Communication device and communication method

Abstract

To provide a communication device or the like that prevents trouble due to slot switching.SOLUTION: In a communication device 10, a receiving unit 24 receives in a first slot or a second slot according to a time-division multiple access method, and a transmitting unit 23 transmits in the first slot or the second slot. An audio signal decoding unit 20 decodes an audio signal of either the first slot or the second slot. A baseband signal processing unit 19 determines priority of outputting audio from information included in the first received signal and the second received signal, and outputs information about the priority. A control unit 18 switches an audio output target from the first slot to the second slot and transmits, in the first slot, an interrupt request signal to a transmission source of the first received signal when the second received signal having a higher priority than the first received signal is received after the first received signal is received in the first slot.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] In a wireless communication technology called DMR (Digital Mobile Radio), the time division multiple access (TDMA (Time Division Multiple Access)) method is used to enable two independent communication accesses (for example, the first slot and the second slot) simultaneously. Using this, when a communication device that is in a call using one slot receives a signal in the other slot, it becomes possible to switch the slot for the call.

[0003] For example, a wireless communication system is disclosed in which a wireless terminal selects one of a plurality of repeaters connected by a communication line when communicating with another wireless terminal (Patent Document 1). This wireless terminal analyzes whether its own terminal exists at the destination of the call information when there is call information in the communication information, determines whether the priority of the call information is higher than that of the current call if it exists, and changes to another repeater channel of the call information when it is higher.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, if a communication device compliant with the DMR method receives a higher-priority signal in the second slot while the first slot is outputting audio from the first slot, it will switch the output audio from the first slot to the second slot. As a result, the user of this communication device will miss part of the audio from the first slot. Furthermore, the person communicating with this communication device via the first slot will not be aware that the slot has switched midway through the conversation.

[0006] The present invention was made to solve these problems, and aims to provide a communication device, etc., that suppresses malfunctions caused by slot switching. [Means for solving the problem]

[0007] The communication device according to the present invention includes a receiving circuit, a transmitting circuit, an audio signal decoding circuit, and a control circuit. The receiving circuit receives in the first or second slot using a time-division multiplex access scheme. The transmitting circuit transmits a transmission signal corresponding to the first or second slot using a time-division multiplex access scheme and half-duplex communication. The audio signal decoding circuit decodes an audio signal, selecting either the first received signal received in the first slot or the second received signal received in the second slot as the target for audio output. The baseband signal processing circuit determines the priority for outputting audio from the information contained in the first and second received signals and outputs information regarding the priority. After receiving the first received signal in the first slot, the control circuit, upon receiving a second received signal with higher priority than the first received signal in the second slot, switches the target for audio output from the first slot of the first received signal to the second slot of the second received signal based on the priority information, and also sends an interrupt request signal as a transmission signal to the source of the first received signal in the first slot.

[0008] The communication method according to the present invention involves a communication device that performs half-duplex communication using a time-division multiplexing access scheme with two slots, and executes the following communication method. The communication device receives a first received signal from the first slot of the two slots and outputs audio, while simultaneously detecting a signal from a second slot that is different from the first slot. When the communication device detects a signal from the second slot, it compares the priority determined from the information contained in the second received signal, which has just begun to be received in the second slot, with the priority determined from the information in the first received signal. If the priority for outputting the audio of the second received signal is higher, it switches to outputting the audio of the second received signal based on the priority information. The communication device continues to detect the first received signal and sends an interrupt request signal to the source of the first received signal. The communication device, in response to the interrupt request signal, designates the slot used for transmission in communication as the first slot from the moment the first received signal is interrupted until the second received signal stops. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a communication device, etc., that suppresses malfunctions caused by slot switching. [Brief explanation of the drawing]

[0010] [Figure 1] This is a block diagram of the communication device according to Embodiment 1. [Figure 2] This is a functional block diagram of the communication device according to Embodiment 1. [Figure 3] This is a schematic diagram of the configuration of a communication system including a communication device 10 according to Embodiment 1. [Figure 4] This is a diagram illustrating the frame structure of the transmitted and received signals according to Embodiment 1. [Figure 5] This figure shows an example of a list chunk format in the communication device 10. [Figure 6] This is a diagram to explain the data contained in a list chunk. [Figure 7] This figure shows an example of a list chunk in the system according to Embodiment 1. [Figure 8] It is a method for reading list chunks executed by the communication device 10. [Figure 9] FIG. 9 is a flowchart showing a process of recording a received signal. [Figure 10] It is a flowchart showing a talk-back process when playing back the recorded voice. [Figure 11] It is a first diagram for explaining the functions of the communication device according to Embodiment 2. [Figure 12] It is a first sequence diagram showing the processes executed by the communication device according to Embodiment 2. [Figure 13] It is a second diagram for explaining the functions of the communication device according to Embodiment 2. [Figure 14] It is a second sequence diagram showing the processes executed by the communication device according to Embodiment 2. [Figure 15] It is a sequence diagram showing the processes executed by the communication device according to Embodiment 3. [Figure 16] It is a sequence diagram showing the processes executed by the communication device according to Embodiment 4.

Embodiments for Carrying Out the Invention

[0011] Hereinafter, the present invention will be described through embodiments of the invention, but the invention according to the claims is not limited to the following embodiments. Also, not all of the configurations described in the embodiments are essential as means for solving the problems. For clarity of explanation, the following description and drawings have been appropriately omitted and simplified. In each drawing, the same reference numerals are assigned to the same elements, and duplicate explanations are omitted as necessary.

[0012] <Embodiment 1> Hereinafter, embodiments of the present invention will be described with reference to the drawings. Referring to FIG. 1, a communication device according to an embodiment will be described. FIG. 1 is a configuration block diagram of a communication device 10 according to an embodiment. The communication device 10 is an embodiment of a communication device. The communication device 10 is a radio that transmits and receives frequency-modulated signals and complies with the DMR (Digital Mobile Radio) standard. DMR is a communication standard defined by the European Telecommunications Standards Institute (ETSI).

[0013] The main components of the communication device 10 include a recording device 14, a control unit 18, a baseband signal processing unit 19, a voice signal decoding unit 20, a voice signal processing unit 21, and a transceiver unit 22 (a transmitting unit 23 and a receiving unit 24). In addition to the above configuration, the communication device 10 also has a display unit 11, an operation unit 12, a peripheral unit 13, a speaker 15, a microphone 16, an antenna 17, and an RF switch unit 25.

[0014] The recording device 14 includes a non-volatile memory such as a flash memory. The recording device 14 is set to be able to record at least the voice signal of at least one of the first received signal or the second received signal. The recording device 14 may be built into the communication device 10 or may be configured to be detachable from the communication device 10.

[0015] The control unit 18 is also referred to as a control circuit. Some or all of the components of the control unit 18 may be realized by a general-purpose or dedicated circuitry, a processor, etc., or a combination thereof. These may be constituted by a single chip or may be constituted by a plurality of chips connected via a bus. More specifically, the control unit 18 includes, for example, a CPU (Central Processing Unit) or an MCU (Micro Controller Unit).

