Radio systems and radios

Abstract

To provide a wireless system and a wireless device capable of suppressing complication of configuration and more quickly changing communication channels of the entire network.SOLUTION: A wireless system comprises multiple wireless devices WD. The wireless device WD includes: a second communication unit 32 for transmitting "RIT Data Response" by specifying another wireless device WD when there is information to be transmitted to the another wireless device WD when receiving "RIT Data Request" from the another wireless device WD; a first determination unit 40 for determining whether it is in a wireless wave interference state; a third communication unit 33 for adding channel switching information to "RIT Data Response" to transmit the same, not in the specified state of the another wireless device WD only but to the surroundings when receiving "RIT Data Request" from the another wireless device WD when it is in the wireless wave interference state; and a channel switching unit 60 for switching the channel thereof, after transmitting the channel switching information.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a radio system and a radio device. [Background technology]

[0002] A wireless system has been proposed that includes a wireless slave device provided in a home equipment device, a center side device that collects various data of the home equipment device, and a wireless master device that communicates with the wireless slave device via a wireless line to collect various data of the home equipment device and also communicates with the center side device via the line (see, for example, Patent Document 1). In this wireless system, the wireless master device has a carrier busy count unit that periodically checks the radio wave conditions. Therefore, when a busy state is detected on the frequency used for communication, the wireless master device reports information to that effect to the center side device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2004-180105 A Summary of the Invention [Problem to be solved by the invention]

[0004] Here, the inventors of the present invention are considering changing the frequency used for wireless communication (changing the communication channel) when a busy state (radio wave interference state) is detected as in the wireless system described in Patent Document 1.

[0005] However, when changing the communication channel, it is necessary to change it quickly for all of the multiple wireless devices in the network. In other words, if it takes a long time to change the communication channel, wireless devices that have changed the communication channel and wireless devices that have not changed the channel will be mixed until the change is completed, which may cause communication problems in the network.

[0006] Therefore, in order to change the communication channel, it is conceivable to mount another device capable of communication. For example, if communication between wireless devices is normally performed in a specific frequency band, and a separate device that communicates in a frequency band separate from the specific frequency band is mounted on each of the multiple wireless devices, then when radio interference occurs, the separate device can be used to disseminate communication channel change information throughout the network, thereby changing the communication channel throughout the entire network.

[0007] In this case, however, it is necessary to mount another device, which leads to a complicated configuration.

[0008] The present invention has been made to solve such problems, and its object is to provide a wireless system and wireless device that can reduce the complexity of the configuration and more quickly change the communication channel of the entire network. [Means for solving the problem]

[0009] A wireless system according to the present invention is a wireless system in which information can be transmitted and received within a network configured with a plurality of wireless devices, a specific wireless device among the plurality of wireless devices can transmit and receive information to and from a center side, and non-specific wireless devices among the plurality of wireless devices other than the specific wireless device transmit and receive information to and from the specific wireless device via or without passing through other non-specific wireless devices, and transmit and receive information to and from the center side through the specific wireless device, wherein the wireless device has a first communication unit that transmits first information to the surroundings, and a first communication unit that transmits the first information to the surroundings when the first information is received from another wireless device and there is information that needs to be transmitted to a source of the first information. The wireless communication device includes a second communication unit that transmits second information by specifying an information transmission source and thereafter transmits and receives information with the transmission source of the first information, an interference determination unit that determines whether the wireless communication device itself is in a radio wave interference state based on the radio wave strength of a channel currently in use, and a third communication unit that, when the interference determination unit determines that the wireless communication device itself is in a radio wave interference state, adds channel switching information to the second information or transmits channel switching information in place of the second information when the wireless communication device receives the first information from another wireless device, rather than only specifying the transmission source of the first information, and a channel switching unit that switches the wireless communication device's own channel after transmitting the channel switching information by the third communication unit.

[0010] The radio device of the present invention includes a first communication unit that transmits first information to the surroundings, a second communication unit that, when receiving the first information from another radio device, specifies a source of the first information and transmits second information when there is information that needs to be transmitted to the source of the first information, and thereafter transmits and receives information with the source of the first information, an interference determination unit that determines whether the radio device itself is in a state of radio wave interference based on the radio wave strength of a channel currently in use, a third communication unit that, when the interference determination unit determines that the radio device itself is in a state of radio wave interference, adds channel switching information to the second information or transmits channel switching information instead of the second information to the surroundings rather than specifying only the source of the first information when the radio device receives the first information from the other radio device, and a channel switching unit that switches its own channel after transmitting the channel switching information by the third communication unit. Effect of the Invention

[0011] According to the present invention, information to be transmitted is transmitted and received through transmission and reception of first information and second information, and if it is determined that radio wave interference exists, when the first information is received from another wireless device, channel switching information is transmitted in addition to or instead of the second information. Therefore, the channel switching information is transmitted in the same manner as when normal information is transmitted and received, and it is possible to prevent the configuration from becoming complicated as in the case where a separate device is provided.

