Patent Application
20080186174
1. Field of the Invention
This invention relates generally to radio frequency identification (RFID) systems, and more particularly, to RFID systems that acquire information from each of a plurality of items.
2. Description of the Related Art
Radio frequency identification (RFID) systems are used in many different applications including for example, in retail environments to obtain information relating to items tagged with RFID identifiers. For example, an RFID tag can be attached or integrated within a product or product packaging. Using an RFID interrogator, which may be a fixed, portable or handheld device, RFID tags within the interrogation zone of the interrogator may be activated and provide information regarding the item associated with the RFID tag (e.g., inventory information, product descriptor, serial number, location, etc.). These RFID tags receive and respond to radio frequency (RF) signals to provide the information. In general, modulators of the RFID tags may transmit back a signal using a transmitter or reflect back a signal to the RFID readers. Additionally, information may be communicated to the RFID tags (e.g., encoding information) using RFID encoders. Thus, RFID systems may be used to monitor the inventory of products in a retail environment and provide product identification using the storage and remote retrieval of data using RFID tags or transponders.
RFID systems include RFID readers that can detect and receive information from a large number of RFID tags at the same time. Additionally, RFID readers can transmit and receive at the same time on the same frequency. For example, in a retail environment using an RFID system to track inventory, it is known to provide numerous read points that each include the use of RF multiplexers and numerous cables to connect to each read point. Further, in such known systems a separate communication and control system is typically needed to manage and control the RF multiplexers. Thus, the cost and complexity of these RFID systems is typically high. Further, the time and complexity to install the components also may be high, for example, when having to install bulky cable harnesses, etc. Also, it is often difficult, if not impossible, to obtain a complete inventory of, for example, a complete pallet because of the material used to package the contents. For example, metal foil or metalized plastic films and/or RF absorbent material may be and are commonly used in the packaging of pharmaceuticals and food products. This packaging can shield the passive RFID tags attached to the products within the packaging. Thus, often only the outer layer of RFID tags can be read using the known RFID systems and information acquisition methods. Accordingly, the breaking or opening of the pallet or case is often needed to examine the contents and confirm the inventory.
It is also known to use multiple RFID interrogators in such systems to monitor RFID tags in different locations. The use of multiple RFID interrogators also adds cost and complexity to the system. Further, the RFID interrogators may have to be moved in order to interrogate an entire area. For example, individual RFID interrogators may have to be constantly moved to interrogate an entire shelf or shelf unit. This adds time and cost when performing, for example, an RFID inventory.
A method for performing a radio frequency identification (RFID) inventory may be provided. The method may include selectively controlling with an RF signal each of a plurality of multiplexers connected to a plurality of local antennas and selectively enabling with an RF signal the plurality of local antennas using the plurality of multiplexers to perform RFID interrogation on a plurality of RFID tags. The method further may include acquiring inventory information based on the RFID interrogation.
A method for controlling the acquisition of information during an RFID item level inventory may be provided. The method may include transmitting an identification (ID) request command to each of a plurality of multiplexers during an ID acquisition state. The ID request command may activate multiplexers in a transmission range. The method further may include identifying, using the plurality of multiplexers, antenna arrays available to acquire RFID tag information. The method also may include initiating an inventory acquisition process wherein each of a plurality of local antennas of the antenna arrays is selectively activated to acquire the RFID tag information.
Radio frequency identification (RFID) inventory information also may be obtained by the method for performing a radio frequency identification (RFID) inventory.
For a better understanding of various embodiments of the invention, reference should be made to the following detailed description that should be read in conjunction with the following figures wherein like numerals represent like parts.
For simplicity and ease of explanation, the invention will be described herein in connection with various embodiments thereof. Those skilled in the art will recognize, however, that the features and advantages of the various embodiments may be implemented in a variety of configurations. It is to be understood, therefore, that the embodiments described herein are presented by way of illustration, not of limitation.
In general, various embodiments of the invention provide a method and system for performing an item level inventory. The item level inventory is generally performed using radio frequency (RF) controlled multiplexers. Thus, the various embodiments may provide a method for obtaining real time inventories of items tagged with RFID identifiers.
