Analysis of different approaches to distributed multiuser MIMO in the 802.11ac

Joseph Kampeas, Asaf Cohen, Omer Gurewitz

Research output: Contribution to journalArticlepeer-review


The 802.11ac is a significant landmark in wireless communications, as it pushes towards new rate limits by utilizing downlink multiuser multiple-input multiple-output (MIMO) beamforming to transmit data to various locations simultaneously. However, successful beamforming relies on intelligent user selection which requires, in turn, extensive overhead of channel calibration between the AP and each of the candidate users. The large overhead involved in the user selection procedure overwhelms the multiuser gain and hinders the utilization of multiuser MIMO. The phenomenon is even more acute when APs handle large groups of mobile users, which frequently associate and disconnect, making the process of acquiring channel state from all users and selecting the appropriate group even harder. Thus, the subtle relation between the achievable rate of a scheduling algorithm and the overhead it requires is significant for the 802.11ac performance analysis. In this paper, we provide a rigorous analysis of distributed algorithms that schedule a group of users for the downlink. In particular, we accommodate common scheduling methods for the 802.11ac protocol and analyze both their achievable rate and their calibration process overhead. Both analysis and extensive simulations depict the superiority of simple threshold-based methods in terms of the throughput.

Original languageEnglish
Article number8778735
Pages (from-to)2548-2561
Number of pages14
JournalIEEE Transactions on Mobile Computing
Issue number11
StatePublished - 1 Nov 2020


  • distributed scheduling
  • overhead analysis

ASJC Scopus subject areas

  • Software
  • Computer Networks and Communications
  • Electrical and Electronic Engineering


Dive into the research topics of 'Analysis of different approaches to distributed multiuser MIMO in the 802.11ac'. Together they form a unique fingerprint.

Cite this