Determination device, determination method that determines process related to reproduction of speech signal

An input unit receives a request for transmission of a speech signal to a predetermined group. When the request for transmission is received in the input unit, a determination unit determines a process related to reproduction of the speech signal in a terminal device expected to receive a speech, based on a distance between terminal devices expected to receive the speech signal, excluding the terminal device outputting the request from a plurality of terminal devices belonging to the predetermined group. An output unit outputs the detail determined in the determination unit.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2017-040108, filed on Mar. 3, 2017, the entire contents of which are incorporated herein by reference.

BACKGROUND

The present invention relates to communication technology and, more particularly, to a determination device and determination method for determining a process related to reproduction of a speech signal.

2. Description of the Related Art

For the purpose of realizing smooth group calls, a terminal device to connect to is selected from terminal devices belonging to the same group, by measuring a distance between a caller and a receiver by using at least position information. This inhibits reception in a terminal device in the neighborhood of the caller and promotes clarity of the call (see, for example, patent document 1).

In the related art document, the distance between the caller and the receiver is considered but the distance between receivers is not considered. When a plurality of terminal devices located in the neighborhood of each other reproduce the same speech, it would be difficult to hear the speech clearly due to the speech heard around. When a delay that differs from one terminal device to another occurs while the speech is reproduced, it would be further difficult to hear the speech. Further, since all of the terminal devices belonging to the same group reproduce the speech, electric power is consumed in all of the terminal devices.

SUMMARY

To address the aforementioned issue, a determination device according to an embodiment comprises: an input unit that receives a request for transmission of a speech signal to a predetermined group; and a determination unit that determines a process related to reproduction of the speech signal in a terminal device expected to receive a speech, based on a distance between terminal devices expected to receive the speech signal, excluding the terminal device outputting the request from a plurality of terminal devices belonging to the predetermined group.

Another embodiment also relates to a determination device. The device comprises: an input unit that receives a request for transmission of a speech signal to a predetermined group; and a determination unit that determines a process related to reproduction of the speech signal in a terminal device expected to receive a speech, based on a distance between the terminal device expected to receive the speech signal and a user using the terminal device expected to receive the speech signal, excluding the terminal device outputting the request from a plurality of terminal devices belonging to the predetermined group.

Still another embodiment relates to a determination method. The method comprises: receiving a request for transmission of a speech signal to a predetermined group; and determining a process related to reproduction of the speech signal in a terminal device expected to receive a speech, based on a distance between terminal devices expected to receive the speech signal, excluding the terminal device outputting the request from a plurality of terminal devices belonging to the predetermined group.

Still another embodiment relates to a determination method. The method comprises: receiving a request for transmission of a speech signal to a predetermined group; and determining a process related to reproduction of the speech signal in a terminal device expected to receive a speech, based on a distance between the terminal device expected to receive the speech signal and a user using the terminal device expected to receive the speech signal, excluding the terminal device outputting the request from a plurality of terminal devices belonging to the predetermined group.

Optional combinations of the aforementioned constituting elements, and implementations of the embodiments in the form of methods, apparatuses, systems, recording mediums, and computer programs may also be practiced as additional modes of the embodiments.

DETAILED DESCRIPTION

A summary will be given before describing the invention in specific details. Embodiment 1 relates to a communication system in which group calls are made in a group including a plurality of terminal devices. Group calls are made by using a Push to Talk (PTT) service. In PTT, the user pushes a button to start a conversation and releases the button when the conversation is terminated. One of the terminal devices in a group transmits a speech signal and the other terminal devices in the group receive speech data. Therefore, all of the terminal devices reproduce a speech even when users carrying the plurality of terminal devices belonging to the same group are located at distances where the users can hear the speech reproduced by the terminal devices sufficiently. This makes the same speech heard from a plurality of locations and makes it difficult for users to catch the speech. When a speech reproduction delay inherent to terminal devices occurs, reproduction of the speech is timed differently in those devices so that users find it even more difficult to catch the speech. Because all of the terminal devices belonging to the same group reproduce the speech, electric power is consumed in all of the terminal devices. To address this, the embodiment selects a recipient terminal device to which the speech signal should be transmitted, based on the distance between the terminal devices expected to receive the speech.