Specifically, and referring to
As another example, as shown in
In various embodiments, RFID tags 60 may be passive radio reflective identification tags or passive RFID tags as shown in
In other various embodiments, RFID tags 70 may be active radio reflective identification tags or active RFID tags as shown in
It should be noted that the objects 54 shown in
It should be noted that the RFID interrogator 52 may be a stand alone unit, for example, a portable or handheld unit or may be integrated with another communication device, such as mobile or cellular telephones, personal digital assistants (PDAs), Blackberry devices, etc. Alternatively, the RFID interrogator 52 may be formed as part of a backplane as described in detail below. Further, components within, for example, a cellular telephone, such as the transceiver, processor and/or software may be modified to provide the same functionality and operation of the RFID interrogator 52. Still other alternatives include a plug-in or add-on unit, such as, a plug-in module for a PDA that includes therein the RFID interrogator 52.
In various embodiment, the RFID interrogator 52 may include an interrogator antenna 80 as shown in
In operation, and referring to the one or more multiplexers 84, these devices may be configured as switches to control switching between the local antennas 86. The one or more multiplexers 84 may operate such that the multiplexers 84 appear as passive RFID tags to the RFID interrogator 52. The RFID interrogator 52 transmits via the interrogator antenna 80 at least one of data and power to the main antenna 82. For example, a high frequency signal may transmit RFID control commands to control the switching and interrogation of the RFID tags 88 via the local antennas 86 and a low frequency signal may transmit power to the one or more multiplexers 84. Specifically, the one or more multiplexers 84 may not include a battery or other power source and when radio waves from the RFID interrogator 52 or other RFID transmitter (as is known) are detected by the main antenna 82, the energy is converted into electricity that can power up the one or more multiplexers 84. For example, a rectifier and regulator configuration may be used to derive DC power from the RF field of the RFID interrogator 52. The one or more multiplexers are then able to control, for example, switching and communication between the local antennas 86 and the RFID tags 88. The one or more multiplexers 84 may be configured in different manners. One configuration for the one or more multiplexers 84 is described in co-pending U.S. patent application Ser. No. ______, assigned to the assignee of the present application, the entire disclosure of which is hereby incorporated by reference herein. It should also be noted that the power signal from the RFID interrogator 52 also may power any passive RFID tags 88.
The one or more multiplexers 84 may each include a unique identification number and may be controlled by RFID interrogator commands from the RFID interrogator 52. For example, a write command from the RFID interrogator 52 may be addressed to one or more of the multiplexers 84 to power and control the switching of the one or more multiplexers 84.
Various embodiments may be implemented in different applications to communicate using an RFID system and to acquire, for example, inventory information, which may be provided real-time or updated automatically (e.g., periodically performing interrogation of a plurality of RFID tags). For example, an RFID shelf inventory system may be provided as described in co-pending U.S. patent application entitled “Radio Frequency Identification (RFID) System for Item Level Inventory” having Ser. No. 11/520,123, assigned to the assignee of the present application, the entire disclosure of which is hereby incorporated by reference herein. The various embodiments are not limited to, for example, shelf inventories. For example, RFID inventories of pallets, moving objects, boxes, etc. may be performed.
In general, the various embodiments provide a method 100 as shown in
The local antennas may be selectively activated by the first multiplexer. For example, a first local antenna may be activated to transmit an RFID interrogation signal using any know RFID transmission scheme to activate RFID tags associated with items on a row of the shelf or pallet. It should be noted that the RFID interrogation signal originated from an RFID interrogator. The RFID tags respond with item or product information as is known. For example, Electronic Product Codes (EPCs) and/or Universal Product Codes (UPCs) are read for each of the items as stored in the RFID tags. Thereafter, a determination is made at 110 as to whether other local antennas are connected to the first multiplexer. If other local antennas are connected to the first multiplexer then the local antenna is selectively activated at 106. This process is repeated using each of the local antennas associated with the first multiplexer. If a determination is then made at 110 that no more local antennas are connected to the first multiplexer, a determination is made at 112 as to whether other multiplexers are present. If other multiplexers are present, for example, provided as part of the shelf unit or in the pallet, such as in another row, the local antennas connected to that multiplexer, for example, a second multiplexer, third multiplexer, etc. are activated at 106. It should be noted that the multiple multiplexers may be controlled by a main multiplexer. If no other multiplexers are present, then the item level inventory is completed at 114. The item information acquired may then be communication, for example, to an inventory management program, an item reordering system, a statistics system, etc.
