Abstract:
A method and system for reading and identifying RFID tags of the invention is disclosed. The invention is capable of registering and storing information of a plurality of RFID tags attached to objects of the same group into a memory block of at least a specified RFID reader or RFID tag. The invention is also capable of enabling at least a specified RFID reader/tag in response to a first inquiry of an interrogator by transmitting each identification code of the plurality of RFID tags to the interrogator for acknowledgement. The method is capable of achieving the objective of reducing the overall communication time as the reader does not have to inquire one by one to the RFID tags to save the number of times of communication between the inquiry of the reader and the response of the RFID tags. In addition, the reading rate of the RFID system can be improved effectively since at least one of the RFID tags can function as a spokesman for those RFID tags hidden deeply inside a pile of the objects of the group.

Description:
FIELD OF THE INVENTION 
   The invention relates to a radio frequency identification (RFID) method and system, and more particularly, to a RFID method and system with mass identification capability, by its capability to identify simultaneously “hidden” or visible objects. 
   BACKGROUND OF THE INVENTION 
   Radio frequency identification (RFID) is an automatic identification technology with ability to wireless communication (read and write data without direct contact) and without the necessity for line-of-sight, such that it is convenient, easy to use and well suited for automatic operation and can function under a variety of environment conditions while providing a high level of data integrity. RFID is a technology with bright future and is going to replace the conventional bar coding system for many companies and organizations. The RFID system, mainly consisted of RFID tags, readers and a computer system, can be implemented by various applications and produced by many different manufacturers. 
   Nevertheless, there is no any current RFID system that has the ability to achieve 100 percent reading rate, especially for those using passive RFID tags. The unsatisfactory reading rate may be caused by several reasons. One of the reasons is the adverse effect caused by the material to which a RFID tag is attached thereto, e.g. an absorbent material, such as water, is capable of absorbing electromagnetic waves emitting from a RFID reader for interrogating the tag; and a reflective material, such as metal, is capable of reflecting the electromagnetic waves. Another cause of poor reading rate is that RFID tags, being attached to objects placed in the center of a pile composed of such objects regrouped within a support (case, box, pallet, etc.), are not able to transmit signals out of the pile. Please refer to  FIG. 1 , which shows a group of objects being stacked and placed on a pallet. As seen in  FIG. 1 , each object  11  is tagged by a RFID tag  111  whereas there are a plurality of such objects  11  being stacked as a pile and placed on a pallet  10 . It is obvious that the RFID tags attached to those objects hidden deeply inside the pile might not be able to be inquired and read correctly. Thus, such pile of objects might cause erroneous information to be registered into the RFID system. Generally, the former cause can be mended by improving the antenna design of RFID tag, such as the near field design by Impinj. However, the improved antenna has little effect on those objects hidden in the pile. 
   Therefore, it is in need of a method and system for reading and identifying RFID tag that can overcome the aforesaid problems troubling those prior-art RFID systems. 
   SUMMARY OF THE INVENTION 
   The invention is to provide a method and system for reading and identifying RFID tag, that is capable of registering and storing information of a plurality of RFID tags, being attached to objects of the same group, into a memory block of at least a specified RFID reader or tag in a successive manner during the formation of the group, and enabling the at least one specified RFID reader/tag to act as a spokesman of the group and respond to a first inquiry of an interrogator by transmitting each identification code of the plurality of RFID tags to the interrogator for acknowledgement, by which the reading rate of the RFID system can be improved. 
   The invention is to provide a method and system for reading and identifying RFID tag, by which the overall time required for the interrogator to inquire each RFID tag in the group can be reduced since it is no longer required for the interrogator to inquire every RFID tag of the group in an one-by-one manner, rather, it needs only to inquire at least one specified RFID reader/tag. 
   The invention is to provide a method and system for reading and identifying RFID tag capable of copying and backing up required data into different RFID tags, by which the copies of backup data can be checked in a reciprocal manner and thus data loss can be avoided. 
