New Spatial Modulation Scheme based on Quaternary Quasi-Orthogonal Sequence for 8 Transmit Antennas

Abstract

BSTRACTRecently, a spatial modulation (SM) scheme achieving high throughput based on quaternary quasi-orthogonal sequences (Q-QOSs), referred to as Q-QOS-SM, is presented for        ⋯ transmit antennas. In this paper, based on the design approach of the conventional Q-QOS-SM, new improved QO-SM (I-QO-SM)schemes are proposed for 8 transmit antennas. The new schemes employ Q-QOSs of length 4 or 2 unlike of 8 in the original one, which guarantees more information bits to be allocated for antenna index parts compared to the conventional Q-QOS-SM. By computer simulation results, the proposed scheme are shown to enjoy much higher throughputs compared to the conventional other SM schemes for all simulation environments. include the space-time block code (STBC) [1][2][3] and the vertical Bell Labs layered space-time (V-BLAST) [4][5] , whereby the former provides diversity gain and the latter achieves a high transmission data rate. However, STBC cannot improve the data rate and the orthogonality is lost in the case where there are more than two transmit antennas. Likewise, although V-BLAST can offer many improvements in spectral efficiency and data rate, the high decoding complexity in the optimal receiver and large inter-channel interference make it restricted in practice.

Generalized Quaternary Quasi-Orthogonal Sequences Spatial Modulation

“…The SMM of G-QO-SM for the arbitrary number of transmit antennas is given in (13) and (17), and the size of SMM is designed as   ×    , thereby guaranteeing that the G-QO-SM transmits   spatial bits over   transmit antennas.…”

“…The SMMs of the odd and even antennas are presented in (13) and (17), respectively. From the (7)- (17), it can be observed that the SMM of G-QO-SM is designed to guarantee the size of In original SM [6][7][8] , conventional Q-QOS-SM [10] , QSM [14] and ESM [15] , the number of transmit …”

“…In the Q-QOS-SM, a spatial modulation matrix (SMM) [11,12] is introduced as a group of weighting vectors, and the spatial bits are mapped into one column vector of the SMM per symbol duration. The improved Q-QOS-SM (I-QO-SM) [13] has been then reported to further improve the data throughput of the Q-QOS-SM, but it is only designed for eight transmit antennas.…”