JP7572079B2 - Mobile radio terminal - Google Patents

Description

The present invention relates to a public wireless communication area expansion system, a mobile wireless terminal, and a public wireless communication area expansion program, and in particular to a public wireless communication area expansion system, a mobile wireless terminal, and a public wireless communication area expansion program that enable wireless communication areas to be expanded without simply increasing the number of wireless equipment in wireless communication used to carry out public business.

In the field of public safety, such as firefighting, disaster prevention, transportation, and defense, as described in, for example, Patent Document 1, JP 2013-48323 A, "Wireless Communication System," each public organization independently operates public wireless communication networks that use wireless equipment for their own infrastructure. However, the number of wireless equipment (base stations/relay stations) that can be installed is limited due to factors such as installation space and costs, and the communication area (for example, the area where calls can be made) of the public wireless communication network is also limited.

As a result, public wireless terminals used by workers performing public work at actual sites may be out of range depending on the communication area conditions, resulting in situations where communication is not possible (e.g., calls cannot be made), and it may not be possible to respond to an emergency.

JP 2013-48323 A

As mentioned above, in public wireless communication networks operated independently by public organizations such as firefighting, disaster prevention, transportation, and defense, there are cases where public wireless terminals used by workers performing public work at the actual site are unable to communicate (e.g., unable to make calls) depending on the conditions of the communication area.

To avoid such a situation and always enable wireless communication for public services, some kind of solution is needed that will allow the expansion of communication areas (e.g. areas where calls can be made) without simply increasing the number of wireless facilities (base stations and relay stations) in the public wireless communication network, and there are issues with current technology that need to be resolved.

(Objective of this development)
In view of these problems, the objective of this development is to provide a public wireless communication area expansion system, a mobile wireless terminal, and a public wireless communication area expansion program that make it possible to expand the wireless communication area for wireless communications used to conduct public services without simply increasing the number of wireless equipment.

To solve the above problems, the public wireless communication area expansion system, mobile wireless terminal, and public wireless communication area expansion program according to the present invention mainly adopt the following characteristic configurations.

(1) A public wireless communication area extension system according to the present invention comprises:
A public wireless communication area extension system for extending a wireless communication area for carrying out public services, comprising:
The public service includes two wireless terminals operated by employees who perform the public service: a public wireless terminal that wirelessly connects to a public wireless communication network that is installed specifically for the public service, and a public wireless terminal that wirelessly connects to a public wireless communication network that provides public wireless communication services;
And, in both the public wireless terminal and the public wireless terminal,
a local connection means for locally connecting the public wireless terminal and the public wireless terminal;
And, in either the public wireless terminal or the public wireless terminal,
a communication network selection means for selecting either the public wireless communication network or the public wireless communication network according to the state of reception electric fields received from both the public wireless communication network and the public wireless communication network, and setting one of the two wireless terminals, the public wireless terminal and the public wireless terminal, which is wirelessly connected to the selected communication network, to a state where wireless communication for the public service is performed;
and a control console operated by a commander who issues commands regarding the public service has communication means for communicating with both the public radio communication network and the public radio communication network.
It is characterized by:

(2) The mobile radio terminal according to the present invention comprises:
A mobile radio terminal operated by a public service worker,
The implementation means of both the public wireless terminal for wirelessly connecting to a public wireless communication network independently installed for the public business and the public wireless terminal for wirelessly connecting to a public wireless communication network providing a public wireless communication service are integrated and implemented in one housing.
It is characterized by:

(3) The public wireless communication area expansion program according to the present invention is
A public wireless communication area expansion program for executing a process of expanding a wireless communication area for carrying out public services by a computer, comprising:
The public service includes two wireless terminals operated by employees who perform the public service: a public wireless terminal that wirelessly connects to a public wireless communication network that is installed specifically for the public service, and a public wireless terminal that wirelessly connects to a public wireless communication network that provides public wireless communication services;
And, in both the public wireless terminal and the public wireless terminal,
a local connection function for locally connecting the public wireless terminal and the public wireless terminal;
And, in either the public wireless terminal or the public wireless terminal,
a communication network selection function for selecting either the public wireless communication network or the public wireless communication network according to the state of reception electric fields received from both the public wireless communication network and the public wireless communication network, and setting a state in which wireless communication for the public service is performed using one of the two wireless terminals, the public wireless terminal and the public wireless terminal, which is wirelessly connected to the selected communication network;
and a control console operated by a commander who issues commands regarding the public service has a communication function for communicating with both the public radio communication network and the public radio communication network.
It is characterized by:

