DE102005044151A1 - Mobile data storage e.g. radio frequency identification tag, disposing method for communication, involves disposing storage when difference between distances of writing implement/reader and storage is smaller than maximum difference value - Google Patents

Abstract

The method involves determining a distance and another distance, according to a time delay, between a writing implement/reader and a mobile data storage. A transmission channel is used with a set of channels for distance determination. Figure of merits is determined for the distances, and the storage is disposed if figure of merit is smaller than a preset threshold. A difference between the distances is determined when the figure of merits lies between two thresholds. The storage is disposed when the difference is smaller than a maximum distance difference value. Independent claims are also included for the following: (1) a computer program product with a computer executable instruction to execute a method of disposing a mobile data storage for communication through a writing implement/reader (2) a device for disposing a mobile data storage for communication through a writing implement/reader.

Description

The The invention relates to a method and a device for classification a mobile data store for communication with a read / write device in general and a procedure and a device for increasing the detection rate of a read / write device in particular.

To In the prior art, identification systems are known which have a or more stationary Base stations, so-called read / write devices containing the data with mobile data storage, such as RFID tags attached to mobile Objects are attached over a radio-based data transmission link contactless change. Such identification systems are used in technical Used in facilities in which a variety of objects or goods as fast as possible and have to be moved freely. Things can be different types, for example, packages in one Shipping facility, assembly parts in a production plant or Luggage in one Transportation system.

One example for An identification system is described in the ISO-18000-4-MOD-3 standard entitled "Radio Frequency Identification Standard for Item Management - Air Interface "described. The standard provides that through the read / write device a query presence of a mobile data memory in the detection area he follows. For this purpose, it sends an unmodulated RF carrier signal with a fixed RF carrier frequency with for example 2.45 GHz. This carrier signal can passively from a near located mobile data storage, for example, by so-called Back scattering to the read / write device with data modulated backscattered and then processed there. When operating from two or more base stations arranged close to one another and multiple mobile data memories, such as neighboring ones Production lines, Care must be taken that there is no unwanted interaction between the individual base stations and the respective mobile data memories comes. It is therefore necessary that the coverage of the respective Base station restricted becomes. This can for example be based on a distance determination between the base station and the respective mobile data memory, where a mobile data storage, for example, only with him on next standing Read / write device communicated.

In the published patent application DE 102 61 098 A1 A method for determining the distance between a base station and a mobile data memory and a base station and an identification system for such a method will be described. In this method, an RF carrier frequency is sequentially increased or decreased by an offset frequency by means of an IQ modulation such that the HF carrier frequency frequencies resulting in a then modulated RF carrier signal have the same phase during frequency changes. The RF carrier signal is then transmitted and simultaneously mixed with an RF carrier signal backscattered by the mobile object to form a carrier phase signal. For both RF carrier corner frequencies, the associated carrier phase is determined sequentially and then the difference between the base station and the respective mobile object is determined from its difference.

at the identification of mobile data stores for one queuing to another Communication in the transmission protocol of the read / write device occur however, when using a pure distance measurement in particular then errors occur when the mobile data stores are static or quasi-static are arranged. The detection rate, i. the number of mobile Data storage for Another communication to be ranked, to the total number of mobile data memory is therefore when using a distance measurement low.

Of the The invention is therefore based on the object, an improved method and an improved mobile data storage enqueuing device for the Specify communication with a read / write device.

The The object is achieved by the method specified in claim 1 and with the specified in claim 9 device for classification for communication solved. Further advantageous embodiments are in the subclaims listed.

The invention provides an improved method for the classification for the communication, wherein the read / write device performs the following steps: a first distance is determined and after a time delay a second distance, wherein the time delay is predetermined. Furthermore, a first figure of merit for the first distance is determined and a second figure of merit for the second distance is determined. If the first figure of merit is less than a predetermined first threshold, then the mobile data memory is enqueued. If the second figure of merit is less than the first threshold, then the mobile data memory is also queued. If the first figure of merit and the second figure of merit lie between the first threshold and a second threshold, the second threshold being greater than the first threshold, then a difference between the first distance and the second threshold is obtained th distance determined. It follows a classification of the mobile data memory if the difference is smaller than a maximum distance difference value, wherein the maximum distance difference value is predetermined.

classification here means that the mobile data store for further communication in the of the read / write device for data transmission used protocol structure is incorporated. That is, it will first determined if there is a mobile data store near a Read / write device and whether the criteria for classification according to the invention are Fulfills are.

is this is the case, so can then e.g. additional data between the read / write device and the mobile Transfer data memory become.

