In general, 802.11ac could be seen as a lateral extension of 802.11n in which the two basic notions of multiple input, multiple output (MIMO) and wider channel bandwidth, anchored in 802.11n [5], [6] are enhanced. The basic idea is that the theoretical maximum PHY data rate can be linearly increased by a factor of the number of spatial streams (transmit/receive antennas) or channel bandwidth. In other words, PHY data rate can be doubled (quadrupled) by doubling the number of spatial streams or (and) channel bandwidth. Fig. 1 illustrates the key mandatory and optional PHY features, as well as the MAC enhancements introduced in 802.11ac. Note that the blocks in dashed lines represent the new PHY features and key MAC enhancements of 802.11ac in contrast to 802.11n at the time of writing.