Communication equipment and communication methods

Abstract

Determine the target channel to switch to in order to ensure smooth operation after the channel switch. [Solution] The availability information processing unit 30 updates availability information D1, which indicates the availability of each channel in its own device. The availability information processing unit 30 obtains availability information D2 and availability information D3 from other devices belonging to the same group as its own device, which indicate the availability of each channel in those other devices. The interference detection unit 31 detects interference communication during operation. When interference communication is detected, the switching destination channel determination unit 33 determines the switching destination channel for the group to which its own device belongs, based on availability information D1 to availability information D3. The channel switching processing unit 34 executes channel switching processing based on the switching destination channel.

Description

Technical Field

[0001] The present invention relates to a communication device and a communication method.

Background Art

[0002] Patent Document 1 discloses a technique in which initial settings are made to perform electric field measurements on all channels, store at least two channels with measurement results below a predetermined electric field in a memory, start operation using one of the channels stored in the memory, and when there is interfering radio wave during operation, select an unused channel from the channels stored in the memory and continue operation.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a scenario where the channel used for a group call is switched due to detection of interfering communication during operation of the group call, there is a possibility of detecting interfering communication even after the switch.

[0005] An object of the present disclosure is to provide a technique for determining a switching destination channel so that operation can be performed without problems after channel switching.

Means for Solving the Problems

[0006] From the perspective of this disclosure, a communication device is provided that includes: a self-device availability information update unit that updates self-device availability information showing the availability of each channel in the self-device; an other-device availability information acquisition unit that acquires other-device availability information showing the availability of each channel in other devices belonging to the same group as the self-device; an interference detection unit that detects interference communications during operation; a switching destination channel determination unit that, when interference communications are detected, determines the switching destination channel of the group to which the self-device belongs based on the self-device availability information and the other-device availability information; and a channel switching processing unit that executes channel switching processing based on the switching destination channel.

[0007] A communication method is provided in which a computer updates its own device availability information, which indicates the availability of each channel in its own device; obtains other device availability information, which indicates the availability of each channel in other devices, from other devices belonging to the same group as the computer itself; detects interfering communications during operation; and, if such interfering communications are detected, determines the destination channel for the group to which the computer belongs based on the own device availability information and the other device availability information; and executes a channel switching process based on the destination channel. [Effects of the Invention]

[0008] According to this disclosure, the target channel can be determined so that operation can proceed without problems after the channel switch. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic diagram of the communication system. (First embodiment) [Figure 2] This is a functional block diagram of a transceiver. (First Embodiment) [Figure 3] This is a data structure diagram of availability information. (First Embodiment) [Figure 4] This is a data structure diagram of integrated availability information. (First embodiment) [Figure 5]This is the control flow for a transceiver. (First Embodiment) [Figure 6] This is a sequence diagram of a communication system. (First Embodiment) [Figure 7] This is a functional block diagram of the transceiver. (Second Embodiment) [Figure 8] This is the control flow for a transceiver. (Second Embodiment) [Figure 9] This is a sequence diagram of a communication system. (Second Embodiment) [Modes for carrying out the invention]

[0010] The present invention will be described below through embodiments of the invention, but the invention claimed is not limited to the following embodiments. Furthermore, not all of the configurations described in the embodiments are necessarily essential as means of solving the problem. For clarity of explanation, the following descriptions and drawings have been omitted and simplified as appropriate. In each drawing, the same elements are denoted by the same reference numerals, and redundant explanations have been omitted where necessary.

[0011] In the following embodiments, the description will be divided into multiple sections or embodiments where necessary for convenience. Unless otherwise specified, these are not unrelated, and one may be a modification, application, detailed explanation, or supplementary explanation of part or all of the other. Furthermore, in the following embodiments, when referring to the number of elements (including number, numerical value, quantity, and range), unless otherwise specified or clearly limited to a specific number in principle, it is not limited to that specific number, and may be greater than or less than that number.

[0012] Furthermore, in the following embodiments, the components (including operation steps, etc.) are not necessarily essential unless specifically stated or considered to be fundamentally essential. Similarly, in the following embodiments, when referring to the shape or positional relationship of components, etc., it shall include those substantially similar to or resembling their shape, etc., unless specifically stated or considered to be fundamentally different. The same applies to the numbers, etc. (including number, numerical value, quantity, and range) mentioned above.

