Abstract—The IEEE 802.11ac is an emerging very high
throughput (VHT) WLAN standard that could achieve PHY data
rates of close to 7 Gbps for the 5 GHz band. In this paper, we
introduce the key mandatory and optional PHY features, as well
as the MAC enhancements of 802.11ac over the existing 802.11n
standard in the evolution towards higher data rates. Through
numerical analysis and simulations, we compare the MAC performance
between 802.11ac and 802.11n over three different frame
aggregation mechanisms, viz., aggregate MAC service data unit
(A-MSDU), aggregate MAC protocol data unit (A-MPDU), and
hybrid A-MSDU/A-MPDU aggregation. Our results indicate that
802.11ac with a configuration of 80MHz and single (two) spatial
stream(s) outperforms 802.11n with a configuration of 40 MHz
and two spatial streams in terms of maximum throughput by
28% (84%). In addition, we demonstrate that hybrid A-MSDU/AMPDU
aggregation yields the best performance for both 802.11n
and 802.11ac devices, and its improvement is a function of the
maximum A-MSDU size.