FIG. 1shows a configuration of a communication system100. The communication system100includes a first terminal device10a, a second terminal device10b, a third terminal device10c, a fourth terminal device10d, a fifth terminal device10e, which are generically referred to as terminal devices10, and a call controller20. The number of terminal devices10is not limited to “5”. The communication system100includes a base station device (not shown). The base station device performs wireless communication with the terminal devices10and performs wired communication with the call controller20. Therefore, the base station device relays communication between the terminal devices10and the call controller20. An example of the communication system100like this is a business wireless system.

Identification information (hereinafter, also referred to as “UID”) identifying the terminal device10is assigned to each terminal device10. For example, the UID of the first terminal device10ais “1”, the UID of the second terminal device10bis “2”, and the UID of the third terminal device10cis “3”. Further, a plurality of terminal devices10form a group. Identification information (hereinafter, referred to as “GID”) identifying a group is assigned to each group. For example, “GID=1” is set for the first terminal device10athrough the fifth terminal device10e. Each terminal device10acquires position information and transmits a position notification200including the position information to the call controller20. The process is performed periodically. The call controller20receives the position notification200from the terminal devices10and manages the position information of the terminal devices10.

FIG. 2shows a configuration of the terminal device10. The terminal device10includes a position information acquisition unit30, a transmission instruction unit32, a speech input unit34, a speech output unit36, a controller38, a storage unit40, and a communication unit42. The storage unit40stores the UID and GID for identifying the terminal device10. The position information acquisition unit30is comprised of, for example, a Global Positioning System (GPS) wave receiver and acquires current position information of the terminal device10. For example, the position information is comprised of latitude and longitude.

The controller38generates the position notification200when necessary (e.g., every 10 seconds).FIG. 3shows a data structure of the position notification200generated in the terminal device10. The position information acquired by the position information acquisition unit30and the UID stored in the storage unit40are set in the position notification200. Reference is made back toFIG. 2. The communication unit42transmits the position notification200generated in the controller38to the call controller20. The other constituting elements inFIG. 2will be discussed later.

The features are implemented in hardware such as a CPU, a memory, or other LSI's, of a computer and in software such as a program loaded into a memory. The figure depicts functional blocks implemented by the cooperation of these elements. Therefore, it will be obvious to those skilled in the art that the functional blocks may be implemented in a variety of manners by hardware only, by software only, or by a combination of hardware and software.

FIG. 4shows a configuration of the call controller20. The call controller20includes a communication unit50and a determination device60. The determination device60includes an input unit70, a storage unit72, a determination unit74, and an output unit76. The communication unit50communicates with the terminal device10via the base station device. The input unit70receives the position notification200from each terminal device10via the communication unit50when necessary (e.g., every 10 seconds). The input unit70outputs the position notification200to the storage unit72.

The storage unit72stores a database.FIG. 5shows a data structure of a database stored in the storage unit72. The UIDs of the terminal devices10and the position information are mapped to each other in the database (hereinafter, referred to as “position database”). The position database is created based on the position notification200received from the input unit70.FIG. 6shows a data structure of a further database stored in the storage unit72. In the further database (hereinafter, referred to as “GID database”), the GIDs of the groups and the UIDs of the terminal devices10belonging to the groups are mapped to each other. The other constituting elements inFIG. 4will be described later.

FIG. 7shows a configuration of the communication system100relevant to the process that follows the process inFIG. 1. The first terminal device10arepresents the terminal device10at the transmitting end, and the other terminal devices10represent the terminal devices expected to receive the speech. The terminal device10transmits a group call transmission request202to the call controller20to initiate a group call. Referring toFIG. 2, the transmission instruction unit32of the terminal device10is comprised of, for example, a PTT button, which is switched into a pressed state or a released state (non-pressed state) according to the user operation. The speech input unit34is comprised of, for example, a microphone. The speech input unit34collects a speech of the user and converts the speech into an electrical signal.

The controller38detects the pressed state of the transmission instruction unit32and, while the pressed state is being detected, generates the group call transmission request202.FIG. 8shows a data structure of the group call transmission request202generated in the terminal device10. The UID stored in the storage unit40is set in the transmission source UID of the group call transmission request202. The GID stored in the storage unit40is set in the transmission source GID of the group call transmission request202. Information of the electrical signal produced by conversion in the speech input unit34is set in the speech information in the group call transmission request202. Reference is made back toFIG. 2. The communication unit42transmits the group call transmission request202generated in the controller38to the call controller20.