[0013] (First Embodiment) Hereinafter, a first embodiment of the present disclosure will be described with reference to Figures 1 to 6. Figure 1 is a schematic diagram of a communication system 1. As shown in Figure 1, the communication system 1 consists of a plurality of transceivers 2. Each transceiver 2 is a specific example of a communication device. Each transceiver 2 is typically a low-power radio station that does not require a radio operator's license or a radio station license for operation. As shown in Figure 1, the plurality of transceivers 2 are divided into several groups G, and each group G communicates with each other using group calls. For the sake of explanation, in Figure 1, the plurality of transceivers 2 are assumed to belong to one of the following groups G: group Ga, group Gb, or group Gc.

[0014] Furthermore, group Ga includes transceivers 2a1 and 2a2, group Gb includes transceivers 2b1, 2b2, and 2b3, and group Gc includes transceivers 2c1 and 2c2.

[0015] In Figure 1, each group G is depicted with a dashed line. However, please note that these dashed lines merely indicate grouping and do not represent the range of radio waves or anything similar.

[0016] Here, a group call is a function that prevents interference between multiple groups G using the same channel by setting the same group number in transceiver 2 within each group G. Thus, a transceiver 2 does not output an audio of a group call (group transmission, group call) from a group different from the group to which the transceiver 2 belongs. Note that the above interference means that a call in a group different from the group to which one belongs can be heard. Also, other groups using the same channel with different group numbers receive other data (such as group numbers) while the received audio is in a silent state.

[0017] Again, for convenience of explanation, assume that both group Ga and group Gb are operating on channel 1, and group Gc is operating on channel 4. Also, when a group call is started by a plurality of transceivers 2 belonging to group Gb, although the plurality of transceivers 2 of group Gb were closely grouped in a small area, assume that transceiver 2b1 and transceiver 2b3 moved over time. Specifically, assume that transceiver 2b1 received a group call from group Ga because it got closer to transceiver 2a1 or transceiver 2a2. In this case, although transceiver 2b1 does not output an audio of a group call from group Ga different from the group Gb to which transceiver 2b1 belongs, in transceiver 2b1, channel 1 used in group Gb is frequently interfered by the group call from group Ga, so there is an obstacle to the group call. Therefore, in this case, transceiver 2b1 performs a channel switching process to switch the operation channel of group Gb.

[0018] Hereinafter, referring to FIGS. 2 to 6, the configuration and operation of the representative transceiver 2b1 will be described. The configuration and operation of the transceiver 2 belonging to the group Gb other than the transceiver 2b1 are the same as those of the transceiver 2b1, so the description will be omitted as appropriate. The configuration and operation of each transceiver 2 belonging to the group G other than the group Gb may be the same as or different from the configuration and operation of the transceiver 2b1.

[0019] FIG. 2 is a functional block diagram of the transceiver 2. The transceiver 2 includes a processor 20, a memory 21, an LCD 22 (Liquid Crystal Display), a communication interface 23, and an input interface 24. The processor 20 can access the memory 21. The processor 20 reads and executes a program stored in the memory 21. Thereby, the processor 20 causes hardware such as the processor 20 to function as various functional units. The LCD 22 displays an operation channel and a group number. The communication interface 23 is an interface for wireless communication with other transceivers 2. The input interface 24 is an interface for a user to set an operation channel and a group number.

[0020] In the present embodiment, the various functional units include a free status information processing unit 30, an interference detection unit 31, an interference detection notification processing unit 32, a switching destination channel determination unit 33, a channel switching processing unit 34, a pre-transmission processing unit 35, a re-switching processing unit 36, and a switching completion notification processing unit 37.

[0021] The free status information processing unit 30 is a specific example of a self-device free status information update unit and an other-device free status information acquisition unit. The free status information processing unit 30 generates self-device free status information indicating the free status of each channel in the self-device, and updates the self-device free status information at a predetermined interval. Further, the free status information processing unit 30 acquires, via the communication interface 23, other-device free status information indicating the free status of each channel in another device belonging to the same group as the self-device from the other device.

[0022] Here, Figure 3 shows the data structure of the availability information D. Figure 3 illustrates availability information D1, which shows the availability of each channel on transceiver 2b1; availability information D2, which shows the availability of each channel on transceiver 2b2; and availability information D3, which shows the availability of each channel on transceiver 2b3. The availability information of the own device corresponds to availability information D1, while the availability information of other devices corresponds to availability information D2 and availability information D3.

