RADIO BASE STATION AND SYSTEM HAVING SAID RADIO BASE STATION

Abstract

The invention relates to a base station or a radio access point having a plurality of radio modules, of which one communicates with electronic price indication signs. If a plurality of radio modules use the same frequencies and communicate simultaneously, disturbances can occur in the form of interference. The invention solves this problem in that the radio modules (21, 22, 23) are coupled (24) such that a radio module (22) can influence another radio module (21, 23) with regard to the radio activity of said other radio module. In particular, the radio module that communicates with the electronic price indication signs (22) can silence the other radio modules (21, 23) by means of a radio activity control signal (FS).

Claims

1. A radio base station (17), comprising a first radio module (21, 23) for radio communication with first radio communication devices (11, 16) assigned thereto, and a second radio module (22) for radio communication with second radio communication devices (2-10) assigned thereto, the two radio modules (21, 22, 23) have a coupling (24) to each other, and the one radio module (22) is designed to influence the radio activity of the other radio module (21) by means of the coupling (24) and the other radio module (21, 23) is designed such that it can be influenced with regard to the radio activity thereof.

2. The radio base station (17) according to claim 1, wherein the one radio module (22) is designed to generate and output a radio activity control signal (FS) to the other radio module (21, 23) and the other radio module (21, 23) is designed for receiving and evaluating the radio activity control signal (FS) with regard to its information content and for influencing the radio activity thereof in accordance with the information content.

3. The radio base station (17) according to claim 1, wherein the coupling (24) is implemented by means of a cable or cabling system between the two radio modules (21, 22, 23).

4. The radio base station (17) according to claim 1, wherein the other radio module (21, 23), which can be influenced with regard to the radio activity thereof, is designed in such a way that in accordance with the influencing by the one radio module (22) it: suspends its radio activity, and/or resumes its radio activity, and/or suspends its radio activity during a predefined time period or in accordance with a time period defined by the one radio module (22) and/or adjusts its transmission power automatically to a predefined value or adapts it to a value defined by the one radio module (22), and/or adapts its radio channel assignment according to a predefined scheme, or to a scheme defined by the one radio module (22).

5. The radio base station (17) according to claim 1, wherein the other radio module (21, 23), which can be influenced with regard to the radio activity thereof, is designed to communicate in accordance with a WLAN standard with WLAN-enabled radio communication devices (11, 16), or to communicate with electronic price indication signs as radio communications devices.

6. The radio base station (17) according to claim 1, wherein the one radio module (22) designed for influencing is also designed to communicate with electronic price indication signs as the second radio communication devices (2-10).

7. The radio base station (17) according to claim 5, wherein in the communication with the electronic price indication signs (2-10) a time-slot communication method is applied, in which in a recurring sequence a number of time slots (Z1-ZN) are available for communication per time-slot cycle, wherein in particular each time slot (Z1-ZN) is identified by a unique time slot symbol (ZS1-ZSN).

8. The radio base station (17) according to claim 1, wherein the one radio module (22) designed for influencing is designed to predictively determine the time at which the influencing occurs.

9. The radio base station (17) according to claim 8, wherein the time at which the influencing occurs is specified on the basis of the expected time at which a communication occurs between a radio communication device (2-10) and the one radio module (22) designed for influencing.

10. The radio base station (17) according to claim 1, which comprises a host computer (20) that can be coupled by means of a wired computer network (19) to a server (18) and is designed to exchange data between the server (18) and the radio modules (21-23), wherein the host computer (20) is designed: for transmitting data between the server (18) and the host computer (20) based on a network protocol, in particular the TCP/IP protocol, and between the radio modules (21-23) and the host computer (20) based on an interface protocol, in particular a serial interface protocol, and for tunnelling raw data traffic between the radio modules (21-23) and the server (18).

11. A system (1), comprising: a radio base station (21-23) according to claim 1, and a server (18) coupled to the radio base station (17) for providing or processing data relating to the communication with the radio communication devices (21-23).