[0012] Furthermore, when transmitting and receiving the first information and the second information, the second information is normally transmitted by specifying the source of the first information, but when there is radio interference, the channel switching information is transmitted in addition to or instead of the second information without specifying the source of the first information. Therefore, the channel switching information is received not only by the wireless device that transmitted the first information, but also by other wireless devices in the vicinity. Therefore, the channels of the surrounding wireless devices can be switched collectively, and the communication channel of the entire network can be changed more quickly.

[0013] Therefore, it is possible to provide a wireless system and a wireless device that can suppress the complexity of the configuration and can change the communication channel of the entire network more quickly. [Brief description of the drawings]

[0014] [Figure 1] 1 is a configuration diagram showing a wireless system according to an embodiment of the present invention. [Diagram 2] 2 is a functional block diagram showing the configuration of each of the multiple wireless devices shown in FIG. 1. [Diagram 3] 4 is a conceptual diagram showing how information is transmitted and received by a first communication unit. FIG. [Figure 4] 4 is a conceptual diagram showing transmission and reception of information by a first communication unit and a second communication unit. FIG. [Diagram 5] FIG. 1 is a conceptual diagram showing how information is transmitted and received in a radio wave interference state. [Figure 6]1 is a conceptual diagram showing how a wireless device that has received channel switching information from a wireless device in a radio interference state transmits and receives information; [Figure 7] 4 is a conceptual diagram showing transmission and reception of information when a second determination unit determines a radio wave interference state. FIG. [Figure 8] FIG. 11 is a conceptual diagram showing channel switching by a wireless device constituting a wireless system according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] The present invention will be described below along with preferred embodiments. Note that the present invention is not limited to the embodiments shown below, and can be modified as appropriate within the scope of the present invention. In addition, in the embodiments shown below, some configurations are omitted from illustration and description, but it goes without saying that publicly known or well-known technologies are appropriately applied to the details of the omitted technologies within the scope of no contradiction with the contents described below.

[0016] Fig. 1 is a configuration diagram showing a wireless system according to an embodiment of the present invention. As shown in Fig. 1, the wireless system 1 according to the embodiment includes a plurality of connection devices M, a plurality of wireless devices WD, and a center side device CA.

[0017] The multiple connection devices M are gas meters, gas alarm devices, etc., and are connected to each wireless device WD by, for example, wires. These connection devices M transmit information to the center side device CA via the multiple wireless devices WD, and receive information from the center side device CA via the multiple wireless devices WD. Information transmitted from the connection devices M to the center side device CA corresponds to, for example, meter reading information and fault information of the gas meter, and alarm information and fault information of the gas alarm device. Information received from the center side device CA corresponds to, for example, information to open and close the shutoff valve of the gas meter, audio information output from the gas alarm device, etc.

[0018] The multiple wireless devices WD are capable of wirelessly transmitting and receiving information to and from other wireless devices WD within a network configured with the multiple wireless devices WD. The multiple wireless devices WD include a specific wireless device WD1. The specific wireless device WD1 is capable of transmitting and receiving information to and from a center side device CA via a line in accordance with a communication standard such as LTE (Long Term Evolution).

[0019] Among the multiple wireless devices WD, the non-specific wireless device WD2, excluding the specific wireless device WD1, is capable of transmitting and receiving information to and from the center side device CA via the specific wireless device WD1. To explain in more detail, for example, the first wireless device WD21 transmits and receives information to and from the center side device CA only via the specific wireless device WD1 without having any other non-specific wireless device WD2. The second wireless device WD22 transmits and receives information to and from the specific wireless device WD1 via the first wireless device WD21, and transmits and receives information to and from the center side device CA via the specific wireless device WD1. Furthermore, the third wireless device WD23 transmits and receives information to and from the specific wireless device WD1 via the first wireless device WD21 and the second wireless device WD22, and transmits and receives information to and from the center side device CA via the specific wireless device WD1.

[0020] Fig. 2 is a functional block diagram showing the configuration of each of the multiple wireless devices WD shown in Fig. 1. As shown in Fig. 2, each wireless device WD includes an input unit 10, an output unit 20, a communication unit 30, a first determination unit (interference determination unit) 40, a second determination unit (second interference determination unit) 50, and a channel switching unit 60.

[0021] The input unit 10 inputs information to be transmitted to the center side device CA (see FIG. 1) from the connected connection device M (see FIG. 1). When information is input by the input unit 10, the wireless device WD determines that there is information to be transmitted. Furthermore, when information to be transmitted is received from another wireless device WD, the wireless device WD also determines that there is information to be transmitted.

[0022] The output unit 20 outputs information transmitted from the center side device CA to the connected connection device M. The connection device M receives information from the output unit 20 of the wireless device WD and executes control according to the received information.