The Protocol structure may consist of a sequence of time blocks, for example, the sequence being sent repeatedly and being in the individual time blocks from the read / write device Data about the mobile data store will be collected or data between the Read / write device and the mobile data storage.

The inventive method is particularly advantageous because a mobile data store immediately queued if the first figure of merit is below the first threshold. In addition, a first threshold ensures if it is set to low, a high measurement reproducibility. This results in a very robust method of classification for communication. Another advantage arises from the fact that a first and a second distance, for the the determined figures of merit are below the second threshold, compared with each other and if the difference of distances is less than a maximum distance difference value, the mobile Datastore is queued. This will increase the capture rate of the read / write device elevated, if the second threshold and the maximum distance accordingly be chosen large. Just like the first threshold are the second threshold and the Distance difference value adjustable, predetermined values.

To an advantageous variant of the method is iteratively after each Expiration of the time delay further distance between the read / write device and the mobile data memory determined, where for the further distance another figure of merit is determined, wherein the mobile data memory is queued, if the further figure of merit is smaller is considered the first threshold. So it will be several times after each one Time Delay the distance between the mobile data memory and the read / write device is determined. By comparing the for a distance determined figure of merit the first threshold determines if the mobile data store is immediately queued. The process according to the invention is particular advantageous because a mobile data store is queued up immediately, if one of the other figures of merit is below the first threshold. In addition, a first assures Threshold, if set accordingly low, a high Measurement reproducibility. This results in a very robust process for classification for the communication.

To Another advantageous variant of the method is iteratively in each case after expiration of the time delay another distance between the read / write device and the determined mobile data storage, wherein for the further distance a further figure of merit is determined, and wherein the mobile data store is queued, if the further figure of merit is smaller than the second threshold and if the difference of the other Distance to a determined in the previous iteration step Distance is less than the maximum distance difference value. It will after expiration of the time delay each determined a further distance and another figure of merit, where total a predetermined total number of intervals is determined. By comparing the figures of merit with the second threshold and by comparing the distance with the determined in the previous iteration step, it is determined whether the mobile data storage is queued. A classification due of goodness numbers, which are smaller than the second threshold is therefore only permissible if the successively measured distances from each other not strong differ. This will add an extra Plausibility check performed.

These Process variant has the advantage that thereby the detection rate elevated is, as it is tested several times, whether the mobile data storage the criterion given above for complies with the classification.

To Another advantageous variant of the method is the mobile Data store not queued for communication, if the first Figure of merit or the second figure of merit is larger as the second threshold. In this case, the measured distance as not valid. "This means that at the next Measurement of the determined distance difference value is large. This will be for the classification either a measurement with a figure of merit less than the first threshold necessary, or at least two more measurements are carried out the criterion for to fulfill the classification.

To an advantageous variant of the method is a transmission channel with a or more channels for distance determination between the read / write device and the used mobile data storage, where the transmission channel the notification Channel of the ISO-18000-4-MOD-3 standard. It is the Time Delay specified by the ISO-18000-4-MOD-3 standard.

To a further advantageous variant of the method is the classification for the Communication for selectively a mobile data store from a group of mobile Data storage performed.

In In another aspect, the invention relates to a computer program product with computer-executable Instructions for carrying out the method according to the invention.

In In another aspect, the inventive method is in an identification system with a read / write device and at least one mobile data store attached to transport items for determination of object-related status and process data used.

