Method of diagnosing communication problems of electronic price labels

0001The present invention relates to electronic price label (EPL) systems used in transaction establishments, and more specifically to a method of diagnosing communication problems of electronic price labels.

0002EPL systems typically include a plurality of EPLs for each merchandise item in a store. EPLs typically display the price of corresponding merchandise items on store shelves and are typically attached to a rail along the leading edge of the shelves. A store may contain thousands of EPLs to display the prices of the merchandise items. The EPLs are coupled to a central server from where information about the EPLs is typically maintained in an EPL data file. Price information displayed by the EPLs is obtained from the PLU file.

0003EPLs today may be wired or wireless. Wireless EPLs may employ infrared or radio frequency transmitters to transmit acknowledgment signals acknowledging receipt of messages and to relay acknowledgment signals from other EPLs to receiving devices coupled to a main EPL computer. An EPL only sends an acknowledgment if the message is addressed to it.

0004EPLs typically differ on their ability to effectively receive and respond to messages from the central server. The primary causes for this difference are the location of EPLs within a transaction establishment and individual design differences among EPLs. Some EPLs may be located in areas of poor reception, where signals are attenuated more than in other areas.

0005Therefore, it would be desirable to provide a method of diagnosing communication problems of EPLs. It would also be desirable to assign EPLs to groups based upon their ability to receive and transmit messages and to locate EPLs within each of the groups to determine the source of a reception problem.

0006It is the object of the present invention to provide a method of diagnosing communication problems of electronic price labels.

0007According to the invention there is provided a method of diagnosing a communication problem of electronic price labels in a transaction establishment characterized by the steps of: <ul id="ul0001" list-style="none" compact="compact"><li>(a) assigning the electronic price labels to groups based upon their ability to provide a response message to a computer;</li><li>(b) identifying the physical locations of the electronic price labels;</li><li>(c) mapping said locations of the electronic price labels and their groups;</li><li>(d) identifying a group of electronic price labels having the reception problem; and</li><li>(e) determining the cause of the reception problem.</li></ul>

0008The invention will now be described by way of example with reference to the accompanying drawings, in which: <ul id="ul0002" list-style="none" compact="compact"><li>Fig. 1 is a block diagram of an EPL system;</li><li>Fig. 2 is a block diagram of an EPL;</li><li>Fig. 3 is a map of a transaction establishment;</li><li>Fig. 4 is a flow diagram illustrating the operation of EPL locator software;</li><li>Fig. 5 is a flow diagram illustrating a first method of grouping EPLs;</li><li>Fig. 6 is a flow diagram illustrating the operation of EPL diagnostic software; and</li><li>Fig. 7 is a flow diagram illustrating a second method of grouping EPLs.</li></ul>

0009In Fig. 1, EPL system 10 includes computer 12, storage medium 14, communication base station (CBS) 16a-d, and electronic price labels (EPLs) 18.

0010Computer 12 executes EPL control software 20, EPL diagnostic software 21, EPL locator software 22, and EPL grouping software 24. EPL control software 20 records, schedules, and transmits all messages to EPLs through CBS 16, and receives and analyzes status messages from EPLs 18 through CBS 16. EPL control software 20 also maintains and uses EPL data file 28, which contains item information, EPL identification information, item price verifier information, and status information for each of EPLs 18.

0011EPL control software 20 primarily includes data scheduler 34 and CBS manager 36. Data scheduler 34 schedules EPL price change messages to be sent to EPLs 18 through CBS 16.

0012EPL diagnostic software 21 identifies areas of a transaction establishment that may be causing poor reception of messages by EPLs positioned in these areas. EPL diagnostic software 21 uses EPL location information and EPL group information stored within EPL configuration file 27. EPL diagnostic software 21 stores its results in EPL diagnostic data file 31.