[0023] The communication unit 30 is a functional unit that performs wireless communication with other wireless devices WD. The communication unit 30 includes a first communication unit 31, a second communication unit 32, a third communication unit 33, a fourth communication unit 34, and a fifth communication unit 35.

[0024] The first communication unit 31 transmits a "RIT Data Request" (first information) to the surroundings. This "RIT Data Request" is beacon information that allows the wireless device WD to inform other wireless devices WD of its presence. When the first communication unit 31 of the wireless device WD transmits a "RIT Data Request", the wireless device WD enters a short-time reception state (short reception state). Furthermore, when the wireless device WD wirelessly receives a "RIT Data Request" from another wireless device WD, it can recognize that it is capable of communicating with the other wireless device WD.

[0025] FIG. 3 is a conceptual diagram showing how information is transmitted and received by the first communication unit 31. FIG. 3 illustrates an example of a wireless device A that is one of the multiple wireless devices WD and a wireless device B that is the other. The first communication unit 31 of the wireless device A (see FIG. 2) transmits a "RIT Data Request" at a specific period. As shown in FIG. 3, the first communication unit 31 of the wireless device A enters a short reception state after transmitting the "RIT Data Request". This short reception state is a state in which the first communication unit 31 waits for a reply to the "RIT Data Request" ("RIT Data Response" described later). In this way, the wireless device A transmits a "RIT Data Request" periodically by the first communication unit 31, and enters the short reception state after each transmission.

[0026] The same applies to the wireless device B. That is, the wireless device B periodically transmits a "RIT Data Request" via the first communication unit 31, and enters a short reception state every time the wireless device B transmits.

[0027] Referring again to Fig. 2, the second communication unit 32 replies when it receives a "RIT Data Request" from another wireless device WD and has information to be transmitted. At this time, the second communication unit 32 specifies the sender of the "RIT Data Request" and replies with a "RIT Data Response" (second information) as an SREQ (request to transmit). In particular, when the second communication unit 32 receives a "RIT Data Request" from another wireless device WD while it has information to be transmitted, it replies quickly so that the "RIT Data Response" arrives while the other wireless device WD is in a short reception state.

[0028] Fig. 4 is a conceptual diagram showing how information is transmitted and received by the first communication unit 31 and the second communication unit 32. In Fig. 4, radio devices A and B are used as examples. As described with reference to Fig. 3, radio devices A and B periodically transmit "RIT Data Requests" and enter a short reception state after each transmission. Here, assume that radio device B has information that needs to be transmitted and should be transmitted to radio device A. In this case, the first communication unit 31 (see Fig. 2) of radio device B stops the periodic transmission of "RIT Data Requests" and enters a reception state in which it waits for a "RIT Data Request" from radio device A.

[0029] Next, when wireless device B receives the "RIT Data Request" from wireless device A, it quickly transmits a "RIT Data Response" to wireless device A (while wireless device A is in the short receive state). Then, wireless device A receives the "RIT Data Response" from wireless device B.

[0030] In this way, when wireless device A is in a short reception state, wireless device B transmits a "RIT Data Response" and wireless device A receives it, thereby establishing one-to-one communication between the two devices (i.e., a unicast state).

[0031] Please refer to Fig. 2 again. As shown in Fig. 2, the second communication unit 32 includes first to third functional units 32a to 32c. As described above, when one-to-one communication is established, the second communication unit 32 transmits and receives information between both wireless devices WD by the first to third functional units 32a to 32c.

[0032] When the first functional unit 32a receives a “RIT Data Response” from another wireless device WD, it transmits a “RACK” (request information) to the other wireless device WD that is the sender of the “RIT Data Response” to request information to be transmitted.

[0033] When the second functional unit 32b receives a "RACK" from another wireless device WD, it transmits "DATA", which is information to be transmitted, to the other wireless device WD that is the source of the "RACK".

[0034] The third functional unit 32c, when receiving "DATA (information to be transmitted)" from another wireless device WD, transmits "DACK" (acknowledgement information) to the other wireless device WD that is the sender of the information to be transmitted.

[0035] Referring again to Fig. 4, as described above, when wireless device A is in a short reception state, wireless device B transmits a "RIT Data Response" and wireless device A receives it, thereby establishing one-to-one communication between the two devices. After that, the first functional unit 32a of wireless device A transmits a "RACK" specifying wireless device B. When the second functional unit 32b of wireless device B receives the "RACK", it transmits "DATA" specifying wireless device A. Next, when the third functional unit 32c of wireless device A receives the "DATA", it transmits a "DACK" specifying wireless device B.

[0036] As described above, as shown in Fig. 4, the transmission-required information of the wireless device B is transmitted to the wireless device A. After that, the wireless device A transmits the transmission-required information to the specific wireless device WD1 via another non-specific wireless device WD2, etc. When the specific wireless device WD1 receives the transmission-required information, it transmits the transmission-required information to the center side device CA via a base station, etc.

