Antenna grouping based generalized spatial modulation system

Spatial modulation (SM) technology [1], compared with the vertical Bell Labs layered space-time (V-BLAST) [2] and multiple-input and multiple-output (MIMO) [3] schemes, can significantly combat the inter-channel interference (ICI) and reduce the detection complexity at the receiver. SM exploits both the signal and the spatial domains to convey the information bits. However, traditional SM cannot obtain both the transmit diversity gain and the multiplexing gain effectively. As an extension of SM, generalized SM (GSM) [4] [5] can achieve the diversity gain and improve the spectral efficiency (SE) by simultaneously allowing multiple active transmit antennas (TAs) to convey the information. In order to enhance the multiplexing gain, current research on GSM with multiple TAs, such as multiple active spatial modulation (MA-SM) [6] and generalized spatial index modulation (GSIM) [7], allows several activated TAs to transmit different signals at the same time. To further achieve the multiplexing and diversity gains, the related literature also investigated the in-phase and quadrature index dimensions of SM, named as quadrature spatial modulation (QSM) [10], to transmit more index bits.