Improving Generalized Spatial Modulation Using Translation Patterns

Abstract

Generalized spatial modulation (GSM) is a spectral-efficient technique used in multiple-input multipleoutput (MIMO) wireless communications when the number of radio frequency chains at the transmitter is less than the number of transmit antenna elements. We propose a family of signal constellations, as an improvement over GSM, which splits the information bits into three parts, and encodes the first part into a set of complex symbols, the second part into the choice of a subset of antennas activated for transmission (as in GSM), and the third into a translation pattern that offsets the symbols transmitted through the activated antennas. The nominal coding gain (the ratio of the squared minimum distance between transmit vectors to the transmit power) of our scheme is higher than that of GSM by at least 0.86 dB, and this improvement can be as much as 2.87 dB based on the system parameters. We show that the new scheme has advantages over other known signal constellations for GSM, in terms of error performance, nominal coding gain and design flexibility.

Generalized Quadrature Index Modulation With Multi-Index and Dimension-Extended Constellation

“…Furthermore, Fig. 4 also depicts the BER curves for the GSM-MIM with the parameters of (1,1,4,32), QIM-TDC with 64-3DCII constellation that is provided in [17], GSM with both 16QAM and 32QAM, ESM with 64QAM and QSM with 128QAM, SM-SC with the parameters of (3,32). According to the analysis of the squared MED provided by TABLE 3, at the spectral efficiency of 13 b/s/Hz, since GQIM has bigger squared MED than GSM, ESM, QSM, GSM-MIM and QIM-TDC, it will have better BER performance.…”

“…In order to further prove that the GQIM system using other E3DQAM constellations also has better BER performance than the existing classic systems, Fig. 5 depicts the BER versus SNR curves at 14 bits/s/Hz and [N t , N r ] = [8, 8] for the GQIM system with both 16-ary E3DQAM and 16-ary E3DPSK that are respectively obtained by rotating 8-ary 2D QAM constellation (i.e., ∈ {±1 ± 1j, ±2 ± 2j}) and 8PSK constellation, the SM-SC system with (3, 64), the QIM-TDC system with 128-3DCII constellation that is provided in [17], the GSM system with 32QAM, the GSM-MIM system with (1,1,8,32), the QSM system with 256QAM. Similarly to the analysis of Fig.…”

“…• GQIM: d2 S,min that is obtained by ( 16) and (17). where E ψ av denote the average energy per TSV of the ψ system.…”

“…In [14], inspired by QSM, the spatial constellation of SM is expanded to a new multi-dimensional constellations for the improvement of the BER performance. In [15]- [17], the approaches are proposed to improve the BER performance of the GSM system, even more reducing the detection complexity. Furthermore, to further improve the spectral efficiency, with the aid of a rotation angle, double spatial modulation (DSM) [18] scheme directly superimposes two independent SM transmission vectors for the achievable BER performance.…”