Peter Bright at Ars Technica has an article out on a key feature coming with the latest generation of 802.11ac WLAN Access Points. At the CES in Las Vegas at the start of the year, multiple companies announced new devices that incorporate multi-user multiple input multiple output (MU-MIMO) technology. The technology allows multiple users to access the internet off of the same AP and still maintain Gbps speeds, according to Bright.
With ordinary access points, every other device on the network must wait its turn while that AP is talking with the first device. This results in bandwidth getting shared between devices, resulting in much lower speeds than advertised.
MU-MIMO, on the other hand, would allow multiple devices to get top speeds simultaneously, resulting in little to no sharing of bandwidth. How does this work? Apparently through a little something called Beamforming. Bright explains how it applies here:
“A MU-MIMO router measures the time it takes for a client to receive data on the network, and by comparing the different timings from the different antennas, the base station can figure out which direction the client lies in. Using this information, the base station can then modulate the signals transmitted from its antennas so that the signal is strongest in the direction of the client and reduced everywhere else.
This means that instead of broadcasting the signal equally in all directions, the base station is only sending it in the client’s direction. Here’s where the “multi user” aspect kicks in: the base station can simultaneously send a signal beam to a second client, provided that the client isn’t in the same direction as the first client.”
Beamforming is also used increase the range of 802.11ac APs, among other benefits. In order for beamforming to assist with MU-MIMO, there are some additional requirements, however. First is the need for APs/routers with multiple antennas. Second, in order for MU-MIMO to work both the AP and the mobile device need to support the feature. Finally, as Bright hints at above, the mobile devices need to be spatially separated from each other relative to the AP, or else the AP will not be able to tell the signals apart as easily and those mobile devices will go back to sharing bandwidth. Bright says that both Netgear and D-Link of APs/routers shipping this year that support MU-MIMO.
So if you have multiple users that need blazing fast speeds off the same AP, you now know what to look for.