0013EPL locator software 22 automatically monitors EPL system 10 for received signal strength and determines the location of identified EPLs within groups of EPLs. EPL locator software 22 stores the location information in EPL system configuration file 27. EPL system configuration file 27 tells computer 12 how system 10 is configured, i.e., the electronic addresses of EPL system components and their physical location within the transaction establishment relative to other components within system 10, and the location of different types of goods in system 10. EPL system configuration file 27 includes a map containing grid coordinates identifying the locations of EPLs 18 and CBSs 16.

0014EPL grouping software 24 organizes EPLs 18 into groups based upon their abilities to receive messages from CBSs 16. The groups may be based upon the number of message re-transmissions required for different signal strength and noise levels. If EPLs within a group having a high message retry rate are located within the same area of the transaction establishment, that area of the transaction establishment may have a barrier to effective transmission and reception. Upon inspection by personnel, this barrier may be isolated and removed.

0015Storage medium 14 is preferably a fixed disk drive. Storage medium 14 stores EPL system configuration file 27 and EPL data file 28.

0016CBS 16 necessarily includes at least one transmit antenna 37 and preferably includes one to four receive antennae 38 for transmitting and receiving messages between CBS 16 and EPLs 18. CBS 16 includes CBS circuitry 39 which controls operation of CBS 16. EPL system 10 preferably includes a plurality of CBSs 16 connected together in series.

0017CBS manager 36 transmits price change messages to EPLs 18 and receives status messages from EPLs 18 for predetermined time slots.

0018Turning now to Fig. 2, EPLs 18 are illustrated.

0019EPLs 18 each include battery 40, transmit and receive antenna 42, display 46, memory 47, and EPL circuitry 48.

0020Battery 40 provides power to EPLs 18.

0021Transmit and receive antenna 42 receives price change and status messages from CBS 16. For EPLs 18 designed for displaying blinking and non-blinking promotional messages, transmit and receive antenna 42 receives promotional messages as well.

0022Transmit and receive antenna 42 transmits responses to price change and status messages to CBS 16.

0023Display 46 displays price and possibly additional information. Display 46 is preferably a liquid crystal display (LCD).

0024Memory 47 stores price verifier information and EPL type information. Preferably, the price verifier information is a checksum of the displayed price. Memory 47 may also store other information, such as promotional information.

0025EPL circuitry 48 controls the internal operation of EPLs 18.

0026In Fig. 3, a map of a transaction establishment illustrates the location of shelves 50 (shown shaded), a group of EPLs 18a, and another EPL 18b. This group may be defined by and contain EPLs having the highest message retry levels. Thus, it would be advantageous to attempt to diagnose the cause.

0027The locations of EPLs 18a are referenced to a two-dimensional coordinate system in which rows are identified by numerals and columns are identified by letters.

0028There are four transmit antennas 37, located respectively at positions 5C, 5F, 5I and 5L. Each antenna is surrounded by four receive antennas 38; for example the transmit antenna of at 5C is surrounded by receive antennas 38 at locations 3A, 3D, 7D, 7A and the transmit antenna at 5F is surrounded by receive antennas 38 at locations 3E, 3G, 7G and 7E. The four receive antennas are at the corners of a rectangle with the associated transmit antenna approximately in its centre; the rectangles associated with each transmit/receive system do not overlap.

0029Conveniently, the antennas are installed in the ceiling space of the transaction establishments, and are cable-connected to the CBS awaiting 39 (see Fig.1).

0030In this example, EPLs 18a are located in close proximity to each other and close to an end of shelf 51, while EPL 18b is distant from the group. Looking at the map, a store employee may assume that the high retry levels for EPLs 18a in the group are due to a common external cause. Thus, the store employee may look in the vicinity of EPLs 18a and to relevant end of shelf 51 to determine the cause for the high retry level. The store employee may also look at EPLs surrounding EPLs 18a to determine whether retry levels improve with radial distance from the center of the group containing EPLs 18a. For the EPL 18b, the store employee may look at adjacent EPLs having different retry levels to determine whether the high retry level for the EPL 18b is likely to be caused by internal or external problems.

