Methods for a radio-frequency SIM card with low-frequency magnetic communication to trigger a transaction according to determined distance thresholds

摘要

A method for a radio-frequency SIM card with low-frequency magnetic communication to trigger a transaction according to determined distance thresholds comprises: setting a Threshold 1 as a low-frequency magnetic field intensity value corresponding to a distance to trigger the transaction; setting a Threshold 2 as a low-frequency magnetic field intensity value corresponding to an effective communication distance of the low-frequency magnetic field; setting a Threshold 3 as a low-frequency magnetic field intensity value corresponding to a farthest transaction distance; examining an intensity of the low-frequency magnetic field transmitted by a card reader and determining whether the intensity is >=the Threshold 2; if yes, receiving and storing information of the low-frequency magnetic field; further determining whether a low-frequency magnetic field intensity is >=the Threshold 1; if yes, initiating a transaction process; during the transaction process, determining whether a low-frequency magnetic field intensity is < the Threshold 3; if yes, interrupting the transaction.

主权项

1. A method for a radio-frequency Subscriber Identity Module (SIM) card with low-frequency magnetic communication to trigger a transaction according to determined distance thresholds, wherein the radio-frequency SIM card carries out a distance control of a short-distance communication with a corresponding card reader through a low-frequency channel and conducts the transaction with the card reader through the radio-frequency channel, the method comprising:
Step a: setting a Threshold 1 as a low-frequency magnetic field intensity value corresponding to a distance to trigger the transaction; setting a Threshold 2 as a low-frequency magnetic field intensity value corresponding to an effective communication distance of the low-frequency magnetic field; and setting a Threshold 3 as a low-frequency magnetic field intensity value corresponding to a farthest transaction distance; wherein the Threshold 1 is greater than or equal to the Threshold 3, and the Threshold 3 is greater than or equal to the Threshold 2; Step b: examining continuously, by the radio-frequency SIM card, an intensity of the low-frequency magnetic field transmitted by the card reader; determining whether the intensity is greater than or equal to the Threshold 2; and upon determining that the intensity is greater than or equal to the Threshold 2, receiving and storing information of the low-frequency magnetic field; Step c: further determining, by the radio-frequency SIM card, whether an intensity of the low-frequency magnetic field transmitted by the card reader is greater than or equal to the Threshold 1; and upon determining that the intensity is greater than or equal to the Threshold 1, initiating, by the radio-frequency SIM card, a transaction process; Step d: during the transaction process, examining, by the radio-frequency SIM card, an intensity of the low-frequency magnetic field transmitted by the card reader; determining whether the intensity is less than the Threshold 3; and upon determining that the intensity is less than the Threshold 3, interrupting the transaction; and wherein in the Step a, the steps for determining the Threshold 1, the Threshold 2, and the Threshold 3 are as follows: A. through experiments, measuring, using a radio-frequency SIM card, intensities of a low-frequency magnetic field transmitted by a card reader that matches with the radio-frequency SIM card; determining a correspondence relationship between the intensities and distances; and establishing a correspondence table between the intensities and the distances; and B. based on the correspondence table and requirements for a transaction-triggering distance, setting a low-frequency magnetic field intensity value corresponding to the transaction-triggering distance as the Threshold 1; based on a communication rate of the low-frequency magnetic field and a data size that a data transmission needs in the low-frequency magnetic field for the radio-frequency SIM card, calculating an effective communication distance of the low-frequency magnetic field and setting a low-frequency magnetic field intensity value corresponding to the effective communication distance as the Threshold 2; based on requirements for a farthest transaction distance control, setting a low-frequency magnetic field intensity value corresponding to the farthest transaction distance as the Threshold 3.