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.