The input unit70of the call controller20ofFIG. 4receives the group call transmission request202from the terminal device10(e.g., the first terminal device10a) via the communication unit50. The group call transmission request202can be said to be a request to transmit a speech signal to a predetermined group. When the input unit70receives the group call transmission request202, the determination unit74performs the subsequent process.

(1) The determination unit74receives the group call transmission request202from the input unit70.

(2) The determination unit74refers to the GUI database stored in the storage unit72and identifies the UIDs of the terminal devices10belonging to the group of the transmission destination GID in the input group call transmission request202. Given that the transmission destination GID of the group call transmission request202is 1, for example, 1, 2, 3, 4, 5 are identified as the UIDs.

(3) When the transmission source UID of the group call transmission request202is included in the UIDs identified in (2) above, the determination unit74excludes the UID from the identified UIDs. Given that the transmission source ID of the group call transmission request202is 1, the identified UIDs will be 2, 3, 4, 5.

(5) The determination unit74subjects each subgroup identified in (4) above to the following determination.

(5-1) The determination unit74identifies UIDs that are identified in (3) above and that are not included in each subgroup identified in (4) above. In the case of the subgroup “(i) 3, 5”, for example, the UIDs 2, 4 are identified.

(5-2) The determination unit74refers to the position database and determines whether the position indicated by the position information corresponding to the respective UIDs identified in (5-1) above is within a threshold value from any of the position information corresponding to the UIDs included in the relevant subgroup. For example, the threshold value is 3 m. The threshold value is shown inFIG. 7as a second determination range12bfor the second terminal device10b. The third determination range12cthrough the fifth determination range12eare similar. For example, a determination is made as to whether the position information2is within the predetermined distance of 3 m from the position information3or the position information5. Further, a determination is made as to whether the position information4is within the predetermined distance of 3 m from the position information3or the position information5.

(5-3) The determination unit74identifies a subgroup for which all determinations made in (5-2) have found that the position information is within the threshold value. For example, the subgroup “(i) 3, 5” is identified.

(6) The determination unit74identifies the UIDs included in the subgroup identified in (5-3) as the transmission destination UIDs. For example, the determination unit74determines the transmission destination UIDs to be 3, 5. When a plurality of subgroups are identified in (5-3), the determination unit74identifies one subgroup based on a predetermined condition (e.g., a subgroup including fewer UIDs) and determines the transmission destination UIDs accordingly. The terminal device10may transmit the battery level to the call controller20periodically, the storage unit72may store the battery level of the terminal devices10, and the determination unit74may determine the recipient terminal device10based on the battery level of the terminal devices10expected to receive the speech. In this process, it is ensured that the terminal device10with a low battery level is not selected.

In other words, the determination unit74determines the recipient terminal device10that should receive the speech signal, based on the distances between the terminal devices10expected to receive the speech, excluding the terminal device10outputting the transmission request from the plurality of terminal devices10belonging to the predetermined group. Determining the recipient terminal device10that should receive the speech signal represents determining a process related to the reproduction of the speech signal in the terminal device10expected to receive the speech. For determination of the recipient terminal device10that should receive the speech signal, a result of comparison between the distance between the terminal devices10expected to receive the speech and the threshold value is used. According to the aforementioned example, the distances between the terminal devices excluding the terminal device10outputting the transmission request are indicated as the distance between the position information2and the position information3, the distance between the position information2and the position information4, the distance between the position information2and the position information5, the distance between the position information3and the position information4, the distance between the position information3and the position information5, and the distance between the position information4and the position information5.

(7) The determination unit74generates a specified transmission destination call204.FIG. 9shows a data structure of the specified transmission destination call204generated in the call controller20. The specified transmission destination call204is comprised of the transmission destination UID identifying one or a plurality of transmission destination terminal devices10and speech information. The determination unit74sets the transmission destination UIDs determined in (6) above in the transmission destination UIDs of the specified transmission destination call204. For example, 3 and 5 are set. Further, the determination unit74sets the input speech information in the speech information of the specified transmission destination call204. Reference is made back toFIG. 4. The output unit76outputs the specified transmission destination call204determined in the determination unit74to the communication unit50, and the communication unit50transmits the specified transmission destination call204via the base station device. For example, the communication unit50broadcasts the specified transmission destination call204.

