RFID

Radio frequency identification, a form of wireless communication that uses radio waves to identify and track objects.

• Uniquely identify an individual item.
• Identify items without directly line-of-sight.
• Identify many items simultaneously.
• Identify items within a vicinity of between a few centimeters to several meters.

consists of :

• RFID reader
• RFID antenna
• RFID tags
• network
• workstation

Communication process of RFID

• Host manages Readers and issues commands
• Reader and tags communicate via RF signal
• Carrier signal created by the reader
• Sent out through the antennas
• Hits tags
• Tag receive and modifies signal, “sends back” modulated signal
• Antennas receive the modulated signal and send to reader
• Reader decodes the data
• Results returned to the host application

Reader functions

• Communicate with tags by antennas
• Performing any number of tasks including simple continuous inventorying, filtering, writing to select tags
• Communicate with workstation by network port, RS232 Serial Interface or USB, providing the information of objects with tags to the enterprise system software.

EPC code ——RFID tags里唯一的标识

The electronic product code is designed as a universal identifier that provides a unique identity for every physical object anywhere in the world, for all time.

• Header 标头（8）
• EPC Manager 厂商识别代码（28）
• Object class 对象分类代码（24）
• Serial Number 序列号（36）
  98 bit code.

Different types of RFID systems

1. Frequency band:

   • Low Frequency (LF)
   • High Frequency (HF)
   • Ultra-high Frequency (UHF)
   • Super-high Frequency (SHF)

2. Power supply: Active, Passive, Semi-active/passive

Different types of RFID tags

1. Active, Passive, Semi-Active/Passive
2. Read-only, Write once Read many (WORM), Read/Write tags

The advantages RFID over barcodes (5)

• No line of sight required for reading
• Multiple items can be read with a single scan
• Each tag can carry a lot of data (Read/Write)
• Passive tags have a virtually unlimited lifetime
• Active tags can be read from great distances

The relationship between RFID and IoT

• In the IoT, RFID will embed intelligence in the physical object, so that simple physical objects can also “say”.
• In the IoT, RFID allows a physical object to be uniquely identified in a way similar to the “IP Address” of a computing node in the Internet.
• In the IoT, RFID provides a low-cost communication way to achieve effective communication between nodes.
• In the IoT, RFID makes the physical objects in a passive environment achieve “passive intelligence”, providing fundamental guarantee for the “thing-thing connection”.