   In an embodiment, the method for reading and identifying RFID tag, comprising the steps of: enabling a reading unit to acquire information stored in a plurality of RFID tags, whereas the RFID tags are of the same group; registering the acquired information into a memory block of the reading unit; and enabling the reading unit to respond to an inquiry of an interrogator by transmitting the information stored in the memory block to the interrogator. 
   In an embodiment, the method for reading and identifying RFID tag, comprising the steps of: enabling at least one reading unit to acquire information stored in a plurality of RFID tags; comparing the information acquired by at least one reading unit with one another in a reciprocal manner; enabling each of the reading units to register information of a portion of the RFID tags specified especially and respectively thereof by a distribution algorithm; and enabling each of the reading units to respond to an inquiry of an interrogator by transmitting the information stored therein to the interrogator. 
   In an embodiment, the method for reading and identifying RFID tag, comprising the steps of: enabling an interrogator to inquire information stored in a plurality of RFID tags; using a distribution algorithm to specify and distribute information of a specific portion of the RFID tags to at least a reading unit; and enabling each of the reading units to respond to an inquiry by transmitting the information stored therein. 
   In another embodiment, the method for reading and identifying RFID tag further comprises the step of: enabling each of the reading units to back up the information stored therein onto at least a backup unit. 
   In another embodiment, the distribution algorithm comprises the steps of: comparing the free memory block size of each of the reading units with one another; and dividing and distributing the information of the RFID tags to be registered by each reading unit in accordance with the free memory block size thereof. 
   In another embodiment, the distribution algorithm comprises the steps of: comparing the free memory block size of each of the reading units with one another; and evenly dividing and distributing the information of the RFID tags to be registered by each reading unit in accordance with a numbering sequence of the reading units while the free memory block sizes of each of the reading units are the same. 
   In an embodiment, the system for reading and identifying RFID tag, comprising: a plurality of RFID tags, being respectively attached to each of a group of objects placed on a storage platform; and at least a reading unit, each being disposed on the storage platform for enabling the reading of information of the plurality of RFID tags; wherein the reading unit is capable of comparing the information acquired thereby with one another while using the comparison as basis to select a portion of the RFID tags to be registered. 
   In another embodiment, the reading unit can be a device selected from the group consisting of a RFID reader and an active RFID tag. 
   In another embodiment, the storage platform can be an article selected from the group consisting of a shopping cart, a pallet, a container, a rack, a box, a cage, and a chassis with a specific enclosure for storage. 
   In another embodiment, the system for reading and identifying RFID tag further comprises: an interrogator, connected to an external computer system, capable of accessing information stored in at least one reading unit. In an aspect, the interrogator can be a device selected from the group consisting of a RFID reader and an active RFID tag. 
   Moreover, in another embodiment, the system for reading and identifying RFID tag further comprises: an interrogator being connected to an external computer system is capable of accessing the information stored in each of the plurality of RFID tags when the group of objects is stacked on the storage platform and thus dividing the accessed information and distributing the information to be registered into at least a reading unit. In an aspect, the interrogator can be a device selected from the group consisting of a RFID reader and an active RFID tag. 
   Other aspects and advantages of the invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating by way of examples and the principles of the invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  shows a group of objects being stacked and placed on a pallet. 
       FIG. 2  is a flow chart depicting steps of a method for reading and identifying RFID tag in accordance with a first embodiment of the invention. 
       FIG. 3  is a flow chart depicting steps of a method for reading and identifying RFID tag in accordance with a second embodiment of the invention. 
       FIG. 4A  and  FIG. 4B  show a system for reading and identifying RFID tag in accordance with a embodiment of the invention. 
       FIG. 4C  is a schematic diagram showing a system for reading and identifying RFID of the invention, being interrogated by an interrogator. 
       FIG. 5A  is a flow chart depicting steps of a distribution algorithm used in a method for reading and identifying RFID tag of the invention, whereas the free memory block size of the RFID tags are not the same. 
       FIG. 5B  shows a distribution of the RFID tags in accordance with the distribution algorithm of  FIG. 5A . 