[0023] In this embodiment, availability is quantitatively expressed, for example, by continuous availability time. Continuous availability time refers to the period of time, retrospectively from the present, during which the corresponding channel has not been used. The availability information processing unit 30 updates the availability information D at predetermined intervals. For example, the availability information processing unit 30 measures the reception sensitivity of channel N every 30 seconds, and if the reception sensitivity falls below a predetermined value multiple times consecutively, the value obtained by multiplying 30 seconds by the number of consecutive occurrences is taken as the continuous availability time for channel N. Referring to Figure 3, according to the availability information D1, the continuous availability time for channel 1 in transceiver 2b1 is 0 seconds, and the continuous availability time for channel 4 is 900 seconds. Since transceivers 2b1, 2b2, and 2b3 are currently making frequent group calls to each other using channel 1, the continuous availability time for channel 1 is approximately 0 seconds in the availability information D of each of the transceivers 2b1, 2b2, and 2b3. Furthermore, as shown in Figure 1, transceiver 2b3 is close to transceivers 2c1 and 2c2, which belong to group Gc and are operating using channel 4. As shown in the availability information D3 in Figure 3, the continuous free time for channel 4 on transceiver 2b3 is 0 seconds.

[0024] In this embodiment, as described above, the availability status is quantitatively expressed as continuous availability time, but the availability status may be quantified by other methods. For example, the availability status may be quantified as continuous usage time. In this case, the availability status information processing unit 30 measures the reception sensitivity of channel N every 30 seconds, and if the reception sensitivity exceeds a predetermined value multiple times in a row, the value obtained by multiplying 30 seconds by the number of consecutive times may be used as the continuous usage time of channel N. Alternatively, the availability status information processing unit 30 may quantify the availability status as the number of consecutive times described above.

[0025] Returning to Figure 2, the interference detection unit 31 detects interference during operation. Here, interference is defined as communication output by another group (group Ga or group Gc) that is different from the group (group Gb) to which the device (transceiver 2b1) belongs, using the operating channel (channel 1) of the group (group Gb) to which the device belongs. Here, if the communication between multiple transceivers 2 is digital communication, the communication packet stores the group number of group G to which the transceiver 2 that is the source of the communication belongs. Therefore, the interference detection unit 31 determines whether or not the communication packet is interference by referring to the group number stored in the received communication packet.

[0026] The interference detection notification processing unit 32 is a specific example of the first change declaration transmission unit. The interference detection notification processing unit 32 uses the pre-switching channel (channel 1), which is the operating channel before the channel switching process is executed, to send an interference detection notification via group call, declaring that its group (group Gb) will change its operating channel (channel 1) from the pre-switching channel (channel 1). The interference detection notification is a specific example of the first change declaration. Therefore, referring to Figure 1, the interference detection notification sent from transceiver 2b1 can be received by transceivers 2a1 and 2a2 belonging to group Ga, which are operating on channel 1. As a result, from the perspective of transceivers 2a1 and 2a2, by receiving the interference detection notification, even if they detect interference communication after receiving it, they can quickly know that the source of the interference communication will switch operating channels, thus preventing them from unnecessarily switching operating channels.

[0027] When the interference detection unit 31 detects interference, the switching channel determination unit 33 determines the switching channel for group Gb based on the availability information of its own device (availability information D1) and the availability information of other devices (availability information D2 and availability information D3). Here, Figure 4 shows the integrated availability information E, which is obtained by integrating the availability information D1 to availability information D3 shown in Figure 3. As shown in Figure 4, the switching channel determination unit 33 generates integrated availability information E for each channel by integrating the continuous availability time of availability information D1, availability information D2, and availability information D3. Specifically, for each channel, the switching channel determination unit 33 uses the shortest continuous availability time among the continuous availability time of availability information D1, availability information D2, and availability information D3 as the integrated continuous availability time for that channel. The switching channel determination unit 33 also sets a priority for each channel so that channels with longer integrated continuous availability times are selected with priority over other channels. In this specification, the priority of a channel to be given relative priority is set to a relatively small number. In the example in Figure 4, since channel 5 has the longest continuous free time, its priority is set to 1 so that channel 5 is given the highest priority. Also in the example in Figure 4, since channels 2 and 3 have the next longest continuous free time, their priorities are set to 2 or 3 so that channels 2 and 3 are given the next highest priority. Here, for convenience, if the continuous free time is equal among multiple channels, the channel with the relatively small channel number is given priority. Therefore, in this embodiment, the priority of channel 2 becomes 2 and the priority of channel 3 becomes 3. Similarly, the priority of channel 1 becomes 4 and the priority of channel 4 becomes 5. Then, in the example in Figure 4, the switching destination channel determination unit 33 refers to the integrated free status information E and determines that channel 5, which is the channel with the lowest priority, is the switching destination channel for group Gb.

