Patent ID: 7978676

Claim:
A radio terminal apparatus of a radio communication system which includes the radio terminal apparatus and a radio relay apparatus that periodically transmits a beacon, wherein the radio terminal apparatus includes a reception section which receives the beacon to perform data transmission/reception when an own address of the radio terminal apparatus exists in the beacon, the radio terminal apparatus comprising: an identification information storage section which stores terminal identification information for identifying the radio terminal apparatus; and a control section which calculates a timing of starting the reception section based on group identification information included in the beacon received by the reception section and the stored terminal identification information, and which causes an operation of the reception section to be stopped until the calculated timing, wherein the group identification information indicates whether or not the received beacon is addressed to a group to which the radio terminal apparatus belongs, and wherein the group identification information includes: a sequence number which is a value that increases every transmission time of the beacon, and mask information which defines a value of the sequence number to be extracted based on a total number of classified groups of a plurality of the radio terminal apparatuses, and wherein the control section: (i) calculates a difference value between a first calculation value indicating the extracted value of the sequence number using the mask information and a second calculation value extracted from the terminal identification information using the mask information, (ii) calculates a third calculation value indicating a value obtained by multiplying a preset interval of transmitting the beacon by the difference value, and (iii) stops the operation of the reception section until the timing based on a time obtained by adding the third calculation value to a time of receiving the beacon.