The combination of the spatial modulation (SM) and of the full duplex (FD) is a challenging research direction because it brings high spectral efficiency and even energy consumption reduction because of the use of a unique radio frequency (RF) receiving chain. This paper presents a full-duplex spatial modulation (FDSM) system over the Rician fading channel. A least-square self-interference (SI) esti-mator is implemented for the self-interference cancellation (SIC). Moreover, the impact of IQ imbalance on the bit error rate (BER) performance is analyzed. The obtained results show that the proposed estimator can reduce SI at a low level. The system is more sensitive to the IQ imbalance under low noise environment.