[0028] The channel switching processing unit 34 executes the channel switching process described above. The channel switching process includes the following processes (1) to (3). (1) Using the channel before switching, the process of sending a channel switching request specifying the destination channel via a group call to other devices belonging to the same group as the device. (2) The process of switching the operating channel of the device to the destination channel specified in the channel switching request in response to a channel switching request received from another device belonging to the same group as the device. (3) The process of switching the operating channel of the device to the destination channel determined by the destination channel determination unit 33.

[0029] The pre-transmission processing unit 35 is a specific example of the second change declaration transmission unit. The pre-transmission processing unit 35 sends a pre-transmission declaring that its group will change its operating channel to the switching destination channel using the switching destination channel. The pre-transmission is a specific example of the second change declaration. This allows for the rapid resolution of overlapping operating channels when multiple groups simultaneously perform channel switching processing and multiple groups happen to switch their operating channels to the same channel. As described above, the pre-transmission processing unit 35 sends a pre-transmission using the switching destination channel. At this time, the communication packet of the pre-transmission will store the group number of the group to which the transceiver 2, the source of the pre-transmission, belongs, and the channel number of the channel before switching. However, if multiple pre-transmissions are sent in a short period of time, the communication packet of the pre-transmission will store the channel number stored in the communication packet of the first pre-transmission.

[0030] The re-switching processing unit 36 ​​uses the pre-transmission signal described above to determine whether multiple groups have coincidentally switched their operating channels to the same channel. If the re-switching processing unit 36 ​​determines that multiple groups have coincidentally switched their operating channels to the same channel, it determines whether it is necessary to switch the operating channel of group G to which its own device belongs. For example, if the re-switching processing unit 36 ​​receives a pre-transmission signal from another group at almost the same time that the pre-transmission processing unit 35 transmits a pre-transmission signal, and the channel number of the group's pre-switch channel is smaller than the channel number of the other group's pre-switch channel, it determines that it is necessary to switch the operating channel of its own group again. Here, the rule for determining which group to switch the operating channel of again between the group and the other group is not limited to the channel number of the pre-switch channel described above. Also, "at almost the same time" means, for example, "within a time span of 500 milliseconds before and after."

[0031] The switching completion notification processing unit 37 sends a switching completion notification via group call using the destination channel to indicate that it has switched the operating channel of its device to the destination channel specified in the channel switching request, in response to the received channel switching request.

[0032] Next, the operation of communication system 1 will be explained with reference to Figures 5 and 6. First, the operation of transceiver 2 alone will be explained with reference to Figure 5, and then the operation of the entire communication system 1 will be explained with reference to Figure 6. Figure 5 shows the control flow of transceiver 2. Below, the operation of transceiver 2b1 will be explained as a representative of multiple transceivers 2.

[0033] First, the availability information processing unit 30 updates the availability information D1 (S300). Next, the channel switching processing unit 34 determines whether it has received a channel switching request via group call (S310). If the answer in step S310 is NO, then the interference detection notification processing unit 32 determines whether it has received an interference detection notification (S320). If the answer in step S320 is NO, then the interference detection unit 31 detects interference communication during operation (S330). If the answer in step S330 is NO, the interference detection unit 31 returns to step S300. On the other hand, if the answer in step S330 is YES, the interference detection notification processing unit 32 sends an interference detection notification via group call declaring that its group (group Gb) will change its operating channel (channel 1) from the previous channel (channel 1) using the previous channel (channel 1).

[0034] Next, the switching destination channel determination unit 33 receives availability information D2 and availability information D3 from the other device that received the interference detection notification (S350). Next, the switching destination channel determination unit 33 determines the switching destination channel for group Gb based on availability information D1 to availability information D3 (S360). Next, the channel switching processing unit 34 sends a channel switching request to transceivers 2b2 and 2b3 via group call using the channel before switching (S370). The channel number of the switching destination channel is stored in the communication packet of the channel switching request. Next, the channel switching processing unit 34 switches the operating channel of its own device to the switching destination channel (S380).

