1. Field of the Invention
The present invention relates radio frequency identification, and more particularly, to a method and system for facilitating communication between a radio frequency identification (RFID) device and RFID tags.
2. Introduction
Item level tagging is a process of placing Radio Frequency Identification (RFID) tags on individual product items. Currently, there are some RIFD applications where an RIFD tag is placed on the actual shipping pallet containing multiple items to identify the pallet and then using a database to associate the pallet ID number, the pallet with what was believed to have been placed on the pallet. This process requires manual entry at some stages and mistakes can be and are made. Thus, this process does not account for accuracy and the potential for tampering.
Therefore, industry is looking at RIFD up and down the supply chain as a way to improve inventory accuracy and tracking down to the item level. However, one of the problems with RIFD is that since it is a wireless communication technology (radio frequency (RF) technology) it subject to electromagnetic phenomenon common to all radio signals that can interfere with signal transmission and reception.
This problem is particularly apparent if the signal must penetrate an obstructed volume that includes containers with arbitrary materials, different sizes, orientation, etc. As a result, the signal becomes very unpredictable for that volume. For example, in a pallet-type situation, signals from containers having RFID tags located in the interior of the volume will be difficult to receive because of the electromagnetic effects and density of the packaging volume. Thus, with the current systems it is difficult to guarantee that the signal will penetrate to every tag in the volume stack to allow RFID tags to be read in order to get an accurate inventory.
A method and system for facilitating radio frequency (RF) communication between a radio frequency identification (RFID) device and RFID tags is disclosed. The method may include associating one or more RFID tags to one or more containers that comprise a container volume, wherein the RF signal communication between the RFID device and one or more of the RFID tags is at least partially obstructed, and integrating at least one conductive surface into the container volume, wherein if the RFID device is coupled to at least one of the conductive surfaces and energized, the RFID device, the at least one conductive surface and one or more of the RFID tags are capacitively coupled allowing RF signals to be communicated between the RFID device and the one or more RFID tags in the container volume without being obstructed.
In order to describe the manner in which the above-recited and other advantages and features of the invention can be obtained, a more particular description of the invention briefly described above will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. Understanding that these drawings depict only typical embodiments of the invention and are not therefore to be considered to be limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The features and advantages of the invention may be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims. These and other features of the present invention will become more fully apparent from the following description and appended claims, or may be learned by the practice of the invention as set forth herein.
Various embodiments of the invention are discussed in detail below. While specific implementations are discussed, it should be understood that this is done for illustration purposes only. A person skilled in the relevant art will recognize that other components and configurations may be used without parting from the spirit and scope of the invention.
The description herein uses several terms of art throughout and will be described in context below. “RFID device” may be a receiver, tag reader, transmitter, tag programmer, transceiver, etc. The term “associated” may be defined as being inside the container, attached to the container, sealing the container, etc. The “container volume” may include one container, or several containers. The “one or more RFID tags” may be associated with every container, some of the containers or just one of the containers in the container volume. An “RF signal” may be defined as any radio frequency signal or similar energy transmission that may be received and/or transmitted through any medium, including any wireless and/or wired medium. The term “obstructed” may be defined as not permitting or hindering RF signal communication. “RF signal communication” maybe defined as the transmission and/or reception of RF signals.
The present invention comprises a variety of embodiments, such as a system and method, and other embodiments that relate to the basic concepts of the invention. This invention may be particularly well suited to capacitively-coupled RFID systems which typically make use of near-field coupling mechanisms.
In this manner, the distances d1 and d1′ from
Depending on the numbers of columns and rows of containers 720, the number of conductive surfaces 590, 595 may vary in accordance with the invention. The pallet 710 may be such that one or more of the containers 720 may not have any RFID tags 300, while other containers 720 may have one or more RFID tags 300.
Therefore, if the plates of an RFID reader are coupled to the conductive surfaces 590, 595, the RFID tag 300 in the container located in the middle of the row of containers 700 may be read, transmitted to, communicated with, etc. As an alternative to using conductive sheeting as a way of introducing a conductive surface, conductive material can be incorporated in the surface of the containers such that a continuous conductive surface is formed when the containers are assembled on a pallet 710. In one possible embodiment, the conductive material may be deposited or printed on the surface of the containers using a low cost printing process. In addition, the products themselves may provide or aid in capacitive coupling if such products have electrically conductive properties, such as soda cans, for example.
The excitation mode for the RFID tag reader 110 could be single-ended monopole (one surface grounded) or balanced dipole (the pair of surfaces driven 180 degrees out of phase), as is well-known to those skilled in the art. In the case of a handheld device, single-ended excitation may be preferable since the operator could provide body-coupled ground to both the reader (through its handle) and to the grounded surface with the user's hand, thus requiring only one electrode on the reader.
Stacking provides the required capacitive coupling c5 and c5′ between tote structures. Capacitive coupling between layers of totes in the stack may also be aided by and/or provided using the products themselves if the product container has electrically conductive properties, such as a soda cans, for example. Thus, the capacitive coupling may be achieved by direct contact or indirect contact. In either case, the capacitive coupling provides electrical connection to each tote contained in the structure which enables communication between an RFID tag reader 110 and an RFID tag 300 in the tote structure.
