SU-MIMO And MU-MIMO
Multiple-input and multiple-output (MIMO), first seen on 802.11n devices, takes advantage of a radio phenomenon known as multipath propagation, which increases the range and speed of Wi-Fi. Multipath propagation is based on the ability of a radio signal to take slightly different pathways between the router and client, including bouncing off intervening objects as well as floors and ceilings. With multiple antennas on both the router as well as the client—and provided they both support MIMO—then using antenna diversity can combine simultaneous data streams to increase throughput.
When MIMO was originally implemented, it was SU-MIMO, designed for a Single User. In SU-MIMO, all of the router's bandwidth is devoted to a single client, maximizing throughput to that one device. While this is certainly useful, today's routers communicate with multiple clients at one time, limiting the SU-MIMO's technology's utility.
The next step in MIMO's evolution is MU-MIMO, which stands for Multiple User-MIMO. Whereas SU-MIMO was restricted to a single client, MU-MIMO can now extend the benefit to up to four. The first MU-MIMO router released, the Linksys EA8500, features four external antennas that facilitate MU-MIMO technology allowing the router to provide four simultaneous continuous data streams to clients.
Before MU-MIMO, a Wi-Fi network was the equivalent of a wired network connected through a hub. This was inefficient; a lot of bandwidth is wasted when data is sent to clients that don't need it. With MU-MIMO, the wireless network becomes the equivalent of a wired network controlled by a switch. With data transmission able to occur simultaneously across multiple channels, it is significantly faster, and the next client can "talk" sooner. Therefore, just as the transition from hub to switch was a huge leap forward for wired networks, so will MU-MIMO be for wireless technology.
Beamforming was originally implemented in 802.11n, but was not standardized between routers and clients; it essentially did not work between different manufacturers' products. This was rectified with 802.11ac, and now beamforming works across different manufacturers' gear.
What beamforming does is, rather than have the router transmit its Wi-Fi signal in all directions, it allows the router to focus the signal to where it is needed to increase its strength. Using light as an analogy, beamforming takes the camping lantern and turns it into a flashlight that focuses its beam. In some cases, the Wi-Fi client can also support beamforming to focus the signal of the client back to the router.
While beamforming is implemented in 802.11ac, manufacturers are still allowed to innovate in their own way. For example, Netgear offers Beamforming+ in some of its devices, which enhances throughput and range between the router and client when they are both Netgear products and support Beamforming+.
Other Wi-Fi Features
When folks visit your house, they often want to jump on your wireless network, whether to save on cellular data costs or to connect a notebook/tablet. Rather than hand out your Wi-Fi password, try configuring a Guest Network. This facilitates access to network bandwidth, while keeping guests off of other networked resources. In a way, the Guest Network is a security feature, and feature-rich routers offer this option.
Another feature to look for is QoS, which stands for Quality of Service. This capability serves to prioritize network traffic from the router to a client. It's particularly useful in situations where a continuous data stream is required; for example, with services like Netflix or multi-player games. In fact, routers advertised as gaming-optimized typically include provisions for QoS, though you can find the functionality on non-gaming routers as well.
Another option is Parental Control, which allows you to act as an administrator for the network, controlling your child's Internet access. The limits can include blocking certain websites, as well as shutting down network access at bedtime.