A communication method of a server that transmits a packet by multicast or broadcast via a wireless base station to at least one or more wireless terminals (14a and 14b) connected to the wireless base station via a wireless network using a channel, the method comprising: generating the packet including data regarding which a priority of the data included in the packet has been set beforehand; acquiring channel-used time that is time over which the channel is used per unit time at the wireless base station ; calculating channel-usable time T usable that is time over which the channel can be used per unit time T, for the wireless base station to transmit the packet to the wireless terminal , based on the channel-used time T used , wherein T usable = α × (T - T used ), for 0 < α ≤ 1; calculating a first channel usage estimated time that is time estimated to be used for the wireless base station to use the channel to transmit the packet to the wireless terminal ; setting an initial value for a wireless transmission rate, calculating the wireless transmission rate to be applied when the wireless base station transmits the packet to the wireless terminal , based on the priority of the data included in the packet, to where the first channel usage estimated time is within the channel-usable time; wherein in the calculating of the wireless transmission rate, the initial value of the wireless transmission rate is changed based on the priority of the data included in a particular packet, in a case where the first channel usage estimated time exceeds the channel-usable time, and transmitting, from a first transmitter in the server , the packet, and information indicating the wireless transmission rate, to the wireless base station . generating the packet including data regarding which a priority of the data included in the packet has been set beforehand; acquiring channel-used time that is time over which the channel is used per unit time at the wireless base station ; calculating channel-usable time T usable that is time over which the channel can be used per unit time T, for the wireless base station to transmit the packet to the wireless terminal , based on the channel-used time T used , wherein T usable = α × (T - T used ), for 0 < α ≤ 1; calculating a first channel usage estimated time that is time estimated to be used for the wireless base station to use the channel to transmit the packet to the wireless terminal ; setting an initial value for a wireless transmission rate, calculating the wireless transmission rate to be applied when the wireless base station transmits the packet to the wireless terminal , based on the priority of the data included in the packet, to where the first channel usage estimated time is within the channel-usable time; wherein in the calculating of the wireless transmission rate, the initial value of the wireless transmission rate is changed based on the priority of the data included in a particular packet, in a case where the first channel usage estimated time exceeds the channel-usable time, and transmitting, from a first transmitter in the server , the packet, and information indicating the wireless transmission rate, to the wireless base station . <EOS>