In this paper, we present a non-coherent energy detection scheme for spatial
modulation (SM) systems. In particular, the use of SM is motivated by its
low-complexity implementation in comparison to multiple-input multiple-output
(MIMO) systems, achieved through the activation of a single antenna during
transmission. Moreover, energy detection-based communications restrict the
channel state information to the magnitude of the fading gains. This
consideration makes the design applicable for low-cost low-powered devices
since phase estimation and its associated circuitry are avoided. We derive an
energy detection metric for a multi-antenna receiver based on the
maximum-likelihood (ML) criterion. By considering a biased pulse amplitude
modulation, we develop an analytical framework for the SM symbol error rate at
high signal-to-noise ratios. Numerical results show that the diversity order is
proportional to half the number of receive antennas; this result stems from
having partial receiver channel knowledge. In addition, we compare the
performance of the proposed scheme with that of the coherent ML receiver and
show that the SM energy detector outperforms its coherent counterpart in
certain scenarios, particularly when utilizing non-negative constellations.
Ultimately, we implement an SM testbed using software-defined radio devices and
provide experimental error rate measurements that validate our theoretical
contribution.Comment: This work has been submitted to an IEEE journal for possible
publicatio