  A novel space-time parallel index modulation scheme is proposed in this paper
for conveying extra digital information with the aid of space and time indices.
In this proposed scheme, time-indexing is cleverly performed in parallel
spatial modulation (PSM) schemes using transmit antenna grouping, and referred
to as time-indexed parallel spatial modulation (TI-PSM). In this scheme,
transmit antennas are divided into groups to adopt TI-SM scheme in large-scale
multiple input multiple output (MIMO) systems with inter-channel interference
(ICI) avoidance. This scheme is attractive due to both the high data rate and
good performance improvement that can be achieved. The bit error rate (BER)
performance of the TI-PSM scheme is evaluated and compared to that of the
conventional schemes. Simulation results demonstrated that a significant
improvement is achieved by the TI-PSM scheme as compared to the TI-SM and PSM
schemes for the same achieved rate. It is also shown that TI-SM and TI-PSM
schemes provide higher performance drop with channel estimation errors (CEEs)
than the conventional SM and PSM systems. Therefore, due to the high
performance improvements achieved in TI-PSM scheme, it can be effectively
regarded as a promising solution for various 5G and beyond wireless networks.
