Analysis of Very High Throughput (VHT) at
MAC and PHY Layers under MIMO Channel inIEEE 802.11ac WLAN
Gul Zameen Khan*, Ruben Gonzalez*, Eun-Chan Park**, Xin-Wen Wu**School of Information and Communication Technology, Griffith University, Australia**Dept. of Information and Communication Engineering, Dongguk University, South Korea
gz.khan@griffithuni.edu.au, r.gonzalez@griffith.edu.au, ecpark@dongguk.edu, x.wu@griffith.edu.au

Abstract—This paper analyses the very high system throughput of IEEE 802.11ac by taking into consideration of the key features
MAC and PHY layers under a Multiple In Multiple Out (MIMO) channel. Throughput at the MAC layer is calculated from thetransmission probability, contention window and transmission stage. Likewise, the new critical attributes of 802.11ac PHY (i.e.
modulation and coding schemes, spatial streams, and channel bandwidth) are used to determine the throughput at the PHY layer. To
this end, a theoretical model is formulated at the MAC and PHY layers followed by a system model of MIMO multipath fading
channel for 802.11ac. The system model is verified by simulation analysis. The results compare theoretical and simulation findings fordifferent sets of parameters. Furthermore, important trends and trade-offs are identified between system throughput and (MAC +PHY) features as a function of number of contending stations and payload size. The system throughput of 802.11ac networks issignificantly improved due to the addition of new PHY features. However, the system may degrade upto 50% in terms of symbol
reception in case of a high error-prone MIMO channel. The performance of 802.11ac systems is also analyzed under different MIMO
TGn channel models in terms of Packet Error Rate (PER). Thus based on our simulation results, an appropriate channel model canbe chosen for 802.11ac network under a given configuration to achieve a better performance.
Keyword — Performance, analysis, throughput, MAC, physical, MIMO, multipath, fading, transmission probability, contention window,modulation, coding, spatial streams, channel bandwidth, channel model
Gul Zameen Khan received a Bachelor degree in Computer Systems Engineering from University of Engineering and Technology
Peshawar Pakistan in 2007 and a Master degree in Computer Engineering from Hanyang University South Korea in 2011. He is currentlyworking as a researcher with the Intelligent Wireless Technology and Applications research group at Griffith University Australia. He has
worked as Lab Engineer in Ghulam Ishaq Khan Institute of Engineering Sciences and Technology Pakistan. In addition, he has worked aslecturer in Sarhad University of IT Peshawar Pakistan and COMSATS Institute Abbottabad Pakistan. He has also worked as a ResearchAssistant at Wireless Networks Lab, Dongguk University, South Korea. His areas of interest are MAC and PHY layers analysis of 802.11,
multicast in Wi-Fi Direct, and wireless sensor networks. Mr. Gul Zameen Khan is a member of IEEE and Institute for Integrated andIntelligent Systems, Griffith University Australia. He is also a professional member of Pakistan Engineering Council.

Dr. Ruben Gonzalez received a B.E. and PhD from the University of Technology, Sydney (UTS) and is currently a senior Lecturer in theSchool of ICT, at Griffith University Australia. He is also the director of the bachelor of computer science at Griffith University.
Previously he was founder and CTO of ActiveSky Inc, a wireless media technology company and has also held research positions at
Wollongong University, OTC Ltd Research Labs and UTS. He has also held software engineering positions at various private enterprises.
Dr. Ruben Gonzalez is a member of the Institute for Integrated and Intelligent Systems, Griffith University Australia. He has over 80
refereed publications and a number of patents.

Prof. Eun-Chan Park received the B.S., M.S., and Ph.D. degrees from the School of Electrical Engineering and Computer Science, Seoul
National University, Seoul, Korea, in 1999, 2001, and 2006, respectively. He worked for Samsung Electronics, Korea, as a senior engineer
from 2006 to 2008. He is currently an Associate Professor in the Department of Information and Communication Engineering, Dongguk
University-Seoul, Korea. He is also the head of the Wireless Networks Lab, at Dongguk University South Korea. His research interests
include performance analysis, resource allocation, quality of service, congestion control, and cross-layer optimization in wired andwireless networks. Dr. Eun-Chan Park is a member of IEEE Communications Society.

Dr. Xin-Wen Wu received the Ph.D. degree from the Chinese Academy of Sciences, Beijing, China. He was with the Chinese Academyof Sciences; the University of California at San Diego, La Jolla, CA, USA, as a Post-Doctoral Researcher; and the University ofMelbourne, Parkville, VIC, Australia, as a Research Fellow. He was with the faculty of School of Information Technology andMathematical Science, University of Ballarat, VIC, Australia. He is currently with the faculty of School of Information andCommunication Technology, Griffith University, Gold Coast, QLD, Australia. Mr. Xin-Wen Wu is a senior member of IEEE. His
research interests include cyber and data security, coding and information theory and their applications, communications and networks.
He has co-authored over 70 research papers, book chapters and two books in the above-mentioned areas.