Patent ID: 8014441
Filing Date: 2011-09-06
Classification: G06Q,H04W,Y02D

Abstract:
1. A communication channel establishing method used in a communication system including a base station that transmits a beacon on a predetermined communication channel and an electronic inventory tag including a communication unit that receives the beacon from the base station and establishes communication with the base station using the predetermined communication channel, the method comprising the steps of: detecting at the base station whether a main power supply to supply power to the base station has been shut off; driving the base station by a backup power supply and transmitting a power supply shutoff notification signal from the base station to the electronic inventory tag by wireless communication upon detecting that the main power supply has been shut off; storing a current communication channel of the electronic inventory tag when the power supply shutoff notification signal from the base station is received by the communication unit, the electronic inventory tag including a display unit to display information about products and being driven by a battery; and reestablishing wireless communication with the base station the electronic inventory tag using the stored current communication channel upon recovery of the main power supply, wherein the beacon includes an identification number of the electronic inventory to with which the wireless communication is to be established, and wherein the base station transmits the beacon periodically at a head of a frame, the frame including the beacon and a null beacon, the null beacon having a function different from the beacon.