January 01, 2018

Novel Lattice Reduction Algorithms: Precoder reduction and vector perturbation tradeoffs

  • Guenach M.

In this letter we present a novel iterative lattice reduction algorithm in precoded multiple input multiple output (MIMO) transmission. A unified framework is developed for this purpose, to reduce the precoder maximum row norm by iteratively minimizing the weighted sum of the precoder rownorms. We show that at each iteration in the optimization, the objective can be minimized using the least-squares or the sphere encoding (SE) or equivalently sphere decoding traditionally used for uplink data detection or for the computation of the vector perturbation (VP) in downlink precoded MIMO systems. We further investigate the different tradeoffs between the precoder reduction and the VP computation. Simulation results reveal that the proposed SE-based lattice reduction algorithm outperforms the state of the art LLL algorithm, and further relaxes the usage of advanced complex VP algorithms such as the sate of the art SE.

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Recent Publications

January 01, 2019

Friendly, appealing or both? Characterising user experience in sponsored search landing pages

  • Bron M.
  • Chute M.
  • Evans H.
  • Lalmas M.
  • Redi M.
  • Silvestri F.

© 2017 International World Wide Web Conference Committee (IW3C2), published under Creative Commons CC BY 4.0 License. Many of today's websites have recognised the importance of mobile friendly pages to keep users engaged and to provide a satisfying user experience. However, next to the experience provided by the sites themselves, ...

January 01, 2019

Analyzing uber's ride-sharing economy

  • Aiello L.
  • Djuric N.
  • Grbovic M.
  • Kooti F.
  • Lerman K.
  • Radosavljevic V.

© 2017 International World Wide Web Conference Committee (IW3C2), published under Creative Commons CC BY 4.0 License. Uber is a popular ride-sharing application that matches people who need a ride (or riders) with drivers who are willing to provide it using their personal vehicles. Despite its growing popularity, there exist ...

January 01, 2019

The paradigm-shift of social spambots: Evidence, theories, and tools for the arms race

  • Cresci S.
  • Petrocchi M.
  • Pietro R.
  • Spognardi A.
  • Tesconi M.

© 2017 International World Wide Web Conference Committee (IW3C2), published under Creative Commons CC BY 4.0 License. Recent studies in social media spam and automation provide anecdotal argumentation of the rise of a new generation of spambots, so-called social spambots. Here, for the first time, we extensively study this novel ...