FIG. 10shows a configuration of the communication system100relevant to the process that follows the process inFIG. 7. As described above, the call controller20broadcasts the specified transmission destination call204destined to the third terminal device10cand the fifth terminal device10e. The communication unit42of the terminal device10ofFIG. 2receives the specified transmission destination call204from the call controller20. The controller38receives an input of the transmission destination UIDs of the specified transmission destination call204received in the communication unit42. The controller38determines whether any one of the UIDs set in the transmission UIDs matches the UID stored in the storage unit40. If a match is found, the controller38receives an input of the speech information of the specified transmission destination call204. If a match does not occur, the controller38does not receive an input of the speech information of the specified transmission destination call204. For example, the speech output unit36is comprised of a speaker. When the controller38receives an input of the speech information, the speech output unit36reproduces a speech based on that speech information.

A description will now be given of the operation of the communication system100with the above configuration.FIG. 11is a sequence chart showing a communication procedure in the communication system100. The first terminal device10athrough the fifth terminal device10etransmit the position notification200to the call controller20(S10-S18). The call controller20stores the position information (S20). The first terminal device10atransmits the group call transmission request202to the call controller20(S22). The call controller20generates the specified transmission destination call204(S24). The call controller20broadcasts the specified transmission destination call204to the first terminal device10athrough the fifth terminal device10e(S26˜S34). The first terminal device10athrough the fifth terminal device10emake a determination to see whether the UIDs match (S36˜S44). The third terminal device10creproduces the speech (S46), and the fifth terminal device10ereproduces the speech (S48).

The determination unit74as described so far determines the recipient terminal device10that should receive the speech signal by comparing the distance between the terminal devices10expected to receive the speech with the threshold value. In this process, the threshold value is defined to be a fixed value. The threshold value may be variable in order to adjust the recipient terminal device10that should be determined. In the following, variations directed to configuring the threshold value to be variable will be described.

Referring toFIG. 2, the controller38of each terminal device10acquires information set in the speech output unit36and related to the sound volume of reproduced speech signal (hereinafter, referred to as “sound volume setting information”). Further, the controller38transmits the sound volume setting information to the call controller20via the communication unit42. Referring toFIG. 4, the communication unit50of the call controller20receives the sound volume setting information from each terminal device10. The storage unit72receives the sound volume setting information from each terminal device10via the input unit70and stores the received information.FIG. 12shows a data structure of a database stored in the storage unit72. The sound volume setting information is added to the position database. For example, the larger the value of the sound volume setting information, the larger the reproduced sound volume. Reference is made back toFIG. 4. In (5-2) above, the determination unit74changes the threshold value in accordance with the sound volume of reproduced speech signal set in the terminal device10of the UID included in the subgroup. For example, it is ensured that the larger the reproduced sound volume, the larger the threshold value.

Referring toFIG. 2, the controller38of each terminal device10acquires information set in the speech output unit36and related to a method of reproducing the speech signal (hereinafter, referred to as “reproduction method information”). The method of reproducing the speech signal is, for example, “headset” or “speaker”. Further, the controller38transmits the reproduction method information to the call controller20via the communication unit42. Referring toFIG. 4, the communication unit50of the call controller20receives the reproduction method information from each terminal device10. The storage unit72receives the reproduction method information from each terminal device10via the input unit70and stores the received information.FIG. 13shows a data structure of a database stored in the storage unit72. The reproduction method information is added to the position database. For example, the headset or the speaker is indicated. Reference is made back toFIG. 4. In (5-2) above, the determination unit74changes the threshold value in accordance with the method of reproducing the speech signal set in the terminal device10of the UID included in the subgroup. For example, the threshold value is set to 3 m in the case of the speaker and to 0 m in the case of the headset.

Referring toFIG. 2, the controller38of each terminal device10acquires environmental sound around the terminal device10via the speech input unit34. Further, the controller38generates information related to environmental sound volume (hereinafter, referred to as “environmental sound volume information”) based on the sound volume of the environmental sound. Further, the controller38transmits the environmental sound volume information to the call controller20via the communication unit42. Referring toFIG. 4, the communication unit50of the call controller20receives the environmental sound volume information from each terminal devices10. The storage unit72receives the environmental sound volume information from each terminal devices10via the input unit70and stores the received information.FIG. 14shows a data structure of a database stored in the storage unit72. The environmental sound volume information is added to the position database. For example, the larger the value of the environmental sound volume information, the larger the environmental sound volume. A situation with a large environmental sound volume represents a situation with a large noise. Reference is made back toFIG. 4. In (5-2) above, the determination unit74changes the threshold value in accordance with the environmental sound volume around the terminal device10expected to receive the speech. For example, it is ensured that the larger the environmental sound volume, the smaller the threshold value.

