Amendment to 802.11ac spec unveils MU MIMO technology, expands Wi-Fi throughput by 10x

The IEEE's amendment to the original 802.11ac spec expands 5-GHz band data rates up to 7 Gbps.

Jan 7th, 2014

At this week's 2014 International CES in Las Vegas, the IEEE announced approval of the IEEE 802.11ac-2013 specification, intended to foster higher multi-user throughput in wireless local area networks (WLANs). The new amendment to the original 802.11ac Wi-Fi spec is intended to improve WLAN user experience by providing data rates up to 7 Gbps in the 5 GHz band -- more than 10x the speed that was previously standardized.

According to IEEE, the new IEEE 802.11ac specification adds channel bandwidths of 80 MHz and 160 MHz with both contiguous and non-contiguous 160 MHz channels for flexible channel assignment. It adds higher order modulation in the form of 256 quadrature amplitude modulation (QAM), providing an additional 33-percent improvement in data rate. A further doubling of the data rate is achieved by increasing the maximum number of spatial streams to eight.

See also: Analyst sees WLAN growth stalling in 802.11ac transition

Significantly, the IEEE 802.11ac amendment also introduces a revolutionary new technology to support multiple concurrent downlink transmissions, referred to as “multi-user multiple-input, multiple-output” (MU MIMO). By using smart antenna technology, MU MIMO enables more efficient spectrum use, higher system capacity and reduced latency by supporting up to four simultaneous user transmissions. This is particularly useful for client devices with a limited number of antennas, such as smartphones and tablets.

Finally, the IEEE 802.11ac amendment streamlines the existing transmit beamforming mechanisms and is increasing the adoption of the technology across devices. Transmit beamforming is a valuable technology that significantly improves coverage, reliability and data rate performance.

“As wireless networks become more widely deployed, users are able to transition applications from fixed links to the convenience, freedom and versatility of wireless links,” comments Bruce Kraemer, chair of the IEEE 802.11 working group.

Kraemer adds, “These transitions create an evolutionary demand to enhance the capacity of wireless networks in order to support the increasing number of users, as well as new classes of applications with higher bandwidth requirements. Moreover, as WLAN usage of shared spectrum grows, the wireless access mechanisms need to be improved to achieve higher multi-user throughput. IEEE 802.11ac is intended to meet these evolving needs for higher data rates and to help enable new generations of data-intensive wireless applications.”

For more information, visit http://standards.ieee.org/.

More news: In-depth: Gigabit Wi-Fi 802.11ac technology

More in Wireless/5G