A base station includes a first receiver that receives a signal from the base station, the signal indicating a first wireless quality that is a wireless quality of signals received by a mobile station which uses software-defined radio and communicates with the base station using a first communication protocol, and a processor that executes processing to download communication software that causes the mobile station to execute communication processing according to a second communication protocol based on a first condition of the first wireless quality, and executes processing to transmit a handover instruction signal to cause a handover of the mobile station to a second base station that communicates with the mobile station using the second communication protocol based on a second condition of the first wireless quality, wherein the first condition is a condition set to be satisfied before the second condition when the first wireless quality decreases.