RFID Gen 2 - What is it? - Smart RFID!
The following page is a White Paper RFID on the current RFID World and what it means.
In order to understand what Gen 2 is we first have to look at what EPC and EPCglobal means.
EPC is the new Electronic Product Code that replaces the older UPC (Universal Product Code) found on many item labels and is a set of numbers plus a bar code. Since UPC first started in 1963 it became out of date with today's global economies and EPC is the Radio Frequency Identification (RFID) modern day equivalent of the older UPC.
EPCglobal is the organization(s) that lead the development of industry global wide standards for the EPC to support the use of RFID in today's global, information hungry trading networks. EPCglobal organizations are in every country that is working towards making the EPC the end to end supply chain standard.
Gen 2 or EPCglobal Class 1 Generation 2 defines the physical and logical requirements for a passive-backscatter, Interrogator (RFID Gen 2 Reader) Talks First (ITF), RFID system operating in the 860 MHz ~ 960 MHz frequency range. The system is comprised of Readers and Tags (also known as labels). The prior EPC Tag standards were known as Class 0 and Class 1. EPC C1 Gen 2 represents a major step in standardization, performance and quality.
If you are having trouble understanding this, we recommend you enrol in our Free RFID 6 Lesson Introduction - 1 Lesson per day for 6 days to get a complete overview on RFID.
Gen 2, EPC Gen 2, EPC C1G2 are the short names commonly used instead of "Electronic Product Code Class 1 Generation 2" standard.
Gen 2 operates in the 860 MHz ~ 960 MHz frequency range and EPCglobal readers and EPC global tags can also operate over the entire frequency range allocated. Since there are a number of Organizations and Governing bodies that regulate the frequency and power capabilities (See RFID Frequencies and Transmission Power for more information) of this frequency range, no country can legally operate over the entire bandwidth. There are two basic frequencies of operation - 860 MHz ~ 868 MHz and 902 MHz ~ 928 MHz. North America is all 902 MHz ~ 928 MHz and has the highest transmission power specifications.
In addition to operating in the 860 MHz ~ 960 MHz frequency range the Gen 2 standard also uses FHSS (Frequency Hopping Spread Spectrum) which rapidly switches the carrier among many frequency channels during the radio signal transmission, reading tags at slightly different frequencies to get the best possible read from the tag. FHSS reads the tag on several different frequencies and then compares the results to determine if the read was successful or not.
For more detailed information about Gen 2 and the EPCglobal standards - http://www.epcglobalinc.org
Now that we have a basic understanding of Gen 2 we can look at the 2 main components - the Gen 2 Readers and the Gen 2 Tags.
Gen 2 Readers
Gen 2 readers come in two main flavors - EPC Gen 2 Certified and Gen 2. Both types of readers are capable of reading and writing to Gen 2 tags. In some cases the readers may also read and write to the earlier Class 0 and Class 1 tags (ISO 18000 - 6B).
EPC Gen 2 Certified are 860 MHz ~ 960 MHz readers that use the same O/S (operating system), the same low level reader command set (LLRP) and are totally interchangeable with other manufacturers without any changes. Simple swap in and swap out. The differences between manufacturers relate to enhanced functionalities not in the Gen 2 standard, enhanced read and write sensitivities, tag direction sensing and more.
EPC Gen 2 Certified readers have 3 reader modes (single, multiple and dense) which are required by the Gen 2 standard for using the reader in different environmental situations. The EPC Gen 2 Certified readers are firmware upgradeable to ensure full compliance with all of the still unfinalized EPCglobal specifications. Gen 2 Certified readers also have 2 read modes - fast - over 1600 tags per second and slow - less than 600 tags per second. The read speeds are automatic and depend entirely on the actual read conditions for each tag. The high speed read is called FM0 Baseband and reads tags at a speed of 40 ~ 640 Kbits/s and the low speed read is called Miller and operates at 5 ~ 320 Kbits/s. Miller low speed is automatic when the reader senses a tag but can not read it using FM0 Baseband.
SkyRFID carries several Gen 2 Certified readers lines - Impinj and Sirit - two top world class readers with excellent hardware, software, service and support.
Gen 2 readers also operate in the 860 MHz ~ 960 MHz frequency and are capable of reading all of the standard Gen 2 tags. The major difference is that the reader and antenna control codes are not interchangeable between manufacturers and they may not be interchangeable between different models by the same manufacturer. Other differences are that they usually do not have the read rate of the Gen 2 Certified readers, their power ratings may be less and the pricing is much different usually 30 - 50% less than a Gen 2 Certified reader.
SkyRFID OEM's a number of different manufacturers Gen 2 Readers and several of the reader lines have the same engine and therefore the same programming standard from the single port integrated reader/antenna to the 4 port reader.
If your company is seeking to be fully EPCglobal compliant then you need Gen 2 Certified readers. If your company is looking to use the Gen 2 technology in a localized or regional environment then the Gen 2 reader will provide everything that you need at a much lower cost. Gen 2 readers also come in several different power configurations and short and long range single antenna integrated reader/writer/antenna - perfect for the small to mid size coverage areas.
