Patent Description:
<CIT> discloses an FA system in which a PC and a controller are connected via a field network. In <CIT>, transmission and reception of wireless messages are carried out.

<CIT> discloses a time-division multiple access radio communication device that can automatically generate acknowledgement data and send the data for response.

<CIT> refers to a method and apparatus for quick retransmission of signals in a communication system.

<CIT> is directed to a timing information calculating part in a base station apparatus that calculates timing information indicating a timing when each transmission buffer becomes empty.

However, in the conventional system, it is not always possible to realize rapid wireless communication.

The present invention has the object of solving the aforementioned problems.

The problems are solved by a base wireless device according to claim <NUM> and a wireless communication method according to claim <NUM>. A preferred embodiment is provided by claim <NUM>.

A base wireless device according to an aspect of the present invention includes a base wireless device that carries out transmission and reception of signals to and from a plurality of remote wireless devices, including a plurality of transmission buffers configured to store a plurality of signals to be transmitted to the plurality of remote wireless devices, the plurality of signals having transmission destinations that are different from each other, a transmission processing unit configured to transmit the signals to the plurality of remote wireless devices respectively, by transmitting the signals stored in the plurality of transmission buffers in a predetermined order, regardless of whether or not each transmission has been made successfully, and a storage control unit, wherein when a transmission of a signal stored in one of the transmission buffers has been made successfully, the storage control unit is configured to overwrite the one transmission buffer from which the transmission has been made successfully, with another signal to be transmitted to a transmission destination that is different from a transmission destination of a signal stored in a transmission buffer other than the one transmission buffer from which the transmission has been made successfully, among the plurality of transmission buffers.

A wireless communication method according to another aspect of the present invention includes a method in which a base wireless device and a plurality of remote wireless devices carry out transmission and reception of signals to and from each other. The method includes storing, in a plurality of transmission buffers, a plurality of signals to be transmitted to the plurality of remote wireless devices, the plurality of signals having transmission destinations that are different from each other, transmitting the signals to the plurality of remote wireless devices respectively, by transmitting the signals stored in the plurality of transmission buffers in a predetermined order, regardless of whether or not each transmission has been made successfully, and overwriting, when a transmission of a signal stored in one of the transmission buffers has been made successfully, the one transmission buffer from which the transmission has been made successfully, with another signal to be transmitted to a transmission destination that is different from a transmission destination of a signal stored in a transmission buffer other than the one transmission buffer from which the transmission has been made successfully, among the plurality of transmission buffers.

According to the present invention, it is possible to provide a base wireless device and a wireless communication method that are capable of realizing rapid wireless communication.

A base wireless device and a wireless communication method according to an embodiment will be described below with reference to <FIG>. <FIG> is a diagram illustrating a wireless communication system according to the present embodiment. <FIG> is a block diagram illustrating the wireless communication system according to the present embodiment.

As shown in <FIG>, a wireless communication system <NUM> according to the present embodiment may include a computer <NUM>, a base wireless device <NUM>, and a remote wireless device <NUM>. The wireless communication system <NUM> may include a plurality of base wireless devices <NUM>. The single computer <NUM> and the plurality of base wireless devices <NUM> may be connected via a fieldbus <NUM>. Pairing may be performed in advance between the base wireless device <NUM> and the remote wireless device <NUM>. A synchronous connection may be made between the paired base wireless device <NUM> and the remote wireless device <NUM>. A plurality of remote wireless devices <NUM> can be synchronously connected to a single base wireless device <NUM>. The base wireless device <NUM> may transmit signals to and receive signals from the plurality of remote wireless devices <NUM>. A plurality of networks <NUM> may be configured by synchronously connecting the plurality of remote wireless devices <NUM> to each of the base wireless devices <NUM>.

The computer <NUM> can monitor and control industrial equipment. As the computer <NUM>, for example, a PLC (Programmable Logic Controller) may be used, but the computer <NUM> is not limited thereto. As illustrated in <FIG>, the computer <NUM> may include, for example, a computation unit <NUM> and a storage unit <NUM>.