[0037] Referring again to FIG. 2, the first determination unit 40 determines whether or not it is in an interference state based on the radio wave strength of the channel currently in use (performs what is called carrier sense). Here, the wireless device WD described above may be in a radio wave interference state in which it is difficult to transmit and receive information depending on the surrounding environment. For this reason, the first determination unit 40 determines whether or not it is in a radio wave interference state based on whether or not the surrounding radio wave strength is equal to or greater than a predetermined value.

[0038] Here, it is preferable that the first determination unit 40 makes a determination when transmitting information. Specifically, the wireless device WD determines whether or not there is radio wave interference based on the radio wave intensity of the currently used channel when the first communication unit 31 transmits an "RIT Data Request." The first determination unit 40 also determines whether or not there is radio wave interference when the first functional unit 32a to the third functional unit 32c transmit information.

[0039] When the first determination unit 40 determines that there is radio wave interference, the first communication unit 31 and the first to third functional units 32a to 32c are prohibited from transmitting information.

[0040] In such a radio wave interference state, it is necessary to switch the currently used channel, and it is preferable to switch channels quickly throughout the entire network. However, providing a dedicated device for switching would lead to a complex configuration. Therefore, the wireless system 1 according to this embodiment is provided with a third communication unit 33 and a fourth communication unit 34 to execute channel switching using the information transmission and reception method shown in FIG.

[0041] 2 transmits channel switching information when the radio interference weakens by chance and the third communication unit 33 can receive an "RIT Data Request" from another radio device WD if the first determination unit 40 determines that the radio device WD is in a radio interference state. At this time, the third communication unit 33 adds the channel switching information to the "RIT Data Response" and transmits it to the surroundings without designating the other party as the sender.

[0042] More specifically, when there is no radio interference, the second communication unit 32 designates the other party as the sender of the "RIT Data Request" and transmits the "RIT Data Response." On the other hand, when there is radio interference, the third communication unit 33 adds channel switching information to the "RIT Data Response" without designating the other party as the sender and transmits it to the surroundings.

[0043] This makes it possible to transmit channel switching information to other wireless devices WD located within a communicable distance from the wireless device WD (that is, to devices other than the source of the "RIT Data Request").

[0044] Fig. 5 is a conceptual diagram showing the transmission and reception of information in a radio wave interference state. In Fig. 5, an example will be described using radio devices A and B. First, it is assumed that the first communication unit 31 (see Fig. 2) of radio device A periodically transmits a "RIT Data Request", and the first determination unit 40 (see Fig. 2) of radio device B determines that it is in a radio wave interference state.

[0045] When there is radio interference, radio device B generally cannot receive the "RIT Data Request" from radio device A. However, there may be times when the radio interference weakens temporarily, at which point radio device B can receive the "RIT Data Request" from radio device A.

[0046] When the first determination unit 40 determines that radio wave interference exists and receives a "RIT Data Request" from wireless device A, the third communication unit 33 of wireless device B (see FIG. 2) adds channel switching information to the "RIT Data Response" and transmits it in time for wireless device A's short reception state. In particular, the third communication unit 33 does not perform so-called unicasting, but transmits the channel switching information to the surroundings by broadcasting or multicasting. As a result, the channel switching information is received by many surrounding wireless devices WD.

[0047] In this case, no information is transmitted or received by the first functional unit 32a to the third functional unit 32c (see FIG. 2). However, if the radio device B has information that needs to be transmitted, communication may be performed by the first functional unit 32a to the third functional unit 32c.

[0048] 2 again. The channel switching unit 60 switches the channel of its own wireless device WD after the third communication unit 33 transmits the channel switching information. In this embodiment, for example, communication is possible through two communication channels, and the channel switching unit 60 switches from the currently used channel to the other channel.

[0049] Furthermore, the wireless device WD according to this embodiment is configured to quickly switch channels in the network by the fourth communication unit 34. When the fourth communication unit 34 receives channel switching information from another wireless device WD, it transmits the channel switching information to the surroundings. In this embodiment, it is assumed that the fourth communication unit 34 transmits the channel switching information together with the transmission of "DATA".

[0050] Fig. 6 is a conceptual diagram showing the state of information transmission and reception by a wireless device WD that has received channel switching information from a wireless device WD in a radio wave interference state. In Fig. 6, an example will be described in which a wireless device A that has received channel switching information and another wireless device C have received the channel switching information.

[0051] First, it is assumed that the wireless device A receives channel switching information from the wireless device B as described with reference to FIG. 5. It is also assumed that the wireless device A holds the transmission-required information. In this case, the wireless device A replies with a "RIT Data Response" in response to the "RIT Data Request" from the wireless device C. Next, when the wireless device A receives a "RACK" from the wireless device C, it replies with the transmission-required information (DATA). At this time, the fourth communication unit 34 (see FIG. 2) of the wireless device A adds the channel switching information to the transmission-required information and transmits it. In addition, the fourth communication unit 34 transmits this transmission-required information to the surroundings by broadcast or multicast. As a result, the channel switching information is received by the surrounding wireless devices WD other than the wireless device C. Note that the transmission-required information is not necessary for the surrounding wireless devices WD other than the wireless device C, so it may be discarded. However, in consideration of the instability of communication accompanying channel switching, it may be transmitted to the other wireless devices WD without discarding it. 6. When the wireless device C receives the transmission requirement information and the channel switching information, it executes processing for the upper wireless device WD (the wireless device WD on the center side) and the like, in the same manner as the wireless device A shown in FIG.