       FIG. 6A  is a flow chart depicting steps of a distribution algorithm used in a method for reading and identifying RFID tag of the invention, whereas the free memory block size of the RFID tags are equal. 
       FIG. 6B  shows a distribution of the RFID tag in accordance with the distribution algorithm of  FIG. 6A . 
       FIG. 7  is a flow chart depicting steps of a method for reading and identifying RFID tag in accordance with a third embodiment of the invention. 
       FIG. 8A  and  FIG. 8B  show a system for reading and identifying RFID tag in accordance with another embodiment of the invention. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   For your esteemed members of review committee to further understand and recognize the fulfilled functions and structural characteristics of the invention, several preferable embodiments cooperating with detailed description are presented as follows. 
   Please refer to  FIG. 2 , which is a flow chart depicting steps of a method for reading and identifying RFID tag in accordance with a first embodiment of the invention. The flow starts at step  20 . At step  20 , a reading unit is enabled to acquire information stored in a plurality of RFID tags, whereas the RFID tags are of the same group, and then the flow proceeds to step  21 . At step  21 , all the acquired information is registered into a memory block of the reading unit, and then the flow proceeds to step  22 . At step  22 , the reading unit is enabled to copy and register the stored information onto at least a backup unit, and then the flow proceeds to step  23 . At step  23 , the reading unit is enabled to respond to an inquiry of an interrogator by transmitting the information stored in the memory block thereof to the interrogator. It is noted that the reading unit can be a RFID reader or an active RFID tag; and the backup unit can be a RFID reader, an active RFID tag or a passive RFID tag. 
   In this embodiment, the group of RFID tags can be defined as a group of objects, each being attached by one of the RFID tags and all being stacked as a pile on a platform, such as a shopping cart, a pallet, a container, a rack, a box, a cage, or a chassis with a specific enclosure for storage. As the RFID tags attached to those objects hidden deeply inside the pile might not be able to be inquired and read correctly, the RFID method of  FIG. 2  will first enable a reading unit to read each RFID tag and store the accessed information into the memory of the reading unit, as that depicting in step  20 , thus, when the pile of objects are inquired by an interrogator, the reading unit can act as the spokesman for all the RFID tags and reply a response back to the interrogator. 
   Please refer to  FIG. 3 , is a flow chart depicting steps of a method for reading and identifying RFID tag in accordance with a second embodiment of the invention. The flow of  FIG. 3  starts at step  30  and, for clarity, please also refers to  FIG. 4A  and  FIG. 4B  for articles addressed in the flow. At step  30 , a storage platform  40  is provided, on which at least a reading unit is being arranged, and then the flow proceeds to step  31 . In the embodiment shown in  FIG. 4A  and  FIG. 4B , there are two reading units  41  and  42 , each can be a RFID reader or an active RFID tag, whereas the storage platform  40  can be an article selected from the group consisting of a shopping cart, a pallet, a container, a rack, a box, a cage, and a chassis with a specific enclosure for storage. 
   At step  31 , a group of objects  43  is being stacked onto the storage platform  40 , whereas each object has an unique RFID tag  44  attached thereon, and then the flow proceeds to step  32 . It is noted that the RFID tag  44  can be an active RFID tag or a passive RFID tag. At step  32 , the two reading units  41 ,  42  are enabled to acquire information stored in the RFID tags  44  respectively, and then the flow proceeds to step  33 . At step  33 , the information acquired by the two reading units  41 ,  42  are compared with one another, and then the flow proceeds to step  34 . At step  34 , each of the two reading units  41 ,  42  is enabled to register information of a portion of the RFID tags, specified especially and respectively thereof by a distribution algorithm, and then the flow proceeds to step  35 . At step  35 , each of the two reading units  41 ,  42  is enabled to back up the information stored therein, and then the flow proceeds to step  36 . In this embodiment, the backing up of the information performed by each of the two reading units  41 ,  42  is that each of the two reading units  41 ,  42  is enabled to interrogate with at least one RFID tag which can be selected from one of the RFID tags  44  in the pile, while using the interrogated RFID tags for backing up the information stored therein. Moreover, the actual amount of RFID tags being interrogated by each of the two reading unit  41 ,  42  is dependent upon actual need. 