The computation unit <NUM> may include, for example, a processor such as a CPU (Central Processing Unit). That is, the computation unit <NUM> may include processing circuitry. The computation unit <NUM> includes a control unit <NUM>. Although components other than the control unit <NUM> may be included in the computation unit <NUM>, the components other than the control unit <NUM> are omitted herein for the sake of simplicity of description. The control unit <NUM> governs the overall control of the computer <NUM>. The control unit <NUM> may monitor and control industrial equipment. The control unit <NUM> may be realized by programs, which are stored in the storage unit <NUM>, being executed by the computation unit <NUM>. At least a part of the control unit <NUM> may be realized by an integrated circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field-Programmable Gate Array). At least a part of the control unit <NUM> may be an electronic circuit including a discrete device.

The storage unit <NUM> may include a volatile memory (not illustrated) and a nonvolatile memory (not illustrated). Examples of the volatile memory may include, for example, a RAM (Random Access Memory) or the like. Examples of the nonvolatile memory may include, for example, a ROM (Read Only Memory), a flash memory, or the like. Data and the like may be stored, for example, in the volatile memory. Programs, tables, maps, and the like may be stored, for example, in the nonvolatile memory. At least a part of the storage unit <NUM> may be included in the above-described processor, integrated circuit, or the like. The storage unit <NUM> may further include an HDD (Hard Disk Drive), SSD (Solid State Drive), and the like.

The computer <NUM> is provided with an input/output interface <NUM> for realizing fieldbus connection. The computer <NUM> may communicate with the base wireless device <NUM> via the fieldbus <NUM>.

The base wireless device <NUM> includes, for example, a computation unit <NUM> and a storage unit <NUM>.

The computation unit <NUM> may include, for example, a processor such as a CPU. That is, the computation unit <NUM> may include a processing circuit. The computation unit <NUM> may include a control unit <NUM>, an acquisition unit <NUM>, a transmission/reception processing unit <NUM>, and a storage control unit <NUM>. The computation unit <NUM> may be equipped with other components apart from these components noted above. However, the components other than these components are omitted herein for the sake of simplicity. The control unit <NUM>, the acquisition unit <NUM>, the transmission/reception processing unit <NUM>, and the storage control unit <NUM> may be realized by programs, which are stored in the storage unit <NUM>, being executed by the computation unit <NUM>. The control unit <NUM> governs the overall control of the base wireless device <NUM>. At least a part of the control unit <NUM>, the acquisition unit <NUM>, the transmission/reception processing unit <NUM>, and the storage control unit <NUM> may be realized by an integrated circuit such as an ASIC or an FPGA. At least a part of the control unit <NUM>, the acquisition unit <NUM>, the transmission/reception processing unit <NUM>, and the storage control unit <NUM> may be an electronic circuit including a discrete device.

The storage unit <NUM> may include a volatile memory (not illustrated) and a nonvolatile memory (not illustrated). Examples of the volatile memory may include, for example, a RAM or the like. Examples of the non-volatile memory may include, for example, a ROM, a flash memory, or the like. Data and the like may be stored, for example, in the volatile memory. Programs, tables, maps, and the like may be stored, for example, in the nonvolatile memory. At least a part of the storage unit <NUM> may be included in the above-described processor, integrated circuit, or the like.

The base wireless device <NUM> is provided with an input/output interface <NUM> for realizing fieldbus connection. The base wireless device <NUM> may be connected to the computer <NUM> via the fieldbus <NUM> as described above.

The base wireless device <NUM> may be provided with a communication unit <NUM> for carrying out wireless communication. The base wireless device <NUM> may carry out wireless communication with the remote wireless device <NUM> using the communication unit <NUM>.

The remote wireless device <NUM> may be provided in each of the plurality of devices <NUM> (see <FIG>) included in the industrial equipment. As an example of the device <NUM>, there may be cited a sensor, a valve, and the like, although the device <NUM> is not limited thereto. The remote wireless device <NUM> is provided with, for example, a computation unit <NUM> and a storage unit <NUM>.

