This blog post explores how radio waves have permeated our daily lives beyond traditional broadcasting, evolving into various technologies like RFID and NFC.
When most people hear the word ‘radio,’ they likely think of DJ-hosted radio broadcasts or DMB. However, the term ‘radio’ extends beyond just a broadcasting medium; it also signifies radio waves and communication technology. Radio waves are now utilized in diverse technologies and deeply embedded in our daily lives. For instance, when borrowing books at a library, you no longer need to scan each book’s barcode individually. Simply stack multiple books on the self-checkout machine, and they are automatically recognized and checked out. Similarly, at toll gates, vehicles pass through without stopping, paying fees automatically. On buses, transportation cards are used instead of tokens. All of this is made possible by radio waves, specifically RFID (Radio Frequency Identification) technology. RFID makes our lives more convenient. In this article, let’s explore RFID—the ‘radio’ technology in our daily lives that we often overlook—and NFC, which evolved from it.
First, let’s take a closer look at RFID. RFID gives objects that cannot speak their own unique voice—a specific frequency—to convey brief information. Objects with this unique frequency can exchange information without direct contact with a terminal. For example, a transit card can convey the passenger’s age group and card balance to a transit card terminal even when inside a wallet or bag. Similarly, a student ID can prove the cardholder’s student status to a library entrance gate through a wallet. In this way, RFID has become deeply embedded in our daily lives without us even realizing it.
The basic operating principle of RFID involves a tag acting as the object’s vocal cords, an antenna serving as the ear that listens and the mouth that issues commands, and a reader that understands what the object is communicating. A crucial point here is that RFID communicates using radio waves at a predetermined frequency, not sound. The process begins when a tag attached to or embedded within an object transmits radio waves at a specific frequency. These radio waves carry 96 bits of information, including the type of RFID device, the device’s unique ID, and the information to be exchanged. An antenna tuned to the exact frequency then receives these radio waves.
The received information is processed by the reader. If necessary, the antenna transmits radio waves containing information again to modify the data stored on the tag. “RFID is broadly categorized into Active RFID and Passive RFID based on the tag’s power supply method. Active RFID is a type where power is supplied directly to the tag, enabling it to continuously transmit information at a high volume.
Thanks to these characteristics, Active RFID is used in applications requiring relatively long-range communication, such as object location tracking and Hi-Pass systems. In contrast, Passive RFID uses tags that receive temporary power via induced current from the reader terminal. It is primarily used in cards that do not require a power source, such as public transportation cards or student IDs.
RFID is also categorized by the frequency band it uses. Low Frequency (LF) RFID is inexpensive but has a very short communication range and slow data transfer speed, making it suitable for applications like livestock management. Conversely, Ultra High Frequency (UHF) RFID offers long communication ranges and fast data transfer speeds, making it ideal for applications like high-speed sports event timing. RFID using HF (High Frequency, 13.56MHz) frequencies did not achieve widespread use due to an imbalance between cost and performance. However, its utility has increased recently with the development of NFC technology.
Now, let’s learn about NFC. NFC is an advanced technology that compensates for RFID’s limitations, transforming short communication distances into high security. Simply bumping phones together allows exchanging business cards or making payments, and using phones as transit cards is also thanks to NFC technology. NFC differs from RFID in enabling mutual communication. While RFID terminals only function as antennas and readers with tags existing separately, NFC devices integrate the tag, antenna, and reader. Consequently, NFC devices can not only read and transmit information from other tags but also be read by other NFC devices themselves. This is akin to the evolution of a pager (RFID) into a mobile phone (NFC) capable of exchanging text messages.
However, for NFC to usher in an era where smartphones replace wallets, challenges remain to be addressed. One of these is ‘insufficient security’. Despite operating over short distances and encrypting information, NFC is fundamentally a short-range communication technology, meaning 100% security cannot be guaranteed. For instance, in a crowded subway, a hacker using an NFC device to scan people’s bags or pockets could potentially leak vast amounts of personal information in an instant. For this reason, NFC is currently primarily used in applications like transit cards, where large-scale losses are less critical. However, major card companies like PayPal, Visa, Mastercard, and American Express are investing to address security concerns, raising expectations that smartphones will soon replace wallets in the near future.
It is crucial for us to understand and adapt to the rapidly changing technological landscape. While enjoying the convenience offered by RFID and NFC, we must also recognize and prepare for the risks lurking behind them. Just as radio once connected people through music, stories, and images, radio waves now connect people with machines and objects, making our lives more convenient and smarter.