[0052] Next, the wireless device A adds the channel switching information to the transmission-required information and transmits it, and then receives a "DACK" from the wireless device C. When the channel switching unit 60 of the wireless device A confirms the reception of the "DACK", it switches the channel.

[0053] In the example shown in Fig. 6, the channel switching information is transmitted together with "DATA", but this is not limited to this. For example, when a "RIT Data Request" is received from another wireless device WD (not limited to wireless device C), the channel switching information may be transmitted by broadcast or multicast together with a "RIT Data Response". This is possible because the channel switching information can be spread to the surroundings even if the wireless device WD does not have information to be transmitted.

[0054] In addition, in the example shown in Fig. 6, when the wireless device A has the channel switching information and the transmission required information, the information shown in Fig. 6 is transmitted and received, but this is not limiting, and the wireless device A may transmit and receive the information shown in Fig. 6 when it has the channel switching information but does not have the transmission required information. In this case, the wireless device A will broadcast or multicast only the channel switching information without transmitting "DATA".

[0055] 2 again. Furthermore, the wireless system 1 according to the present embodiment not only allows the wireless device WD to determine its own radio wave interference state by the first determination unit 40, but also includes the second determination unit 50, which allows the wireless device WD to determine whether another wireless device WD is in a radio wave interference state.

[0056] More specifically, the second judgment unit 50 judges that the other wireless device WD is in a state of radio interference when it receives a "RIT Data Response" from the other wireless device WD and sends a "RACK" but is unable to receive "DATA" (when there is no reply).

[0057] Moreover, the wireless device WD according to this embodiment includes a fifth communication unit 35, and when the second determination unit 50 determines that there is radio interference from another wireless device WD, the fifth communication unit 35 transmits channel switching information to the surroundings. At this time, when the fifth communication unit 35 receives a "RIT Data Request" from a wireless device WD other than itself, it adds the channel switching information to a "RIT Data Response" and transmits the channel switching information to the surroundings by broadcast transmission or multicast transmission.

[0058] 7 is a conceptual diagram showing how information is transmitted and received when the second determining unit 50 determines the state of radio interference. In FIG. 7, wireless devices A and B will also be described as an example.

[0059] First, wireless device A periodically transmits a "RIT Data Request" and enters a short reception state each time it transmits. Now, assume that wireless device B has transmission information to send to wireless device A. In this case, when wireless device B receives a "RIT Data Request" from wireless device A, it transmits a "RIT Data Response" while wireless device A is in the short reception state. After that, wireless device A transmits a "RACK" to wireless device B.

[0060] Next, it is assumed that the wireless device B receives the "RACK" and transmits "DATA" to the wireless device A, but the "DATA" is not received by the wireless device A. At this time, the second determination unit 50 of the wireless device A determines that the wireless device B is in a radio wave interference state.

[0061] After that, it is assumed that the wireless device A receives a "RIT Data Request" from a wireless device WD other than itself (it can be wireless device B). As a result, the fifth communication unit 35 of the wireless device A adds channel switching information to the "RIT Data Response" and transmits the channel switching information to the surroundings by broadcasting or multicasting. As a result, the wireless device A can determine the radio wave interference state of the wireless device B and transmit the channel switching information to the surroundings.

[0062] Next, the operation of the wireless system 1 according to this embodiment will be described. First, each wireless device WD shown in Fig. 1 periodically transmits a "RIT Data Request" as shown in Fig. 3. Here, for example, assume that a gas alarm device (connected device M) connected to the third wireless device WD23 detects a gas leak and issues an alarm. In this case, the input unit 10 of the third wireless device WD23 inputs alarm information as information to be transmitted. Then, the third wireless device WD23 enters a receiving state in which it waits for a "RIT Data Request" from the second wireless device WD22, which is a higher-level device, in order to transmit information to be transmitted to the center-side device CA, as shown in Fig. 4.

[0063] Next, when the third wireless device WD23 receives a "RIT Data Request" from the second wireless device WD22, the first communication unit 31 of the third wireless device WD23 replies with a "RIT Data Response" in time for the second wireless device WD22 to enter a short reception state. After that, the first functional unit 32a of the second wireless device WD22 transmits a "RACK" by designating the third wireless device WD23, and the second functional unit 32b of the third wireless device WD23 transmits a "DATA" by designating the second wireless device WD22. Next, the third functional unit 32c of the second wireless device WD22 transmits a "DACK" by designating the third wireless device WD23. As a result, the alarm information of the third wireless device WD23 ("DATA" which is information to be transmitted) is transmitted to the second wireless device WD22.