[0016] The control unit 18 receives various signals from each component of the communication device 10 and controls each component according to the received signals. For example, the control unit 18 receives a predetermined operation from the operation unit 12 and makes the communication device 10 perform its functions according to the received operation. At this time, the control unit 18 can exchange signals with the baseband signal processing unit 19 and the voice signal processing unit 21 in order to realize the functions according to this embodiment. Also, for example, when the communication device 10 receives a received signal, the control unit 18 receives accompanying information contained in this signal from the baseband signal processing unit 19 and processes the received information. That is, for example, if the accompanying information of the received signal contains a message to be displayed, this message is displayed on the display unit 11.

[0017] The control unit 18 also performs processing for each of the first and second slots in accordance with DMR. More specifically, for example, if the control unit 18 receives a first received signal in the first slot but no signal is received in the second slot, it reads the accompanying information contained in the first received signal and supplies the read accompanying information to the control unit 18. Furthermore, the control unit 18 supplies the audio signal contained in the first received signal to the audio signal decoding unit 20 for the purpose of outputting the audio signal from the speaker 15.

[0018] Furthermore, if the control unit 18 receives a second reception signal in the second slot after receiving a first reception signal in the first slot, and the second reception signal has a higher priority than the first reception signal, it switches the target of the audio output from the first slot of the first reception signal to the second slot of the second reception signal. In this case, the control unit 18 also continues to detect the first reception signal and causes the recording device to start recording at least the signal corresponding to the audio signal from the first reception signal.

[0019] The baseband signal processing unit 19 is a circuit block including, for example, a DSP (Digital Signal Processor), and may be referred to as a baseband signal processing circuit. The baseband signal processing unit 19 can exchange signals with the control unit 18 and the audio signal processing unit 21 in order to realize the functions according to this embodiment. The baseband signal processing unit 19 receives the received signal received by the communication device 10 via the transmission unit 23 and reads the information contained in the received received signal.

[0020] More specifically, for example, the baseband signal processing unit 19 reads the first received signal from the first slot and the second received signal from the second slot, respectively, which are compliant with the DMR, and determines the priority from the information contained in the first and second received signals. The baseband signal processing unit 19 supplies the information regarding the determined priority to the control unit 18. The information contained in the received signal may indicate that the type of signal relates to a type of call, such as an individual call or a group call, or that it is a special call (e.g., an emergency call). The priority for these types of calls must be set in advance when operating a wireless communication system using this communication device. In addition, the information contained in the received signal may also include information indicating the priority. This embodiment is a technology that focuses on the priority determined from the information contained in the received signal. Therefore, in the following description, expressions such as "reading the priority contained in the received signal" may be used.

[0021] For example, the baseband signal processing unit 19 supplies a predetermined received signal to the audio signal decoding unit 20 with the aim of outputting audio to the speaker 15. In this case, the baseband signal processing unit 19 receives the audio signal decoded by the audio signal decoding unit 20. Furthermore, the baseband signal processing unit 19 supplies the received audio signal to the speaker 15 via the audio signal processing unit 21. As a result, the speaker 15 outputs the audio signal contained in the received signal.

[0022] The audio signal decoding unit 20 is also called an audio signal decoding circuit or vocoder. The audio signal decoding unit 20 decodes the audio signal, selecting either the first received signal or the second received signal as the target for audio output. The audio signal decoding unit 20 receives the received signal from the baseband signal processing unit 19 and decodes it. The audio signal decoding unit 20 then supplies the decoded audio signal to the baseband signal processing unit 19.

[0023] The audio signal processing unit 21 is also called the audio signal processing circuit. The audio signal processing unit 21 can exchange signals with the baseband signal processing unit 19 and the control unit 18 in order to realize the functions according to this embodiment. The audio signal processing unit 21 converts the audio signal received from the microphone 16 using A / D conversion (Analog to Digital conversion), applies various processing such as bandwidth limiting to generate a modulated wave, and supplies it to the transmitting and receiving unit 22. The audio signal processing unit 21 also converts the audio signal received from the audio signal decoding unit 20 using D / A conversion (Digital to Analog conversion), demodulates and decodes it, and supplies the generated audio signal to the speaker 15.

[0024] The transmitting / receiving unit 22 is a circuit block that includes a transmitting unit 23 and a receiving unit 24. The transmitting / receiving unit 22 transmits data to other radios using a half-duplex communication method. The transmitting / receiving unit 22 receives data transmitted by other radios using a half-duplex communication method. The other radios may operate as relay stations.

[0025] When the transmitting / receiving unit 22 receives a signal via the antenna 17 and the RF switch unit 25, it supplies the received signal (received signal) to the audio signal processing unit 21. When the transmitting / receiving unit 22 receives a signal to be transmitted to another radio (transmitted signal) from the audio signal processing unit 21, it outputs the received transmitted signal to the antenna 17 via the RF switch unit 25. The RF switch unit 25 is also called a high-frequency switch. The RF switch unit 25 appropriately switches the paths of the received signal and the transmitted signal, respectively.

[0026] The receiving unit 24 is also called the receiving circuit. The receiving unit 24 alternately receives the first received signal received in the first slot and the second received signal received in the second slot using a time-division multiplex access method.

[0027] The transmitting unit 23 is also called the transmitting circuit. The transmitting unit 23 transmits the transmission signal corresponding to the first or second slot using a time-division multiplex access scheme and half-duplex communication.

[0028] The display unit 11 is a display device including a liquid crystal panel that displays various information. The display unit 11 receives instructions from the control unit 18 regarding the content to be displayed. The display unit 11 can, for example, display information about the receiving station. The communication device 10 may, for example, receive signals in both the first slot and the second slot, output the audio from one of the slots from the speaker, and record the audio from the other slot in the recording device without outputting it from the speaker. In this case, the display unit 11 may display, for example, "Back slot busy," to indicate that it is receiving a signal from the slot that is not outputting audio from the speaker. Here, "Back slot busy" means that the back slot is also receiving, with the slot that is outputting audio being the front and the slot that is not outputting audio being the back.

[0029] The operation unit 12 is a user interface, such as operation keys, provided for the communication device 10 to perform its functions. The operation unit 12 includes, for example, a PTT switch.

[0030] The PTT switch is an operating unit for realizing half-duplex communication using push-to-talk. For example, when a user speaks and transmits an audio signal, the user presses the PTT switch. The control unit 18 puts the communication device 10 into a receive-standby state when the PTT switch is not pressed, and puts the communication device 10 into a transmit state when the PTT switch is pressed.

[0031] The peripheral part 13 may include, for example, interfaces for externally connected devices such as earphones or USB (Universal Serial Bus) terminals, as well as user interfaces such as LEDs (light-emitting diodes) and buzzers.

[0032] Next, the functional configuration of the communication device 10 will be explained using Figure 2. Figure 2 is a functional block diagram of the communication device 10 according to Embodiment 1. Figure 2 shows, in particular, the function of the communication device 10 recording an audio signal from a received signal. The signal processing block 100 shown in the figure represents the function realized by the components of the communication device 10, and does not necessarily have a physical correspondence with the configuration shown in Figure 1. The signal processing block 100 may be realized by the mutual relationship of multiple components shown in Figure 1. Alternatively, the signal processing block 100 may represent a part of the function of the control unit 18, etc.