12. The system (1) according to claim 11, wherein the server (1) is designed to provide a virtual instance (34; 35, 36) of a radio base station, and the radio base station (17) is designed for tunnelling a raw data traffic (RD) between the radio modules (21-23) and the virtual instance (34; 35, 36) of the radio base station.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0043] The invention is explained again hereafter with reference to the attached figures and on the basis of exemplary embodiments, which nevertheless do not limit the scope of the invention. In the different figures the same components are labelled with identical reference numbers. They show in schematic fashion:

[0044] FIG. 1 a system according to the invention;

[0045] FIG. 2 a first state diagram;

[0046] FIG. 3 a second state diagram;

[0047] FIG. 4 a third state diagram.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

[0048] FIG. 1 shows a system 1 according to the invention for radio communication with different radio communication devices, which is installed on the premises of a supermarket. The system 1 implements a radio network and enables the radio communication with a set of electronic price indication signs 2-10, hereafter referred to in short as ESL 2-10, as well as portable electronic barcode reading devices 11 (only a single one is shown), which are part of an electronic stock management system of the supermarket. Each ESL 2-10 has a display unit 100 and is mounted on shelves 12-14 of a shelf unit 15 corresponding to products (not shown) positioned on the shelf, price and product information relating to which is displayed using the ESL. In addition, customers of the supermarket, using their own mobile radio communication devices (also only one shown), such as mobile phones or portable computers, hereafter designated in short as user devices 16, can use on-line services via a guest access to the radio network of the supermarket. The radio network enables communication with the different groups of radio communication devices 2-10, 11, 16 with different protocols and different priority.

[0049] In order to implement this radio network, the system 1 comprises a radio base station 17, hereafter designated in short as station 17), and a server 18, which are connected to each other via a local-area, wired network (LAN) 19. Via this LAN 19 the server 18 communicates with the station 17 using the TCP/IP protocol, wherein raw data RD, embedded in communication data KD, can be exchanged with the individual devices 2-10, 11 and 16.

[0050] The station 17 has a host computer 20, a first radio module 21 for communication with the barcode readers 11 in accordance with a WLAN standard, a second radio module 22 for communication with the ESL 2-10 according to a proprietary protocol, which is discussed in detail below, and a third radio module 23 for communication with the mobile user devices 16 according to a WLAN standard. The second radio module 22 is connected via a control cable 24 to the first and the third radio module 21, 23. The control cable 24 is part of a coupling of the second radio module with the other two radio modules 21, 23, and is implemented in two parts only because of the chosen placement of the radio modules 21-23. It should be noted, however, that in accordance with another exemplary embodiment, two separate control cables can be used. The control cable 24 is used to transmit a radio activity control signal, hereafter designated in short as control signal FS, from the second radio module 22 to the other two radio modules 21, 23, which is used to influence the radio activity of the other two radio modules 21, 23. In the present case the control signal FS is a signal in which a first level (0V or GND) indicates that no influence is present, and a second level (+2.5V or HIGH) indicates that an influence is present. In the implementation shown here, upon the occurrence of the second level and as long as the second level is present, the radio activity of the other two radio modules 21, 23 is suspended, thus no radio signals are broadcast (muted). Only in the presence of the first level do the other two radio modules have normal radio activity, in which they can broadcast radio signals. It should be mentioned at this point that between the radio modules, in order to implement the influencing, a serial or parallel data transmission system or else a data bus may also be present.

[0051] In addition, for each of the radio modules 21-23 the station 17 comprises an antenna 25-27 which can be used for the radio traffic of the station. Each of the radio modules 21-23 comprises the functional units (not shown in detail) that are necessary for the physical radio communication, implemented by means of their hardware and/or software, and is connected to its own antenna 25-27.

