A Physical Transmitter Implementation of a Quadrature Space Shift Keying MIMO System

Quadrature space shift keying (QSSK) is a variant of space modulation techniques. QSSK strictly transmits spatial symbols through the use of two orthogonal unmodulated carriers. The hardware implementation model of QSSK affirms that QSSK can be realized via RF switches and without the need for any RF-chain. Nevertheless, no physical implementation has been accomplished to date to confirm such affirmations. Hence, in this brief, a 2 × 2 MIMO implementation of a QSSK system using commercial-off-the-shelf (COTS) RF-switches is realized. A detailed discussion of the hardware implementation is presented and results reveal an accurate match with existing QSSK Monte Carlo simulation results over a Rician fading channel. The results are also compared with a standard 802.11n 2 × 2 MIMO implementation and QSSK demonstrates significant enhancement. This brief is viewed as a crucial step towards commercial deployments of quadrature space modulation techniques.