[0033] The communication device 10 shown in Figure 2 includes a signal processing block 100 which comprises a digital signal detection unit 101, a chapter generation unit 102, a received voice conversion unit 104, a recorded data generation unit 105, a recorded voice control unit 106, a voice signal extraction unit 107, an associated information extraction unit 108, a PTT operation detection unit 109, a voice output control unit 110, and a display control unit 111. The signal processing block 100 is also connected to a display unit 11, a recording device 14, a speaker 15, a baseband signal processing unit 19, a transmitting / receiving unit 22, a PTT switch 26, and a non-volatile memory 27, respectively, in a manner that allows communication between them.

[0034] The digital signal detection unit 101 of the signal processing block 100 reads the received signal and supplies information about the receiving station to the chapter generation unit 102. Information about the receiving station may include, for example, the frequency of the received signal, the ID (identification, identifier) ​​of the receiving station, the priority of the received signal, whether the received slot is the first slot or the second slot, and the reception start time. Upon receiving the above information, the chapter generation unit 102 supplies this information to the recording data generation unit 105 as appropriate. The received audio conversion unit 104 performs A / D conversion of the received audio signal and supplies the converted data to the recording data generation unit 105.

[0035] Next, the recording data generation unit 105 synthesizes the audio signal and information about the other station to generate recording data. The recording data generation unit 105 supplies the generated recording data to the recording audio control unit 106. Furthermore, the recording audio control unit 106 executes the process of writing the recording data to the recording device 14.

[0036] When playing back recorded audio, the recording audio control unit 106 reads data from the recording device 14 and supplies the read data to the audio signal extraction unit 107 and the associated information extraction unit 108, respectively. The audio signal extraction unit 107 extracts the audio signal contained in the recorded data and supplies the extracted audio signal to the audio output control unit 110. The audio output control unit 110 outputs the received audio signal from the speaker 15.

[0037] Meanwhile, the ancillary information extraction unit 108 extracts ancillary information, such as information about the other station, contained in the recorded data, and supplies predetermined information from the extracted ancillary information to be displayed on the display unit 11 to the display control unit 111. The display control unit 111 receives the predetermined ancillary information from the ancillary information extraction unit 108 and displays it on the display unit 11.

[0038] Next, we will explain the processing that occurs when the PTT switch is pressed while the recorded audio signal is being played back. When the PTT switch 26 is pressed while the communication device 10 is outputting the audio signal related to the recorded data from the speaker 15 (i.e., playing back the recorded audio), it can send a signal to the other station whose audio is being played back (i.e., perform a talkback). That is, for example, when the user of the communication device 10 presses the PTT switch 26, the signal processing block 100 obtains the ID of the other station from the accompanying information of the audio signal being played back and uses the obtained ID to send the signal. As a result, the communication device 10 can send a signal to the other station whose audio signal is being played back, even after it has finished receiving the other station's signal.

[0039] The non-volatile memory 27 is, for example, a memory included in the control unit 18, and stores, for example, a computer program (hereinafter simply referred to as "the program") for executing the communication method according to this embodiment. The control unit 18 loads the program from the recording device 14 into the random access memory and executes the program.

[0040] Next, an example of a communication system including the communication device 10 will be described with reference to Figure 3. Figure 3 is a schematic diagram of the configuration of a communication system including the communication device 10 according to Embodiment 1. Figure 3 shows terminals A, B, C, and a repeater, which are the communication devices 10. Terminals A, B, and C each transmit and receive signals in accordance with the DMR standard. The repeater is a relay device that relays the signals from terminals A, B, and C. In Figure 3, the rectangular strips and arrows shown between terminals A, B, and C and the repeater represent images of the signals transmitted and received by each terminal.

[0041] In the configuration described above, terminal B starts transmitting a signal using the first slot out of the two slots (the first and second slots). At this time, terminal A receives the signal from the first slot transmitted by terminal B via the repeater.

[0042] Meanwhile, terminal C begins transmitting a signal using the second slot, out of the two slots (the first and second slots). At this time, terminal A receives the signal transmitted by terminal C via the repeater.

[0043] As described above, terminal A can receive both the signal from terminal B in the first slot and the signal from terminal C in the second slot. Terminal B can set a priority when transmitting signals. Similarly, terminal C can set a priority when transmitting signals. In the example shown in Figure 3, the priority of the signal transmitted by terminal C is assumed to be higher than the priority of the signal transmitted by terminal B. In this case, terminal A outputs the audio signal from terminal C through its speaker, regardless of the order in which the signals arrive. Regarding the setting of priority, it may be possible to set it directly, but as described above, if the receiving side has already set a priority depending on the type of call, selecting a call type that has a higher priority is also considered setting the priority.

[0044] Next, we will explain the outline of the frame configuration of the DMR's transmitted and received signals using Figure 4. Figure 4 is a diagram illustrating the frame structure of the transmitted and received signals according to Embodiment 1. In Figure 4, the base station's transmitted signal (BS TX) is shown on the upper side, and the mobile station's transmitted signal (MS TX) is shown on the lower side.

[0045] The base station's transmission signal, shown in the upper part of Figure 4, is composed of alternating first and second slots. The base station's transmission signal is defined as a single frame consisting of the first and second slots, with each slot having a transmission period of 30 milliseconds, resulting in a combined transmission period of 60 milliseconds for one frame. Each slot also includes a 108-bit payload and a 48-bit SYNC or embedded signal. The payload includes the voice signal. Furthermore, the base station's transmission signal includes a period of 2.5 milliseconds between adjacent slots in the first and second slots during which a 24-bit CACH signal (Common Announcement Channel) indicating the usage status of each slot is transmitted.

[0046] The transmission signal of the mobile station shown at the bottom of Figure 4 is also composed of alternating first and second slots. The transmission signal of the mobile station is defined as a combination of the first and second slots as one frame, with each of the first and second slots having a transmission period of 30 milliseconds, and the combined transmission period for one frame being 60 milliseconds. Each slot also contains a 108-bit payload and 48 bits of SYNC or embedded signaling. Note that the transmission signal of the mobile station does not contain a signal during the 2.5-millisecond period adjacent to each of the first and second slots.

[0047] Next, the list chunk format in the communication device 10 will be described with reference to Figure 5. Figure 5 is a diagram showing an example of the list chunk format in the communication device 10 according to Embodiment 1.

[0048] The list chunk format according to this embodiment consists of four elements: "Chunk ID," "Chunk Data Size," "Type ID," and "List of Text Labels and Name." The "Chunk ID" is fixed as the string "LIST." The "Chunk Data Size" indicates the size of the data section, which is the sum of all the chunks under it plus 4 bytes. The "List of Text Labels and Name" shows the actual content of the data.

[0049] Next, we will explain the data contained in the list chunk with reference to Figure 6. Figure 6 is a diagram illustrating the data contained in the list chunk. The data contained in the list chunk includes "Chapter Address" and "Unit ID". The data size of both "Chapter Address" and "Unit ID" is 4 bytes. "Chapter Address" indicates the starting position of the audio data. "Unit ID" stores the ID of the receiving wireless terminal.