[0064] Thereafter, the second wireless device WD22 performs communication similar to that of the first wireless device WD21 to transmit the alarm information to the first wireless device WD21, and the first wireless device WD21 performs communication similar to that of the specific wireless device WD1 to transmit the alarm information to the specific wireless device WD1. The specific wireless device WD1 transmits the alarm information to the center side device CA via a base station or the like in accordance with a communication standard such as LTE.

[0065] In addition, the center side device CA that receives such alarm information transmits shutoff information ("DATA", which is information that needs to be transmitted) to a specific wireless device WD1 via a base station, etc., in order to close the shutoff valve of, for example, a gas meter (connected device M) connected to the second wireless device WD22.

[0066] The specific wireless device WD1 transmits the shutoff information to the second wireless device WD22 via the first wireless device WD21 in the same manner as described above. The second wireless device WD22 that receives the shutoff information transmits the shutoff information to the gas meter via the output unit 20. This causes the gas meter to close its own shutoff valve.

[0067] In the process of transmitting and receiving such information, for example, assume that the second wireless device WD22 transmits a "RACK" to the first wireless device WD21 but does not return a "DATA." In this case, the second determination unit 50 of the second wireless device WD22 determines that the first wireless device WD21, which is the other party in the unicast communication, is in a radio wave interference state, as shown in FIG.

[0068] Then, the second wireless device WD22 receives a "RIT Data Request" from another wireless device WD. At this time, the fifth communication unit 35 of the second wireless device WD22 adds channel switching information to the "RIT Data Response" and transmits the channel switching information to the surroundings by broadcasting or multicasting. As a result, the channel switching information is transmitted not only to the first wireless device WD21, which was the communication partner of the second wireless device WD22, but also to the surrounding wireless devices WD. The channel switching unit 60 of the second wireless device WD22 switches the channel after transmitting the channel switching information.

[0069] Furthermore, apart from the above-mentioned transmission and reception process of the required transmission information, the first determination unit 40 of each wireless device WD determines whether it is in a radio wave interference state. Here, it is assumed that the first determination unit 40 of the second wireless device WD22 determines that it is in a radio wave interference state. In this case, when the radio wave interference of the second wireless device WD22 temporarily weakens and the second wireless device WD22 is able to receive a "RIT Data Request" from another wireless device WD, the second wireless device WD22 adds channel switching information to the "RIT Data Response" and transmits the channel switching information to the surroundings by broadcasting or multicasting. As a result, for example, the first wireless device WD21 and the third wireless device WD23 that are present near the second wireless device WD22 receive the channel switching information. The channel switching unit 60 of the second wireless device WD22 switches the channel after transmitting the channel switching information.

[0070] The first wireless device WD21 that has received the channel switching information is in a holding state of the channel switching information, and when it receives transmission-required information from another wireless device WD or inputs transmission-required information from the connected device M via the input unit 10, it transmits and receives the information shown in FIG. 6. That is, the first wireless device WD21 receives, for example, a "RIT Data Request" from a specific wireless device WD1 and returns a "RIT Data Response." Next, when it receives a "RACK" from the specific wireless device WD1, the fourth communication unit 34 adds the channel switching information to the "DATA" and performs broadcast communication or multicast communication. As a result, the channel switching information is received not only by the specific wireless device WD1 but also by other wireless devices WD in the vicinity. The channel switching unit 60 of the first wireless device WD21 switches the channel after transmitting the channel switching information.

[0071] In this way, according to the wireless system 1 and wireless device WD of this embodiment, information that needs to be transmitted is transmitted and received through transmission and reception of a "RIT Data Request" and a "RIT Data Response." If it is determined that a state of radio wave interference exists, when a "RIT Data Request" is received from another wireless device WD, channel switching information is transmitted in addition to or instead of the "RIT Data Response." This means that the channel switching information is transmitted in the same manner as when normal information is transmitted and received, and it is possible to prevent the configuration from becoming complicated as in the case where another device is provided.

[0072] Furthermore, when transmitting and receiving a "RIT Data Request" and a "RIT Data Response," the "RIT Data Response" is normally sent specifying the sender of the "RIT Data Request," but when there is radio interference, the "RIT Data Response" is sent in addition to the "RIT Data Response" without specifying the sender of the "RIT Data Request." As a result, the channel switching information is received not only by the wireless device WD that sent the "RIT Data Request," but also by other wireless devices WD in the vicinity. This makes it possible to switch channels of the surrounding wireless devices WDs all at once, making it possible to change the communication channel of the entire network more quickly.

[0073] Therefore, it is possible to provide a wireless system 1 that can suppress the complexity of the configuration and can more quickly change the communication channel of the entire network.

