Internet of Things (IoT) and RFID

Internet of Things (IoT)

• Internet of Things (IoT) is the concept of connecting everyday devices to the internet, allowing them to communicate and exchange data.

Radio Frequency Identification (RFID)

• Radio Frequency IDentification (RFID) uses radio waves to identify and track objects.
• RFID is a technology that uses radio waves to automatically identify and track tags attached to objects.
• An RFID reader transmits a radio signal that activates the RFID tag, which then transmits data back to the reader

Historical Background of RFID

• Identification Friend or Foe (IFF) system was used by Allied bombers during World War II.
• Passive RFID was introduced in 1948.
• In 1972, an "inductively coupled transmitter-responder" with 2 antennas was created.
• In 1979, an "identification device" combined both antennas into one.
• In the 1970s, scientists at Lawrence Livermore Laboratory (LLL) developed a handheld receiver powered by RF for secure access to nuclear facilities.

RFID Systems Components

• Tags (transponders) are a key component, consisting of a microchip and antenna.
• A tag reader, with a decoder and antenna, sends an energy pulse and awaits a response.
• Tag readers can be continuously active or activated by an external event.

RFID Tags Variations

• Variations in memory size range from 16 bits to 512 Kbytes.
• Tags can be Read-Only, Read/Write, or Write Once Read Many (WORM).
• Arbitration (Anti-collision) is the ability to read/write one or many tags at a time.
• Frequency ranges from 125KHz to 5.8 GHz.
• Price ranges from 0.10to0.10 to 0.10to250.
• Physical dimensions range from thumbnail size to brick sizes.

Tiny RFID Tags

• In 2007, Hitachi produced an RFID device measuring 0.05×0.05 mm, thin enough to be embedded in paper.
• The data can be extracted from a few hundred meters away.

Active RFID

• Active RFID tags use internal batteries.
• Active tags have a "self-powered" function that uses an interrogator RF beam for wake-up and communication.
• Active tags have a greater range of 20-200m.
• Active tags have a very low required signal strength.
• Active tags have a data storage of up to 512 KB.
• Active tags can have a 10yr life.
• Active tags have multiple sensor capabilities.
• Active tags can recognize 1000's of tags recognized up to 100mph.

Passive RFID

• Passive RFID tags are powered by energy transferred using RF from the reader.
• Passive tags do not use batteries.
• Passive tags have a data storage of 16 bits – 1 KB.
• Passive tags have a very high required signal strength.
• Passive tags have limited range of <10m (frequency dependent).
• Passive tags allow communication & power from interrogator RF beam.
• Passive tags can recognize a few hundred tags within 3m of reader, about 3 sec per read => at most 3 mph.

Radio Frequency (RF) Modulation

• Modulation is how information is added to the carrier signal (RF radio frequency)
• Modulation works by modulating the properties of a wave like its amplitude, frequency or phase depending on what information is being transmitted, and in order to receive the information transmitted you need a demodulator to extract the data that was inserted in the signal at transmission.

Low Frequency, Load Modulation

• Integrated circuit sends a signal to an oscillator, which creates an alternating current in the reader's coil.
• That current generates an alternating magnetic field that serves as a power source for the tag.
• The field interacts with the coil in the tag, inducing a current that causes charge to flow into a capacitor, where it is trapped by the diode.
• Charge accumulates which increases the voltage across it and activates the tag's integrated circuit, which transmits its identifier code.
• Variations in the resistance of the circuit, due to the transistor turning on and off, cause the tag to generate its own varying magnetic field, which interacts with the reader's magnetic field.
• Variations in current flow in the reader coil are sensed by a device that converts this pattern to a digital signal.
• This technique, called load modulation, causes magnetic fluctuations that change the current flow from the reader to its coil in the same pattern as the ones and zeros transmitted.

High Frequency, Backscatter Modulation

• An integrated circuit sends a digital signal to a transceiver.
• A radio-frequency signal is generated that is transmitted by a dipole antenna.
• The electric field of the propagating signal gives rise to a potential difference across the tag's dipole antenna.
• The potential difference causes current to flow into the capacitor, whose resulting charge is trapped there by the diode.
• The voltage across the capacitor turns on the tag's integrated circuit where it sends a series of digital high- and low- voltage levels.
• The transistor gets turned on or off by the highs and lows of the digital signal.
• The highs and lows alternately cause the antenna to reflect back or absorb some of the incident radio- frequency energy from the reader.
• The variations in the amplitude correspond to the pattern of the transistor turning on and off.
• The reader's transceiver detects the reflected and converts them to a digital signal that is relayed to the integrated circuit.