[0050] Next, a specific example of a list chunk will be described with reference to Figure 7. Figure 7 is a diagram showing an example of a list chunk in the system according to Embodiment 1. The data of the list chunk shown in Figure 7 is shown with signals separated into 4-byte segments.

[0051] The first data entry, C11, has "list" set as the chunk ID. The second data entry, C12, has "00 00 00 18" set as the chunk data size. In other words, in this example, the data size is set to 24 bytes (0x18). The third data entry, C13, has "adtl" set as the "Type ID". The fourth data entry, C14, has "00 40 00 00" set as the address. The next data entry, C15, has "00 00 00 01" set as the remote station ID.

[0052] Next, a specific example of a list chunk will be explained with reference to Figure 8. Figure 8 shows the method by which the communication device 10 reads a list chunk.

[0053] When the communication device 10 receives a signal from any other communication device, it reads it and determines whether the read data is list chunk data (step S101). If it does not determine that the data is list chunk data (step S101: NO), the communication device 10 terminates this process. If it determines that the read data is list chunk data (step S101: YES), the communication device 10 expands the list chunk into RAM (step S102).

[0054] Next, the communication device 10 obtains the data size of the list chunk expanded into RAM (step S103).

[0055] Next, the communication device 10 obtains the Type ID and determines whether or not the Type ID is adtl (step S104). If it is determined that the Type ID is not adtl (step S104), the communication device 10 terminates this process. If it is determined that the Type ID is adtl (step S104), the communication device 10 proceeds to step S105 and beyond.

[0056] In steps S105 to S110, the communication device 10 performs a read operation corresponding to the data size of the chunk data. Specifically, the communication device 10 repeats the following operations within the size of the chunk data: The communication device 10 obtains the address (step S106). Next, the communication device 10 advances the address to be read by 4 bytes (step S107). Next, the communication device 10 obtains the other station ID (step S108). Next, the communication device 10 advances the address to be read by 4 bytes (step S109). The communication device 10 repeats the above operations until the processing for the size of the data is completed (step S110). After the processing for the size of the data is completed, the communication device 10 terminates the operation.

[0057] Next, referring to Figure 9, we will explain the process of recording the ID of the receiving station when recording a received signal from another communication device. Figure 9 is a flowchart of the process of recording a received signal.

[0058] The communication device 10 determines whether or not there is an instruction to start recording the audio signal included in the received signal (step S111). If it is determined that there is no instruction to start recording the audio signal (step S111: NO), the communication device 10 repeats step S111. If it is determined that there is an instruction to start recording the audio signal (step S111), the communication device 10 proceeds to step S112.

[0059] In step S112, the communication device 10 obtains the ID of the receiving station included in the received signal (step S112).

[0060] Next, the communication device 10 determines whether the ID of the other station has changed compared to the previous recording process (step S113). If it is determined that the ID of the other station has not changed (step S113: NO), the communication device 10 proceeds to step S116. On the other hand, if it is determined that the ID of the other station has changed (step S113: NO), the communication device 10 proceeds to step S114.

[0061] In step S114, the communication device 10 adds the ID of the changed partner station (step S114).

[0062] Next, if the communication device 10 adds the ID of the other station, it adds the recording start address to the ID of the other station in the data to be recorded (step S115).

[0063] In step S116, the communication device 10 determines whether or not there is a recording stop instruction (step S116). If it is determined that there is no recording stop instruction (step S116: NO), the communication device 10 returns to step S112. If it is determined that there is a recording stop instruction (step S116: YES), the communication device 10 terminates the process.

[0064] Next, with reference to Figure 10, the talkback process performed by the communication device 10 during playback of recorded data will be described. Figure 10 is a flowchart showing the talkback process when playing back recorded audio.

[0065] First, the communication device 10 determines whether or not there is an instruction to play back the recorded data (step S121). If it does not determine whether or not there is an instruction to play back the recorded data (step S121: NO), the communication device 10 repeats step S121. If it determines that there is an instruction to play back the recorded data (step S121: YES), the communication device 10 proceeds to step S122.

[0066] In step S122, the communication device 10 obtains the playback address corresponding to the audio signal being played (step S122). Next, the communication device 10 displays a talkback message on the display unit 11 (step S123).

[0067] Next, the communication device 10 determines whether or not the PTT switch has been pressed (step S124). If it is determined that the PTT switch has not been pressed (step S124: NO), the communication device 10 returns to step S122. If it is determined that the PTT switch has been pressed (step S124: YES), the communication device 10 proceeds to step S125.

[0068] In step S125, the communication device 10 pauses audio playback (step S125). Furthermore, as talkback processing, the communication device 10 transmits a signal related to the audio picked up by the microphone 16 of the communication device 10 (step S126).

[0069] Next, the communication device 10 determines whether the pressed PTT switch has been released (step S127). If it is determined that the PTT switch has not been released (step S127: NO), the communication device 10 repeats step S127. If it is determined that the PTT switch has been released (step S127: YES), the communication device 10 terminates the transmission of the transmission signal (step S128).

[0070] Next, the communication device 10 resumes playback of the audio that was paused (step S129). Subsequently, the communication device 10 determines whether or not it has been instructed to stop the audio being played (step S130). If it does not determine that it has been instructed to stop the audio being played (step S130: NO), the communication device 10 returns to step S122 and repeats the process. If it determines that it has been instructed to stop the audio being played (step S130: YES), the communication device 10 terminates this process.

[0071] The communication device 10 according to Embodiment 1 has been described above. The communication device 10 according to Embodiment 1 may receive signals from other communication devices via a repeater, as shown in Figure 3, or it may receive signals directly without going through a repeater. With the above configuration and functions, the communication device 10 can transmit and receive two signals compliant with DMR.

[0072] Furthermore, if the communication device 10 receives a second reception signal in the second slot, for example, after receiving a first reception signal in the first slot, and then receives a second reception signal with higher priority than the first reception signal in the second slot, it switches the target of the audio output from the first slot of the first reception signal to the second slot of the second reception signal. In addition, the communication device 10 causes the recording device to start recording at least the audio signal from the first reception signal. This prevents the user from missing audio from a relatively lower-priority station.

[0073] Furthermore, if the communication device 10 is not receiving signals in either the first or second slot, and is playing back recorded audio data, it will transmit a transmission signal to the other station corresponding to the audio data being played back when the PTT switch is pressed. This allows the communication device 10 to easily resume communication with the other station corresponding to the recorded received signal.

[0074] As described above, this embodiment provides a communication device and the like that can suppress malfunctions caused by slot switching.

[0075] <Embodiment 2> Next, Embodiment 2 will be described. The communication device 10 according to Embodiment 2 differs from Embodiment 1 in that the processing performed by the control unit 18 is different.

[0076] The control unit 18 according to this embodiment will be described below. For ease of understanding, the following description will use as an example the case in which a first received signal is received in the first slot, and then a second received signal with higher priority than the first received signal is received in the second slot. In this case, the control unit 18 switches the target of the audio output from the first slot of the first received signal to the second slot of the second received signal. The control unit 18 may also cause the recording device to start recording at least the signals corresponding to the audio signal from the first received signal.