The computation unit <NUM> may include, for example, a processor such as a CPU. That is, the computation unit <NUM> may include a processing circuit. The computation unit <NUM> may include a control unit <NUM> and a transmission/reception processing unit <NUM>. The computation unit <NUM> may be equipped with other components apart from these components noted above. However, the components other than these components are omitted herein for the sake of simplicity. The control unit <NUM> and the transmission/reception processing unit <NUM> may be realized by programs, which are stored in the storage unit <NUM>, being executed by the computation unit <NUM>. The control unit <NUM> governs the overall control of the remote wireless device <NUM>. At least a part of the control unit <NUM> and the transmission/reception processing unit <NUM> may be realized by an integrated circuit such as an ASIC or an FPGA. At least a part of the control unit <NUM> and the transmission/reception processing unit <NUM> may be an electronic circuit including a discrete device.

The remote wireless device <NUM> is provided with a communication unit <NUM> for carrying out wireless communication. The remote wireless device <NUM> may carry out wireless communication with the base wireless device <NUM> using the communication unit <NUM>.

As described above, the base wireless device <NUM> may include the transmission/reception processing unit <NUM>. The transmission/reception processing unit <NUM> may include a transmission processing unit 26A and a reception processing unit 26B. The transmission processing unit 26A performs a signal transmission process. The reception processing unit 26B performs a signal reception process. As described above, the remote wireless device <NUM> may include the transmission/reception processing unit <NUM>. The transmission/reception processing unit <NUM> and the transmission/reception processing unit <NUM> govern transmission/reception processes of signals between the remote wireless device <NUM> and the base wireless device <NUM>. Communication by a frequency hopping method may be carried out between the base wireless device <NUM> and the remote wireless device <NUM> that are synchronously connected. That is, between the synchronously connected base wireless device <NUM> and remote wireless device <NUM>, signal transmission and reception may be carried out by switching hopping frequencies at predetermined hopping periods Tfh(n) (see <FIG>).

As described above, the base wireless device <NUM> may be provided with the acquisition unit <NUM>. The acquisition unit <NUM> may sequentially acquire signals (data packets) supplied from the computer <NUM>. The signal supplied from the computer <NUM> may include information indicating the remote wireless device <NUM> that is a transmission destination of the signal.

As described above, the base wireless device <NUM> may include the storage unit <NUM>. The storage unit <NUM> may include a standby buffer <NUM>. The acquisition unit <NUM> sequentially stores a plurality of signals supplied from the computer <NUM> in the standby buffer <NUM>. The standby buffer <NUM> may store signals acquired by the acquisition unit <NUM> in chronological order.

The storage unit <NUM> may further include a plurality of transmission buffers 46A and 46B. The transmission buffers 46A and 46B may temporarily store signals to be transmitted to the remote wireless device <NUM>. The reference numeral <NUM> will be used when describing the buffers in general, whereas the reference numerals 46A and 46B will be used when describing the individual buffers. The plurality of transmission buffers <NUM> may store a plurality of signals to be transmitted to the plurality of remote wireless devices <NUM>. A plurality of signals having transmission destinations that are different from each other may be stored in the plurality of transmission buffers <NUM>. That is, when a signal is stored in the transmission buffer 46B, a signal to be transmitted to a transmission destination different from the transmission destination of the signal stored in the transmission buffer 46B is stored in the transmission buffer 46A. When a signal is stored in the transmission buffer 46A, a signal to be transmitted to a transmission destination different from the transmission destination of the signal stored in the transmission buffer 46A is stored in the transmission buffer 46B.

The transmission processing unit 26A transmits the signals stored in the plurality of transmission buffers <NUM> in a predetermined order, regardless of whether or not each transmission has been made successfully. The transmission processing unit 26A transmits the signals stored in the plurality of transmission buffers <NUM> in a predetermined order, so as to transmit the signals to each of the plurality of remote wireless devices <NUM>.