[0035] Next, the pre-transmission processing unit 35 sends a pre-transmission via group call, declaring that its group will change its operating channel to the switching channel using the current channel, i.e., the switching destination channel (S390). The pre-transmission communication packet stores the channel number of the channel before the switching (channel 1). Next, the pre-transmission processing unit 35 determines whether it has received a pre-transmission from another group at approximately the same time that it sent the pre-transmission (S400). If the answer in step S400 is NO, the re-switching processing unit 36 ​​then determines whether it has received a re-switching request (S410). If the answer in step S410 is NO, the switching completion notification processing unit 37 determines whether it has received switching completion notifications from all transceivers 2 belonging to the same group as its own device (S420). If the answer in step S420 is NO, the switching completion notification processing unit 37 returns to step S410. On the other hand, if the answer in step S420 is YES, the switching completion notification processing unit 37 returns to step S300.

[0036] If the answer in step S400 is YES, the re-switching processing unit 36 ​​determines whether it is necessary to switch the operating channel of group Gb again (S430). If the answer in step S430 is NO, the re-switching processing unit 36 ​​proceeds to step S410. If the answer in step S430 is YES, the re-switching processing unit 36 ​​returns to step S360. In response to this, in step S360, the switching destination channel determination unit 33 determines a channel with a priority one higher than the previously determined channel as the switching destination channel.

[0037] If the answer in step S410 is YES, the re-switching processing unit 36 ​​returns to step S360. In response to this, in step S360, the switching destination channel determination unit 33 determines a channel with a priority one higher than the previously determined channel as the switching destination channel.

[0038] If the answer to step S320 is YES, the interference detection notification processing unit 32 determines whether the received interference detection notification was sent from the same group G (S500). If the answer to step S500 is YES, the availability information processing unit 30 sends the availability information of its own device via group call (S510) and returns the process to S300. On the other hand, if the answer to step S500 is NO, the interference detection unit 31 temporarily suspends interference detection (S520) and returns the process to S300. Here, temporary suspension means, for example, 0 to several seconds.

[0039] If the answer in step S310 is YES, the channel switching processing unit 34 switches the operating channel of its own device to the destination channel specified in the channel switching request in response to the received channel switching request (S600). Next, the pre-transmission processing unit 35 sends a pre-transmission via group call, declaring that its group will change its operating channel to the destination channel using the current channel, i.e., the destination channel (S610). Next, the pre-transmission processing unit 35 determines whether it received a pre-transmission from another group at approximately the same time that the pre-transmission processing unit 35 sent the pre-transmission (S620). If the answer in step S620 is NO, the switching completion notification processing unit 37 sends a switching completion notification via group call (S630) and returns the process to step S300. On the other hand, if the answer in step S620 is YES, the re-switching processing unit 36 ​​determines whether it is necessary to switch the operating channel of group Gb again (S640). If the answer in step S640 is YES, the re-switching processing unit 36 ​​sends a re-switching request via group call (S650) and returns the process to step S300. On the other hand, if the answer in step S640 is NO, the re-switching processing unit 36 ​​proceeds the process to step S630.

[0040] Next, the operation of the entire communication system 1 will be explained with reference to Figure 6. Figure 6 is a sequence diagram of the communication system 1. The symbols in Figure 6 correspond to the symbols in Figure 5. Below, the operation of transceiver 2b1 will be explained in order. In the example in Figure 6, a case is shown in which transceiver 2b1 belonging to group Gb and transceiver 2c2 belonging to group Gc switch their operating channels to the same destination channel (channel 5) at almost the same time.

[0041] First, the availability information processing unit 30 of transceiver 2b1 updates the availability information D1 (P100). Next, a group call using channel 1 is made between transceiver 2b1 and transceiver 2b3 (P110, P120). Next, the interference detection unit 31 detects interference communication during operation by receiving a group call using channel 1 from transceiver 2a2 (P125) (P130). Next, the interference detection notification processing unit 32 sends an interference detection notification via group call using the pre-switching channel (channel 1) to declare that its group (group Gb) is changing its operating channel (channel 1) from the pre-switching channel (channel 1) (P140).

[0042] Next, the availability information processing unit 30 receives availability information D3 from the transceiver 2b3 that received the interference detection notification (P150). Next, the switching destination channel determination unit 33 determines the switching destination channel for group Gb based on availability information D1 to availability information D3 (P160). Next, the channel switching processing unit 34 sends a channel switching request to the transceiver 2b3 using the channel before switching (channel 1) (P170). The channel switching request stores the channel number of the channel after switching (channel 5). Next, the channel switching processing unit 34 switches the operating channel of its own device to the switching destination channel (channel 5) (P180).

