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.