April 01, 2019

Joint alpha-fairness based power allocation and user encoding ordering for zero-forcing nonlinear precoding in G.fast downstream transmission

  • Lanneer W.
  • Maes J.
  • Moonen M.
  • Tsiaflakis P.

In next generation digital subscriber line (DSL) systems, like G.fast that exploits high frequencies up to 212 MHz, the crosstalk levels among lines (i.e. users) get increasingly stronger. To precompensate the crosstalk in downstream transmission, nonlinear precoding (NLP) is proposed as a near-optimal dynamic spectrum management (DSM) technique. However, existing DSM algorithms for multi-tone NLP user encoding ordering (UEO) are rather heuristic in how they approach fairness and suffer from substantial suboptimality. In this paper, we develop a suit of novel DSM algorithms for joint power allocation and UEO that enforce a generalized alpha-fairness policy, called alpha-fair UEO. Since finding the globally optimal UEO is a combinatorial optimization problem with excessive computational complexity, first an algorithm is developed that uses iterative per-tone exhaustive searches and provides near-optimal approximate solutions. To further improve the computational complexity, next two efficient suboptimal methods are suggested to replace the expensive pertone exhaustive searches, leading to two other alpha-fair UEO algorithms which are tractable for large scenarios against only little performance loss. Simulations of a G.fast cable binder show that alpha-fair UEO achieves a trade-off between fairness and performance that outperforms the state-of-the-art UEO methods.

View Original Article

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 ...