Layered Space Shift Keying Modulation over MIMO Channels

Space shift keying (SSK) modulation is an emerging transmission technique for multiple-input multiple-output (MIMO) wireless channels that exploits spatial domain to convey information. In this paper, we present a layered space shift keying (LSSK) modulation scheme to fully exploit spatial domain to transmit information bits, where a layered architecture is developed to achieve spatial multiplexing transmission in SSK system. With the layered structure, LSSK can achieve much higher spectrum efficiency than the conventional SSK modulation system. The proposed LSSK scheme introduces layer mapping and bit-mapping operations at the transmitter to achieve layered SSK modulation directly with low computation overhead. More precisely, leveraging the phase shift keying (PSK) modulation symbols previously known at the transceiver to identify different layers, multiple antennas are activated simultaneously to emit layered signals. The theoretical bit error probability of LSSK with optimal maximum likelihood (ML) detection is also derived in this paper. Results demonstrate that the proposed LSSK scheme substantially improves the spectrum efficiency of SSK system and outperforms other existing MIMO schemes.