The public wireless communication area expansion system, mobile wireless terminal, and public wireless communication area expansion program of the present invention can mainly achieve the following effects:

In other words, in the field of public safety, such as firefighting, disaster prevention, transportation, and defense, if only a public wireless communication network operated by a public organization as wireless equipment for its own infrastructure is used, as is the case with current technology, even if a worker moves out of communication range to an area where wireless communication is not possible, as long as he or she is within the communication range of the public wireless communication network, wireless communication related to public business can be conducted. Therefore, the wireless communication area for public business can be expanded without adding wireless equipment such as wireless base stations and wireless relay stations to the public wireless communication network.

1 is a system configuration diagram showing an example of a system configuration of a public wireless communication area expansion system according to the present invention. FIG. 2 is an explanatory diagram showing a schematic diagram of wireless communication in the public wireless communication area expansion system shown in FIG. 1 . 4 is a flowchart for explaining an example of an operation of the public wireless communication area expansion system shown in FIG. 1 . 2 is an explanatory diagram showing a case where a business worker performs wireless communication using a public wireless communication network in the public wireless communication area expansion system of FIG. 1. 2 is an explanatory diagram showing a case where a business worker performs wireless communication using a public wireless communication network in the public wireless communication area expansion system of FIG. 1. 2 is a terminal configuration diagram showing an example of the configuration of an integrated mobile radio terminal in which the public radio terminal shown in FIG. 1 and the public radio terminal are housed in the same housing; FIG.

Below, preferred embodiments of the public wireless communication area expansion system, mobile wireless terminal, and public wireless communication area expansion program according to the present invention will be described with reference to the attached drawings. Note that, although the public wireless communication area expansion system and mobile wireless terminal according to the present invention will be described below, the functions of the public wireless communication area expansion system and mobile wireless terminal may be implemented as a public wireless communication area expansion program executed by a computer. Also, the reference numerals attached to the following drawings are given to each element for convenience as an example to aid understanding, and needless to say, are not intended to limit the present invention to the illustrated form.

(Features of the present invention)
Prior to describing the embodiments of the present invention, an outline of the features of the present invention will be described first. The present invention provides a configuration in which a public wireless terminal (i.e., a mobile wireless communication device: a portable/vehicle-mounted communication device) capable of communicating in a public wireless communication network (a wireless communication network dedicated to public use such as firefighting, disaster prevention, traffic, and defense) is locally connected to a public wireless terminal (i.e., a portable wireless terminal: a smartphone, a mobile phone terminal, a tablet terminal, etc.) capable of communicating in a public wireless communication network (e.g., an LTE (Long Term Evolution) communication network, etc.) provided by a communication carrier as a public wireless communication service (e.g., a local connection configuration using a wireless connection conforming to the Wi-Fi (Wireless Fidelity) standard).

The main feature of this system is that a control application is implemented in either the public or public wireless terminal, which has a communication network selection function (i.e., a communication type selection control function) that selects whether the public wireless communication network or the public wireless communication network is used for wireless communication depending on the reception electric field conditions (outside/inside range) received from the public wireless communication network and the public wireless communication network.

Here, the communication types to be selected by the control application are, as described above,
(1) Wireless communication using public wireless communication networks (wireless communication networks dedicated to public use such as firefighting, disaster prevention, transportation, and defense)
(2) Wireless communication using a public wireless communication network (such as an LTE network) provided by a telecommunications carrier as a public wireless communication service (in the case of an LTE network, IP (Internet Protocol) wireless communication);
Either:

The control application monitors the status of the receiving electric field of the radio waves from the public wireless communication network and the public wireless communication network, and when the public wireless terminal and the public wireless terminal are both within the wireless communication range of the public wireless communication network and the public wireless communication network to which they are wirelessly connected, selects a communication type that gives priority to the public wireless terminal and the public wireless communication network. Another major feature is that when either the public wireless communication network or the public wireless communication network goes out of communication range, the communication type is switched to and used with the other communication network that is within the communication range.