[0074] Furthermore, when a wireless device WD receives channel switching information from another wireless device WD, it transmits the channel switching information to the surroundings and switches the channel of its own wireless device WD after the transmission. Therefore, not only can the wireless device WD in a radio interference state transmit channel switching information to the surroundings, but also to the wireless device WD that received the channel switching information from that wireless device WD, so that the communication channel of the entire network can be changed more quickly.

[0075] Also, when a "RIT Data Response" is received from another wireless device WD, if the wireless device WD transmits a "RACK" to the other wireless device WD requesting a reply of the transmission-required information (DATA) but does not receive the transmission-required information from the other wireless device WD, the wireless device WD determines that the other wireless device WD is in a radio interference state. Therefore, when there is no radio interference, the reception of the "RIT Data Response", the transmission of the "RACK", and the reception of "DATA" should normally be consecutive, but the inability to receive "DATA" means that the other wireless device WD has suddenly entered a radio interference state. Therefore, when it is unable to receive "DATA", it is possible to determine that the other wireless device WD is in a radio interference state and transmit channel switching information from the wireless devices WD around the wireless device WD in the radio interference state.

[0076] Next, a second embodiment of the present invention will be described. The wireless system according to the second embodiment is similar to that of the first embodiment, but some of the processing content is different.

[0077] Fig. 8 is a conceptual diagram showing channel switching by a wireless device WD constituting a wireless system 1 according to the second embodiment. In Fig. 8, wireless devices A to C, which are one of the wireless devices WD, will be described as an example. It is assumed that the wireless device B is in a state of radio interference. Also, the bars extending from the wireless devices A to C shown in Fig. 8 are filled with white and black, with the white bars indicating the channel before switching and the black bars indicating the channel after switching.

[0078] First, it is assumed that the first determination unit 40 of the wireless device B determines that the wireless device B is in a radio wave interference state. As a result, the third communication unit 33 of the wireless device B adds channel switching information to the "RIT Data Response" and transmits it by broadcast or multicast, in the same manner as described with reference to Fig. 5. The wireless device B that transmitted the channel switching information switches the channel.

[0079] The fourth communication unit 34 of the wireless device A that has received the channel switching information adds the channel switching information to "DATA" and broadcasts or multicasts it, for example, in the same manner as described with reference to Fig. 6. The wireless device A that has transmitted the channel switching information switches the channel. Furthermore, in the second embodiment, after the channel is switched, the fourth communication unit 34 of the wireless device A broadcasts or multicasts the channel switching information again on the channel after the channel is switched. That is, when the fourth communication unit 34 receives channel switching information from another wireless device WD, it transmits the channel switching information to the surroundings on two channels, one before and one after the channel is switched.

[0080] 8, it is assumed that the channel switching information transmitted on the channel before switching does not reach wireless device C due to an accidental deterioration of the radio wave environment. In this case, since the channel has not been switched, wireless device C cannot receive the channel switching information transmitted on the channel after switching, and there is a possibility that wireless device C will be isolated without switching channels.

[0081] Therefore, in this embodiment, the third communication unit 33 of the wireless device B executes a recovery process of transmitting channel switching information again on two channels before and after the channel switching after switching its own channel by the channel switching unit 60. This makes it possible to transmit channel switching information again on the channel before switching to a wireless device WD that is in an isolated state without switching the channel, such as wireless device C.

[0082] Even if the isolated wireless device WD is not at a distance from the wireless device B where the channel switching information can reach it directly, the channel switching information can be made to reach the wireless device C via the wireless device A as shown in Fig. 8. That is, as described above, when the fourth communication unit 34 of the wireless device A receives the channel switching information, it transmits the channel switching information on two channels, one before and one after the switching. Therefore, when the channel switching information is received by the recovery process of the wireless device B, the channel switching information is broadcast or multicast from the wireless device A on the two channels, one before and one after the switching, and the isolated wireless device C can receive the channel switching information on the channel before the switching.

[0083] In this way, in the wireless system 1 according to the second embodiment, for a wireless device WD that has been determined by the first judgment unit 40 to be in a state of radio wave interference, even after the channel switching information has been broadcast or multicast transmitted to switch channels, the channel switching information is again broadcast or multicast transmitted on the two channels before and after the switch by a recovery process.

[0084] Moreover, in the wireless system 1 according to the second embodiment, for a wireless device WD that receives channel switching information, the channel switching information is broadcast or multicast on two channels, one before and one after the switching. Therefore, even if the channel switching information is received by the recovery process, the channel switching information is broadcast or multicast on two channels, one before and one after the switching, and the channel switching information is spread on two channels. As a result, the channels are quickly switched for all wireless devices WD in the network so that no isolated wireless device WD occurs.

[0085] In this way, the wireless system 1 and the wireless device WD according to the second embodiment can achieve the same effects as those of the first embodiment.

[0086] Furthermore, according to the second embodiment, the third communication unit 34 executes a recovery process, so that it becomes possible to transmit channel switching information to the surroundings again to a radio device WD that is isolated because it cannot receive the channel switching information, and therefore it is possible to more reliably switch communication channels throughout the network.