In In another aspect, the invention relates to a device for Classification of a mobile data memory for communication by a read / write device with means to determine a first distance and after a time delay of a second distance between the read / write device and the mobile data memory, being the time delay is predetermined, further comprising means for determining a first figure of merit for the first distance and means for determining a second figure of merit for the second distance. Of Furthermore, the device includes means for classifying the mobile Data memory if the first figure of merit is less than one predetermined first threshold and means for classifying the mobile Data memory, if the second figure of merit is smaller than that first threshold. Furthermore, the device has means for determination a difference between the first distance and the second distance if the first figure of merit around the second figure of merit between the first threshold and a second threshold, the second threshold being greater as the first threshold. About that In addition, the device includes means for classifying the mobile Data memory if the difference is smaller than a maximum Distance difference value, wherein the maximum distance difference value specified is.

preferred embodiments The invention will be explained in more detail with reference to the drawings.

1 shows an identification system and

2 shows a flowchart for performing a method variant according to the invention.

1 shows an identification system with a mobile data storage 104 and a read / write device 102 , The mobile data store 104 is at a certain point in time (t ₀ ) at position A and a predetermined time delay (Δt) 112 later at position B, where positions A and B may also coincide.

The read / write device 102 has a transceiver 126 , an antenna 128 and a memory 132 on. The mobile data store 104 includes an antenna 130 ,

According to the invention, the read / write device generates by means of the transceiver 126 an electrical signal, as in DE 102 61 098 described for determining the distance 108 between the reader / writer and the mobile data storage 104 is used. The signal is transmitted by means of the antenna 128 radiated. It is from the antenna 130 of the mobile data storage 104 received from the mobile data store 104 modulated and from the antenna 130 again radiated. That from the mobile data storage 104 radiated signal is transmitted by antenna 128 from the read / write device 102 receive. By comparing the phases of the received signal with a radiated signal, a distance between the mobile data memory and the read / write device can be calculated.

The distance measurement is performed several times in succession and the first distance 108 between the read / write device 102 and the mobile data store 104 is formed from the average of all distance measurements. For the first distance 108 becomes a first figure of merit 114 determined. This figure of merit 114 is for example the standard variance or the modified standard variance or any other statistical characteristic such as the median of all for determining the first distance 108 carried out measurements.

alternative only one distance measurement is used to determine the first distance carried out. there then corresponds to the first figure of merit e.g. the signal to noise ratio of the evaluated signal for distance measurement.

This first figure of merit 114 comes with a first threshold 118 compared and if the first figure of merit 114 is smaller than the first threshold 118 , becomes the mobile data store 104 classified. If the first figure of merit 114 is greater than a second threshold 120 becomes the mobile data store 104 not immediately queued.

After the time delay 112 becomes the second distance 110 to the mobile data store 104 determined. Here, as already mentioned above, a signal (for example, as in DE 102 61 098 beschrie ben) from the transceiver 126 generated and from the antenna 128 radiated. The signal is from the antenna 130 of the mobile data storage 104 received from the mobile data store 104 modulated and from the antenna 130 again radiated. The re-received signal becomes the second distance 110 certainly.

For the second distance 110 is inventively a second figure of merit 116 determined.

The second figure of merit 116 is for example the standard variance or the modified standard variance or any other statistical characteristic of all for determining the second distance 110 carried out measurements.

alternative can as above for mentioned the first distance, only one distance measurement is performed to determine the second distance. there then corresponds to the second figure of merit e.g. the signal to noise ratio of the evaluated signal for distance measurement.

Is the second figure of merit 116 smaller than the first threshold 118 , then becomes the mobile data store 104 queued for communication. Is the second figure of merit 116 greater than the second threshold 120 , then becomes the mobile data store 104 not queued for communication.

Lie the first figure of merit 114 as well as the second figure of merit 116 between the first threshold 118 and the second threshold 120 then a difference 122 determined between the first and the second distance. Is this difference 122 less than a maximum distance difference value 124 , then becomes the mobile data store 104 queued for communication with the read / write device.

The first distance 108 , the second distance 110 , the time delay 112 , the first figure of merit 114 , the second figure of merit 116 , the first threshold 118 the second threshold 120 , the difference 122 the two distances and the maximum distance difference value 124 be in memory 132 stored.

