<p>Quadrature spatial modulation (QSM) scheme utilizes both in-phase and quadrature components to transmit the real and imaginary parts of the complex data symbol. A modified generalised QSM (mGQSM) scheme improves the spectral efficiency (SE) of the QSM by assuming more than one radio frequency (RF) chain. However, the SE of the conventional space modulation techniques (SMTs) is restricted to logarithmic proportional to the number of transmit antennas. Recently, a fully QSM (F-QSM) was introduced to achieve a linear proportionality between SE and number of transmit antennas by using a novel transmission mechanism. In this paper, we propose a fully generalized QSM (FGQSM) scheme to enhance the SE of F-QSM and mGQSM. In FGQSM, a variable number of transmit antenna combinations are used to transmit multiple data symbols. Moreover, the proposed scheme provides a linear proportionality between SE and number of transmit antennas which gives higher SE for lower number of transmit antennas. The bit error rate (BER) performance of the FGQSM is evaluated using the maximum-likelihood (ML) detector and compared it with mGQSM, RC-mGQSM, and QSM systems. Also, the FGQSM and F-QSM system performances are compared under imperfect channel conditions.</p>