(Embodiments of the present invention)
Next, an example of an embodiment of a public wireless communication area expansion system according to the present invention will be described. In this embodiment, for example, a SCPC (Single Channel Per Carrier) communication network (a commercial digital wireless network: a wireless communication network using a transmission method that is one of the frequency division multiple access (FDMA) methods and that allocates one carrier per channel) is used as a public wireless communication network (i.e., a public wireless communication network operated by a public wireless communication service provider). On the other hand, for example, an LTE (Long Term Evolution) communication network that complies with the LTE standard is used as a public wireless communication network provided by a communication carrier as a public wireless communication service.

Then, for example, a Wi-Fi communication method is adopted as a local communication standard for connecting between a public wireless terminal capable of wirelessly connecting to a public wireless communication network and a public wireless terminal capable of wirelessly connecting to a public wireless communication network. That is, in this embodiment, in order to expand the communication area of public wireless communication, information is transmitted and received between two wireless terminals, the public wireless terminal and the public wireless terminal, using Wi-Fi communication, and depending on the state of the receiving electric field of both communication networks, the SCPC communication network, which is an example of a public wireless communication network, and the LTE communication network, which is an example of a public wireless communication network, one of the communication networks is selected, and wireless terminals capable of wirelessly connecting to the selected communication network are used, thereby making it possible to perform wireless communication for public business.

(Configuration example of the embodiment of the present invention)
Next, a configuration example of a public wireless communication area expansion system according to the present invention will be described with reference to Fig. 1. Fig. 1 is a system configuration diagram showing an example of the system configuration of a public wireless communication area expansion system according to the present invention.

The public wireless communication area expansion system 100 shown in FIG. 1 shows an example of a system configuration for expanding a wireless communication area for wireless communication between workers performing public work at an actual site and commanders issuing commands related to public work, and is configured to utilize two communication networks: a public wireless communication network 10 (i.e., a business digital wireless network, such as an SCPC communication network) and a public wireless communication network 20 (i.e., a wireless communication network providing public wireless communication services, such as an LTE communication network). The public wireless communication network 10 is composed of one or more wireless base stations 15 and wireless relay stations, and the public wireless communication network 20 is composed of one or more wireless base stations 25 (usually wireless base stations 25 with wireless relay functions).

The control console 30 used by the commander who issues commands regarding public business has communication means for communicating with both the public wireless communication network 10 and the public wireless communication network 20, and is configured to be able to send and receive wireless communication information to and from either communication network. Note that while FIG. 1 shows an example in which the control console 30 and the wireless base station 15 and wireless base station 25 of each of the two communication networks are connected by wire, they may also be connected wirelessly. On the other hand, two wireless terminals are used as mobile wireless communication terminals used by business personnel: a public wireless terminal 11 (e.g., a business digital wireless terminal: a mobile/vehicle-mounted wireless communication device) for using the public wireless communication network 10 and a public wireless terminal 21 (e.g., a smartphone) for using the public wireless communication network 20.

Here, the public wireless terminal 11 and the public wireless terminal 21 are locally connected (e.g., Wi-Fi connected). In other words, the public wireless terminal 11 and the public wireless terminal 21 are each equipped with an antenna for wireless connection to the public wireless communication network 10 and the public wireless communication network 20, as well as an antenna for local wireless connection (e.g., Wi-Fi connection) between them.

When an SCPC communication network is used as the public wireless communication network 10, an LTE communication network is used as the public wireless communication network 20, and a Wi-Fi connection is used as the local connection between the public wireless terminal 11 and the public wireless terminal 21, as shown in FIG. 2, the public wireless terminal 11 is equipped with an SCPC communication control unit 11a, a Wi-Fi communication control unit 11b, and a public wireless terminal control application 11c. On the other hand, the public wireless terminal 21 is equipped with an LTE communication control unit 21a, a Wi-Fi communication control unit 21b, and a public wireless terminal control application 21c.

