A reconfigurable intelligent surface-aided rectangular differential spatial modulation (RIS-RDSM) scheme is presented. From the space-time structure of RIS-SM, the RIS-RDSM scheme is designed to achieve diversity to combat channel fading. Then the matched filter (MF)-based low-complexity detector for RIS-RDSM is formulated, and theoretical average bit error rate (ABER) performance bound is derived. Simulation results demonstrate that RIS-RDSM over one time slot T =1 and two time slots T = 2 approaches and outperforms the performance of the existing coherent RIS-SM, respectively.

In this paper, a high-rate and diversity-achieving spatial modulation transmission scheme is proposed, which uses the stacked Alamouti code as the transmitted signal matrix and then is named as stacked Alamouti based spatial modulation (SA-SM) scheme. In this scheme, the spatial constellation (SC) is composed of all the possible activated antennas combinations. According to a specific SC codeword, the corresponding symbols in the stacked Alamouti code are simultaneously activated. Owing to the structure of stacked Alamouti code, the SA-SM scheme can work with arbitrary even number of transmit antennas nT, and any number of activated antennas from 1 to nT. With the same number of activated antennas nA, the SA-SM scheme carries more symbols than the spatially modulated orthogonal space-time block codes (SM-OSTBC) scheme, thus SA-SM can achieve higher spectral efficiency. Without the need of any parameter or matrix optimization, the SA-SM scheme enjoys the non-vanishing determinants property. Moreover, owing to possessing the block-orthogonal structure, SA-SM enables faster metric computations in the QR decomposition-M detection, and then it achieves significant decoding complexity reduction without performance loss. Under various system configurations, the performance advantages of SA-SM over several existing diversity-achieving SM schemes such as GSTSK and SM-OSTBC, are shown by simulation results for various spectral efficiencies.

In this letter, a new multiple-input multiple-output orthogonal frequency division multiplexing with index modulation (MIMO-OFDM-IM) scheme achieving diversity is proposed. It combines space-frequency code and MIMO-OFDM-IM to take advantage of both, and we call it as the space-frequency coded index modulation (SFC-IM) scheme. The proposed SFC-IM scheme can achieve the transmit diversity order of 2 by optimizing an angle parameter. A linear-complexity maximum likelihood receiver is given for the new scheme, which profits from the orthogonality between the real and imaginary parts of the symbols contained in the SFC-IM codewords. The simulation results show the performance advantage of the SFC-IM scheme over the MIMO-OFDM-IM scheme.

This correspondence corrects an error in Section III-B of the paper titled “Spatially Modulated Orthogonal Space-Time Block Codes with Non-Vanishing Determinants”, published in the IEEE Transactions on Communications, vol. 62, no. 1, pp. 85–99, Jan. 2014.