An improved spatial modulation scheme for MIMO channels

Spatial modulation (SM) has recently emerged as a very promising technique to exploit further the potential of multiple-input multiple-output (MIMO) systems using low-complexity transceivers. Based on this concept, this paper proposes a novel spatial modulation technique named Extended Spatial Modulation (ESM). The proposed method maps the incoming bits to the transmission vector in a new and simple way. Results show that ESM inherits most of the SM properties but more important increases the system´s spectral efficiency linearly with the number of transmit antennas rather than a base-two logarithm factor like other existing SM schemes. Furthermore, ESM eliminates the constraint of SM to work with a number of transmit antennas in power of two. In addition, a two-stage adaptive detector is also introduced for SM-based techniques. From simulation results, it is shown that the proposed ESM scheme achieves better tradeoffs between capacity and performance/complexity as compared with standard SM schemes over time-varying Rayleigh flat-fading channels.