Information technology - Automatic identification and data capture techniques - Air interface specification for Mobile RFID interrogators
ISO/IEC 29143:2011 provides an air interface specification for Mobile radio frequency identification (RFID) interrogators being part of a passive backscatter system. This system comprises one or more mobile interrogators, also known as Mobile RFID interrogators, and an undefined number of tags, also known as labels.
Interrogators are not required to support channel sensing, i.e. do not need to implement Listen Before Talk (LBT), and transmit commands on the off chance under the risk of colliding with one or more peer-interrogators. Moreover, interrogators compliant to ISO/IEC 29143:2011 are not obliged to synchronize by any means (wired or wireless), i.e. no control channel dedicated to coordinating Time Division Multiplexing (TDM) is provided.
Tags are powered by the RF signal provided by the interrogator and respond to an interrogator by modulating the reflection coefficient of its antenna, thereby backscattering data to the interrogator. The working mode adopted by the tags is purely passive, i.e. tags do not actively initiate any kind of RF communication.
In ISO/IEC 29143:2011, collision arbitration and collision avoidance for Mobile RFID applications are defined by specifying methods aimed at mitigating the impact of emerging collisions and mechanisms used to avoid follow-up collisions.
ISO/IEC 29143:2011 applies to Mobile RFID interrogator devices used to inventory passive or semi-passive backscatter tags at 860 MHz to 960 MHz in a mobile (non-fixed) application independent from specific communication details, i.e. modulation technique and command set.
Furthermore, the scope of ISO/IEC 29143:2011 is mobile consumer applications, whereas mobile enterprise applications are not covered as long as operating in a closed environment.
An operating environment is considered to be closed if it belongs to a central administrative authority able to guarantee for sufficient isolation, i.e. preventing mobile enterprise interrogator devices from being used outside the dedicated operating environment, and if sufficient spatial separation and/or electromagnetic shielding from adjacent operating environments is provided.
An application is considered a consumer application if at least one of two interacting entities is a private individual (consumer) and the interaction is taking place in the public domain. Consequently, a Mobile RFID consumer application is defined as Mobile RFID equipment (e.g. mobile phones equipped with an RFID interrogator) being used in a consumer application.
NOTE As there is currently no active contribution on Mobile HF interrogators, ISO/IEC 29143:2011 covers only UHF.
ISO/IEC 29143:2011 specifies
- Mobile RFID interrogator media access control,
- interrogator to interrogator and multiple interrogator to tag collision arbitration scheme including interrogator requirements,
- interrogator to interrogator and multiple interrogator to tag collision avoidance scheme, and
- tag memory use for Mobile RFID applications.
ISO/IEC 29143:2011 does not specify
- physical interactions (the signaling layer of the communication link) between interrogators and tags,
- interrogator and tag operating procedures and commands, and
- the collision arbitration algorithm used to singulate (separate to the current response slot) a specific tag in a multiple-tag environment.
In particular, ISO/IEC 29143:2011 does not replace any existing RFID air interface specification issued by ISO/IEC but extends the existing methodologies for fixed RFID interrogators with mechanisms addressing the special challenges of Mobile RFID. The concepts and mechanisms described in ISO/IEC 29143:2011 can be integrated in any existing RFID protocol approved by ISO/IEC for the given frequency range of 860 MHz to 960 MHz (unless explicitly prohibited by such protocol) regardless of the actual command set.