EPC Tag Classes
EPC tag capabilties are broken down into classes and each class has specific capabilties and is backward compatible to the preceeding class. Each higher class maintains the previous capabilities and characteristics and adds new capabilities.
EPC Class 0
EPC Class 0 is Generation 1 also called Gen 1. Generation 1 are tags that you can write once and read many times (WORM). This class of tag is factory programmable and not field programmable.
EPC Class 1
EPC Class 1 is Generation 1 and Generation 2, also called Gen 1 and Gen 2. Class 1 tags are WORM tags but can be read by readers from other companies. EPC Class 1 Generation 2 (EPC Gen 2 or just Gen 2) are WMRM (Write Many Read Many) tags that have a minimum memory of 256 bits of which 96 bits is for the EPC number. Gen 2 tags have better tag identification, which allows the reader to eliminate duplicate reads during multiple tag scans. Gen 2 tags can also be read by all Gen 2 readers due to vendor neutral design specifications. Gen 2 tags read up to 10 times faster than Gen 1 and provide extremely high read rates on tags - literally 100%. In addition the actual I/C (Integrated Circuit - that can contain over 50,000 transisters) is 2 to 3 times smaller than the earlier Gen 1!
EPC Class 1 tags also have a function that can render the tag permanently non-responsive. Options to Class 1 tags are decommissioning and recommissioning of the tag, passwords protected access control and optional usery memory.
Gen 2 Tags
EPC Gen 2 tags come in several different flavours - EPCglobal - meaning that the tag can be read at any frequency between 860 MHz and 960 MHz, EPC Gen 2 860 MHz. ~ 868 MHz, also known as European Gen 2 and Gen 2 902 MHz ~ 928 MHz known as the North American Gen 2. An excellent flavour of the EPCglobal tag is an EPC World Tag - this world tag has a maximum read deviation of 1.5 dBi over the entire read spectrum from 860 ~ 960 MHz making it perfect for world/global solutions.
Effectively you can use a single tag throughout the world that positively identifies the tagged item directly back to the source, hence end to end supply chain management and visibility.
Gen 2 tags come in a very wide variety of types, shapes and sizes that are usually designed for a specific application.
Generic longevity specifications for Gen 2 IC's are 40 - 50 year data retention and 100,000 write cycles
A pallet tag can have a read distance of over 10 meters when attached to the cardboard or wooden case, but when attached to a metal shelving support the pallet tag has a read distance of zero to 0.5 meters.
For attaching to metal objects a metal mount tag should be used and depending on the type of metal and the type of metal mount tag you can achieve a read range of 10 meters or more when attached to metal. Each metal object does provide a different metal mount tag requirement and depending on the overall environment the reader frequency may need to be changed in order to achive the best read rate and distance.
Tags can also be orientation sensitive due to the inlays used in making the final tag. Some tags can only be read in a vertical or horizontal postion, some tags will only read on the edge, and then some tags can be read regardless of the orientation. Just because your friend uses XYZ tag does not mean that this is the best tag for your application.
Each application needs to consider the read and write requirements and then look at the tag that meets those requirements. Temperature, read distance, working environment, storage environment, read angles, and more need consideration so you can then determine what Tag IC and antenna combination will work the best.
Using the right tag for your application can make the difference between a successful implementation or a failure!
All Gen 2 tags contain the same basic memory features:
96 bit EPC number support (can and is used for many other purposes as has read write capabilities)
32 - 64 bit tag identifier (TID) - identifies the manufacturer of the tag and also has read write capabilities
32 bit kill password to permanently disable the tag
32 bit access password to lock the read write characteristics of the tag and also set the tag for disabling
User memory - dependant on the manufacturer and can be as little as 0 bits to 64 bits and going as high as 2048 or more now that memory capabilities are being added to the tag IC's.
To view some of the regular tag inlays (the IC, the antenna and the strap) view our RFID Tag Inlays web page.
EPC Class 2
EPC Class 2 tags are enhanced Gen 2 Class 1 tags. They contain all of the Class 1 features plus an entended TAG ID (TID), extended user memory, authenticated access control and additional features that will be defined in the Class 2 specification not yet completed.
EPC Class 3
EPC Class 3 tags have not yet been fully defined, but are battery-assisted passive tags somtimes called semi-passive tags in UHF Gen 2. Anticipated features are a power source to supply power to the tag and/or its sensors and or sensors with optional data logging capabilities.
These new Class 3 tags will still communicate passively, meaning they will require a reader/interrogator to initiate communications and send information to the readder using either backscatter or load -modulation techniques (For a better understanding of RFID communications we recommend you take our 6 free lesson RFID course)
EPC Class 4
EPC Class 4 is active tag technology. The UHF tag will contain a battery and can initiate communications with a reader or with another tag. Class 4 active tags will not interfere with the communications protocls of Class 1, 2 or 3 tags. Class 4 tags with contain an EPC identifier, and extended Tag ID, authenticated access control, a power source, communicaitons via autonomous transmitter, have optional user memory and optional sensors with or without data logging capabilities. This Class 4 tag is still in the early definition stage.
We hope this information has assisted you in the understanding of Gen 2 and how it can relate to your needs.
For more information