At the base of the system 1000 are two electrically conductive strips 120, 130 serving as the plates connected to the RFID tag reader 110. When the RFID tag reader 110 is powered up, the capacitively coupled circuit should be complete (assuming totes with RFID tags are contained within).
As shown in the figure, exemplary RFID tag reader 110 may include a bus 1110, a processor 1120, a memory 1130, a read only memory (RO 1140, a storage device 1150, an input device 1160, an output device 1170, and a communication interface 1180. Bus 1110 may permit communication among the components of the RFID tag reader 110 or RFID tag reading system 100. Certainly, one of skill in the art will recognize that the RFID reader 110 may include all of the elements, some of the elements or include other elements other than those shown in
Processor 1120 may include at least one conventional processor or microprocessor that interprets and executes instructions. Memory 1130 may be a random access memory (RAM) or another type of dynamic storage device that stores information and instructions for execution by processor 1120. Memory 1130 may also store temporary variables or other intermediate information used during execution of instructions by processor 1120. ROM 1140 may include a conventional ROM device or another type of static storage device that stores static information and instructions for processor 1120. Storage device 1150 may include any type of media, such as, for example, magnetic or optical recording media and its corresponding drive.
Input device 1160 may include one or more conventional mechanisms that permit a user to input information to RFID tag reader 110, such as a keyboard, a mouse, a pen, a voice recognition device, etc. Output device 1170 may include one or more conventional mechanisms that output information to the user, including a display, a printer, one or more speakers, or a medium, such as a memory, or a magnetic or optical disk and a corresponding disk drive. Communication interface 1180 may include any transceiver-like mechanism that enables the RFID tag reader 110 to communicate via a network. For example, communication interface 1180 may include a modem, or an Ethernet interface for communicating via a local area network (LAN). Alternatively, communication interface 1180 may include other mechanisms for communicating with other devices and/or systems via wired, wireless or optical connections. In some implementations of the RFID tag reading systems disclosed herein, communication interface 1180 may not be included in the exemplary RFID tag reader 110 when the RFID tag reading process is implemented completely within a particular RFID tag reading system.
The RFID tag reader 110 may perform such functions in response to processor 1120 by executing sequences of instructions contained in a computer-readable medium, such as, for example, memory 1130, a magnetic disk, or an optical disk. Such instructions may be read into memory 1130 from another computer-readable medium, such as storage device 1150, or from a separate device via communication interface 1180.
The RFID tag reading systems discussed herein and the exemplary RFID tag reader 110 illustrated in figures and the related discussion are intended to provide a brief, general description of a suitable computing environment in which the invention may be implemented. Although not required, the invention will be described, at least in part, in the general context of computer-executable instructions, such as program modules, being executed by the RFID tag reader 110 processor 1120. Generally, program modules include routine programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. Moreover, those skilled in the art will appreciate that other embodiments of the invention may be practiced in network computing environments with many types of computer system configurations, including personal computers, hand-held devices, multi-processor systems, microprocessor-based or programmable consumer electronics, network PCs, minicomputers, mainframe computers, and the like.
Embodiments may also be practiced in distributed computing environments where tasks are performed by local and remote processing devices that are linked (either by hardwired links, wireless links, or by a combination thereof through a communications network. In a distributed computing environment, program modules may be located in both local and remote memory storage devices.
For illustrative purposes, the RFID tag reading process will be described below in relation to the block diagrams shown in and discussed in relation to
At step 12300, at least one conductive surface may be integrated into the container volume. Therefore, if the RFID device is coupled to at least one of the conductive surfaces and energized, the RFID device, the at least one conductive surface and one or more of the RFID tags are capacitively coupled allowing RF signals to be communicated between RFID device and the one or more RFID tags in the container volume without being obstructed. The process goes to step 12400, and ends.
Embodiments within the scope of the present invention may also include computer-readable media for carrying or having computer-executable instructions or data structures stored thereon. Such computer-readable media can be any available media that can be accessed by a general purpose or special purpose computer. By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to carry or store desired program code means in the form of computer-executable instructions or data structures. When information is transferred or provided over a network or another communications connection (either hardwired, wireless, or combination thereof to a computer, the computer properly views the connection as a computer-readable medium. Thus, any such connection is properly termed a computer-readable medium. Combinations of the above should also be included within the scope of the computer-readable media.
Computer-executable instructions include, for example, instructions and data which cause a general purpose computer, special purpose computer, or special purpose processing device to perform a certain function or group of functions. Computer-executable instructions also include program modules that are executed by computers in stand-alone or network environments. Generally, program modules include routines, programs, objects, components, and data structures, etc. that perform particular tasks or implement particular abstract data types. Computer-executable instructions, associated data structures, and program modules represent examples of the program code means for executing steps of the methods disclosed herein. The particular sequence of such executable instructions or associated data structures represents examples of corresponding acts for implementing the functions described in such steps.
Although the above description may contain specific details, they should not be construed as limiting the claims in any way. Other configurations of the described embodiments of the invention are part of the scope of this invention. For example, the principles of the invention may be applied to each individual user where each user may individually deploy such a system. This enables each user to utilize the benefits of the invention even if any one of the large number of possible applications do not need the functionality described herein. In other words, there may be multiple instances of the RFID tag reading system embodiments described in