A first modem performs a first communication service in a first frequency band. A second modem performs a second communication service in a second frequency band. The first modem and the second modem are in a first operating mode. The first modem receives, from an access network device, a switching instruction for the first communication service, where the switching instruction is used to instruct the first modem to switch from the first frequency band to a third frequency band. The first modem indicates to an arbitration apparatus that the first modem needs to be switched to the third frequency band. The arbitration apparatus determines whether the third frequency band conflicts with the second frequency band, to perform: maintaining the first operating mode, or switching the first operating mode to a second operating mode for the first modem and the second modem.