A Brief Introduction to Low Level Reader Protocol (LLRP)

PRLog (Press Release) – Sep 25, 2007 – Radio-frequency identification (RFID) depends on the use of readers to identify tags that are in their field of view.  An RFID reader operating in the ultra-high-frequency (UHF) band represents a complex control problem.  It is necessary to specify a number of physical-layer parameters related to the antennas and analog signals before any attempt is made to read the ID of a tag.  Attempts to read tag ID’s and manipulate individual tags require the use of sophisticated protocols with a number of options, selection of which depends on the circumstances of operation and the intent of the user.  Much work must be done before one can get to the level of abstraction where one can focus on reading a pallet tag with a given ID at a given dock door.  
 
Historically, vendors met these challenges by writing one or more custom control interfaces specific to their hardware and embedded software.  These control interfaces all solve generally similar sets of problems, but have distinct and incompatible architectures, control models, command vocabularies, and protocol options.  While at any given moment in time, it is possible to construct drivers for a given vendor’s products, a higher-level software application must also maintain those drivers as vendors modify both their software and hardware.  When this problem is multiplied by the large vendor selection that must be supported by higher-level applications, it can become a significant cost.  It is therefore in the interest of software vendors and systems integrators that the control interface to the readers be standardized.   And if a given standard becomes widely accepted, it is also in the interests of reader vendors to support operation of their equipment under that standard.

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