On exploring NFC for half-duplex communication in read/write mode

Abstract

Near Field Communication (NFC) is relatively a new technology, working on the principle of “tap and transfer” paradigm for secure, short range communication. The data transfer between two NFC devices at any instance depends upon available memory of the tag, ranging from 48 bytes to 1 kilobytes and more. In this paper, we are addressing the synchronization issue of the Read/Write mode of NFC. The Read/Write mode is commonly used for one-way transfer of data. In this paper, we are trying to extend the boundaries of this mode towards a half-duplex mode of communication between two devices. Applications, where we can use NFC Read/Write mode are counters and for transmitting data in a cyclic manner whenever the data size is larger than the tag size. An intermediate passive tag placed between user smart phone and NFC reader, facilitates the data transfer. We propose an algorithm, SOFT, to transmit data in multiple cycles between two NFC devices, through NFC tag, to handle the memory limitation of NFC tag. Another important feature of Read/Write mode is that the Writer device does not leave any digital footprint when it writes any data on the passive tag. For evaluation of our concept, we developed prototype applications to transmit data between two NFC enabled mobile devices with an intermediate tag placed between them, so that data can be sent in a cyclic manner and making a half-duplex channel.