Thus, in operation, the RF interrogator 52 (shown in
Thus, the various embodiments may be used, for example, to perform an RFID inventory, such that an array of multiplexed antennas are controlled using the same RF channels and air protocols as the RFID tags being inventoried. It should be noted that the various embodiments may be used in connection with different types of RFID systems operating using different RFID protocols. For example, the various embodiments are not limited to EPC Class 1 Gen 1 and EPC Class 1 Gen 2 air protocols.
A method 170 for controlling the acquisition of information in an RFID item level inventory is shown in
Then, at 174, after identifying and storing a list of available antenna arrays as determined by the multiplexers responding to the ID request command, an inventory acquisition process may be initiated to determine an inventory of items associated with each local antenna. In particular, each of the local antennas is selectively activated by write commands issued to corresponding multiplexers and as described in more detail herein. Specifically, each of the local antennas is separately activated and an identification of items having responding RFID tags in the range of the local antenna is made. Essentially, an inventory of all items with RFID tags responding to RFID interrogation by the local antenna is determined. With respect to the write command for selectively activating multiplexers connected to local antennas, a control word is written to, for example, a controller, such as a main multiplexer to determine which of the local antennas is to be enabled. An example sequence follows:
Thus, various embodiments of the invention may acquire inventory information, and allow for a perpetual RFID shelf inventory wherein communication to perform the inventory is provided wirelessly. It should be noted that the power for the controllers, such as the multiplexers, to interrogate the RFID tags may be supplied by the RF signal from the RFID interrogator. The RFID interrogator also may wirelessly activate selected local antennas to perform RFID inventory operations to identify, for example, item IDs and location (e.g., location within a rack or shelf unit).
The various embodiments or components for performing the RFID inventory may be implemented as part of one or more computer systems. The computer system may include a computer, an input device, a display unit and an interface, for example, for accessing the Internet. The computer may include a microprocessor. The microprocessor may be connected to a communication bus. The computer may also include a memory. The memory may include Random Access Memory (RAM) and Read Only Memory (ROM). The computer system further may include a storage device, which may be a hard disk drive or a removable storage drive such as a floppy disk drive, optical disk drive, and the like. The storage device may also be other similar means for loading computer programs or other instructions into the computer system.
As used herein, the term “computer” may include any processor-based or microprocessor-based system including systems using microcontrollers, reduced instruction set circuits (RISC), application specific integrated circuits (ASICs), logic circuits, and any other circuit or processor capable of executing the functions described herein. The above examples are exemplary only, and are thus not intended to limit in any way the definition and/or meaning of the term “computer”.
The computer system executes a set of instructions that are stored in one or more storage elements, in order to process input data. The storage elements may also store data or other information as desired or needed. The storage element may be in the form of an information source or a physical memory element within the processing machine.
The set of instructions may include various commands that instruct the computer as a processing machine to perform specific operations such as the methods and processes of the various embodiments of the invention. The set of instructions may be in the form of a software program. The software may be in various forms such as system software or application software. Further, the software may be in the form of a collection of separate programs, a program module within a larger program or a portion of a program module. The software also may include modular programming in the form of object-oriented programming. The processing of input data by the processing machine may be in response to user commands, or in response to results of previous processing, or in response to a request made by another processing machine.
As used herein, the terms “software” and “firmware” are interchangeable, and include any computer program stored in memory for execution by a computer, including RAM memory, ROM memory, EPROM memory, EEPROM memory, and non-volatile RAM (NVRAM) memory. The above memory types are exemplary only, and are thus not limiting as to the types of memory usable for storage of a computer program.
While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the various embodiments of the invention can be practiced with modification within the spirit and scope of the claims.