When the remote wireless device <NUM> receives the signal from the base wireless device <NUM>, the remote wireless device <NUM> transmits to the base wireless device <NUM> a reception completion notification indicating that the signal has been received. Transmission of a signal from the base wireless device <NUM> to the remote wireless device <NUM> and transmission of a reception completion notification from the remote wireless device <NUM> to the base wireless device <NUM> are carried out within one hopping period. When the reception processing unit 26B receives the reception completion notification within the hopping period in which the signal is transmitted from the base wireless device <NUM> to the remote wireless device <NUM>, the control unit <NUM> determines that the transmission of the signal to the remote wireless device <NUM> has been made successfully. When the reception processing unit 26B does not receive the reception completion notification within the hopping period in which the signal is transmitted from the base wireless device <NUM> to the remote wireless device <NUM>, the control unit <NUM> determines that the transmission of the signal to the remote wireless device <NUM> has failed.

As described above, the base wireless device <NUM> may include the storage control unit <NUM>. The storage control unit <NUM> stores a signal that is transmitted to a remote wireless device <NUM> in the transmission buffer <NUM>. The storage control part <NUM> stores a plurality of signals having transmission destinations that are different from each other in the plurality of transmission buffers <NUM>. When the transmission of the signal stored in the transmission buffer <NUM> has been made successfully, the storage control unit <NUM> performs the following process. That is, in this case, the storage control unit <NUM> overwrites the transmission buffer <NUM> from which transmission has been made successfully, with a signal to be transmitted to a transmission destination different from a transmission destination of a signal stored in a transmission buffer <NUM> other than the transmission buffer <NUM> from which transmission has been made successfully, among the plurality of transmission buffers <NUM>. For example, when the transmission of the signal stored in the transmission buffer 46A has been made successfully, the storage control unit <NUM> performs the following control. That is, in this case, the storage control unit <NUM> overwrites the transmission buffer 46A, with a signal to be transmitted to a transmission destination that is different from a transmission destination of the signal stored in the transmission buffer 46B other than the transmission buffer 46A, among the plurality of transmission buffers <NUM>. When the transmission of the signal stored in the transmission buffer 46B has been made successfully, the storage control unit <NUM> performs the following control. That is, in this case, the storage control unit <NUM> overwrites the transmission buffer 46B, with a signal to be transmitted to a transmission destination that is different from a transmission destination of the signal stored in the transmission buffer 46A other than the transmission buffer 46B, among the plurality of transmission buffers <NUM>.

The storage control unit <NUM> stores, in the transmission buffers <NUM>, signals selected from the signals stored in the standby buffer <NUM> in accordance with priority. For example, the earlier the time at which the signal was acquired, the higher the priority may be. That is, the priority of a signal acquired earlier by the acquisition unit <NUM> (acquisition time is old) may be higher than the priority of a signal acquired later by the acquisition unit <NUM> (acquisition time is new).

The operation of the base wireless device <NUM> according to the present embodiment will be described below with reference to <FIG> is a flowchart illustrating an example of operation of the base wireless device according to the present embodiment. The basic operation of transmitting a signal is illustrated in <FIG>.

In step S1, the storage control unit <NUM> provided in the base wireless device <NUM> stores in the plurality of transmission buffers <NUM> a plurality of signals having transmission destinations that are different from each other.

In step S2, the transmission processing unit 26A provided in the base wireless device <NUM> transmits the signals stored in the plurality of transmission buffers <NUM> in a predetermined order. The process shown in <FIG> may be performed repeatedly.

The operation of the base wireless device <NUM> according to the present embodiment will be described below with reference to <FIG> is a flowchart illustrating an example of operation of the base wireless device according to the present embodiment. <FIG> shows an example of the operation corresponding to the success or failure of the transmission of the signals stored in the transmission buffers <NUM>.

In step S11, the control unit <NUM> determines whether or not the transmission of the signal stored in the transmission buffer 46A has been made successfully. If the transmission of the signal stored in the transmission buffer 46A has been made successfully (YES in step S11), the process proceeds to step S12. If the transmission of the signal stored in the transmission buffer 46A has failed (NO in step S11), the process proceeds to step S13.

In step S12, the storage control unit <NUM> overwrites the transmission buffer 46A with a new signal. That is, the storage control unit <NUM> overwrites the transmission buffer 46A with a signal to be transmitted to a transmission destination that is different from the transmission destination of the signal stored in the transmission buffer 46B. When step S12 is completed, the process proceeds to step S13.