[0043] Next, the pre-transmission processing unit 35 sends a pre-transmission via group call, declaring that its group will change its operating channel to the switching channel (channel 5) using the current channel (P190). The pre-transmission communication packet contains the channel number of the channel before switching (channel 1). The pre-transmission processing unit 35 also receives a pre-transmission from transceiver 2b3 (P195). However, since transceiver 2b3 has received a pre-transmission from transceiver 2c1 that includes channel 5, it sends a re-switching request to transceiver 2b1 via a group call using channel 5. Next, the re-switching processing unit 36 ​​receives a re-switching request from transceiver 2b3 (P200). Next, the switching channel determination unit 33 determines channel 2, which has one higher priority than the previously determined channel, as the switching channel (P210).

[0044] Next, the channel switching processing unit 34 sends a channel switching request to the transceiver 2b3 using the channel before switching (channel 5) (P220). Then, the channel switching processing unit 34 switches the operating channel of its own device to the destination channel (channel 2) (P230).

[0045] Next, the pre-transmission processing unit 35 sends a pre-transmission via group call, declaring that its group will change its operating channel to the switching channel (channel 2) using the current channel (P240). The pre-transmission communication packet contains the channel number of the channel used before the switch (channel 1) in step P110. The pre-transmission processing unit 35 also receives a pre-transmission from transceiver 2b3 (P245). Next, the switching completion notification processing unit 37 receives a switching completion notification from transceiver 2b3 (P250). As a result, transceiver 2b1 can properly switch the operating channel of group Gb. Transceivers 2a2 and 2c2 will not unnecessarily switch their operating channels.

[0046] The first embodiment of this disclosure has been described above, and the above embodiment has the following features.

[0047] Transceiver 2 (communication device) includes an availability information processing unit 30 (self-device availability information update unit, other-device availability information acquisition unit), a jamming detection unit 31, a switching destination channel determination unit 33, and a channel switching processing unit 34. The availability information processing unit 30 updates availability information D1 (self-device availability information), which shows the availability of each channel in the self-device (transceiver 2b1). The availability information processing unit 30 acquires availability information D2 and availability information D3 (other-device availability information), which show the availability of each channel in other devices (transceivers 2b2, transceivers 2b3) belonging to the same group (group Gb) as the self-device (transceiver 2b1). The jamming detection unit 31 detects jamming communications during operation. When the switching destination channel determination unit 33 detects jamming communications, it determines the switching destination channel for the group (Gb) to which the self-device (transceiver 2b1) belongs, based on availability information D1 to availability information D3. The channel switching processing unit 34 executes channel switching processing based on the destination channel. With the above configuration, the destination channel can be determined so that operation can proceed without problems after the channel switch.

[0048] Transceiver 2 further includes a interference detection notification processing unit 32 (first change declaration transmission unit). The interference detection notification processing unit 32 uses the pre-switching channel (channel 1), which is the operating channel before the channel switching process is executed, to send an interference detection notification (first change declaration) declaring that its own group (group Gb) will change its operating channel (channel 1) from the pre-switching channel (channel 1). With the above configuration, it is possible to prevent other groups (group Ga) from unnecessarily switching their operating channels at the same time as group Gb.

[0049] Transceiver 2 further includes a pre-transmission processing unit 35 (second change declaration transmission unit). The pre-transmission processing unit 35 transmits a pre-transmission (second change declaration) declaring that its group (group Gb) will change its operating channel (channel 1) to the switching destination channel (channel 5) using the switching destination channel (channel 5). With this configuration, if another group switches its operating channel to the same switching destination channel at the same time that group Gb switches its operating channel to the switching destination channel, the subsequent confusion can be resolved as quickly as possible.

[0050] (Second Embodiment) Next, a second embodiment of this disclosure will be described with reference to Figures 7 to 9. The following description will focus on the differences between this embodiment and the first embodiment, omitting any redundant explanations.

