.11n?

802.11ac uses wider channels (up to 160 MHz), more spatial streams (up to 8), and higher-order modulation compared to 802.11n.

What are the main fields in an 802.11ac PPDU?

Fields include the Legacy Short Training Field (L-STF), Legacy Long Training Field (L-LTF), VHT-SIG, VHT-STF, VHT-LTF, and the data payload.

What is VHT-SIG in 802.11ac PPDU?

VHT-SIG carries important transmission parameters like bandwidth, MCS, number of spatial streams, and coding rates.

How is channel bandwidth represented in 802.11ac PPDU?

Channel bandwidth can be 20, 40, 80, or 160 MHz and is indicated in the VHT-SIG fields.

Does 802.11ac PPDU support beamforming?

Yes, beamforming information is included to improve signal quality and spatial multiplexing.

What is the maximum number of spatial streams in 802.11ac PPDU?

Up to 8 spatial streams can be used to increase data throughput.

How does 802.11ac handle guard intervals in PPDUs?

802.11ac supports both 800 ns and 400 ns guard intervals to reduce inter-symbol interference.

What types of PPDUs are used for control frames?

Control frames typically use legacy PPDU formats to ensure backward compatibility.

Are there any special PPDU formats for management frames?

Management frames usually use legacy formats, but some enhancements can be supported within 802.11ac.

How does 802.11ac ensure backward compatibility with older devices?

By including legacy preambles in PPDUs, 802.11ac devices can coexist with older 802.11a/n devices.

What is the typical PPDU duration in 802.11ac?

Duration varies depending on data rate, channel width, and payload size but is optimized for high throughput.

Can 802.11ac PPDUs aggregate multiple frames?

Yes, frame aggregation is supported to improve efficiency and throughput.

Where can I find detailed PPDU format specifications for 802.11ac?

Detailed PPDU formats are defined in the IEEE 802.11ac amendment to the 802.11 standard.

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