COMMUNICATION SYSTEM, COMMUNICATION METHOD, AND DATA PROCESSING APPARATUS

摘要

A communication system and communication method enable various types of near field communication. NFC communication apparatuses have two features in that each can perform communication in two communication modes and that each can perform data transmission at a plurality of transfer rates. The two communication modes consist of a passive mode and an active mode. In the passive mode, between the NFC communication apparatuses, for example, a first NFC communication apparatus transmits data to a second NFC communication apparatus by modulating electromagnetic waves generated by itself, while the second NFC communication apparatus transmits data to the first NFC communication apparatus by performing load modulation on the electromagnetic waves generated by the first NFC communication apparatus. Alternatively, in the active mode, either of the NFC communication apparatuses transmits data by modulating electromagnetic waves generated by itself. The present innovation can be applied to, for example, an IC card system, etc.

主权项

1. A communication system of performing, by first and second data processing apparatuses, electromagnetic-induction communication using a carrier having a single frequency,
wherein: the first and second data processing apparatuses each comprises:
modulating means for modulating the carrier into a signal of data to be transmitted at one of a plurality of transfer rates; anddemodulating means for demodulating a signal of data transmitted at one of a plurality of transfer rates; a transfer rate for use between the first and second data processing apparatuses is changeable in one transaction; each apparatus of the first and second data processing apparatuses has, as communication modes,
an active mode in which the apparatus transmits data by outputting a carrier; anda passive mode in which one data processing apparatus of the first and second data processing apparatuses transmits data by outputting a carrier, while the other data processing apparatus transmits data by performing load modulation on the carrier output by said one data processing apparatus; and data transmission is performed by using any communication mode of the active mode and the passive mode, the communication mode being maintained during at least one transaction.