Spatial modulation for massive MIMO

Abstract

Multiple-input multiple-output (MIMO) systems can increase wireless link capacity without requiring additional bandwidth and power. On the one hand, MIMO systems heavily depend on channel state information (CSI) at the receiver. It has also been shown that CSI at the transmitter (CSIT) can improve the link capacity and reliability considerably but with the disadvantage of extra feedback and computational costs. On the other hand, energy efficiency of MIMO systems could adversely increase with the number of antennas in the link. Therefore, there are considerable interests in energy efficient practical transmission schemes for MIMO links without CSIT. In this study, an emerging wireless communication concept which is termed as spatial modulation (SM) is considered for large scale MIMO. The results show that in information-theoretic viewpoint, SM achieves capacity comparable to the open-loop MIMO capacity even though a subset of transmit antennas is activated in every channel use. The reason is both the channel coefficients and input symbols carry information in SM. As a result, SM regains (compensates) the loss of information capacity due to activating a subset of antennas by modulating information in the antenna index. This means that the sum information rate remains high.

An Overview of Signal Processing Techniques for Terahertz Communications

“…By enabling the selection of various combinations of antennas at the same time, a generalized index modulation scheme can be defined [196], [197]. Typical massive MIMO SM and generalized SM solutions [198], [199] should be revisited in the ultra-massive THz context. Furthermore, when enabling adaptive antenna-frequency maps, generic index modulation (IM) solutions that take full advantage of the available resources can be configured, in which information bits are also mapped to frequency allocations.…”

Massive MIMO Detection Techniques: A Survey

“…• Capacity and link reliability: Massive MIMO increases the diversity gain, and hence, provides link robustness as it resists fading [21]. It is approved that the capacity increases without a bound as the number of antenna increases, even under a pilot contamination, when multicell minimum mean square error (MMSE) precoding/ combining and spatial channel correlation are used [22].…”

Terahertz-Band Ultra-Massive Spatial Modulation MIMO

“…where S is the number of AEs that can be simultaneously activated. The literature is rich in SM and GSM solutions for massive MIMO [81], [82]. However, even more efficient lowcomplexity algorithms are required at such large scales.…”