Patent Publication Number: US-2010127869-A1

Title: Hierarchy of rfid tags for accessing history and other data

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates generally to a hierarchical configuration of RFID tags and, more particularly, to a hierarchical configuration of RFID tags where the RFID tags can be placed on products, containers that identify the products therein and delivery systems that transport the containers in a hierarchical manner so that reading an RFID tag at an upper level provides information about things at lower levels. 
     2. Discussion of the Related Art 
     Radio frequency identification (RFID) tags are well known in the art. RFID tags store an identification number or code, and other information, such as location produced, shelf life, etc, for a thing that the tag is attached to, such as a product, a container, a place, etc. An RFID tag includes an antenna and suitable processing circuitry for receiving an interrogation signal from an RFID reader. The RFID tag interrogates an RFID reader by transmitting and receiving RF signals. The RFID tag can be active or passive, where a passive tag does not include a power source, but employs inductive coupling where the interrogation signal from the reader generates the power necessary to transmit the RFID code. An active RFID tag includes a power source that provides the power to transmit the RFID code to the reader. 
     Current RFID tags are programmed with an identification code that identifies information about the particular thing that it is attached to. However, these RFID tags are not programmed to identify information about other things that may be associated with the thing that the RFID tag is attached to. For example, an RFID tag on a container may only identify information about the container, and not information about the contents of the container. It may be desirable to provide a hierarchical configuration of RFID tags where upper level RFID tags can obtain information about lower level things associated with that RFID tag. 
     SUMMARY OF THE INVENTION 
     In accordance with the teachings of the present invention, a hierarchical configuration of RFID tags is disclosed. The hierarchical configuration includes a plurality of RFID tags having lower level RFID tags, intermediate level RFID tags and at least one upper level RFID tags, where each RFID tag stores an identification code and other information about the thing it is attached to. Further, each intermediate level RFID tag also obtains information about a group of lower level RFID tags that it is associated with and the at least one upper level RFID tag obtains information about more than one intermediate RFID tag it is associated with. 
     Additional features of the present invention will become apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram of an RFID tag and associated RFID reader; and 
         FIG. 2  is a block diagram of a hierarchical configuration of RFID tags. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     The following discussion of the embodiments of the invention directed to a hierarchical configuration of RFID tags is merely exemplary in nature, and is in no way intended to limit the invention or its applications or uses. 
       FIG. 1  is a block diagram of a system  10  showing an RFID tag  12  and an associated RFID reader  14 . The RFID tag  12  includes a processor  16  that controls the operation of the RFID tag  12 . The RFID tag  12  also includes an antenna  20  that receives interrogation signals from the reader  14  and transmits RFID signals including information that is stored in a memory  18  back to the reader  14 . The information that is stored in the memory  18  can be any information suitable for a particular purpose, such as an identification code, a product code, a location code, manufacturing information, travel information, specifications, product history, etc. The size of the RFID tag  12  and the amount of processing circuitry therein would depend on the specific application it is being used for, where that application could be nearly limitless. The operation of RFID tags, whether passive or active, are well understood in the art and the frequencies that they operate at are also well understood. 
       FIG. 2  is a plan view of a hierarchical configuration  30  of RFID tags  32 . The hierarchical configuration  30  of the RFID tags  32  is arranged in hierarchical layers, including a lower layer  34 , an intermediate layer  36  and an upper layer  38 . Arrows  40  in the configuration  30  show the direction of information flow from the lower levels to the upper levels of the configuration  30 . The RFID tags  32  associated with the lower layer  34  may store information about a particular thing, such as a product. The RFID tags  32  in the intermediate layer  36  may store information about a group of the things in the lower layer  34 . In this non-limiting example, each RFID tag  32  in the intermediate layer  36  stores information about three separate things identified by RFID tags  32  in the lower layer  34 . Thus, someone reading an RFID tag  32  in the intermediate layer  36  can obtain information about the things having the RFID tags  32  in the lower layer  34 . A single RFID tag  32  is associated with the upper level  38 , and stores information about a plurality of the RFID tags  32  in the intermediate layer  36 , here three. Thus, someone reading the RFID tag  32  at the upper level  38  can obtain information about things in the intermediate layer  36 . 
     Although the above discussion is logical operational, the implementation may be different because RFID tags may not be able to directly talk to each other. 
     The lower level RFID tags  32  may be placed on specific products and the intermediate level RFID tags  32  may be placed on containers in which the specific products are stored. Further, the upper level RFID tag  32  may be placed on a truck, where the containers including the intermediate level RFID tags  32  are being transported. Thus, someone using the RFID reader  14  can read a single upper level RFID tag  32  to determine specific information about the truck itself and the containers on the truck, and can read an RFID tag  32  on a container on the truck to obtain information about the container and things stored within the container. Therefore, if somebody wants to know what items are in a particular container and what containers are on a particular truck, they only need to read one RFID tag to make that determination. 
     Although containers and trucks are used in this example, the hierarchical configuration  30  of RFID tags  32  is intended to be provided for any situation where RFID tags can identify certain things and upper level RFID tags can be used to identify groups of lower level RFID tags. 
     In another application, the hierarchical configuration  30  could use the RFID tags  32  for plant floor management and vehicle assembly operations. 
     If the arrangement of the RFID tags  32  changes, for example, where the containers identified by the intermediate level RFID tags  32  are put on a different truck having a different upper level RFID tag, the upper level RFID tag  32  can be programmed with information for the new RFID tags at the intermediate level  36 . 
     Further, the RFID tags  32  can be programmed with their history to show where they have been. For example, if the containers have been moved from one truck to another truck, the intermediate level RFID tags  32  and the upper level RFID tag  32  can be programmed to include the information about where they came from. The upper level RFID tag  32  can store information about containers that have been removed from the truck and the intermediate level RFID tags can store information concerning previous trucks that the containers where on. 
     The hierarchical configuration  30  could be used, for example, to check whether a container is full or to check which parts may be missing in an assembly. The analysis of the history data can help derive the optimal solutions in packaging parts in a container, grouping containers in the shipment, etc. 
     The hierarchical configuration  30  offers greater potential flexibility. For example, the upper level  38  of the hierarchical configuration  30  could be implemented in software within an accessing device, such as a computer. In addition, lower level hierarchical RFID tags can be removed from the hierarchical configuration  30  and be inserted into another configuration. RFID tags of different vendors can be arranged as sub-trees above a larger tree, provided that the root nodes of the sub-trees adhere to the same present communication protocol with the higher level nodes of the larger tree. 
     The foregoing discussion discloses and describes merely exemplary embodiments of the present invention. One skilled in the art will readily recognize from such discussion and from the accompanying drawings and claims that various changes, modifications and variations can be made therein without departing from the spirit and scope of the invention as defined in the following claims.