Interference due to null space mismatch in cooperative multipoint MIMO cellular networks

Alexandros Manolakos, Yair Noam, Andrea J. Goldsmith

Research output: Chapter in Book/Report/Conference proceedingConference contribution

5 Scopus citations

Abstract

Cooperative Multi-Point (CoMP) has emerged as a new paradigm to improve both average cell and cell edge throughput in cellular networks. However, the performance is significantly degraded due to Out-of-Group Interference (OGI). One way to mitigate OGI is to restrict the interfering signal to lie inside the null space of the unintended receiver. Yet, accurately tracking this null space is a challenge in time-varying channels. In this work, we address the effect of null space variations on the OGI mitigation. A measure for accuracy of null space estimates is proposed and bounds are derived on the residual average worst-case interference. We define the Null Space Update Rate as the inverse of the Null Space Coherence Time; i.e., the time it takes a null space estimate to become outdated relative to an interference threshold on the unintended receiver. In the case of Rayleigh fading channels, we derive a bound on the Null Space Coherence Time in closed form, and compare the performance of a given null space tracking algorithm against this bound. Both Monte Carlo simulations and the analytical bounds show that the worst-case interference levels are sensitive to null space variations, independent of the null space learning algorithm employed.

Original languageEnglish (US)
Title of host publication2014 IEEE International Conference on Communications, ICC 2014
PublisherIEEE Computer Society
Pages5148-5153
Number of pages6
ISBN (Print)9781479920037
DOIs
StatePublished - 2014
Externally publishedYes
Event2014 1st IEEE International Conference on Communications, ICC 2014 - Sydney, NSW, Australia
Duration: Jun 10 2014Jun 14 2014

Publication series

Name2014 IEEE International Conference on Communications, ICC 2014

Other

Other2014 1st IEEE International Conference on Communications, ICC 2014
CountryAustralia
CitySydney, NSW
Period6/10/146/14/14

All Science Journal Classification (ASJC) codes

  • Computer Networks and Communications

Keywords

  • Cooperative Multi-point communications
  • MIMO
  • Null Space Coherence Time
  • Null Space Mismatch
  • Out of Group interference mitigation

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