[0051] Comparing Figure 2 and Figure 7, the transceiver 2 of this embodiment has a simpler configuration compared to the transceiver 2 of the first embodiment. Specifically, the transceiver 2 of this embodiment omits the pre-transmission processing unit 35 and the re-switching processing unit 36, which are functions of the transceiver 2 of the first embodiment. Accordingly, comparing Figure 5 and Figure 8, the operation of the transceiver 2 of this embodiment omits the operations corresponding to the pre-transmission processing unit 35 and the re-switching processing unit 36 ​​of the transceiver 2 of the first embodiment, i.e., steps S390, S400, S410, S430, S610, S620, S640, and S650. Similarly, comparing Figure 6 and Figure 9, the operation of the communication system 1 in this embodiment is the same as the operation of the communication system 1 in the first embodiment, but with the operations corresponding to the pre-transmission processing unit 35 and the re-switching processing unit 36 ​​omitted, i.e., steps P190, P195, P200, P210, P220, P230, P240, and P245 omitted. In this way, the pre-transmission processing unit 35, the re-switching processing unit 36, and the operations related thereto can be omitted.

[0052] Although the present disclosure has been described above with reference to the first and second embodiments, the present disclosure is not limited thereto. Various modifications to the structure and details of the present disclosure are possible, which can be understood by those skilled in the art within the scope of the invention.

[0053] For example, although the transceiver 2 in the first and second embodiments described above was configured to avoid interference in group calls by multiple groups G, it is not limited to this and may also be applied to individual calls.

[0054] Furthermore, the availability information processing unit 30 of the transceiver 2 in the first and second embodiments described above updates the availability information D1 at a predetermined interval. Immediately after the power of the transceiver 2 is turned on, there is no availability information D1. In this case, the transceiver 2 makes the aforementioned pre-transmission using the operating channel set by the user, and if there are other groups using the same channel, it is conceivable that the transceiver 2 of the other group that received the pre-transmission will be configured to automatically send a pre-transmission response indicating that the channel used in that pre-transmission is in use. With this configuration, the transceiver 2 that is about to start a call can be made aware that the channel set as the operating channel is currently in use, so that it can quickly select another channel as the operating channel, thereby avoiding interference between groups.

[0055] Furthermore, in the first and second embodiments described above, a group number is set on the transceiver 2 in order to perform a group call. This group number may be a group-specific and unique group-specific ID issued individually by the vendor of the transceiver 2. [Explanation of Symbols]

[0056] 1. Communication System 1 channel 2 transceivers 2a1 transceiver 2a2 transceiver 2b1 transceiver 2b2 transceiver 2b3 transceiver 2c1 transceiver 2c2 transceiver 20 processors 21 memory 22 LCD 23 Communication Interface 24 Input Interfaces 30 Availability Information Processing Unit 31 Interference detection unit 32 Interference Detection Notification Processing Unit 33 Switching destination channel determination unit 34 Channel switching processing unit 35 Pre-oscillation processing unit 36 Re-switching processing unit 37 Switching Completion Notification Processing Unit G Group Ga Group Gb Group Gc Group D Availability Information D1 Availability Information D2 Availability Information D3 Availability Information E. Integrated Availability Information

Claims

1. A device availability information update unit updates the device availability information, which shows the availability status of each channel in the device. A device availability information acquisition unit acquires other device availability information, which indicates the availability status of each channel in other devices, from other devices belonging to the same group as the aforementioned device. An interference detection unit that detects interference communications during operation, When the aforementioned interfering communication is detected, a switching channel determination unit determines the switching channel to which the group to which the device belongs is based on the availability information of the device itself and the availability information of other devices, A channel switching processing unit that executes channel switching processing based on the aforementioned switching destination channel, including, Communication device.

2. The aforementioned jamming communication is a communication output by a different group using the operational channel of the group to which the device belongs. The communication device according to claim 1.

3. The system further includes a first change declaration transmission unit that transmits a first change declaration declaring that the group will change its operating channel from the pre-switch channel, using the pre-switch channel which is the operating channel before the channel switching process is executed. The communication device according to claim 1.

4. The system further includes a second change declaration transmission unit that transmits a second change declaration declaring that the group will change its operating channel to the aforementioned switching channel using the aforementioned switching channel. The communication device according to claim 1.

5. Computers The device's availability information, which shows the availability of each channel on the device, is updated. The device acquires other device availability information, which indicates the availability of each channel in other devices, from other devices belonging to the same group as the aforementioned device. Detecting jamming communications during operation, When the aforementioned interfering communication is detected, the system determines the switching destination channel for the group to which the system belongs, based on the availability information of the system itself and the availability information of other systems. The channel switching process is executed based on the destination channel. Communication method.

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