802.11ac Physical Rates

What frequency band does 802.11ac operate in?

802.11ac operates exclusively in the 5 GHz band to avoid interference and achieve higher throughput.

What is the maximum physical data rate supported by 802.11ac?

It supports a maximum physical layer data rate of up to 6.93 Gbps under optimal conditions.

How does 802.11ac achieve higher data rates compared to previous standards?

By using wider channel bandwidths (up to 160 MHz), higher order modulation (up to 256-QAM), and Multi-User MIMO (MU-MIMO).

What channel bandwidths are supported in 802.11ac?

20 MHz, 40 MHz, 80 MHz, and optionally 160 MHz channels are supported.

What modulation schemes are used in 802.11ac?

BPSK, QPSK, 16-QAM, 64-QAM, and 256-QAM are supported, with 256-QAM providing the highest data rates.

What is MU-MIMO and how does it affect physical rates?

MU-MIMO allows simultaneous transmission to multiple devices, effectively increasing throughput and spectral efficiency.

How many spatial streams does 802.11ac support?

Up to 8 spatial streams can be used, improving data rates by parallel transmission.

What role does beamforming play in 802.11ac physical rates?

Beamforming focuses signal energy towards the receiver, improving signal quality and data rates.

Are all channel widths available everywhere?

160 MHz channels are optional and may not be supported on all devices or regulatory domains.

What is the relationship between modulation and data rate?

Higher-order modulations carry more bits per symbol, thus increasing data rates but requiring better signal quality.

How does coding rate affect physical rates in 802.11ac?

Coding rates (e.g., 3/4, 5/6) determine error correction levels, balancing throughput and reliability.

Does 802.11ac support dynamic rate adaptation?

Yes, devices adapt their data rates based on channel conditions to maintain optimal performance.

What is the symbol duration in 802.11ac?

The symbol duration is 3.6 microseconds, shorter than previous standards to increase data throughput.

How does guard interval length impact physical rates?

A short guard interval (0.4 µs) reduces overhead, increasing throughput compared to the standard 0.8 µs interval.

Can 802.11ac devices fall back to lower rates?

Yes, fallback mechanisms allow devices to switch to lower rates for better reliability in poor conditions.

What is the maximum data rate with 160 MHz channel and 8 spatial streams?

Approximately 6.93 Gbps, combining maximum channel width, modulation, and spatial streams.

How does 802.11ac physical rates compare to 802.11n?

802.11ac offers roughly 3 times higher maximum data rates than 802.11n by leveraging wider channels, more spatial streams, and advanced modulation.

Where can I find detailed physical rate tables for 802.11ac?

The IEEE 802.11ac amendment and Wi-Fi Alliance documentation provide detailed rate and modulation tables.

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