In step S13, the control unit <NUM> determines whether or not the transmission of the signal stored in the transmission buffer 46B has been made successfully. If the transmission of the signal stored in the transmission buffer 46B has been made successfully (YES in step S13), the process proceeds to step S14. When the transmission of the signal stored in the transmission buffer 46B has failed (NO in step S13), the process illustrated in <FIG> is completed.

In step S14, the storage control unit <NUM> overwrites the transmission buffer 46B with a new signal. That is, the storage control unit <NUM> overwrites the transmission buffer 46B with a signal to be transmitted to a transmission destination that is different from the transmission destination of the signal stored in the transmission buffer 46A. When step S14 is completed, the process shown in <FIG> is completed. The process shown in <FIG> may be performed repeatedly.

The operation of the base wireless device <NUM> according to the present embodiment will be described below with reference to <FIG> is a time chart illustrating an example of operation of the base wireless device according to the present embodiment.

<FIG> shows an example in which signals (data packets) DPA to DPC are stored in the standby buffer <NUM>. The signal DPA is a signal to be transmitted to a remote wireless device 16A among the plurality of remote wireless devices <NUM>. The signal DPB is a signal to be transmitted to a remote wireless device 16B among the plurality of remote wireless devices <NUM>. The signal DPC is a signal to be transmitted to a remote wireless device 16C among the plurality of remote wireless devices <NUM>. The symbol DP will be used when describing the signals in general, and the symbols DPA to DPC will be used when describing the individual signals.

The transmission buffer <NUM> stores a signal selected from the signals stored in the standby buffer <NUM> in accordance with priority. The time at which the signal DPA was acquired by the acquisition unit <NUM> is earlier than the time at which the signal DPB was acquired by the acquisition unit <NUM>. The time at which the signal DPB was acquired by the acquisition unit <NUM> is earlier than the time at which the signal DPC was acquired by the acquisition unit <NUM>. Therefore, the priority of the signal DPA is higher than that of the signal DPB. Further, the priority of the signal DPB is higher than the priority of the signal DPC. Therefore, the storage control unit <NUM> stores the signal DPA in the transmission buffer 46A. The storage control unit <NUM> also stores the signal DPB in the transmission buffer 46B. Since the number of transmission buffers <NUM> is two, the number of signals that can be simultaneously stored in a plurality of transmission buffers <NUM> is two. Therefore, the signal DPC is not stored in any of the transmission buffers <NUM> at this stage.

The signals DP stored in the plurality of transmission buffers <NUM> are transmitted in a predetermined order. In a hopping period Tfh(<NUM>), the signal DPA stored in the transmission buffer 46A is transmitted. Specifically, the signal DPA is transmitted from the base wireless device <NUM> to the remote wireless device 16A. <FIG> shows an example in which the transmission of the signal DPA fails in the hopping period Tfh(<NUM>).

In a hopping period Tfh(<NUM>) subsequent to the hopping period Tfh(<NUM>), the signal DPB stored in the transmission buffer 46B is transmitted. Specifically, the signal DPB is transmitted from the base wireless device <NUM> to the remote wireless device 16B. <FIG> shows an example in which the transmission of the signal DPB fails in the hopping period Tfh(<NUM>).

In a hopping period Tfh(<NUM>) subsequent to the hopping period Tfh(<NUM>), the signal DPA stored in the transmission buffer 46A is transmitted. Specifically, the signal DPA is transmitted from the base wireless device <NUM> to the remote wireless device 16A. <FIG> shows an example in which the transmission of the signal DPA has been made successfully in the hopping period Tfh(<NUM>). When the transmission of the signal DPA stored in the transmission buffer 46A has been made successfully, the transmission buffer 46A is overwritten with the signal DPC.

In a hopping period Tfh(<NUM>) subsequent to the hopping period Tfh(<NUM>), the signal DPC stored in the transmission buffer 46A is transmitted. Specifically, the signal DPC is transmitted from the base wireless device <NUM> to the remote wireless device 16C. <FIG> shows an example in which the transmission of the signal DPC has been made successfully in the hopping period Tfh(<NUM>).

