 Welcome to this portion of our online training about NFC basics and standardization. In this course, we'll take an NFC overview. We'll look at RFID and NFC technologies at a glance and how they differ. We'll also look at NFC devices and modes and NFC use cases and device types. From there, we'll go into communication basics and then finally end with standardization. RFID technologies can be divided into three different categories. The first is LF. In LF, the coupling mode is inductive and the operating frequency is 125 kHz to 134 kHz. The antenna is a coil and the max operating distance is up to one meter. The regulation is worldwide harmonized so that anywhere in the world all LF readers operate the same. And it's based upon two ISO standards. Its primary function is animal tagging. HF, like LF, is also inductively coupled but it operates at 13.56 MHz. The antenna is also a coil and is broken up into two categories, vicinity, which is less than 1.5 meters and proximity, which is less than 10 centimeters. The regulation is also worldwide harmonized and it's based on several ISO standards as well as NFC forum. The main applications for HF are product identification, public transport and access control as well as payment. UHF RFID is based upon electromagnetic backscatter, so this is more akin to radar. The operating frequency is 860 MHz to 960 MHz and the antenna is typically a dipole. The max operating distance for these systems is typically about 10 meters. Regulation differs from country to country and this is why you have the wide range of operating frequency. It's based upon an ISO standard and also EPC Class 1 Gen 2. Its main functions are typically inventory control, so pallet and container ID, retail logistics and some authentication. Near field communication is a low data rate, short range wireless technology and it's complimentary to both Wi-Fi and Bluetooth. In fact, NFC is typically used for Bluetooth and Wi-Fi pairing. It's also very low power since one side of the technology is passive. NFC devices can act like either an active device or a passive device. If they're an active device, they're a reader or writer and if they're a passive device, they're a tag or a card. There are three main NFC modes. The first is reader mode. In this mode, the reader-writer drives the communication with the tag and the tag can only answer the reader-writer requests. There's also card emulation mode and this is simply when a device acts like a tag or a card. In addition, there's peer-to-peer mode and each device can switch personalities between a reader and a tag on the fly. Now let's look at the communication basics of an NFC system. First, we'll look at how do the reader and the tag communicate. We'll also look at how the magnetic field is generated and captured. Then we'll look at the reader-to-tag communication link in vice versa and finally we'll look at system performance. So the first question is, how can we communicate? And before we can answer this question, we have to ask several others. First, how do we generate a magnetic field? How to capture the magnetic field? How to supply power to a passive tag? And then how do we send information to the tag? And then finally, how to receive back the information that the tag is sending us. So in an NFC system, communication is based on a magnetic field. And so the simplest way to think about this is think of it as a transformer. The reader generates an alternating magnetic field, which is the carrier frequency, and that powers the tag. The reader then modulates that carrier frequency to be able to talk to the tag. And finally, the tag modulates the reader's field to provide an answer to the reader. So to generate a magnetic field, we simply pass a current through a loop. So at short distance, the magnetic field is higher closer to the antenna conductors. And at high distance, the magnetic field is higher along its central axis. The amount of radiated magnetic field depends on several factors. First, the current that's applied to the loop. Two, the number of turns in the antenna. Three, the radius of the antenna. And four, the distance from the reader antenna. So you can see here that the magnetic field strength for a small reader antenna is higher very close to the antenna. Where a larger reader antenna, this is normalized over the distance. To capture the magnetic field, we simply place a loop in the magnetic field. This induces the field into the secondary loop and causes current flow. So the best performance is when the coil is perpendicular to the magnetic field. It's important to remember that tag orientation has an impact on the application. Because the energy captured depends on the antenna orientation in the magnetic field. We stated earlier that an antenna that's perpendicular to the magnetic field will couple the most amount of energy. So we can see here that these two antennas that are tangent to the magnetic field won't couple energy. So for tag to reader coupling, the reader generates a 13.56 megahertz signal. And that's sent to the real reader coil antenna. This creates a magnetic field that's coupled to the tag coil. Once it's coupled to the tag coil, the tag takes a 13.56 megahertz signal and rectifies it and creates a DC voltage to power itself. For the reader to communicate to the tag, it simply modulates the 13.56 megahertz carrier. This is then induced to the tag coil and the tag decodes the modulation that's on the carrier. For the tag to reader communication link, the tag simply modulates its own impedance. This creates load modulations on the 13.56 megahertz carrier, which is then coupled to the reader and the reader decodes this signal. So let's review the modulation. The reader generates a 13.56 megahertz signal. The signal is taken by the tag rectified and used to power itself up. Then the reader modulates the 13.56 megahertz carrier to communicate to the tag. The tag then modulates its impedance so that it creates load modulation on the carrier frequency and then this is decoded by the reader. Several factors affect system performance. On the reader side, more output power generates more field, which equates to longer read range. But it also means higher power consumption. In addition, a larger antenna will also yield longer read range. Performance factors on the tag side include the distance between the reader and the tag, the tag antenna size, the tag orientation, the tag antenna impedance, and the tag antenna tuning frequency. So now let's focus our attention on standardization. So for standardization, we'll ask, why do