802.11an Physical Rates

What are physical rates in IEEE 802.11an?

Physical rates refer to the data transmission speeds supported at the PHY layer.

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

Up to 600 Mbps using 4 spatial streams and 40 MHz channels.

How does 802.11an achieve higher data rates compared to 802.11a?

By using channel bonding (40 MHz channels) and MIMO technology.

What modulation schemes are used in 802.11an?

BPSK, QPSK, 16-QAM, and 64-QAM with various coding rates.

What is the role of spatial streams in physical rates?

Multiple spatial streams transmitted simultaneously increase throughput proportionally.

How many spatial streams does 802.11an support?

Up to 4 spatial streams.

What channel widths are supported in 802.11an?

20 MHz and 40 MHz channels.

How does channel bonding affect physical rates?

Combining two 20 MHz channels into one 40 MHz channel doubles the data rate.

What is the modulation and coding scheme (MCS) index?

A number defining the combination of modulation type, coding rate, and spatial streams.

How many MCS levels are defined in 802.11an?

Typically 32 MCS indexes (0-31) combining modulation, coding, and streams.

What determines the selected physical rate during communication?

Signal quality, channel conditions, and rate adaptation algorithms.

Can 802.11an devices dynamically change physical rates?

Yes, rate adaptation mechanisms adjust data rates based on real-time link conditions.

What frequency band does 802.11an operate in?

The 5 GHz band.

How does MIMO improve physical rates?

By transmitting multiple data streams simultaneously on different antennas.

What is the impact of coding rate on physical rates?

Higher coding rates increase throughput but require better signal quality.

How does 802.11an handle interference affecting physical rates?

Rate adaptation lowers modulation and coding to maintain reliable links under interference.

Are 802.11an physical rates backward compatible with 802.11a?

Yes, but only when using 20 MHz channels and single spatial stream.

What is the minimum physical rate in 802.11an?

Typically 6.5 Mbps using BPSK with coding rate 1/2 and 20 MHz channel.

How is physical rate information communicated between devices?

Through SIGNAL and HT-SIG fields in the PPDU header.

How do antenna configurations affect physical rates?

More antennas enable more spatial streams, increasing the maximum physical rate.

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