In a hopping period Tfh(<NUM>) subsequent to the hopping period Tfh(<NUM>), the signal DPB stored in the transmission buffer 46B is transmitted. Specifically, the signal DPB is transmitted from the base wireless device <NUM> to the remote wireless device 16B. <FIG> shows an example in which the transmission of the signal DPB has been made successfully in the hopping period Tfh(<NUM>). In this way, the transmission of the signals DP may be carried out sequentially.

If the number of transmission buffers <NUM> is only one, the signal DPC cannot be transmitted until after the transmission of the signal DPB has been made successfully or until after the number of retries of the transmission of the signal DPB reaches a predetermined number. In contrast, since the plurality of transmission buffers <NUM> are provided in the present embodiment, even if transmission of the signal DPB has failed, the signal DPC may be transmitted. Therefore, as illustrated in <FIG>, the signal DPC may be successfully transmitted before the signal DPB is successfully transmitted. As described above, according to the present embodiment, rapid wireless communication can be realized.

For example, in the above-described embodiment, although an exemplary case has been described in which the number of transmission buffers <NUM> is two, the present invention is not necessarily limited to this feature. The number of transmission buffers <NUM> may be three or more.

The above-described embodiments can be summarized in the following manner.

The base wireless device (<NUM>) carries out transmission and reception of signals to and from the plurality of remote wireless devices (<NUM>), and includes the plurality of transmission buffers (46A, 46B) configured to store a plurality of signals to be transmitted to the plurality of remote wireless devices, the plurality of signals having transmission destinations that are different from each other, the transmission processing unit (26A) configured to transmit the signals to the plurality of remote wireless devices respectively, by transmitting the signals stored in the plurality of transmission buffers in a predetermined order, regardless of whether or not each transmission has been made successfully, and the storage control unit (<NUM>), wherein when the transmission of the signal (DPA) stored in one of the transmission buffers (46A) has been made successfully, the storage control unit is configured to overwrite the one transmission buffer (46A) from which the transmission has been made successfully, with other signal (DPC) to be transmitted to the transmission destination (16C) that is different from the transmission destination (16B) of the signal (DPB) stored in the transmission buffer (46B) other than the one transmission buffer (46A) from which the transmission has been made successfully, among the plurality of transmission buffers. If the number of transmission buffers is only one, another signal cannot be transmitted until after the transmission of one signal has been made successfully or until after the number of retries of the transmission of the signal DPB has reached a predetermined number. On the other hand, in the configuration of the present invention, since a plurality of transmission buffers are provided, even when transmission of one signal has failed, transmission of another signal can be carried out. Therefore, before one signal is successfully transmitted, another signal can be transmitted successfully. According to such a configuration, rapid wireless communication can be realized.

The base wireless device further includes the standby buffer (<NUM>) configured to store a plurality of signals supplied from the computer (<NUM>) connected by the fieldbus (<NUM>), wherein the storage control unit stores, in the transmission buffers, signals selected from the signals stored in the standby buffer in accordance with priority. According to such a configuration, signal transmission can be accurately carried out.

Claim 1:
A base wireless device (<NUM>) that carries out transmission and reception of signals to and from a plurality of remote wireless devices (<NUM>), comprising:
a plurality of transmission buffers (46A, 46B) configured to store a plurality of signals to be transmitted to the plurality of remote wireless devices, the plurality of signals having transmission destinations that are different from each other, wherein each of the plurality of transmission buffers is capable of storing different signals to be transmitted to different transmission destinations;
a transmission processing unit (26A) configured to transmit the signals to the plurality of remote wireless devices respectively, by transmitting the signals stored in the plurality of transmission buffers in a predetermined order, regardless of whether or not each transmission has been made successfully; and
a storage control unit (<NUM>), wherein when a transmission of a signal (DPA) stored in one of the transmission buffers (46A) has been made successfully, the storage control unit is configured to overwrite the one transmission buffer (46A) from which the transmission has been made successfully, with another signal (DPC) to be transmitted to a transmission destination (16C) that is different from a transmission destination (16B) of a signal (DPB) stored in a transmission buffer (46B) other than the one transmission buffer (46A) from which the transmission has been made successfully, among the plurality of transmission buffers.