RFID Frequency Ranges and Characteristics

• LOW (100-500 KHz): Short to medium read range, inexpensive, low read speed, used for access control, animal identification, and inventory control.
• HIGH (10-15MHz, 850-950MHz): Short to medium read range, potentially inexpensive, medium reading speed, used for access control and smart cards.
• ULTRA-HIGH (2.4-5.8 GHz): Long read range, high reading speed, line of sight required, expensive, used for railroad car monitoring, toll collection systems, and vehicle identification.

Codes

• RFID tags and bar codes are used for product identification.

Electronic Product Code (EPC)

• Header (8 bits): Identifies the EPC's version number and allows for the evolving of different lengths or types of EPC.
• EPC Manager (28 bits): Identifies the manufacturer of the product which it derives from the company's prefix.
• Object Class (24 bits): Refers to the exact type of product which is the GTIN (Global Trade Item Number) without the prefix or the item reference.
• Serial Number (36 bits): The specific serial number of the individual item.

Communication and Collisions

• Packet formats are very simple.
• A general structure is Sync, Header, Command, Data, and CRC.
• Reader-to-tag and tag-to-reader formats are somewhat different.
• Typically 2 byte CRC (Cyclic Redundancy Check) is used.

Collisions in RFID Systems

• All tags respond when receiving a query, which can lead to collisions.
• Many readers have "simultaneous read" capabilities to resolve collisions.
• "Carrier sense" is not possible.

Binary Tree Algorithm for Collision Avoidance

• Tags are polled bit-by-bit to avoid collisions.
• Example queries and responses:
  • "x": 7 tags respond, resulting in a collision.
  • "0x": 3 tags respond, resulting in a collision.
  • "00x": 1 tag responds.
  • "01x": 2 tags respond, resulting in a collision.
  • "010x": 2 tags respond, resulting in a collision.
  • "0100x": 1 tag responds.
  • "0101x": 1 tag responds
  • "011x": no response
  • "1x": 4 tags respond, resulting in a collision.
  • "10x": 1 tag responds.
  • "11x": 3 tags respond, resulting in a collision.

RFID Application Scenarios

• Tracking the movement of consumer product goods
• Animal identification/tracking/counting
• Toll collection
• Implantation of RFID chips into people, e.g., Alzheimer's patients

RFID Applications

• Keyless entry systems
• Proximity cards
• Supply chain management

RFID Implants

• Implants are a controversial application of RFID technology.
• Small glass cylinders are approximately 2 or 3mm wide and between 1 and 1.5cm long.
• An implant consists of a microchip, a coiled antenna, and a capacitor.
• Implants are typically implanted under the skin of the arm or the back of the neck.

Instant Checkout Systems

• Instant checkout systems use RFID to scan entire shopping baskets.

Concerns about RFID

• Clandestine tracking
• Inventorying

Security/Privacy Issues and Solutions

• Unauthorized Reading can be prevented by using metal foil in passports or by scanning closed boxes outside.
• The Unauthorized Writing of RFID tags can be prevented with authentication and can be killed.
• RFID Zapper can burn a tag using overcurrent.
• RSA Blocker Tag is placed near another RFID to prevent its reading.
• Authentication requires the reader to know a PIN.
• Put Tag to Sleep: Can wake up later and reuse the tags.
• Re-label Tag and Dual-Use Tag: Allows customer to see differed info or customer can over-write tag with useful information.

Near-Field Communication (NFC)

• NFC is a short-range wireless communication technology.
• NFC offers safe and simple communication between electronic devices.
• Exchange of data between devices happens over a distance of 4 cm or less.
• NFC operates at 13.56 MHz and rates ranging from 106 kbit/s to 848 kbit/s.

How NFC Works

• NFC is based on RFID technology that uses magnetic field induction between electronic devices in close proximity.
• Two devices must have an NFC reader/writer and an NFC tag to communicate
• The NFC tag is essentially an integrated circuit containing data, connected to an antenna, that can be read or written by the reader.
• NFC combines the interface of a smartcard and a reader into a single device, and is compatible with contactless infrastructure already in use for public transportation and payment using exisiting ISO/IEC14443 smartcards and readers.
• NFC is primarily aimed at usage in mobile phones
• There were approximately 600 million NFC-equipped phones in use in 2015 (estimate that 5% are used at least once a month)

NFC Applications

• Card emulation.
• Reader mode.
• P2P mode.
• Mobile/electronic ticketing
• Smart objects
• Electronic keys
• P2P data transfers
• NFC configures and initiates other wireless network connections such as Bluetooth or Wi-Fi.