Referring toFIG. 4, the storage unit72of the call controller20stores aural characteristic information on the user using the terminal device10expected to receive the speech.FIG. 15shows a data structure of a database stored in the storage unit72. Aural characteristic information is added to the position database. For example, the acoustic pressure level of the minimum sound that can be heard by the ear (minimum audible value) is indicated in the aural characteristic information. Reference is made back toFIG. 4. In (5-2) above, the determination unit74changes the threshold value in accordance with the aural characteristic information of the user using the terminal device10expected to receive the speech. For example, it is ensured that the smaller the minimum audible value, the larger the threshold value, and, the larger the minimum audible value, the smaller the threshold value. The aural characteristic information for the terminal device10of the UID identified in (5-1) is used.

According to the embodiment, the process related to the reproduction of the speech signal in the terminal device expected to receive the speech is determined, based on the distances between the terminal devices expected to receive the speech, excluding the terminal device outputting the transmission request from the plurality of terminal devices belonging to the predetermined group. Therefore, the process adapted to the distance between the terminal devices expected to receive the speech is performed. Further, since the process adapted to the distance between the terminal devices expected to receive the speech is performed, the recipient terminal device that should receive the speech signal is selected. Further, since the recipient terminal device that should receive the speech signal is selected, situations where the speech is output from a plurality of terminal devices located in the neighborhood is inhibited from occurring. Further, since situations where the speech is output from a plurality of terminal devices located in the neighborhood is inhibited from occurring, the difficulty of hearing the group call is inhibited. Further, since the speech is reproduced from limited terminal devices, the speech is made easier to hear. Since the speech is not reproduced in terminal devices removed from the selection, electric power is saved.

Since the embodiment only requires comparing the distance between the terminal devices expected to receive the speech with the the threshold value, the process is simplified. By changing the threshold value in accordance with the reproduction volume of the speech signal set in the terminal device expected to receive the speech, the range of terminal devices that should be selected can be changed depending on the situation. By changing the threshold value in accordance with the method of reproducing the speech signal in the terminal device expected to receive the speech, the range of terminal devices that should be selected can be changed depending on the situation. By changing the threshold value in accordance with the environmental sound volume around the terminal device expected to receive the speech, the range of terminal devices that should be selected can be changed depending on the situation. By changing the threshold value in accordance with the aural characteristic information of the user using the terminal device expected to receive the speech, the range of terminal devices that should be selected can be changed depending on the situation. By determining the recipient terminal device in accordance with the battery level of the terminal device expected to receive the speech, avoidance of reproduction in the terminal device expected to receive the speech with a low battery level is facilitated. Since avoidance of reproduction in the terminal device expected to receive the speech with a low battery level is facilitated, the duration in which such a terminal device can be driven is extended.

A description will now be given of embodiment 2. Like embodiment 1, embodiment 1 relates to a communication system in which group calls are made in a group including a plurality of terminal devices. Embodiment 2 selects a recipient terminal device to which the speech signal should be transmitted, based on the distance between the terminal devices expected to receive the speech signal. In embodiment 2, the detail of the process that should be performed when the recipient terminal device receives the speech signal. The communication system100according to embodiment 2 is of a type similar to those ofFIGS. 1, 7, and 10, the terminal device10is of a type similar to that ofFIG. 2, and the call controller20is of a type similar to that ofFIG. 4. The description here concerns a difference from embodiment 1.

The storage unit72of the call controller20ofFIG. 4stores a database similar to that ofFIG. 12. The determination unit74determines the recipient terminal device10that should receive the speech signal in a process similar to that of embodiment 1 and then determines the detail of the process that should be performed when said recipient terminal device10receives the speech signal. Determining the detail of the process that should be performed when the recipient terminal device10receives the speech signal also represents determining a process related to the reproduction of the speech signal in the terminal device10expected to receive the speech. The detail of the process that should be performed when the recipient terminal device10receives the speech signal is exemplified by generation of an instruction to increase the sound volume when the sound volume is of a predetermined value or lower.

