Advantages of 802.11ac | disadvantages of 802.11ac

This page covers advantages and disadvantages of 802.11ac. It mentions 802.11ac advantages or benefits and 802.11ac disadvantages or drawbacks.

What is 802.11ac?

Introduction:
This standard is one of the series of WLAN standards and its evolution is after IEEE 802.11n. This 802.11ac technology is developed to provide data rate in Gbps for wireless devices mainly for WLAN applications. In the previous versions of 802.11 series of standards were designed for single user operation. In 802.11ac multi user concept was introduced with multiuser MIMO feature. Beamforming has been added to cover more region and specific region with the focused beam concept.

Following are the features of 802.11ac technology.
• Frequency Bands: 5 GHz
• Channel Bandwidths: 20 MHz, 40 MHz, 80+80 MHz, 160 MHz
• FFT sizes: 64, 128, 256, 512
• Subcarrier spacing: 312.5 KHz
• OFDM symbol duration: 3.2µs + 0.8/0.4 µs CP
• Modulation scheme (highest): 256 QAM
• Data rates: 433 Mbits/sec(with 80 MHz and 1 Spatial Streams(SS)), 6.933 Gbits/sec (with 160MHz, 8 SS)
Refer 802.11ac tutorial >> for more information.

Benefits or advantages of 802.11ac

Following are the benefits or advantages of 802.11ac:
➨It offers gigabit speeds which is 3 times compare to 802.11n.
➨It offers whole home coverage with fewer dead spots.
➨It uses wider channel bandwidths (80 MHz and 160 MHz).
➨It uses complex modulation schemes upto 256-QAM. This delivers 33% increase in data rates.
➨It uses multiple spatial streams which delivers N-fold increase in the efficiency.
➨It uses Multi-User MIMO as shown in the figure. This enables simultaneous downlink transmission to single stream clients. This helps in improvement of network capacity.

Drawbacks or disadvantages of 802.11ac

Following are the drawbacks or disadvantages of 802.11ac:
➨2.4 GHz band is not supported.
➨It supports symbol duration with only small length.
➨Higher modulation scheme such as 1024QAM is not supported.
➨The uplink access is contention based. This leads to collisions, backoffs and reduction in effective throughput when there are more number of devices.
➨MU-MIMO is not supported in the uplink. In 802.11ac wave-2, MU-MIMO is used only in the downlink with 4 simultaneous streams.

Also refer advantages and disadvantages of 802.11ax >>.

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