[0077] In this embodiment, if the reception of the first received signal is completed before the reception of the second received signal, the control unit 18 sets the first slot to enable transmission of a transmission signal for a preset first period after the completion of reception of the first received signal. The timing of the end of the preset first period may be no later than the completion of reception of the second received signal.

[0078] Furthermore, if the reception of the second received signal is completed before the reception of the first received signal, the control unit 18 sets the transmission slot to the second slot for a preset second period after the reception of the second received signal is completed. The preset second period is the normal response waiting time.

[0079] Furthermore, if the control unit 18 continues to receive the first received signal after the second period has ended, it continues to record the first received signal, and when the reception of the second received signal has ended, it starts the audio output of the stored first received signal, that is, playback of the received audio. Furthermore, during the preset second period after the reception of the first received signal has ended, the control unit 18 sets the transmission unit 23 to enable transmission of a transmission signal using the first slot.

[0080] If the control unit 18 continues to receive the first received signal after the second period has ended, and after the reception of the first received signal has ended, it sets the first slot as the transmission signal for the period from the end of the audio output of the audio signal in the first slot until the end of a preset third period. The end timing of the preset third period may be at the latest the end of the output of the recorded audio signal, i.e., the end of playback. In other words, after the first received signal has ended and while audio playback is in progress, the control unit 18 sets the slot used for transmission to the first slot.

[0081] Figure 11 is the first diagram illustrating the function of the communication device according to Embodiment 2. Figure 11 shows the status of signal transmission and reception between terminal A and terminals B and C, and the state of terminal A at that time, from top to bottom, along with the passage of time. More specifically, the state of terminal A is indicated from left to right by rectangles showing "1" or "2" for the recording slot, the audio output slot, the transmittable slot, and the receive slot, respectively.

[0082] At time T=T11, terminal B begins transmitting the signal for the first slot to terminal A. Upon receiving the signal from terminal B (the first received signal), terminal A outputs audio for the first slot and sets the transmittable slot to the first slot. Since the communication device 10 performs half-duplex communication, the transmission of a signal from terminal A to terminal B becomes possible only after terminal B has finished transmitting its signal.

[0083] Next, at time T12, following time T11, terminal C begins transmitting the signal for the second slot to terminal A. Here, the priority of the signal transmitted from terminal C is set higher than the priority of the signal transmitted from terminal B. When terminal A receives the signal for the second slot (second received signal), it reads the priority and switches the settings for the audio output slot and the transmittable slot to the second slot. As a result, the audio output from the speaker switches from the first received signal to the second received signal. Terminal A also begins recording the first received signal, which corresponds to the first slot, to the recording device.

[0084] Next, at time T13, following time T12, terminal B terminates the transmission of signals to terminal A. Consequently, terminal A terminates the recording of the first received signal in the recording device. The data from time T12 to time T13 shown in Figure 11 is referred to as recorded data D11.

[0085] Next, during the first period P11 from time T13 to time T15, the transmittable slot is set to the first slot. That is, the communication device 10 according to this embodiment allows the transmission of a signal to the first slot for a predetermined period immediately after the reception of the first slot is completed, even if the audio output from the speaker belongs to the second slot. In other words, the communication device 10 according to this embodiment temporarily permits transmission to terminal B during the first period P11, after the transmission of terminal B has finished but before the transmission of terminal C has finished, even if it is outputting audio of the received signal for terminal C. This allows the communication device 10 to notify the user of terminal B of the status of terminal A. The status of terminal A may be, for example, that it has not listened to the audio transmitted from terminal B from the middle, or that it is outputting a received signal from terminal C, which has a higher priority than terminal B. After the predetermined period has elapsed, if the communication device 10 continues to receive the second received signal from terminal C, it returns the transmittable slot to the second slot.

[0086] Next, at time T15, terminal C terminates the transmission of signals to terminal A. Consequently, the audio output terminates the setting of the second slot. Also, during the period P12 from time T15 to time T16, the communication device 10 continues to set the transmittable slot to the second slot. In other words, this period P12 is immediately after the second received signal transmitted from terminal C has stopped, and is the period during which the device is set to respond to terminal C.

[0087] Next, at any time T16 after the end of period P12, the communication device 10 may play back the recorded data D11 recorded by the recording device. When playback is started, the communication device 10 sets the destination and the available slots based on the recorded content, similar to Embodiment 1. For example, the communication device 10 sets the available slots to the first slot.

[0088] Next, at time T17, after time T16, playback of the recorded data D11 is completed. The communication device 10 may set the transmittable slot to the first slot from time T17 until time T18, after a predetermined period P13 has elapsed. This allows the communication device 10 to respond to terminal B regarding the audio that has finished playback.

[0089] Next, with reference to Figure 12, the processing of the communication device according to this embodiment will be further described. Figure 12 is a first sequence diagram showing the processing performed by the communication device according to Embodiment 2. The sequence diagram shown in Figure 12 corresponds to the operations of terminals A, B, and C shown in Figure 11.

[0090] First, terminal B begins transmitting a signal to terminal A (step S211). Next, terminal A receives the signal transmitted by terminal B as the first received signal in the first slot and outputs the audio corresponding to the first received signal from the speaker (step S212).

[0091] Next, terminal C begins transmitting a signal with a relatively higher priority to terminal A (step S213). Terminal A receives the signal transmitted by terminal C as the second received signal in the second slot (step S214). Communication device 10 compares the priority of the first received signal with the priority of the second received signal (step S215) and switches the audio output from the first received signal to the second received signal. Communication device 10 also begins recording the first received signal (step S216). Therefore, terminal A continues to output the audio of the second received signal, which is the signal transmitted from terminal C, while continuing to record the first received signal, which is the signal transmitted from terminal B.

[0092] Next, terminal B terminates the transmission of a signal to terminal A (step S217). Consequently, terminal A terminates the recording of the first received signal (step S218). At this point, terminal A continues to output the audio of the second received signal, but the user of terminal A can recognize, through a display or other notification means, that the signal from the first slot (the first received signal), which corresponds to the back slot mentioned earlier, has terminated.

[0093] Next, terminal A is configured to send a signal to terminal B during the first period P11 shown in Figure 11. Specifically, terminal A sets the first slot as the available transmission slot from the end of the transmission by terminal B using the first slot until the end of the transmission by terminal C using the second slot.

[0094] Terminal A determines whether an operation to respond to Terminal B has been performed by the user of Terminal A (step S219). That is, in the first period P11 shown in Figure 11, Terminal A determines whether an operation to transmit a signal to Terminal B has been performed by the user of Terminal A. If the user of Terminal A responds to Terminal B (step S219: YES), Terminal A transmits a predetermined message or any voice message uttered by the user of Terminal A to Terminal B (step S220). On the other hand, if the user of Terminal A does not respond to Terminal B (step S219: NO), Terminal A skips step S220. Next, Terminal C terminates the transmission of a signal to Terminal A (step S221). The above operations have been described as being performed by human operation, but it is also possible to configure the system so that a standardized message, for example, a message with the content "Your signal has been interrupted due to the reception of a priority signal," is automatically sent when the conditions for the above processing are met.