[0052] Each of the radio modules 21-23 has a serial interface 28-30 for wired communication with the host computer 20. The host computer is 20 is designed both for communicating with the radio modules 21-23 based on a serial communication protocol and also for TCP/IP-protocol-based communication with the server 18, wherein a raw data traffic between the server 18 and the respective radio module 21-23 is tunnelled from the one protocol to the other protocol. For this purpose, in addition to other functional stages that are not discussed in detail, the host computer comprises a conversion stage 31, which is implemented by means of software that runs on the hardware of the host computer.

[0053] The server 18 has a data storage stage 32, such as a database for storing all information concerning the stock management system and/or the communication with the individual subscribers of the radio network. In operation the server 18 implements a server process stage 33 for the provision of all server processes or functions. The server 18 also implements a virtual instance 34 of the station 17 for providing all station functionalities. For this process, on the server 18, by means of its hardware (CPU, memory, interfaces, etc.) an appropriate piece of software (a program) is processed, which enables the respective functionality to be provided. Due to the use of the virtual instance 34, the station 17 has a significantly reduced load with regard to its physical data processing resources, and the existing computing power of the server 18 is advantageously used for providing the “intelligence” of the station 17. Consequently, relatively inexpensive hardware can be used for the station 17.

[0054] In the present case, a single station 17 on the premises of the supermarket, for example on the ground floor, is assumed. If several stations 17 are used however, such as one per sales floor, it is a simple matter to generate other instances 35, 36 (indicated by blocks framed with dashed lines) on the server 18 in addition to the first instance 33, and to process the raw data traffic RD for the stations 17 (not shown) installed on the other floors (e.g. the first and the second floor). The system 1 is consequently scalable as desired, by adding multiple instances of a relatively inexpensive station 17. The implementation of the system 1 also allows the data traffic on the LAN to be kept constant.

[0055] In the communication between ESL 2-10 and the radio module 22 to which they are assigned, a time-slot communication method is used, the principle of which is represented in FIGS. 2-4, by means of which the functioning of the system is also illustrated. On the abscissa axis the time t is plotted. On the ordinate axis, states Z of the respective components or signals of the system 1 that are considered in the discussion are plotted. The graphs consequently show the temporal sequence of the states.

[0056] In each of FIGS. 2-4 the top state sequence shows the states of the second radio module 22 labelled as ST. During one time-slot cycle period DC (e.g. 15 seconds), N time slots Z1 . . . ZN (e.g. 256) are available, with an identical time-slot duration DS (e.g. approx. 58 milliseconds). During the time-slot cycle duration DC the second radio module 22 switches between a sending state T and a resting state R. The sending state T is always occupied at the beginning of a time slot Z1 . . . ZN and maintained for a synchronization data-signal duration DSD (or send-time duration DSD of the synchronization data signal SD), in order to send a corresponding time-slot symbol, ZS1, ZS2, . . . ZSN with the respective synchronization data signal SD. For the corresponding time-slot cycle symbol ZS1 . . . ZSN, the ordinal number of the respective time slot Z1 . . . ZN in the order of occurrence of the time slot Z1 . . . ZN can be used.

[0057] FIG. 2 shows that the first ESL 2 is in the synchronous state. It wakes up from its extremely energy-saving sleep state S at a first wake-up time TA1, and with a relatively short lead time DV prior to an expected occurrence of a synchronization data signal SD, changes into its receiving-ready state E, receives the synchronization data signal SD during a reception period DE with the first time-slot symbol ZS1, then by comparing the least significant byte B0 of its hardware address with the received time slot symbol ZS1 establishes that the first time slot Z1 intended for the first ESL 2 is displayed (agreement between the bytes: B0 of the hardware address and the first time slot symbol ZS1 to be compared), retains the parameters used for controlling the wake-up for waking up in the subsequent time-slot cycle for the purpose of defining the new wake-up time point, and changes back into the sleep state S with a relatively short follow-on time DN, in order to wake up on schedule after expiry of the sleep-state dwell time DR provided at the new (second) wake-up time TA2 with said lead time DV before the fresh start of the first time-slot cycle Z1. The same applies analogously for the second ESL 3 and for all other ESL 4-10, provided they are in the synchronous state as was the first ESL 1. All ESL 2-10 are designed to detect a non-synchronous state and to synchronize themselves.

