  In the next generation wireless communication system, transmission rates
should continue to rise to support emerging scenarios, e.g., the immersive
communications. From the perspective of communication system evolution,
multiple-input multiple-output (MIMO) technology remains pivotal for enhancing
transmission rates. However, current MIMO systems rely on inserting pilot
signals to achieve accurate channel estimation. As the increase of transmit
stream, the pilots consume a significant portion of transmission resources,
severely reducing the spectral efficiency. In this correspondence, we propose a
belief information based mechanism. By introducing a plug-and-play belief
information module, existing single-antenna channel estimation networks could
be seamlessly adapted to multi-antenna channel estimation and fully exploit the
spatial correlation among multiple antennas. Experimental results demonstrate
that the proposed method can either improve 1 ~ 2 dB channel estimation
performance or reduce 1/3 ~ 1/2 pilot overhead, particularly in bad channel
conditions.
