Patent ID: 8736422
Filing Date: 2014-05-27
Classification: G06K

Abstract:
1. A method for conducting a label query in a radio frequency system comprising a reader to execute a first query for a plurality of passive labels and at least one subsequent query for unacknowledged labels, the method comprising: assigning, by the reader during the first query, a first link frequency for use in a reverse link from each of said plural passive labels to the reader, and commanding each of said plural passive labels to return identification information of each of said plural passive labels at the first link frequency; receiving, at the reader during the first query, the identification information returned from said plural passive labels at the first link frequency, and acknowledging said plural passive labels which have successfully returned the identification information in response to the first query; assigning, by the reader during the at least one subsequent query for unacknowledged labels of each of said plural passive labels, a subsequent link frequency lower than the first link frequency for use in the reverse link, and commanding the unacknowledged labels of each of said plural passive labels to return the identification information at the subsequent link frequency; and receiving, by the reader during the at least one subsequent query for unacknowledged labels of said plural passive labels, the identification information returned from said plural passive labels at the subsequent link frequency, and acknowledging each of said plural passive labels that have successfully returned the identification information in response to the at least one subsequent query; wherein candidate link frequencies are assigned from high to low for selection, a highest candidate link frequency being assigned as the first link frequency for the first query based on a sequencing result, and the subsequent link frequency lower than the link frequency used in the previous query being assigned to be used in the subsequent query based on the sequencing result.