The determination unit74generates a specified transmission destination and process call206.FIG. 16shows a data structure of the specified transmission destination and process call206generated in the call controller20. As in embodiment 1, the specified transmission destination and process call206is comprised of the transmission destination UID and speech information. Further, the specified transmission destination and process call206indicates a processing method in the terminal device10. “Increase by 30” denotes an instruction to increase the volume of the speech output in the speech output unit36by “30”. Reference is made back toFIG. 4. The output unit76outputs the specified transmission destination and process call206determined in the determination unit74to the communication unit50, and the communication unit50transmits the specified transmission destination and process call206via the base station device. For example, the communication unit50broadcasts the specified transmission destination and process call206.

When any one of the UIDs set in the transmission UIDs matches the UID stored in the storage unit40, the controller38of the terminal device10ofFIG. 2receives an input of the speech information of the specified transmission destination and process call206. Further, the controller38checks whether the processing method defined in the specified transmission destination and process call206and corresponding to the UID stored in the storage unit40indicates an increase or decrease of the sound volume. If an increase or a decrease is indicated, the controller38increases or decreases the sound volume in the speech output unit36accordingly. The speech output unit36reproduces a speech based on that speech information with the sound volume thus defined.

A description will now be given of the operation of the communication system100with the above configuration.FIG. 17is a sequence chart showing a communication procedure in the communication system100. The first terminal device10athrough the fifth terminal device10etransmit the position notification200to the call controller20(S100-S108). The call controller20stores the position information (S110). The first terminal device10atransmits the group call transmission request202to the call controller20(S112). The call controller20generates the specified transmission destination and process call206(S114). The call controller20broadcasts the specified transmission destination and process call206to the first terminal device10athrough the fifth terminal device10e(S116˜S124). The first terminal device10athrough the fifth terminal device10eperform a determination as to whether the UIDs match (S126˜S134). The third terminal device10cincreases the sound volume (S136) and reproduces the speech (S138). The fifth terminal device10ereproduces the speech (S140).

According to this embodiment, the detail of the process that should be performed when the recipient terminal device receives the speech signal is determined. Therefore, the recipient terminal device is caused to perform a process according to the detail of the process determined. Since the recipient terminal device is caused to perform a process according to the detail of the process determined, the terminal device that should reproduce the speech signal is selected in an ideal manner.

A description will now be given of embodiment 3. Like the foregoing embodiments, embodiment 3 relates to a communication system in which group calls are made in a group including a plurality of terminal devices. A selection is made of a recipient terminal device that should receive the speech signal. In the foregoing embodiments, the selection is made based on the distance between the terminal devices expected to receive the speech. Meanwhile, in embodiment 3, the selection is made based on a distance between the terminal device expected to receive and output the speech and the user using the terminal different from that outputting terminal device. The communication system100according to embodiment 3 is of a type similar to those ofFIGS. 1, 7, and 10, the terminal device10is of a type similar to that ofFIG. 2, and the call controller20is of a type similar to that ofFIG. 4. The description here concerns a difference from the foregoing embodiments.

The user using the terminal device10included in the communication system100carries a device capable of measuring position information of the user. The position information measured by the device is transmitted to the call controller20. The storage unit72of the call controller20ofFIG. 4stores the position information of the users in the position database. The determination unit74uses, in (5-2), the position information corresponding to the UID determined in (5-1) described above such that the position information of the user carrying the terminal device corresponding to the UID is used instead of the position information of the terminal device10corresponding to the UID. The other steps in the process are the same as the steps already described so that a description thereof is omitted. In essence, the determination unit74determines a process related to the reproduction of the speech signal in the terminal device10expected to receive the speech, based on the distance between the terminal device10expected to receive the speech, excluding the terminal device10outputting the transmission request from the plurality of terminal devices10belonging to a given group, and the users using the terminal devices10expected to receive the speech.

In accordance with the embodiment, the process related to the reproduction of the speech signal in the terminal device expected to receive the speech is determined based on the distance between the terminal device expected to receive the speech and the user using the other terminal devices. Accordingly, the actual easiness for the user to hear can be reflected.

In embodiments 1 through 3, the communication system100uses the business wireless system. However, the communication system100is non-limiting as to the system it uses, and wireless communication systems other than the business wireless system may be used. According to this embodiment, the flexibility of the configuration is improved.

In embodiments 1 through 3, the determination device60is included in the call controller20. The location of the determination device60is non-limiting, and the determination device60may be included in the terminal device10. In this case, the plurality of terminal devices10collect position information mutually, and generate and transmit the specified transmission destination call204or the specified transmission destination and process call206. Further, the call controller20is not necessary. According to this embodiment, the flexibility of the configuration is improved.