Wireless MIMO switching with zero forcing and network coding

Fanggang Wang*, Soung Chang Liew, Dongning Guo

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

23 Scopus citations


A wireless relay with multiple antennas is called a multiple-input- multiple-output (MIMO) switch if it maps its input links to its output links using precode-and-forward. Namely, the MIMO switch precodes the received signal vector in the uplink using some matrix for transmission in the downlink. This paper studies the scenario of K stations and a MIMO switch, which has full channel state information. The precoder at the MIMO switch is either a zero-forcing matrix or a network-coding matrix. With the zero-forcing precoder, each destination station receives only its desired signal with enhanced noise but no interference. With the network-coding precoder, each station receives not only its desired signal and noise, but possibly also self-interference, which can be canceled. Precoder design for optimizing the received signal-to-noise ratios at the destinations is investigated. For zero-forcing relaying, the problem is solved in closed form in the two-user case, whereas in the case of more users, efficient algorithms are proposed and shown to be close to what can be achieved by extensive random search. For network-coded relaying, we present efficient iterative algorithms that can boost the throughput further.

Original languageEnglish (US)
Article number6280251
Pages (from-to)1452-1463
Number of pages12
JournalIEEE Journal on Selected Areas in Communications
Issue number8
StatePublished - 2012


  • Beamforming
  • MIMO switching
  • network coding
  • relay
  • zero-forcing

ASJC Scopus subject areas

  • Computer Networks and Communications
  • Electrical and Electronic Engineering


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