[0087] Furthermore, for a radio device WD that has received channel switching information, the fourth communication unit 34 transmits the channel switching information to the surrounding area on two channels, one before and one after the switching. Therefore, even if an isolated radio device WD is not within a distance where it can receive the channel switching information through recovery processing, the radio device WD that received the channel switching information will relay it, making it possible to switch communication channels even more reliably.

[0088] The present invention has been described above based on an embodiment, but the present invention is not limited to the above embodiment, and modifications may be made without departing from the spirit of the present invention, and known or well-known technologies may be combined to the extent possible.

[0089] For example, in the above embodiment, the channel switching information is added to the "RIT Data Response" or added to "DATA" and transmitted, but it is not limited to being added, and may be transmitted instead of the "RIT Data Response" or "DATA".

[0090] Also, the number of connection devices M connected to one wireless device WD may not be one, but multiple connection devices M may be connected to one wireless device WD. Also, the wireless device WD and the connection devices M may be connected by wire or wirelessly.

[0091] Additionally, the first determining unit 40 according to this embodiment may determine that a radio wave interference state exists when the surrounding radio wave intensity for the current channel is equal to or greater than a predetermined value a predetermined number of times in succession. [Explanation of symbols]

[0092] 1: Wireless system 10: Input section 20: Output section 30: Communications Department 31: First Communications Department 32: Second Communication Department 32a: 1st functional part 32b: 2nd functional part 32c: 3rd functional part 33: Third Communications Department 34: 4th Communications Department 35: 5th Communications Department 40: First judgment unit (interference judgment unit) 50: Second judgment unit (second interference judgment unit) 60: Channel switching section CA: Center side device M: Connected device WD: Radio WD1: Specific radio WD2: Non-specific radio equipment

Claims

1. A wireless system in which information can be transmitted and received within a network including a plurality of wireless devices, a specific wireless device among the plurality of wireless devices can transmit and receive information to and from a center side, and non-specific wireless devices among the plurality of wireless devices other than the specific wireless device transmit and receive information to and from the specific wireless device via or without passing through other non-specific wireless devices, and transmit and receive information to and from the center side through the specific wireless device, The radio device includes: A first communication unit that transmits first information to the surroundings; a second communication unit that, when receiving the first information from another wireless device, transmits second information by designating the source of the first information when there is information to be transmitted to the source of the first information, and thereafter transmits and receives information to and from the source of the first information; an interference determination unit that determines whether or not the own station is in a state of radio interference based on the radio wave strength of a channel currently in use; a third communication unit that, when the interference determination unit has determined that the wireless device itself is in a radio wave interference state and, upon receiving the first information from another wireless device, adds channel switching information to the second information or transmits the channel switching information instead of the second information to surrounding areas, rather than to a specified state of only a transmission source of the first information; a channel switching unit that switches its own channel after transmitting channel switching information by the third communication unit; A wireless system comprising:

2. the wireless device further includes a fourth communication unit that transmits channel switching information to surrounding areas when the wireless device receives channel switching information from another wireless device; The channel switching unit switches its own channel after transmitting channel switching information by the fourth communication unit.

2. The wireless system according to claim 1 .

3. The third communication unit executes a recovery process for transmitting channel switching information again on two channels before and after the channel switching unit switches its own channel.

3. The wireless system according to claim 2.

4. When the fourth communication unit receives channel switching information from another wireless device, the fourth communication unit transmits the channel switching information to the surroundings on two channels before and after the channel switching.

4. The wireless system according to claim 2 or 3.

5. The radio device includes: a second interference determination unit that, when receiving the second information from another wireless device, determines that the other wireless device is in a radio interference state when there is no reply of the required transmission information from the other wireless device despite having transmitted request information requesting a reply of the required transmission information to the other wireless device; a fifth communication unit that, when the second interference determination unit determines that the other wireless device is in a radio wave interference state and receives the first information from the other wireless device, adds channel switching information to the second information and transmits the second information to surrounding areas, rather than to a designated state of only the other wireless device; The wireless system according to any one of claims 1 to 4, further comprising:

6. A first communication unit that transmits first information to the surroundings; a second communication unit that, when receiving the first information from another wireless device, transmits second information by designating the source of the first information when there is information to be transmitted to the source of the first information, and thereafter transmits and receives information to and from the source of the first information; an interference determination unit that determines whether or not the own station is in a state of radio interference based on the radio wave strength of a channel currently in use; a third communication unit that, when the interference determination unit has determined that the wireless device itself is in a radio wave interference state and, upon receiving the first information from another wireless device, adds channel switching information to the second information or transmits the channel switching information instead of the second information to surrounding areas, rather than to a specified state of only a transmission source of the first information; a channel switching unit that switches its own channel after transmitting channel switching information by the third communication unit; A radio device comprising:

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