Qualcomm introduces 802.11ac chipsets with multi-user mimo for faster Wi-Fi

Qualcomm has announced a number of new 802.11ac-compatible Wi-Fi chipsets that can take advantage of multi-user mimo technology. This should allow multiple devices to simultaneously access an 802.11ac access point at high speed.

The second generation of 802.11ac equipment uses a number of existing techniques to obtain more bandwidth. For example, four streams can be used instead of three and the bandwidth per channel can be increased to 160MHz instead of 80MHz. A third improvement is the use of multi user mimo instead of single user mimo.

Currently, with single user mimo, a Wi-Fi device can achieve high speeds on an 802.11ac access point over three or four mimo connections. However, this high speed drops significantly if multiple devices connect to just one or two mimo streams, as each device has to wait “in turn” until it receives or is allowed to send data again. The multi-user mimo technology, which makes use of beamforming or better targeted Wi-Fi signals, must find an answer to this by grouping multiple devices. These are then simultaneously supplied with data by the router, increasing the total available bandwidth.

Qualcomm has announced a number of chipsets in its Atheros line that can handle the new mimo technology. For example, there are four chipsets for business routers and access points as well as for the mainstream models, with the QCA9980 chipset promising gross throughputs of up to 1.73Gbit/s. It uses four antennas and four multi-user mimo connections. The WCN3680 chipset is intended for mobile use and already integrated in the Snapdragon 801 and 805 socs. These use a single mu-mimo stream, although the firmware still needs to be made suitable for this feature. Qualcomm does not expect the first product announcements of particularly multi-user mimo compatible routers until the end of this year and the first concrete products in the first quarter of next year.