2 shows a flowchart for performing a method variant according to the invention. In step 202 the method is started with the determination of the distance d ₀ between a read / write device and a mobile data memory. In step 204 a figure of merit G _{0 is} determined for the distance d ₀ . In step 206 it is determined whether the figure of merit G _{0 is} smaller than a first threshold (NS). If so, then the mobile data store will be in step 234 queued for communication and the procedure ends with step 236 , If this is not the case, then step in 208 determines whether the figure of merit G _{0 is} greater than a second threshold (WS). If this is the case, then in step 232 the mobile data store is not queued for communication and the procedure ends with step 236 without a classification. However, if the figure of merit is less than the second threshold (WS), then in step 210 the distance d ₀ stored.

In step 212 an iteration process is started. Where n is the count index running from 1 to N in one-step increments and in step 212 is set equal to 1. The steps 214 to 231 are carried out during each iteration run. In step 214 the execution of the method is suspended according to a predetermined time delay. This delay can be specified manually and also be changeable.

at Using the ISO-18000-4MOD3 standard is the time delay through set the default because the mobile data store stores the notification sequence, within which the distance between the read / write device and the mobile data storage is determined using a random access method repeated with a period of several 100 ms.

In step 216 Then, a distance d _{n is} determined, where the index n refers to the count index for the iteration in step 212 refers. For the distance d _n is a figure of merit G _n in step 218 determined. In step 220 it is determined whether the figure of merit G _{n is} less than the first threshold (NS). If so, the mobile data store will be in step 234 queued for further communication and the procedure ends in step 236 , If this is not the case, then step in 222 determines if G _{n is} greater than the second threshold (WS). If so, the mobile data store will be in step 232 not queued for communication and the procedure ends with step 236 , If this is not the case, then step in 224 the amount of the difference .DELTA.d = | d _n - d _{n -1} | between the determined in this iteration step and in the previous iteration step distance. Alternatively, the difference between the distance determined in this iteration step and the distance determined in any previous iteration step is determined.

In step 226 it is determined whether the difference .DELTA.d is smaller than a predetermined difference D. If so, then the mobile data memory with step 234 queued for communication and the inventive method with step 236 completed. If this is not the case, then step in 228 the determined distance is saved. In step 231 it is checked whether n is greater than a predetermined number N. If this is not the case, the iteration process with step 230 continued. In step 230 n is increased by 1. The iteration process then begins again with step 214 , Is in step 231 n greater than N, so ends the procedure in step 236 ,

Claims (15)