[0058] The last (bottom) state sequence plotted in FIG. 2 shows the control signal FS changing between the first level P1 and the second level P2. Every time the second radio module 22 tries to send the synchronization data signal SD, the other two radio modules 21, 23 are muted by means of the second level P2 of the control signal FS, so that they show no radio activity. The time period (muting period SSD), during which the muting occurs, could in principle be limited to the period of time of the occurrence of the synchronization data signal SD. Preferably, the muting period SSD is extended by a short lead time (first safety period S1), in particular also by a short follow-on time (second safety period S2) of a few milliseconds, in order to ensure that the synchronization data signal DS always occurs within the muting period SSD. However, the duration of the existence of the second level P2 (muting period) particularly preferably also overlaps or spans (including lead-time and follow-on time) the receiving period DE, thus ensuring that no interference occurs in the radio medium which could adversely affect the reception and consequently also the checking of the synchronism of the ESL 2-10. In the last mentioned implementation it would also be sufficient if the muting period SSD coincides with the receiving period and is consequently equal in length, because in the receiving period DE the lead time DV and the run-time DN is already taken into account in relation to the expected occurrence of the synchronization data signal SD.

[0059] By reference to FIG. 3 an individual addressing of the ESL 2-4 and an individual control of these ESL 2-4 using simple time-slot commands will be discussed. The figure shows only the first time slot Z1 embedded between two synchronization data signals SD. In the synchronization data signal SD of the first time slot Z1, address data AD, command data CD and confirmation time data ZD are embedded by the second radio module 22. The address data AD (e.g. hex B2:00:01) are used to individually address the first ESL 2, the address data AD (e.g. hex B2:00:02) to address the second ESL 3 and the address data AD (e.g. hex B2:00:03) to address the third ESL 4. Using the command data CD, a “ping” command is sent to the first ESL 2, a “ping” command is also sent to the second ESL 3 and a “SWPAG2” command to the third ESL 4. These commands are single time-slot commands, which are processed with negligible time delay in the relevant ESL 2-4 immediately after their decoding. The two “ping” commands are used to test whether the addressed ESL 2, 3 responds with confirmation data ACD, i.e. whether it exists or responds at all and is synchronized. The “SWAPG2” command is used to cause the third ESL 4 to switch from one (first) current memory page to a second memory page, in order, for example, to change the image to be displayed by means of its display screen. In addition, with the synchronization data signal SD a confirmation time point for the first ESL 2 is transmitted by specifying a first rest period DR1, for the second ESL 3 by specifying a second rest period DR2 and for the third ESL 4 by specifying a third rest time DR3. The reference point for the three rest periods DR1-DR3 is always the end of the receiving period DE. In place of the individual rest periods DR1-DR3, maximum time periods for responding can also be specified, which are obtained from the sum of the respective rest periods DR1-DR3 and the time period for outputting the confirmation data ACD. In accordance with FIG. 3, all three ESL 2-4 detect that they are synchronous, because the first time slot symbol Z1 displays the time slot specified for them (least significant byte B0 of the hardware address is hex 00 in all three of the ESL 2-4). The testing of the address data AD indicates that each ESL 2-4 is individually addressed (presence of the remaining three bytes B1-B3 of the respective hardware address in the address data AD), the commands intended for the respective ESL 2-4 are decoded and immediately executed, and also the individual confirmation data ACD after the expiry of the individual rest periods DR1 . . . DR3 after the end of the receiving period DE are transmitted to the second radio module 22, which is ready to receive the confirmation data ACD during a station receiving period SDE. The complete processing of single time-slot commands, including the communication of the confirmation data ACD, takes place in a first part 36 of the time slot Z1, so that a second part 37 is available for other tasks such as the processing of multiple time-slot commands, which will be described in further detail below.