Figure 2 is an explanatory diagram showing a schematic diagram of wireless communication in the public wireless communication area expansion system 100 shown in Figure 1. As shown in Figure 2, when a worker uses a public wireless terminal 11 to perform wireless communication with the commander's control console 30, the SCPC communication control unit 11a is operated according to the operation of the public wireless terminal control application 11c of the public wireless terminal 11, and wireless communication is performed with the control console 30 via the wireless base station 15 and wireless relay station of the public wireless communication network 10 (SCPC communication network).

On the other hand, when a worker uses a public wireless terminal 21 to perform wireless communication with the commander's control console 30, the LTE communication control unit 21a is operated according to the operation of the public wireless terminal control application 21c of the public wireless terminal 21, and wireless communication is performed with the control console 30 via the wireless base station 25 of the public wireless communication network 20 (LTE communication network).

The public wireless terminal 11 and the public wireless terminal 21 are locally connected via Wi-Fi communication, and information regarding each other's operating status is sent and received between the Wi-Fi communication control unit 11b of the public wireless terminal 11 and the Wi-Fi communication control unit 21b of the public wireless terminal 21 by the operation of the public wireless terminal control application 11c and the public wireless terminal control application 21c.

In order to ensure reliable Wi-Fi communication between the public wireless terminal 11 and the public wireless terminal 21, the public wireless terminal 11 and the public wireless terminal 21 are assumed to always be located close to each other within the Wi-Fi communication area. For example, if the public wireless terminal 11 is a portable wireless communication device rather than an in-vehicle device, as shown in FIG. 1, when a worker holds the public wireless terminal 21 in his/her hand, the public wireless terminal 11 is held in a manner that it is attached to a part of the worker's body, for example, at the waist.

In other words, there are two wireless terminals used by workers performing public services at the actual site: a public wireless terminal 11 that wirelessly connects to a public wireless communication network 10 that was installed specifically for the public services, and a public wireless terminal 21 that wirelessly connects to a public wireless communication network 20 that provides public wireless communication services. The public wireless terminal 11 and the public wireless terminal 21 each have, as local connection means for locally connecting them to each other, for example, a Wi-Fi communication control unit 11b and a Wi-Fi communication control unit 21b that perform Wi-Fi communication.

Here, the business employee may be able to use a public wireless terminal 21 (e.g., a smartphone) to make and receive calls regardless of whether the business employee uses the public wireless communication network 10 or the public wireless communication network 20. In other words, when the business employee wishes to use the public wireless communication network 20, the public wireless terminal control application 21c operates to perform call making and receiving operations with the public wireless communication network 20 (LTE communication network) via the LTE communication control unit 21a based on the call making and receiving operation results of the public wireless terminal 21.

On the other hand, when attempting to use the public wireless communication network 10, the results of the call originating/receiving operation of the public wireless terminal 21 are transmitted to the Wi-Fi communication control unit 11b of the public wireless terminal 11 via the Wi-Fi communication control unit 21b by the operation of the public wireless terminal control application 21c, and the call originating/receiving operation with the public wireless communication network 10 (SCPC communication network) is carried out via the SCPC communication control unit 11a by the operation of the public wireless terminal control application 11c of the public wireless terminal 11.

In other words, either the public wireless terminal 11 or the public wireless terminal 21 has the following communication network selection means (i.e., communication type selection control means) as the public wireless terminal control application 11c or the public wireless terminal control application 21c (in this embodiment, as the public wireless terminal control application 21c of the public wireless terminal 21). That is, the communication network selection means selects either the public wireless communication network 10 or the public wireless communication network 20 according to the state of the receiving electric field received from both the public wireless communication network 10 and the public wireless communication network 20, and sets the state to perform wireless communication for public business using either one of the two wireless terminals, the public wireless terminal 11 or the public wireless terminal 21, which is wirelessly connected to the selected communication network.

