User-Centric Interference Nulling in Downlink Multi-Antenna Heterogeneous Networks

Ying Cui, Yueping Wu, Dongdong Jiang, Bruno Clerckx

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)


In heterogeneous networks (HetNets), strong interference due to spectrum reuse affects each user's signal-to-interference ratio (SIR), and hence is one limiting factor of network performance. In this paper, we propose a user-centric interference nulling (IN) scheme in a downlink large-scale HetNet to improve coverage/outage probability by improving each user's SIR. This IN scheme utilizes at most maximum IN degree of freedom (DoF) at each macro-base station to avoid interference to uniformly selected macro (pico) users with signal-to-individual-interference ratio below a macro (pico) IN threshold, where the maximum IN DoF and the two IN thresholds are three design parameters. Using tools from stochastic geometry, we first obtain a tractable expression of the coverage (equivalently outage) probability. Then, we obtain the asymptotic expressions of the coverage/outage probability in the low and high SIR threshold regimes. The analytical results indicate that the maximum IN DoF can affect the order gain of the outage probability in the low SIR threshold regime, but cannot affect the order gain of the coverage probability in the high SIR threshold regime. Moreover, we characterize the optimal maximum IN DoF, which optimizes the asymptotic coverage/outage probability. Finally, numerical results show that the proposed scheme can achieve good gains in coverage/outage probability over some baseline schemes.

Original languageEnglish
Pages (from-to)7484-7500
Number of pages17
JournalIEEE Transactions on Wireless Communications
Issue number11
Publication statusPublished - 2016 Nov


  • Heterogeneous networks
  • inter-tier interference coordination
  • multiple antennas
  • optimization
  • stochastic geometry

ASJC Scopus subject areas

  • Computer Science Applications
  • Electrical and Electronic Engineering
  • Applied Mathematics


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