[0060] By analogy to FIG. 2 the last (bottom) state sequence plotted in FIG. 3 also shows the control signal FS changing between the first level P1 and the second level P2. In the present case, however, the duration of a first muting period SSD1 is longer than the duration of a second muting period SSD2, because in the region of the first muting period SSD1 a longer interference-free communication phase is necessary. The duration of the second muting period SSD2 corresponds to that period shown in FIG. 2, because only the receiving period DE has to be taken into account.

[0061] FIG. 4 shows the processing of a multiple time-slot command, in which the first ESL 2 receives overall data (e.g. relating to an entire display image or even just one image plane of the image) across three consecutive time slots Z1-Z3, decomposed into three data packets DAT1-DAT3 from the second radio module 22. The first ESL 2 detects its synchronous state by means of the synchronization data signal SD and the fact that it is being addressed individually (addressee hex B2:00:01), receives and decodes a “DATA_INIT” command, with which it is commanded to receive the three packets DAT1-DAT3 in said time slots Z1-Z3, and at the end of the receiving period DE goes into the sleep state S for a first waiting period DW1, wherein the first waiting period DW1 expires at the end of the first half of the time-slot duration DS. At the beginning of the second part 37 of the first time slot Z1 the second radio module 22 goes into its transmit state T and the first ESL 2 goes into its receive-ready active state E, so that during a data transmission period DT it receives the first data packet DAT1. Then, by means of partial confirmation data ACD1 during a confirmation period DA, during which the second radio module 22 is also in the receive state E, it confirms the successful reception. The confirmation period DA ends before the end of the first time slot Z1. After expiry of the confirmation period DA, the first ESL 2 waits for a second waiting period DW2, which extends up to the end of the first part 36 of the second (subsequent) time slot Z2, in the sleep state S. At the beginning of the second part 37 of the second time slot Z2 the second radio module 22 goes into its transmit state T and the first ESL 2 goes into its receive-ready active state E, so that during a data transmission period DT it receives the second data packet DAT2. The same applies to the third time slot Z3, at the end of which the data transfer is completed. Each successfully transmitted data packet DAT1-DAT3 is confirmed using the partial confirmation data ACD1-ACD3.

[0062] By analogy to FIG. 2 the last (bottom) state sequence plotted in FIG. 4 also shows the control signal FS changing between the first level P1 and the second level P2. In the present case, however, the duration of a first muting period SSD1 is shorter than the duration of a second muting period SSD2, which in the present case occurs several times in succession. The duration of the first muting period SSD1 corresponds to the duration shown in the FIG. 2, which is favourable for an interference-free reception of the synchronization data signal SD. During the second muting period SSD2, an interference-free radio traffic is provided for handling a plurality of communication events occurring one after another in close succession.

[0063] Quite generally, in conclusion it should be mentioned that in relation to time slots to which no electronic price signs are assigned, no muting of the other two radio modules 21, 23 is preferably carried out. This means that the communication efficiency of the entire radio network is improved.

[0064] In accordance with another exemplary embodiment of the invention, a predefined, graduated hierarchy can also be provided for the radio activities of the radio modules. This can involve, for example, a first radio module having the highest priority, a second radio module having lower priority and possibly a third radio module having the lowest priority. In this exemplary embodiment, the second radio module can only influence the third radio module with regard to its radio activity, whereas the first radio module can influence the other two radio modules with regard to their radio activities. The third radio module cannot exert any influence on the radio activity of the other radio modules.

[0065] To conclude, it will once again be pointed out that the Figures described in detail above are merely exemplary embodiments which can be modified in a wide variety of ways by the person skilled in the art without departing from the scope of the invention. For the sake of completeness, it is also pointed out that the use of the indefinite article “a” or “an” does not exclude such features from also being present more than once.