Cloud radio access network system and control method thereof

A control method of a cloud radio access network system comprising a plurality of remote signal sources, a baseband processing unit pool, an access management server, a software defined network controller and at least one network signal forwarder, the at least one network signal forwarder being electrically connected to the remote signal sources, the baseband processing unit pool and the software defined network controller, the access management server being electrically connected to the software defined network controller, the control method comprising steps of:

• the access management server transmitting an access state signal to the software defined network controller wherein the access state signal contains a plurality of different maximum transmission rates comprising at least a first maximum transmission rate and a second maximum transmission rate, the first maximum transmission rate being lower than the second maximum transmission rate;
• the baseband processing unit pool performing authentication of one of the remote signal sources at the first maximum transmission rate;
• after the baseband processing unit pool authenticates the one remote signal source, the baseband processing unit pool transmitting an authentication notification signal to the access management server;
• and
• the access management server informing the software defined network controller according to the authentication notification signal to make the software defined network controller to increase an upper limit of a signal transmission rate between the baseband processing unit pool and the authenticated remote signal source from the first maximum transmission rate to the second maximum transmission rate.