NFC Technology Basics

In recent years, as in-vehicle systems have become more sophisticated, the use of NFC technology has rapidly increased in ECU development. NFC enables contactless, safe, and efficient data communication, creating new value in various automotive fields, not only in payment and transportation infrastructure, but also in vehicle Access (smart keys, in-vehicle network authentication, etc.) and IoT integration.

This article uses illustrations and concrete examples to provide practical knowledge that can be used by engineers involved in ECU development, from the basics of NFC technology to the latest application examples. If you want to design a new in-vehicle system that utilizes NFC or if you want to learn systematically from the basics to applications, be sure to read to the end.

History and Evolution of NFC

Near-field wireless communication (NFC) is generally defined as a wireless communication technology with a communication distance of approximately several tens of meters. Key technologies include ZigBee (2.4 GHz), Bluetooth (2.4 GHz), and Wi-Fi (2.4 GHz/5 GHz). Among these, NFC (Near Field Communication) uses the 13.56 MHz band, enabling two-way communication at extremely short distances of up to approximately 10 cm. Its communication speed ranges from 106 to 848 kbps, making it suitable for secure data transfer, such as authentication in automotive systems. NFC was developed based on RFID (Radio Frequency Identification) technology, which emerged in the mid-20th century. RFID, which can read tag information wirelessly, has been used in a wide range of applications, including logistics management and animal identification. However, communication distances were typically one-way, from the reader to the tag, and were typically several meters. Systems requiring secure data communication require new technologies that enable shorter-range, two-way communication while reducing the risk of eavesdropping and unauthorized Access.

Around 2002, NXP Semiconductors (formerly Philips) and Sony jointly developed bidirectional communication technology based on the ISO/IEC 14443 standard, which enabled not only tag reading but also information exchange between devices. In 2003, the NFC Forum was established, establishing industry standards for communication protocols, data formats, security specifications, and more. This enabled high compatibility between different manufacturers. Since the 2010s, the incorporation of NFC chips into smartphones has progressed, and the scope of NFC use has rapidly expanded, particularly in cashless payments. NFC is also used for reading transportation IC cards, electronic tickets, exchanging digital business cards, and pairing IoT devices.

NFC standard ISO/IEC14443

ISO/IEC 14443 is one of the international standards for contactless IC cards, and covers short-range communication up to approximately 10 cm. It is the standard that forms the basis of NFC technology, and is used in many contactless services such as transportation IC cards and electronic money.

The main features are as follows:

Communication distance: maximum approximately 10cm
Communication method: 13.56MHz band intercommunication
Card type: Two types: Type A and Type B
Data transfer speed: Supports 106/212/424kbps

NFC communication principle

NFC (Near Field Communication) uses a magnetic field coupling method that utilizes a high frequency of 13.56MHz. When two ANTENNA COILS are brought close to each other within a range of a few centimeters to 10cm, energy and data can be exchanged through electromagnetic induction, achieving stable two-way communication.

The 13.56MHz band is designated as an international ISM band (Industrial, Scientific, and Medical frequency band) and is standardized worldwide because it can be used without a license. It is widely adopted as a major standard for NFC and RFID because it offers a good balance of ANTENNAS size, communication distance, ease of circuit design, and noise resistance.

NFC ANTENNAS are generally loop coil type. Optimizing INDUCTORS, capacitance, and matching circuits is important during design. In particular, for in-vehicle applications, there are many metal parts and noise sources, so EMC (electromagnetic compatibility) measures and shielding design are essential. Stable communication quality can be ensured by carefully considering ANTENNAS placement, board layout, and distance from metal parts, and verifying with EMC testing.

Principle of communication between NFC reader/writer and NFC tag/card

Modulation methods such as ASK (Amplitude Shift Keying) and PSK (Phase Shift Keying) are used as communication protocols. Error detection functions such as CRC (Cyclic Redundancy Check) are also used to maintain data integrity, and encryption technology is also incorporated. In-vehicle systems require enhanced security through encryption of authentication information and challenge-response methods, so the selection of encryption algorithms such as AES and DES and authentication protocols is a key point.

As such, NFC is an area that requires many technical innovations in automotive ECU development, from the physical communication principles to design, implementation, and security. By keeping these points in mind during on-site design and evaluation, it is possible to build a safer, higher-quality automotive NFC system.

NFC Reader/Writer Overview

NFC technology consists of devices with two roles, a reader and a writer, each with different functions. A device that has both of these functions is called an NFC reader / writer (NFC controller).

NFC reader function

An NFC reader is responsible for reading information from NFC tags, cards, and devices. Its main functions are as follows:

Read IDs, authentication information, URLs, etc. stored on NFC tags and cards
User authentication and Access control using the read information
Controlling the start of NFC communication and establishing a connection with the communication partner

NFC writer function

The NFC writer is responsible for writing data to NFC tags and cards. Its main functions are as follows:

Recording text, URLs, settings, etc.
Clearing or formatting tag content
Tamper prevention by tag locking after writing

This section explains the system configuration of an NFC reader/writer. The NFC function consists of a microcontroller, an NFC reader/writer IC which is an analog front-end, a matching circuit, and ANTENNAS. There are also single-chip NFC products that integrate a microcontroller and an NFC reader/writer. NFC reader/writer ICs are important semiconductor products for realizing NFC, and are provided by manufacturers such as NXP Semiconductors, STMicroelectronics, Renesas Electronics, and Sony.

NFC Applications: From Transportation IC Cards to Smartphones

Transportation IC cards have contributed to improving the convenience of public transportation in Japan and around the world. In recent years, in conjunction with NFC technology, they have been expanding their functionality beyond just ticket functions to include electronic money and other functions.

Traditional ticket processing had issues with labor costs and processing capacity during rush hours. As a solution to these issues, transportation IC cards appeared in the late 1990s and early 2000s, making efficient passenger management possible. Transportation IC cards use contactless IC card technology that complies with the ISO/IEC 14443 standard. By simply holding the card over the ticket gate, passengers can record their riding history and pay their fares.

NFC-enabled transportation IC cards can now be linked to a variety of services, including electronic money, point services, and event tickets, in addition to functioning as a passenger ticket, greatly improving convenience for users.

Since the 2010s, smartphones have been equipped with NFC functionality, which has significantly changed how they are used. Because the NFC on smartphones is based on the ISO/IEC 14443 standard, it is compatible with conventional IC cards and can be used as a replacement for IC cards.

Introducing NFC technology to car Access

NFC-based car Access is gaining attention as a safe method for locking and unlocking car doors and starting the engine using a smartphone or dedicated card.

Vehicles are equipped with an NFC reader, and when a device such as a smartphone or NFC card (key) approaches, NFC communication begins. Authentication information (ID and encryption key) stored in the device is sent to the vehicle, and authentication is performed on the vehicle side. The vehicle's system verifies the received authentication information, and if the user is legitimate, the doors can be unlocked and the engine can be started. The combination of NFC's short-range communication characteristics with encryption and authentication technology achieves both high security and convenience.

In the future, with the development of IoT and smart cities, it is expected that car Access systems using NFC will become even more multifunctional and sophisticated.

Summary

NFC technology is a wireless communication technology that will become increasingly important in the field of automotive systems, including ECU development.
This article has explained everything from the basics to application examples, but the possibilities of NFC do not end there.
Understanding and utilizing NFC technology will be a valuable tool for developing future in-vehicle systems and creating new services.
We hope you will use the information in this article in your on-site design and development, and take on the challenge of further technological innovation.