Near field communication method and system

Abstract

The invention relates to a near field communication method and system. The method comprises the following steps: a card reader emits a low-frequency alternating magnetic field signal of which the frequency is equal to or less than the highest frequency f0 for the calibration-free work of a system, and the signal carries identity identification information; a mobile radio frequency device receives and detects a low-frequency signal and amplifies the low-frequency signal into a voltage signal to judge whether a terminal enters an effective-distance zone; if the voltage signal is more than or equal to voltage threshold Vt, the terminal enters an effective card swiping zone to obtain the identity identification information of the card reader, the identity identification information of the terminal and the identity identification information of the card reader are simultaneously transmitted to the card reader via a radio frequency channel; the card reader receives the transmitted information and compares whether the identity identification information in the information is identical with the self identity identification information; and if yes, the card reader carries out card swiping transaction with the radio frequency channel. According to the method and the system, data communication distance between the radio frequency communication terminal containing the mobile radio frequency device and the card reader is reliably controlled with a specified range, and the terminal does not need to be calibrated.

Description

technical field [0001] The present invention relates to the communication field, in particular to a short-distance communication method and system. Background technique [0002] With the popularization of mobile terminals, there is an urgent application demand for mobile terminal payment by using mobile terminals. Currently, there are many implementation schemes, but each has its own disadvantages. At present, there have been methods of adding a radio frequency function (referred to as a radio frequency SIM card) on the Subscriber Identity Module SIM (Subscriber Identity Module) card in the mobile terminal or adding a short-distance communication module on the main board of the mobile terminal to realize the short-distance communication of the mobile terminal. , the latter is called NFC (Near Field Communication, near field communication). The emergence of these methods makes the mobile terminal a super intelligent terminal that can recharge, consume, trade and authenticate,...

AI Technical Summary

Problems solved by technology

[0007] 2. The 13.56MHz frequency used by NFC needs to be calibrated to be used for distance control

It can be seen that the difference in field strength received by different terminals is >30dB, and the field strength change from 1cm to 10cm for the same terminal is about 25dB. The field strength change caused by the difference between mobile phones has exceeded the field strength of the terminal within the control range of 1cm to 10cm Therefore, it is impossible to use the same threshold to control the distance of each terminal, that is, it is impossible to realize distance control without calibration

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