Kong University of Science and Technology. MU-MIMO was included in the 802.11ac standard (developed starting in 2011 and approved in 2014). MU-MIMO capacity appears for the first time in what have become known as "Wave 2" products. Qualcomm announced chipsets supporting MU-MIMO in April 2014. Broadcom introduced the first 802.11ac chipsets supporting six spatial streams for data rates up to 3.2 Gbit/s in April 2014. Quantenna says it is developing chipsets to support eight spatial streams for data rates up to 10 Gbit/s. Massive MIMO, Cooperative MIMO (CO-MIMO), and HetNets (heterogeneous networks) are currently the focus of research concerning 5G wireless. The development of 5G standards is expected to begin in 2016. Prominent researchers to date include Jakob Hoydis (of Alcatel-Lucent), Robert W. Heath (at the University of Texas at Austin), Helmut Bölcskei (at ETH Zurich), and David Gesbert (at EURECOM). Trials of 5G technology have been conducted by Samsung. Japanese operator NTT DoCoMo plans to trial 5G technology in collaboration with Alcatel-Lucent, Ericsson, Fujitsu, NEC, Nokia, and Samsung. References IEEE 802 Information theory Mobile telecommunications standards Radio resource management