Cognitive Blind Interference Alignment for Macro-Femto Networks Articles uri icon

publication date

  • October 2017

start page

  • 5121

end page

  • 5136


  • 19


  • 65

International Standard Serial Number (ISSN)

  • 1053-587X

Electronic International Standard Serial Number (EISSN)

  • 1941-0476


  • We propose a cognitive blind interference alignment (BIA) scheme for macro-femto two-tier networks where the users are equipped with a single reconfigurable antenna. The proposed scheme fully cancels the intracell interference in both the upper and lower tiers. Moreover, it provides the optimal Degrees of Freedom (DoF) in the macro-tier while the lower tier subject to inter-tier interference achieves non-zero DoF. To do so, the proposed scheme relies on a topology management scheme where the users belong to the macro-tier if and only if they can optimally treat the interference caused by the transmission at the femto-tier as noise. The proposed scheme does not require any channel state information at the transmitter or data sharing between the macro-and femto-tiers. An outer bound of the DoF is derived for the considered macro-femto network. It is demonstrated that the proposed scheme can attain the outer bound subject to optimal sum DoF for the macro-tier. Furthermore, compared to previous approaches, cognitive BIA can achieve better sum rates for macro-femto networks for femtocells subject to different levels of inter-tier interference.


  • Computer Science
  • Electronics
  • Telecommunications


  • blind interference alignment; channel state information; degrees of freedom; heterogeneous networks; reconfigurable antennas