0031In Fig. 4, the operation of EPL locator software 22 is explained in more detail, beginning with START 60.

0032In step 61, EPL control software causes CBSs 16 to transmit a query message to a particular EPL.

0033In step 62, EPL locator software 22 listens for an acknowledgment message from the EPL.

0034In step 64, EPL locator software 22 determines the signal strengths and noise levels of any acknowledgment message from the EPL to one of antennae 38 within CBSs 16.

0035In step 66, EPL locator software 22 determines whether signal strength information for the last of antennae 38 has been determined. If all CBSs 16 have been polled for signal strength information about their antennae 38, the method continues to step 68. If a CBS has not been polled, the method returns to step 64.

0036In step 68, EPL locator software 22 determines the primary and secondary estimates of fixes from map information stored within EPL configuration file 27. If multiple antennae 38 receive an acknowledgment message from the same EPL, EPL locator software 22 uses triangulation methods based on the relative signal strengths of the received messages to determine the location of the EPL.

0037Suppose the EPL 18a being polled is at position 3D, on the left side of the shelf block 51 as viewed, and suppose now that three antennae 38 at positions 3D, 3A, and 7D hear the acknowledgment of this EPL. Antenna 3D reports a relative signal strength of "60", and antennae 3A and 7A report relative signal strengths of "30". By calculation from the relative signal strengths, the primary approximation for the fix for this EPL is position 4C.

0038In step 70, EPL locator software 22 optionally converts the fixes to types of goods using information in EPL configuration file 27; this makes location by store personnel easier.

0039If from the information in EPL configuration file 27 it is known that position 4C is 'at the back of the soft drinks aisle', then it is also known that an approximate location for this EPL 18a is 'at the back of the soft drinks aisle' and an operator then visits that area and assesses the cause of any communication problem;

0040In step 72, EPL locator software 22 displays and/or prints primary and secondary estimates of the location coordinates and/or types of goods where the desired EPL is most likely to be located.

0041If store personnel determine that the location of the EPL does not correspond to its location in EPL configuration file 27 (e.g., because a child has removed it and placed it somewhere else), they can place the EPL in its proper location.

0042In step 74, EPL locator software 22 stores the determined fixes in EPL configuration file 27 for use by EPL diagnostic software 21.

0043In step 76, the method ends.

0044In Fig. 5, EPL grouping software 24 is explained in more detail, beginning with START 80.

0045In step 82, EPL grouping software 24 transmits messages to an EPL. EPL grouping software 24 preferably sends 10-200 messages to each EPL.

0046In step 84, EPL grouping software 24 determines signal strength and noise levels of return messages.

0047In step 86, EPL grouping software 24 sets the current retry level to the first retry level, which is arbitrarily chosen by the transaction establishment. For example, a message retry of `1' may be the highest and have an associated minimum signal strength of `68' and a maximum noise level of `57'. A message retry of `2' may be the next highest and have an associated minimum signal strength of `64' and a maximum noise level of `58'. Additional retry levels reflecting ever decreasing performance are also preferably determined.

0048In step 88, EPL grouping software 24 determines how many times the messages received from a particular EPL pass the minimum signal-to-noise ratio for the current retry level. In the example provided, after EPL grouping software 24 has received messages from the EPL, EPL grouping software 24 determines the number of times the measured signal strengths and noise levels meet the criteria for a message retry of `1'.

0049In step 90, EPL grouping software determines whether the pass rate is greater than the minimum for the current level.

0050EPL grouping software 24 assigns the particular EPL to a group having a first message retry level of `1' in step 98 if the pass rate is above the predetermined minimum pass rate.

0051If the pass rate is below the predetermined minimum pass rate, EPL grouping software 24 determines whether the current retry level is the last retry level in step 92. If it is not, then EPL grouping software 24 sets the current retry level to the next retry level in step 94 and returns to step 88 to determine whether the measured signal strengths and noise levels meet the criteria for the next retry level.