[0095] As a result, the transmission of information from the user of terminal B can be made less prone to malfunctions caused by the switching of slots due to the start of transmission by terminal C.

[0096] Next, we will explain the case where the transmission from terminal B shown in Figure 13 is completed first, that is, the case where the first received signal is completed first. Figure 13 is a second diagram for explaining the function of the communication device according to Embodiment 2. Figure 13 differs from the example in Figure 11 in that the transmission from terminal B to terminal A is completed after the transmission from terminal C to terminal A.

[0097] At time T=T21, terminal B begins transmitting the signal for the first slot to terminal A. Upon receiving the first received signal from terminal B, terminal A outputs audio for the first slot and sets the first slot as the available transmission slot.

[0098] Next, at time T22, following time T21, terminal C begins transmitting the signal for the second slot to terminal A. Here, as in the case shown in Figure 11, when terminal A receives the second received signal for the second slot, it reads the priority and switches the settings for the audio output slot and the transmittable slot to the second slot. As a result, the audio output from the speaker switches from the first received signal to the second received signal. Terminal A also begins recording the first received signal for the first slot to the recording device. The data from time T22 to time T25 shown in Figure 13 is referred to as recorded data D21.

[0099] Next, at time T23, following time T22, terminal C terminates the transmission of signals to terminal A. Consequently, terminal A terminates the audio output of the signal it was receiving in the second slot. Also, during the period P21 from time T23 to time T24, the communication device 10 continues to set the transmittable slot to the second slot. In other words, this period P21 is immediately after the second received signal transmitted from terminal C has stopped, and is the period during which the device is set to respond to terminal C.

[0100] Next, at time T24, when period P21 ends, terminal A starts playback of the recorded data D21 recorded by the recording device. If terminal B continues transmitting after time T24, terminal A continues recording to the recording device.

[0101] Next, at time T25, after time T24, if terminal B stops transmitting signals to terminal A, terminal A will stop recording the first received signal (recorded data D21) in the recording device. At this point, terminal A continues to play back (output audio) the recorded data D21, but the user of terminal A can recognize that the signal in the first slot (first received signal) has ended by means of a display or other notification means, such as the cessation of recording or the fact that the first received signal is no longer detected.

[0102] Next, in the second period P22 shown in Figure 13, terminal A is configured to allow the user of terminal A to transmit signals to terminal B. Specifically, terminal A sets the first slot to be transmittable from the time when terminal B finishes transmitting using the first slot (time T25) until the end of playback of recorded data D21 (time T26). Also, if terminal B finishes transmitting during period P21, terminal A starts playback of recorded data D21 after the end of period P21, since terminal B has already finished transmitting using the first slot, and sets the first slot to a transmittable slot. In other words, according to the second embodiment, the communication device 10 sets the first slot to a transmittable slot when terminal A has started playback of recorded data D21 and the first received signal has finished.

[0103] Next, at time T26, after time T25, playback of the recorded data D21 is completed. The communication device 10 may maintain the setting of the first transmittable slot from time T26 until time T27, after the predetermined third period P22 has elapsed. This allows the communication device 10 to respond to terminal B regarding the audio that has finished playback.

[0104] Next, with reference to Figure 14, the processing in the situation shown in Figure 13 will be further explained. Figure 14 is a second sequence diagram showing the processing performed by the communication device according to Embodiment 2.

[0105] First, terminal B begins transmitting a signal to terminal A (step S311). Next, terminal A receives the signal transmitted by terminal B as the first received signal in the first slot and outputs the audio corresponding to the first received signal from the speaker (step S312).

[0106] Next, terminal C begins transmitting a signal with a relatively high priority to terminal A (step S313). Terminal A receives the signal transmitted by terminal C as the second received signal in the second slot (step S314). The communication device 10 compares the priority of the first received signal with the priority of the second received signal (step S315), switches the audio output from the first received signal to the second received signal, and begins recording the first received signal (step S316).

[0107] Next, terminal C ends transmitting a signal to terminal A (step S317). Accordingly, terminal A determines whether or not to respond to terminal C (step S318). That is, during the period P21 shown in Figure 13, terminal A determines whether or not the user of terminal A will transmit a signal to terminal C. If it is determined to respond to terminal C (step S318: YES), terminal A transmits a predetermined message or any voice message uttered by the user of terminal A to terminal C (step S319). On the other hand, if it is determined not to respond to terminal C (step S318: NO), terminal A skips step S319.

[0108] Next, terminal A starts playing back the recorded first received signal (recorded data D21) after period P21 has ended (step S320).

[0109] Next, terminal A continues recording the first received signal while continuing to play back the recorded first received signal. Terminal B ends transmitting a signal to terminal A (step S321). Consequently, terminal A ends recording the first received signal (step S322). Furthermore, terminal A ends playing back the first received signal (step S323).

[0110] Terminal A determines whether an operation to respond to Terminal B has been performed by the user of Terminal A (step 324). That is, in the second period P22 shown in Figure 13, Terminal A determines whether an operation to send a signal to Terminal B has been performed by the user of Terminal A. If the user of Terminal A responds to Terminal B (step S324: YES), Terminal A sends a predetermined message or any voice message uttered by the user of Terminal A to Terminal B (step S325). On the other hand, if the user of Terminal A does not respond to Terminal B (step S324: NO), Terminal A skips step S325. The above operations have been described as being performed by human operation, but it is also possible to configure the system so that a standardized message, for example, a message with the content of "Your signal has been interrupted due to the reception of a priority signal," is automatically sent when the conditions for the above processing are met.

[0111] Furthermore, when the communication device 10 responds during the playback of the first received signal, it may temporarily suspend the playback process of the recorded data D21 when the PTT switch is pressed, and resume playback after the PTT switch is released.

[0112] Embodiment 2 has been described above. As described above, in the communication device 10 according to Embodiment 2, if the transmission of the first slot, which has a relatively lower priority, is completed before the transmission of the second slot, which has a relatively higher priority, the device temporarily makes it possible to respond to terminal B related to the first slot.

[0113] In this case, the communication device 10 cannot transmit spoken audio to terminal B while simultaneously listening to audio transmitted from terminal C. Therefore, for example, the communication device 10 may send a predetermined text message to terminal B under such circumstances.

[0114] As described above, according to Embodiment 2, it is possible to provide a communication device, etc., that suppresses malfunctions caused by slot switching.

[0115] <Embodiment 3> Next, Embodiment 3 will be described. The communication device 10 according to Embodiment 3 differs from the above-described embodiment in that it can transmit a predetermined interrupt request signal to a remote station that is transmitting a signal to itself.

[0116] The interrupt request signal in this embodiment is a signal transmitted at a predetermined timing from a receiving communication device to a transmitting communication device when performing a "call interruption" in the DMR standard. Call interruption is a technique in which a receiving station that is transmitting a signal switches to receiving mode for a predetermined period (for example, the duration of one slot) at a predetermined timing, and when the receiving station that is transmitting a signal to the local station switches to receiving mode as described above, the local station (communication device) sends an interrupt request signal, and the receiving station that receives the interrupt request signal interrupts transmission. The information regarding the predetermined timing is transmitted from the receiving station to the local station before that predetermined timing occurs. The communication device 10 in this embodiment is configured to transmit interrupt request signals to other communication devices, and other communication devices are configured to receive interrupt request signals.