   As soon as each of the objects  43  are stacked on the storage platform  40 , all the information of the RFID tags  44  are finished registering by the two reading units  41 ,  42  in accordance with the distribution algorithm. Thereafter, platform  40  of the pile of objects is sent to a specific location, e.g. a warehouse having at least an interrogator  46  arranged therein, where the step  36  is carried on with reference to  FIG. 4C . At step  36 , the two reading units  41 ,  42 , acting as spokesmen of the pile, are enabled to respond to an inquiry of an interrogator by transmitting the identification codes to the interrogator. By the method depicting in  FIG. 3 , the overall time required for the interrogator to inquire each of the RFID tags in the group can be reduced since it is no longer required for the interrogator to inquire every RFID tag of the group in an one-by-one manner, rather, it needs only to inquire the reading units or backup units. In addition, the reading rate of the RFID system can be improved effectively since at least one specified RFID reader/tag can function as a spokesman for some RFID tags of the group whose communication are blocked as the objects are hidden deeply inside a pile formed by the objects of the group. It is noted that those storage platform  40 , reading units  41 ,  42  and RFID tags  44 , shown in  FIG. 4A  and  FIG. 4B , are only basic components used in a RFID system in accordance with a embodiment of the invention. 
   Please refer to  FIG. 5A  and  FIG. 5B , which respectively is a flow chart depicting steps of a distribution algorithm used in a method for reading and identifying RFID tag of the invention, whereas the free memory block size of the reading units are not the same; and is a schematic diagram showing a distribution of the RFID tags in accordance with the distribution algorithm of  FIG. 5A . The flow of  FIG. 5A  starts at step  340 . At step  340 , the free memory block size of each of the reading units is compared with that of another reading unit so as to evaluate whether the capacity is equal or not, and then the flow proceeds to step  341 . At step  341 , as soon as the evaluation indicated that the capacity is not the same, the information of the RFID tags are divided and distributed to be registered by each of the reading units in accordance with the free memory block size thereof. As the embodiment shown in  FIG. 5B , there are seven objects, numbered from 1 to 7 and stacked in a pile, each being attached with a RFID tag, whereas initially the objects, numbered by 1, 2, 3, 5, 7, are accessed by a reading unit  41  while other objects, numbered by 4, 5, 6, are accessed by another reading unit  42 , the comparison step of  FIG. 5A  indicated that the free memory block sizes of the two reading units  41 ,  42  are not equal and thus, in accordance with a distribution algorithm defined basing on their respectively free memory block sizes, the reading unit  41  is directed to access objects numbered by 1, 2, 3, 4 while the reading unit  42  is directed to access objects numbered by 5, 6, 7. Thereafter, the reading unit  41  is directed to backup the information accessed thereby onto RFID tags of objects numbered by 1, 2, 3, 4, 5 while the reading unit  42  is directed to backup the information accessed thereby onto RFID tags of objects numbered by 6, 7. 
   Please refer to  FIG. 6A  and  FIG. 6B , which respectively is a flow chart depicting steps of a distribution algorithm used in a method for reading and identifying RFID tag of the invention, whereas the free memory block sizes of the reading units are the same; and is a schematic diagram showing a distribution of the RFID tags in accordance with the distribution algorithm of  FIG. 6A . The flow of  FIG. 6A  starts at step  342 . At step  342 , the free memory block size of each of the reading units is compared with that of another reading unit so as to evaluate whether the capacity is equal or not, and then the flow proceeds to step  343 . At step  343 , as soon as the evaluation indicated that the capacity are the same, the information of the RFID tags are evenly divided and distributed to be registered by each of the reading units in accordance with a numbering sequence thereof. As the embodiment shown in  FIG. 6B , there are six objects, numbered from 1 to 6 and stacked in a pile, each being attached with a RFID tag, whereas initially the objects, numbered by 1, 2, 3, 4, are accessed by a reading unit  41  while other objects, numbered by 3, 5, 6, are accessed by another reading unit  42 , the comparison step of  FIG. 6A  indicated that the free memory block sizes of the two reading units  41 ,  42  are equal and thus, in accordance with a distribution algorithm defined basing on a numbering sequence, the reading unit  41  is directed to access objects numbered by 1, 3, 5 while the reading unit  42  is directed to access objects numbered by 2, 4, 6. Thereafter, the reading unit  41  is directed to backup the information accessed thereby onto RFID tags of objects numbered by 1, 3, 5 while the reading unit  42  is directed to backup the information accessed thereby onto RFID tags of objects numbered by 2, 4, 6. 