we have standards? In addition, we'll look at the ISO standards, ISO 14443 and ISO 15693. And then finally, we'll look at the NFC forum standards. So why standards? Well, first, it promotes interoperability among supplier products, both domestically and globally, and among applications. Second, it reduces costs for all, both manufacturers and consumers, and it also allows for multi-vendor choices for transponders and receivers. And finally, we have three standardization bodies. The first is the International Organization for Standardization, or ISO. Next is the NFC forum, and finally the ITU, which is regionally organized. The main standards related with NFC are the ITU standards, and this deals primarily with frequency and power limits. The ISO standards, which are the HFRFID standards originally for contactless cards. They standardize the physical interface, the frames, and the anti-collision. And the main standards that people deal with are 14443A, B, 15693, and 18092. The NFC forum standards are based on the existing ISO standards. The NFC forum reuses them and adds new features. So what they've added is the technical specification of protocols, the data exchange format, the NFC forum tag types, and the NFC record type, and many more. ISO 14443 and 15693 have some common features. They're both based upon a 13.56 megahertz carrier signal. They both have magnetic coupling between the reader and the tag, and it's a passive RF technology. In addition, it's a reader-talk-first communication mechanism. ISO 14443 uses proximity cards and is a short-range operating distance specification. Communication speed is up to 106 kilobits per second. ISO 15693, on the other hand, uses vicinity cards and is a long-range operating distance. The communication speed is 26 kilobits per second. ISO 14443 specifies a PCD, or proximity couple device, which is a reader who emits an electromagnetic field. It also specifies a PIC, or a proximity-integrated circuit card. It's a transformer that can be read or written to by a reader. It also specifies a minimum and maximum operating magnetic field. ISO 14443 also specifies two signal interfaces, type A and type B. In type A, from reader to tag, the bidding coding is modified Miller, and the data modulation is 100% amplitude shift Keen. From the tag to reader, it's Manchester encoding, and the data modulation is either load modulation or on-off Keen of the subcarrier. For type B, reader to tag, the bidding coding is non-return to zero, and it uses 10% amplitude shift Keen. From tag to reader, the bidding coding is also non-return to zero, and the modulation is either load modulation or binary phase shift Keen of the subcarrier. The frame format of ISO 14443 begins with a start of frame, followed by a command code. That's followed by a data block that's managed by the command. That's followed by a CRC, and then finally an end of frame. Anti-collision is also built into 14443A, and this allows the reading of multiple tags in the field. ISO 15693 also defines a VCD, which is a vicinity couple device. This is the reader who emits an electromagnetic field, and a VIC, which is a vicinity integrated circuit card. This is the transponder that can be read or written by the reader. It also specifies a minimum and maximum operating magnetic field. One signal interface is specified. For reader to tag, the bidding coding is either one of four pulse position modulation or one in 256 pulse position modulation. The data modulation is either 10% or 100% amplitude shift Keen. From tag to reader, the bid coding is Manchester, and the data modulation is either load modulation or it could be on off Keen or frequency shift Keen of the subcarrier. The ISO 15693 request frame format begins with a start of frame. That's followed by request flags. These request flags essentially set up the communication parameters. This is followed by command code, which would be similar to read and write blocks, inventory, stay quiet, that sort of thing. And then the parameters of that command code, followed by data, a two byte CRC, and then an end of frame. The response frame format is similar to the request frame format in that it has response flags and parameters and data. However, it does not have a command code. Here we see a comparison of 14443 and 15693 in terms of data signaling and bidding coding from the PCD or VCD to the PICC or the VICC. There are six antenna classes defined in ISO 14443. They're also referred to in 15693. A class one antenna provides the best of performance with respect to the RF electromagnetic field, and this is because this is the largest of all the antennas. A class six antenna provides the best integration properties because it's a very small antenna. However, it delivers less performance. Here we see class one through six of each of the antennas and its dimensions. As we've stated before, NFC forum standards are based upon existing ISO standards. So compliance with legacy standards is denoted as 14443A becomes NFC type A, 14443B becomes NFC type B, FELICA becomes NFC type F, 15693 becomes NFC type 5, and ISO 18092 becomes peer-to-peer. Here we see how the NFC forum standards encompass the ISO standards. We can see that type one and type two and type four tags cover ISO 14443A and B, three covers FELICA, and type five covers ISO 15693. The simple NDEV exchange protocol covers ISO 18092. The NFC forum also standardizes the NDEV file format for data exchange. So here's a simplification of what we've seen in the previous slide. An NFC type A or an ISO 14443-A tag can be an NFC forum type two tag or an NFC forum type four tag. An ISO 14443B tag or NFC type B can be an NFC forum type four. And an NFC type five or an ISO 15693 can be an NFC forum type five. In addition to the tag types, the NFC forum also defines the size of the memory, the data rate, and the anti-collision and capability of each of those tags. I mentioned previously that the NFC forum standardized the NDEV file format for data exchange. NDEV means NFC data exchange format, and it's used across all NFC devices. So every NFC device knows how to interpret the data coming across the link. They're very lightweight binary messages, and it encapsulates one or more NDEV records into a single message. So the NDEV records can be the same or a different type, and each NDEV record contains simply a header and a payload. So some examples that you'll see of NF records are a simple text record, a URI, a V-card, or Bluetooth, or Wi-Fi pairing information. And that concludes this portion of the training. Thank you for your attention.