Multiplex time division duplex (TDD) sync detection module

A technology is described for a repeater that can comprise: a first port; a second port; a first amplification and filtering path coupled between the first port and the second port, wherein the first amplification and filtering path is configured to amplify and filter a first time division duplex (TDD) signal in a first frequency range of a first TDD uplink (UL) signal; a second amplification and filtering path coupled between the first port and the second port, wherein the second amplification and filtering path is configured to amplify and filter a second TDD signal in a second frequency range of a second TDD downlink (DL) signal; and a modem configured to generate an UL/DL indication signal for the first frequency range, and send the UL/DL indication signal to the repeater.