Procedure for classifying mobile data storage (MDS) ( 104 ) for communication by a read / write device (SLG) ( 102 ), whereby the SLG ( 102 ) the following steps are carried out: a) determination of a first distance ( 108 ) and after a time delay ( 112 ) of a second distance ( 110 ) between the SLG ( 102 ) and the MDS ( 104 ), the time delay ( 112 ) is given; b) Determination of a first figure of merit ( 114 ) for the first distance ( 108 ); c) determination of a second figure of merit ( 116 ) for the second distance ( 110 ); d) Classification of the MDS ( 104 ) if the first figure of merit ( 114 ) is less than a predetermined first threshold ( 118 ); e) Classification of the MDS ( 104 ) if the second figure of merit ( 116 ) is less than the first threshold ( 118 ); f) determination of a difference ( 122 ) between the first distance ( 108 ) and the second distance ( 110 ), if the first figure of merit ( 114 ) and the second figure of merit ( 116 ) between the first threshold ( 118 ) and a second threshold ( 120 ), the second threshold ( 120 ) is greater than the first threshold ( 118 ); g) Classification of the MDS ( 104 ) if the difference ( 122 ) is less than a maximum distance difference value ( 124 ), wherein the maximum distance difference value ( 124 ) is given. Method according to claim 1, wherein iteratively in each case after expiration of the time delay ( 112 ) a further distance between the SLG ( 102 ) and the MDS ( 104 ), wherein a further figure of merit is determined for the further distance, whereby the MDS ( 104 ) is ranked, if the further figure of merit is smaller than the first threshold ( 118 ). Method according to one of claims 1 or 2, wherein iteratively in each case after expiration of the time delay ( 112 ) a wider distance between the SLG ( 102 ) and the MDS ( 104 ), wherein a further figure of merit is determined for the further distance, and wherein the MDS ( 104 ), if the further figure of merit ( 114 ) is less than the second threshold ( 120 ) and if the difference ( 122 ) of the further distance to a distance determined in the preceding iteration step is smaller than the maximum distance difference value ( 124 ). Method according to one of the preceding claims, wherein the MDS ( 104 ) is not classified for communication if the first figure of merit ( 114 ) or the second figure of merit ( 116 ) is greater than the second threshold ( 120 ). Method according to one of the preceding claims, wherein a transmission channel having one or more channels for determining the distance between the SLG ( 102 ) and the MDS ( 104 ), where the transmission channel complies with the notification channel of the ISO-18000-4MOD3 standard and the time delay is given by the ISO-18000-4MOD3 standard. Method according to one of the preceding claims, wherein the classification for the communication for selectively an MDS ( 104 ) is performed from a group of mobile data memories. Method according to one of the preceding claims for an identification system with an SLG ( 102 ) and at least one MDS attached to transport objects ( 104 ) for the determination of object-related status and process data. Computer program product with computer-executable Instructions to a method according to one of the preceding claims perform. Device for classifying a mobile data memory (MDS) ( 104 ) for communication by a read / write device (SLG) ( 102 ) with: a) means for determining a first distance ( 108 ) and after a time delay ( 112 ) of a second distance ( 110 ) between the SLG ( 102 ) and the MDS ( 104 ), the time delay ( 112 ) is given; b) means for determining a first figure of merit ( 114 ) for the first distance ( 108 ); c) means for determining a second figure of merit ( 116 ) for the second distance ( 110 ); d) Means of classification of the MDS ( 104 ) if the first figure of merit ( 114 ) is less than a predetermined first threshold ( 118 ); e) Means of classification of the MDS ( 104 ) if the second figure of merit ( 116 ) is less than the first threshold ( 118 ); f) means for determining a difference ( 122 ) between the first distance ( 108 ) and the second distance ( 110 ), if the first figure of merit ( 114 ) and the second figure of merit ( 116 ) between the first threshold ( 118 ) and a second threshold ( 120 ), the second threshold ( 120 ) is greater than the first threshold ( 118 ); g) Means of classification of the MDS ( 104 ) if the difference ( 122 ) is less than a maximum distance difference value ( 124 ), wherein the maximum distance difference value ( 124 ) is given. Apparatus according to claim 9, wherein iteratively in each case after expiration of the time delay ( 112 ) a further distance between the SLG ( 102 ) and the MDS ( 104 ) is determined, wherein for the further distance a further figure of merit is determined, wherein the MDS ( 104 ) is ranked, if the further figure of merit is smaller than the first threshold ( 118 ). Device according to one of claims 9 or 10, wherein iteratively in each case after expiration of the time delay ( 112 ) a further distance between the SLG ( 102 ) and the MDS ( 104 ), wherein a further number of grades is determined for the further distance, and wherein the MDS ( 104 ) is ranked, if the further figure of merit is smaller than the second threshold ( 120 ) and when the difference of the further distance to a distance determined in the preceding iteration step is smaller than the maximum distance difference value. Device according to one of claims 9, 10 or 11, wherein the MDS ( 104 ) is not classified for communication if the first figure of merit ( 114 ) or the second figure of merit ( 116 ) is greater than the second threshold ( 120 ). Device according to one of claims 9 to 12, wherein a transmission channel with one or more channels for distance determination between the SLG ( 102 ) and the MDS ( 104 ), where the transmission channel complies with the notification channel of the ISO-18000-4MOD3 standard and the time delay is given by the ISO-18000-4MOD3 standard. Device according to one of claims 9 to 13, wherein the classification for the communication for selectively an MDS ( 104 ) is performed from a group of mobile data memories. Device according to one of claims 9 to 14 for an identification system with a SLG ( 102 ) and at least one MDS attached to transport objects ( 104 ) for the determination of object-related status and process data.