Patent ID: 8594059

Claim:
An information transmitting method for transmitting information from a master station through a plurality of base stations to a plurality of slave stations, where the plurality of base stations transmit the information to a plurality of areas, respectively, with each area including a subset of the plurality of slave stations, the method comprising, for each respective area: determining, on a basis of an packet error rate of the respective area, a number of times of multicast transmission required to achieve delivery where: an expected value of a number of the subset of the plurality of slave stations, that would be expected to transmit a retransmission request, is equal to or smaller than a predetermined retransmission-request value, or an expected value of a number of retransmitted packets responding to the retransmission request is equal to or smaller than a predetermined retransmitted-packets value, or a probability that the subset of the plurality of slave stations all receive all packets is equal to or larger than a predetermined receipt probability; notifying a determined number of times of multicast transmission as determined by the determining, to the subset of the plurality of slave stations in the respective area; and transmitting, via multicast, to the subset of the plurality of slave stations in the respective area, same information formed of plural packets, for the determined number of times of multicast transmission.