0052Returning to step 92, if the current retry level is the last retry level, then EPL grouping software 24 assigns the particular EPL to a group characterized as non-functioning in step 96. This group is monitored by employees who replace non-functioning EPLs with new EPLs.

0053From both steps 96 and 98, EPL grouping software 24 enters the group information in EPL data file 28 and may also enter the group information in EPL configuration file 27 in step 100. The information may be viewed using display 25 or printed using printer 23.

0054In step 102, EPL grouping software 24 determines whether the current EPL is the last EPL. If it is not, the method returns to step 82 to examine another EPL.

0055If it is the last EPL, the method ends in step 104.

0056Turning now to Fig. 6, EPL diagnostic software 21 is explained in more detail, beginning with START 110.

0057In step 112, EPL diagnostic software 21 identifies a predetermined target group of EPLs 18 from EPL configuration file 27. This group may be the one with the highest retry level, although any group having less than optimal retry levels may be chosen. For purposes of this example, the group is assumed to be a single cohesive group, rather than a plurality of subgroups.

0058In step 114, EPL diagnostic software 21 determines the primary CBS that communicates with the EPLs in the target group from EPL configuration file 27.

0059In step 118, EPL diagnostic software 21 determines the grid coordinates (see Fig.3) for the primary antenna of the primary CBS from EPL configuration file 27. For purposes of this example, it is assumed that only one CBS antenna communicates with EPLs in the target group.

0060In step 124, EPL diagnostic software 21 determines an adjacent group between the primary antenna and the target group.

0061In step 126, EPL diagnostic software 21 determines the retry levels for the adjacent group from EPL configuration file 27.

0062In step 128, EPL diagnostic software 21 determines the difference between the retry level for the target group and the retry level for the adjacent group.

0063In step 130, EPL diagnostic software 21 determines whether the difference exceeds one retry level. If it does, the reception problem is most likely in the vicinity of the target group. EPL diagnostic software 24 logs the grid coordinates between the target group and the adjacent group in EPL diagnostic data file 31 in step 132. The method ends in step 138.

0064If the difference does not exceed one retry level, EPL diagnostic software 21 determines whether there are any additional groups between the target group and the primary antenna in step 134. If there are not, the method ends in step 138. If none of the differences between intermediate groups exceeds on retry level, then the reception problem is most likely caused by the CBS or by an insufficient number of CBSs.

0065If there is an additional intermediate group between the target group and the primary antenna, EPL diagnostic software 21 designates the current adjacent group as the target group and the additional intermediate group as the current adjacent group in step 136 and the method returns to step 124.

0066Thus, the method searches from the original target group to the primary CBS antenna for decreases of at least two retry levels to identify the location of a reception problem. Of course, the method can be extended to search from the target group to other antennae of the CBS and to antennae of other CBSs.

0067Advantageously, the method of the present invention may be used after EPLs 18 have been installed to tune EPL system 10 for higher reliability and performance.

0068Turning now to Fig. 7, a second method for assigning EPLs 18 to groups is illustrated, beginning with START 140.

0069In step 142, EPL locator software 22 reads EPL data file 28.

0070In step 144, EPL locator software 22 identifies a group associated with a particular EPL. The group identity may be determined from a group number, or by comparing the EPL serial number against a group range of serial numbers, or by comparing an EPL installation date against a range of group dates.

0071In step 146, EPL locator software 22 instructs the EPL to load its memory 47 with information identifying the group. This display information may be a group number, a blinking group number, a promotional message, or a blinking promotional message.

0072In step 148, EPL locator software 22 instructs the EPL to display the contents of its memory 47.

0073In step 150, EPL locator software 22 determines whether it has read information for the last EPL in EPL data file 28. If not, the method returns to step 142. If so, the method proceeds to step 152.

0074In step 152, EPLs 18 and their groups are mapped to coordinates by employees. The employees view each EPL and log the displayed group number with the EPL's identification number.

0075In step 154, the method ends.