Abstract: A radio device from which communication is started transmits a confirmation signal to a counterpart, and if an acknowledgement signal is not returned from the counterpart, switches a communication mode to another communication mode. This operation is repeated until the acknowledgement signal is returned from the counterpart. Thus, the communication mode is matched with that of the counterpart, thereby establishing a communication link with the counterpart. A radio device caused to start communication by a second radio device receives a signal from the second radio device. The radio device switches a communication mode to another communication mode if synchronization is failed to be established. This operation is repeated until the synchronization is succeeded to be established. Thus, the communication mode is matched with that of the second radio device to be a communication counterpart, thereby establishing a link with the second radio device.

Abstract: A radio device from which communication is started transmits a confirmation signal to a counterpart, and if an acknowledgement signal is not returned from the counterpart, switches a communication mode to another communication mode. This operation is repeated until the acknowledgement signal is returned from the counterpart. Thus, the communication mode is matched with that of the counterpart, thereby establishing a communication link with the counterpart. A radio device caused to start communication by a second radio device receives a signal from the second radio device. The radio device switches a communication mode to another communication mode if synchronization is failed to be established. This operation is repeated until the synchronization is succeeded to be established. Thus, the communication mode is matched with that of the second radio device to be a communication counterpart, thereby establishing a link with the second radio device.

Abstract: Reconfigurable units each include a hardware circuit having one part of a radio procedure function and a reconfigurable circuit having another part of the radio procedure function. An extension interface unit includes a switch circuit having a changeable connection specification to interconnect the reconfigurable units. A memory unit stores logic information for changing logics of the reconfigurable circuits and the connection specification of the switch circuit. A control unit downloads into the memory unit the logic information supplied from outside of the software defined radio. Rewriting the logics of the reconfigurable circuits according to the logic information and switching connection information of the switch circuit makes it possible to realize an optimum logic circuit in compliance with a radio communication to be used. In other words, it is possible to improve the scalability of the radio procedure function of the software defined radio.