(Description of Operation of the Embodiment of the Present Invention)
Next, an example of the operation of the public wireless communication area expansion system 100 shown in Fig. 1 as an embodiment of the present invention will be described in detail with reference to the flowchart of Fig. 3. Fig. 3 is a flowchart for explaining an example of the operation of the public wireless communication area expansion system 100 shown in Fig. 1, and shows an example of the operation of selecting and using a communication network in the public wireless terminal 21 (e.g., a smartphone) shown in Fig. 1. Note that the flowchart of Fig. 3 explains a case where the public wireless terminal 21 has the above-mentioned communication network selection means as a public wireless terminal control application 21c.

In the flowchart of FIG. 3, when the public wireless terminal 21 (e.g., a smartphone) reaches a predetermined startup period, it first starts the LTE communication control unit 21a to receive radio waves from the wireless base station 25 of the public wireless communication network 20 (LTE communication network), and also starts the Wi-Fi communication control unit 21b to establish a local connection (Wi-Fi connection) with the public wireless terminal 11 (step S1).

The public wireless terminal 21 periodically measures the receiving electric field from the wireless base station 25 of the public wireless communication network 20 at a predetermined cycle in the LTE communication control unit 21a by the operation of the public wireless terminal control application 21c. Meanwhile, the public wireless terminal 11 periodically measures the receiving electric field from the wireless base station 15 of the public wireless communication network 10 at a predetermined cycle in the SCPC communication control unit 11a by the operation of the public wireless terminal control application 11c. Then, the public wireless terminal 11 periodically notifies the public wireless terminal 21 of information related to the measured receiving electric field from the wireless base station 15 of the public wireless communication network 10 via the Wi-Fi communication control unit 11b.

Returning to the explanation of the flowchart in FIG. 3, the public wireless terminal 21 receives information about the reception electric field from the wireless base station 15 of the public wireless communication network 10, transmitted from the public wireless terminal 11, via the Wi-Fi communication control unit 21b by the operation of the public wireless terminal control application 21c (step S2). As a result, the public wireless terminal 21 acquires information about the reception electric field received from each of the wireless base station 25 of the public wireless communication network 20 and the wireless base station 15 of the public wireless communication network 10.

Then, the public wireless terminal 21 checks whether a call has been made from its own terminal or whether there has been an incoming call from another wireless terminal (step S3). If no call has been made or no incoming call has been made (NO in step S3), the terminal is in a standby state and is not ready to perform wireless communication, so the process in FIG. 3 ends and the terminal waits until the next startup cycle.

In contrast, when a call is made from the terminal itself or an incoming call is made from another wireless terminal (YES in step S3), the public wireless terminal 21 and the public wireless terminal 11 perform an operation to determine whether they are in a communicable area (within a communication range) or in an uncommunicable area (outside a communication range) with respect to the communication network they use for their respective wireless communications, based on the reception electric field from the wireless base station 25 of the public wireless communication network 20 measured by the LTE communication control unit 21a and the reception electric field from the wireless base station 15 of the public wireless communication network 10 received via the Wi-Fi communication control unit 21b.

That is, first, based on the received electric field from the wireless base station 15 of the public wireless communication network 10 received via the Wi-Fi communication control unit 21b, it is confirmed whether the public wireless terminal 11 is present within the communication range of the public wireless communication network 10 (SCPC communication network) (step S4).

If the public wireless terminal 11 is present within the communication range of the public wireless communication network 10 (SCPC communication network) (YES in step S4), the public wireless terminal 21 preferentially selects to use the public wireless terminal 11 to make and receive calls to the public wireless communication network 10, regardless of whether the public wireless terminal 21 itself is present within the communication range of the public wireless communication network 20 (LTE communication network). In other words, the public wireless terminal 21 notifies the public wireless terminal 11 that a call is being made to and received from the public wireless communication network 10 via the Wi-Fi communication control unit 21b through the operation of the public wireless terminal control application 21c.

As a result, as shown in FIG. 4, the public wireless terminal 11 that has received the notification from the public wireless terminal 21 performs call origination and reception processing with the public wireless communication network 10 via the SCPC communication control unit 11a through the operation of the public wireless terminal control application 11c. In other words, the business worker uses the public wireless terminal 11 to access the public wireless communication network 10 to perform call origination connection operations with the destination wireless terminal or control console 30, and to perform call origination connection operations from the originating wireless terminal or control console 30 (step S5).