[0117] In this embodiment, the control unit 18, after receiving a first received signal in the first slot, and then receiving a second received signal with higher priority than the first received signal in the second slot, switches the target of the audio output from the first slot of the first received signal to the second slot of the second received signal, and also sends an interrupt request signal as a transmission signal to the source of the first received signal.

[0118] Figure 15 is a first sequence diagram showing the processing performed by the communication device according to Embodiment 3. The sequence diagram in Figure 15 differs from the sequence diagram in Figure 12 in that the processing between step S215 and step S219 is different. Furthermore, the sequence diagram in Figure 15 is the same as the sequence diagram in Figure 12, except for the differences described above.

[0119] In this embodiment, terminal A, the communication device 10 compares the priority of the first received signal with the priority of the second received signal (step S215), and switches the audio output from the first slot of the first received signal to the second slot of the second received signal (step S410). At this point, terminal A starts outputting the audio signal related to the second received signal, while continuing to detect the first received signal. Terminal A also activates notification means to indicate that it is continuing to receive the first received signal. That is, for example, terminal A lights up an LED or the like that indicates that it is receiving the first received signal, such as the "Back Slot Busy" display mentioned above. Terminal A may also start recording the first signal, as in Embodiments 1 and 2.

[0120] Next, terminal A sends an interrupt request signal to terminal B (step S411). Terminal A may be configured to send this interrupt request signal automatically. Alternatively, terminal A may be configured to send this interrupt request signal in response to user operation.

[0121] Terminal B transmits a transmission signal to Terminal A while simultaneously receiving an interrupt request signal. Upon recognizing the interrupt request signal sent from Terminal A, Terminal B terminates the transmission of the transmission signal to Terminal A (step S412). In this case, for example, Terminal B may display a message on its display indicating that an interrupt request signal has been received. The user of Terminal B can recognize that transmission to Terminal A has stopped, that is, that transmission has stopped due to a call interruption, by viewing the message displayed on Terminal B's display. The user of Terminal B cancels the transmission operation because a call interruption has been received.

[0122] Meanwhile, terminal A receives a transmission signal from terminal C, i.e., a second reception signal, and outputs audio while waiting for the transmission from terminal B, i.e., the first reception signal, to end. Since terminal A continues to detect the first reception signal, it can recognize that terminal B has stopped transmitting when the detection of the first reception signal is interrupted. For example, terminal A may stop displaying the "Back Slot Busy" message or using other notification means such as LEDs, or it may notify terminal B that it has stopped transmitting by displaying "Back Slot Open" or using LEDs of a different color, indicating that the back slot is empty.

[0123] Next, terminal A determines whether or not to respond to terminal B (step S219). That is, similar to embodiment 2, terminal A determines whether or not the user of terminal A will send a signal to terminal B during the first period P11 shown in Figure 11. If it is determined to respond to terminal B (step S219: YES), terminal A sends a predetermined message or any voice uttered by the user of terminal A to terminal B (step S220). On the other hand, if it is determined not to respond to terminal B (step S219: NO), terminal A skips step S220. Embodiment 3 differs from embodiment 2 in that terminal A performs a call interruption to stop terminal B from transmitting. In embodiment 2, the processing differs depending on whether the first received signal or the second received signal ends first, but in embodiment 3, the first received signal can be terminated first by a call interruption immediately after the start of reception of the second received signal.

[0124] In Embodiment 3, terminal A can stop terminal B from transmitting. Therefore, terminal A may then start transmitting to terminal B regardless of the user's decision. However, depending on the content of the second received signal, it may be necessary to listen to its content. For this reason, terminal A may leave the decision of whether or not to transmit to the user of terminal A. In any case, the slot set for transmission during the period when the second received signal is being received is not the slot for the second received signal that is currently being received and outputting audio, but rather the slot for the first received signal, that is, the slot that was used for communication with terminal B.

[0125] Embodiment 3 has been described above. Note that Embodiment 3 does not necessarily have a recording device 14. However, if terminal A, which is the communication device 10 according to this embodiment, is configured to transmit an interrupt request signal, it may be equipped with a recording device 14, and the first received signal may be recorded in the recording device 14. In other words, the user of terminal A can choose to either forcibly stop terminal B's transmission by making an interrupt request, or wait until terminal B's transmission is completed while recording the transmission.

[0126] As described above, according to Embodiment 3, it is possible to provide a communication device, etc., that suppresses malfunctions caused by slot switching.

[0127] <Embodiment 4> Next, Embodiment 4 will be described. Embodiment 4 includes a recording device 14 that determines the priority level of the second received signal and decides whether to make an interrupt request or to record. In other words, Embodiment 4 differs from Embodiment 3, in which the transmission of the interrupt request signal was left to the user's operation, in the points described above.

[0128] Throughout this disclosure, it is consistently explained that when the priority of the second received signal is higher than that of the first received signal, the communication device 10 switches the signal to which it outputs audio to the second received signal. In the case of Embodiment 2, the content transmitted by the first received signal may be recorded, and it is possible for the user of terminal A to be fully aware of the content from terminal B. However, in the case of Embodiment 3, terminal A stops the first received signal midway. Therefore, it is not the case that all the content that terminal B wanted to transmit is conveyed to the user of terminal A. Furthermore, regarding whether or not to record the first received signal, Embodiment 3 states that this may be determined by whether or not the user of terminal A performs an interrupt request operation. In this embodiment, the decision of whether or not to record the first received signal is determined by the difference in priority between the first received signal and the second received signal, or by the absolute priority.

[0129] In Embodiment 4, the control unit 18 determines and controls whether to record the first received signal or send an interrupt request signal (call interruption) to the source of the first received signal, based on the priority relationship between the first received signal and the second received signal. More specifically, the control unit 18 determines and controls whether to record the first received signal or send an interrupt request signal (call interruption) to the source of the first received signal, based on the difference in priority between the first received signal and the second received signal or their absolute priority. The control unit 18 may quantify the priority based on the priority information output from the baseband signal processing unit 19. For example, an emergency call might be assigned a value of 3, an intra-group communication a value of 3, and an individual communication a value of 1. The criteria for determination are that if the difference is 1, the signal is recorded, and if the difference is 2, a call interruption is performed. Alternatively, the determination may be that if the second received signal is an emergency call, a call interruption is performed, and otherwise, the signal is recorded.

[0130] Figure 16 is a sequence diagram showing the process performed by the communication device according to Embodiment 4. The sequence diagram in Figure 16 shows an example where the priority included in the first received signal is lower than the priority included in the second received signal, in other words, the priority included in the second received signal is higher than the priority included in the first received signal. Naturally, if the priority included in the first received signal is higher than the priority included in the second received signal, terminal A continues to output audio related to the first received signal received from terminal B.

[0131] In this embodiment, terminal A compares the priority included in the first received signal received from terminal B with the priority included in the second received signal received from terminal C (step S215).

