Communication circuits and communication devices supporting MIMO and dual-mode techniques

A communication circuit and a communication device are provided. The communication circuit includes first, second, and third RF transceivers, first and second baseband transceivers, and first and second modem circuits. The first and second RF transceivers are configured to down-convert first and second RF signals for MIMO. The third RF transceiver is configured to down-convert a third RF signal for a second telecommunication technology. The first baseband transceiver is configured to digitize the down-converted first RF signal to output a first baseband signal. The second baseband transceiver is configured to digitize one of the down-converted second or third RF signals according to a selection signal to output a second baseband signal. The first modem circuit is configured to digitally process the first and second baseband signals using the MIMO technology. The second modem circuit is configured to digitally process the second baseband signal using the second telecommunication technology.