   Please refer to  FIG. 7 , which is a flow chart depicting steps of a method for reading and identifying RFID tag in accordance with a third embodiment of the invention. The flow of  FIG. 3  starts at step  30  and, for clarity, please also refers to  FIG. 8A  and  FIG. 8B  for articles addressed in the flow. At step  50 , a storage platform  60  having at least a reading unit arranged thereon is provided, whereas there is an interrogator  61  being arranged at a position outside the storage platform  60 ; and then the flow proceeds to step  51 . In the embodiment shown in  FIG. 8A  and  FIG. 8B , there are two reading units  62  and  63 , each can be a RFID reader or an active RFID tag, whereas the storage platform  60  can be an article selected from the group consisting of a shopping cart, a pallet, a container, a rack, a box, a cage, and a chassis with a specific enclosure for storage. At step  51 , a group of objects  64  is being stacked onto the storage platform  60 , whereas each object  64  has an unique RFID tag  65  attached thereon, and then the flow proceeds to step  52 . It is noted that the RFID tag  65  can be an active RFID tag or a passive RFID tag. At step  52 , the interrogator  61  is enabled to acquire information stored in the RFID tags  65  respectively during the stacking of the objects  64 , and then the flow proceeds to step  53 . As soon as each of the objects  64  is stacked on the storage platform  60 , all the information of the RFID tags  65  are finished registering by the interrogator  61 . Thereafter, as seen in  FIG. 8B , the step  53  is proceeded. At step  53 , a distribution algorithm is used to specify and distribute information of a specific portion of the RFID tags  65  to the two reading units  62 ,  63  respectively, and then the flow proceeds to step  54 . It is noted that the distribution algorithm can be the same as that illustrated in  FIG. 5A  or  FIG. 6A , so that it is not described further herein. In addition to the aforesaid steps that the interrogator  61  will divide and distribute the accessed information to the reading units only after each of the objects  64  are stacked on the platform, an alteration of the aforesaid steps can be adopted that as soon as one of the objects  64  is stacked on the platform  60  and accessed by the interrogator  61 , the interrogator  61  will immediately distribute the accessed information from object  64  to one reading unit selected from the two reading units  62 ,  63  in accordance with a distribution algorithm. 
   After the distribution is accomplished, the step  54  is being proceeded. At step  54 , each of the two reading units  62 ,  63  is enabled to back up the information stored therein. In this embodiment, the backing up of the information performed by each of the two reading units  62 ,  63  is that each of the two reading units  62 ,  63  is enabled to interrogate with at least one RFID tag which can be selected from one of the RFID tags  65  in the pile, while using the interrogated RFID tags for backing up the information stored therein. Moreover, the actual amount of RFID tags being interrogated by each of the two reading unit  62 ,  63  is dependent upon actual need. Thereafter, platform  60  of the pile of objects  64  is sent to a specific location, e.g. a warehouse having at least an interrogator arranged therein, where the step  55  is carried on. At step  55 , the two reading units  62 ,  63 , acting as spokesmen of the pile, are enabled to respond to an inquiry of the interrogator of the warehouse by transmitting the information stored therein to the interrogator. 
   While the preferred embodiment of the invention has been set forth for the purpose of disclosure, modifications of the disclosed embodiment of the invention as well as other embodiments thereof may occur to those skilled in the art. Accordingly, the appended claims are intended to cover all embodiments which do not depart from the spirit and scope of the invention.