[0132] As described above, terminal A continues to receive the first received signal if the priority of the second received signal is lower than the priority of the first received signal. If the priority of the second received signal is higher than the priority of the first received signal, terminal A switches to the audio output of the second received signal (step S510).

[0133] Next, terminal A determines whether the priority of the second received signal is higher than the priority of the first received signal, and whether the priority of the first received signal and the priority of the second received signal satisfy a predetermined relationship. More specifically, terminal A determines whether terminal B is the target of the interrupt request based on the relationship between the priority of the first received signal and the priority of the second received signal (step S511). If terminal B is determined to be the target of the interrupt request (step S511: YES), terminal A sends an interrupt request signal to terminal B (step S512). In this case, terminal A also skips step S513, which will be described later.

[0134] On the other hand, if terminal B does not determine that it is the target of an interrupt request (step S511: NO), terminal A starts recording the first received signal (step S513).

[0135] If the answer to step S511 is YES, terminal A performs the same processing as shown in Figure 16, which is the same processing as the processing after step S411 shown in Embodiment 3. That is, terminal A stops terminal B's transmission in response to the interrupt request signal and switches the transmission slot to the slot that was used for communication with terminal B until terminal C's transmission stops.

[0136] On the other hand, if the answer in step S511 is NO, terminal A performs the same processing as shown in Figure 16, which is the same processing as the processing after step S216 or step S316 shown in Embodiment 2. That is, terminal A continues to record the first received signal from terminal B while outputting the audio of the second received signal. The processing differs depending on whether the transmission from terminal B or terminal C finishes first, as in Embodiment 2.

[0137] Embodiment 4 has been described above. In this embodiment, the priority may be set by quantifying the priority and setting it according to its absolute value, or, for example, the relative correspondence between the priority of the signal in the first slot and the priority of the signal in the second slot may be set individually. As explained earlier, if the priority of the second received signal (signal in the second slot) is lower than the priority of the first received signal (signal in the first slot), the audio output will continue to output the audio of the first received signal and will not switch to the second received signal.

[0138] In other words, suppose the system is configured to send an interrupt request signal to the first slot if, for example, the priority of the first received signal is "2" and the priority of the second received signal is higher than 2, namely "3". In this case, it would also be possible to configure the system so that if the priority of the first received signal is "1" and the priority of the second received signal is "3", no interrupt request signal is sent to the first slot.

[0139] By individually setting responses according to priority in this manner, the communication device 10 according to this embodiment can flexibly configure responses due to slot switching. In summary, according to Embodiment 4, it is possible to provide a communication device, etc., that suppresses malfunctions caused by slot switching.

[0140] The program described above includes, when loaded into a computer, a set of instructions (or software code) for causing the computer to perform one or more of the functions described in the embodiments. The program may be stored on a non-temporary computer-readable medium or a physical storage medium. Examples, but not limited to, include random-access memory (RAM), read-only memory (ROM), flash memory, solid-state drive (SSD) or other memory technologies, CD-ROM, digital versatile disc (DVD), Blu-ray® disc or other optical disc storage, magnetic cassette, magnetic tape, magnetic disk storage or other magnetic storage devices. The program may be transmitted over a temporary computer-readable medium or a communication medium. Examples, but not limited to, include temporary computer-readable medium or a communication medium that includes electrically, optically, acoustically or otherwise propagating signals.

[0141] It should be noted that the present invention is not limited to the embodiments described above, and can be modified as appropriate without departing from the spirit of the invention. [Explanation of Symbols]

[0142] 10. Communication equipment 11 Display section 12 Control section 13 Peripheral area 14 Recording device 15 speakers 16 Microphones 17 Antenna 18 Control Unit 19 Baseband signal processing unit 20 Audio signal decoding unit 21 Audio signal processing unit 22 Transmitter / Receiver 23 Transmitter 24 Receiving Unit 25 RF Switch Section 26 PTT switches 27 Non-volatile memory 100 Signal Processing Blocks 101 Digital signal detection unit 102 Chapter Generation Unit 104 Receiving audio conversion unit 105 Recording Data Generation Unit 106 Recording Audio Control Unit 107 Audio signal extraction unit 108 Ancillary Information Extraction Unit 109 PTT operation detection unit 110 Audio output control unit 111 Display Control Unit

Claims

1. The receiving circuit receives data in the first or second slot using a time-division multiplex access scheme. and, The transmission signal corresponding to the first or second slot is transmitted via the time-division multiplexed access A transmitting circuit that transmits using a half-duplex communication method, The first received signal received in the first slot or the second received signal received in the second slot Audio signal decoding cycle: Set one of the signals as the target for audio output and decode the audio signal. Road and, From the information contained in the first received signal and the second received signal, the priority for audio output is determined. A baseband signal processing circuit that determines priority and outputs information regarding priority, The slot that receives the first received signal is the target of the audio output in the audio signal decoding circuit. It is set as the first slot of the transmission circuit and is set as the first slot of the transmission circuit. After that, the second received signal, which has a higher priority than the first received signal, is sent to the second slot. When received, the target of the audio output is determined based on the priority information of the first received signal. The transmission circuit switches from the first slot of the second received signal to the second slot of the second received signal. The state in which the first slot is set continues, and the transmission circuit is the first reception Control to send an interrupt request signal to the signal source in the first slot. Circuits and, A communication device equipped with the following features.

2. The control circuit switches the target of the audio output from the first received signal to the second received signal. If this occurs, the detection of the first received signal will be continued. The control circuit, from the moment the detection of the first received signal is interrupted, the second received signal During the period until the unit stops, the setting of the slot on which the transmission is performed by the transmission circuit is set to the first slot Continue in batches. The communication device according to claim 1.

3. The control circuit is configured such that the transmitting circuit is configured to send the first received signal to the source of the first receiving signal via the first slot After controlling the system to send an interrupt request signal, If the reception of the second received signal is completed before the reception of the first received signal, the transmission Switch the transmission slot of the signal circuit to the second slot. The communication device according to claim 1.

4. The recording device further comprises a recording device configured to record the first received signal or the second received signal. picture, The control circuit then processes the slot that received the first received signal into the audio signal decoding circuit. The first slot is set as the target of the audio output, and the first of the transmission circuit After setting it in the slot, the second received signal, which has a higher priority than the first received signal When the number is received in the second slot, the first slot, which is the slot with the lower priority, The recording device is instructed to start recording the first received signal received by the net. The communication device according to claim 1 or 2.

5. A communication method that performs half-duplex communication using a time-division multiplexing access scheme with two slots, The system receives the first received signal from the first of the two aforementioned slots and outputs audio. The steps include setting the transmission setting of the transmission circuit to the first slot, A step of detecting the signal of a second slot that is different from the first slot, When a signal from the second slot is detected, the second slot starts receiving signals. Priority determined from information contained in the received signal, and priority determined from information in the first received signal Compared to the previous time, if the priority for outputting the audio of the second received signal is higher, the second received The steps include switching to audio output of the signal and continuing the settings in the first slot, The transmission circuit remains in the state set to the first slot, and the first reception The step of sending an interrupt request signal to the source of the signal, Communication method.

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