ws 15(3): e4

Research Article

A hybrid TIM-NOMA scheme for the Broadcast Channel

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  • @ARTICLE{10.4108/ws.1.3.e4,
        author={V.  Kalokidou and O.  Johnson and R.  Piechocki},
        title={A hybrid TIM-NOMA scheme for the Broadcast Channel},
        journal={EAI Endorsed Transactions on Wireless Spectrum},
        keywords={Topological Interference Management, Non-Orthogonal Multiple Access},
  • V. Kalokidou
    O. Johnson
    R. Piechocki
    Year: 2015
    A hybrid TIM-NOMA scheme for the Broadcast Channel
    DOI: 10.4108/ws.1.3.e4
V. Kalokidou1,*, O. Johnson2, R. Piechocki1
  • 1: Communication Systems and Networks Research Group, School of Engineering, University of Bristol, Bristol, UK
  • 2: School of Mathematics, University of Bristol, Bristol, UK
*Contact email:


Future mobile communication networks will require enhanced network efficiency and reduced system overhead. Research on Blind Interference Alignment and Topological Interference Management (TIM) has shown that optimal Degrees of Freedom can be achieved, in the absence of Channel State Information at the transmitters. Moreover, the recently emerged Non- Orthogonal Multiple Access (NOMA) scheme suggests a different multiple access approach, compared to the orthogonal methods employed in 4G, resulting in high capacity gains. Our contribution is a hybrid TIM-NOMA scheme in K-user cells, where users are divided into T groups. By superimposing users in the power domain, we introduce a two-stage decoding process, managing “inter-group” interference based on the TIM principles, and “intra-group” interference based on Successful Interference Cancellation, as proposed by NOMA. We show that the hybrid scheme can improve the sum rate by at least 100% compared to Time Division Multiple Access, for high SNR values.