New Signal Designs for Enhanced Spatial Modulation

Abstract

Abstract-In this paper, we present three new signal designs for Enhanced Spatial Modulation (ESM), which was recently introduced by the present authors. The basic idea of ESM is to convey information bits not only by the index(es) of the active transmit antenna(s) as in conventional Spatial Modulation (SM), but also by the types of the signal constellations used. The original ESM schemes were designed with reference to single-stream SM and involved one or more secondary modulations in addition to the primary modulation. Compared to single-stream SM, they provided either higher throughput or improved signal-to-noise ratio (SNR). In the present paper, we focus on multi-stream SM (MSM) and present three new ESM designs leading to increasing SNR gains when they are operated at the same spectral efficiency. The secondary signal constellations used in the first two designs are based on a single geometric interpolation step in the signal constellation plane, while the third design also makes use of additional constellations derived through a second interpolation step. The new ESM signal designs are described for MIMO systems with four transmit antennas two of which are active, but we also briefly present extensions to higher numbers of antennas. Theoretical analysis and simulation results indicate that the proposed designs provide a significant SNR gain over MSM.

Pilot-Based Adaptive Channel Estimation for Underwater Spatial Modulation Technologies

“…Therefore, SM has less receiver complexity, it effectively removes ICI, and it does not require IAS of the MIMO link due to availability of one RF chain at the transmitter. Different SMTs are introduced [10,[15][16][17][18][19][20][21][22][23] by allowing it to enable one or more RF chains using different techniques so that high throughput and enhanced SNR can be achieved. GSM [21,22] is the most prevalent technique, in which the multiple antennas are active in each communication channel so that high data rate can be achieved.…”

“…These variations in the number of activated transmission antennas enhance the realization of the communication channel, resulting in increased available data rate. An additional parameter is also used to map the information bits, i.e., data signal constellations [17]. Therefore, the signal constellation type is also used to carry the transmitted data in addition to indices of the transmit antennas as in SM, GSM, and FGSM.…”

Spatial Lattice Modulation for MIMO Systems

“…For instance, the QAM symbols of MA-SM [9] are rotated to a different phase for each active antenna-subset; as a result, the minimum distance increases. Enhanced spatial modulation (ESM) [15], [16] uses a similar approach. The idea of ESM is to construct a primary and a secondary signal constellation set.…”

Compressed-Sensing Assisted Spatial Multiplexing Aided Spatial Modulation

“…Additionally, other SM variants have also been investigated in [39]- [43]. But the SM variants of [39]- [42] are mainly designed for two RF chains and hence are associated with a low throughput. The TAC set size of the SM variant in [43] …”