  Multidimensional Index Modulations (IM) are a novel alternative to
conventional modulations which can bring considerable benefits for future
wireless networks. Within this scope, in this paper we present a new scheme,
named as Precoding-aided Transmitter side Generalized Space-Frequency Index
Modulation (PT-GSFIM), where part of the information bits select the active
antennas and subcarriers which then carry amplitude and phase modulated
symbols. The proposed scheme is designed for multiuser multiple-input
multiple-output (MU-MIMO) scenarios and incorporates a precoder which removes
multiuser interference (MUI) at the receivers. Furthermore, the proposed
PT-GSFIM also integrates signal space diversity (SSD) techniques for tackling
the typical poor performance of uncoded orthogonal frequency division
multiplexing (OFDM) based schemes. By combining complex rotation matrices (CRM)
and subcarrier-level interleaving, PT-GSFIM can exploit the inherent diversity
in frequency selective channels and improve the performance without additional
power or bandwidth. To support reliable detection of the multidimensional
PT-GSFIM we also propose three different detection algorithms which can provide
different tradeoffs between performance and complexity. Simulation results
shows that proposed PT-GSFIM scheme, can provide significant gains over
conventional MU-MIMO and GSM schemes.