In such a case, if the call does not come through the public wireless communication network 10, but comes directly to the public wireless terminal 21 through the public wireless communication network 20, the public wireless terminal 21 will process the incoming call without notifying the public wireless terminal 11 of the incoming call. Alternatively, in some cases, the wireless terminal that originated the incoming call may be prompted to perform redialing processing specifying the public wireless communication network 10, and the public wireless terminal 21 may receive the incoming call again through the public wireless communication network 10 instead of the public wireless communication network 20.

Figure 4 is an explanatory diagram showing a case where a business worker performs wireless communication using the public wireless communication network 10 in the public wireless communication area expansion system 100 of Figure 1. As shown in Figure 4, when the public wireless terminal 11 is present within the communication range of the public wireless communication network 10, the public wireless communication network 10 is used preferentially, regardless of whether the public wireless terminal 21 is present within the communication range of the public wireless communication network 20, and the business worker performs wireless communication with, for example, the control console 30 using the public wireless terminal 11.

In addition, in step S4, if the public wireless terminal 11 is not within the communication range of the public wireless communication network 10 (SCPC communication network) but is outside the communication range (NO in step S4), the public wireless terminal 21 then checks whether or not it is within the communication range of the public wireless communication network 20 (LTE communication network) based on the received electric field from the wireless base station 25 of the public wireless communication network 20 measured by the LTE communication control unit 21a (step S6).

If the public wireless terminal 21 is not within the communication range of the public wireless communication network 20 (LTE communication network) but is outside the communication range (NO in step S6), wireless communication is not possible for not only the public wireless terminal 11 but also the public wireless terminal 21. Therefore, the public wireless terminal 21 determines that the outgoing call or incoming call process has failed, notifies the worker of this fact, and ends the process without making or receiving a call (step S7).

On the other hand, in step S6, if the public wireless terminal 21 is within the communication range of the public wireless communication network 20 (LTE communication network) (YES in step S6), the public wireless terminal 21 is in a state where wireless communication related to public business is possible. Therefore, since the public wireless terminal 11 is outside the communication range of the public wireless communication network 10 and is in a state where wireless communication cannot be performed, the public wireless terminal 21 switches the communication method for processing the generated outgoing and incoming calls from the SCPC communication method using the public wireless communication network 10 (SCPC communication network) to the LTE communication method using the public wireless communication network 20 (LTE communication network) (step S8).

As a result, as shown in FIG. 5, the public wireless terminal 21 performs outgoing and incoming call processing with the public wireless communication network 20 via the LTE communication control unit 21a by the operation of the public wireless terminal control application 21c. In other words, the business worker uses the public wireless terminal 21 to access the public wireless communication network 20 to perform outgoing connection operations to the destination wireless terminal or the control console 30, and to perform incoming connection operations from the source wireless terminal or the control console 30 (step S9).

Figure 5 is an explanatory diagram showing a case where a business worker performs wireless communication using the public wireless communication network 20 in the public wireless communication area expansion system 100 of Figure 1. As shown in Figure 5, when the public wireless terminal 11 is outside the communication range of the public wireless communication network 10 and the public wireless terminal 21 is within the communication range of the public wireless communication network 20, the business worker uses the public wireless terminal 21 to perform wireless communication, for example, with the control console 30, using the public wireless communication network 20.

Therefore, even if the public wireless terminal 11 is located outside the communication range of the public wireless communication network 10, workers performing public services such as firefighting, disaster prevention, transportation, and defense can use the public wireless terminal 21 to expand the wireless communication area and perform wireless communication.

As described above, the public wireless terminal 21 can further expand the wireless communication area for public services and perform wireless communication by setting it to establish a wireless connection with one of the following communication networks as a result of the public wireless terminal control application 21c operating as a communication network selection means.

(1) When the reception electric field from either of the public wireless communication networks 10 and 20 indicates that the communication network is outside the communication range, the device selects to use the other communication network that indicates a reception electric field within the communication range, and sets the device to establish a wireless connection with the selected other communication network.

For example, when the public wireless communication network 10 is out of range and the public wireless communication network 20 is within range, the public wireless terminal 21 wirelessly connected to the public wireless communication network 20 is used to process incoming and outgoing communications, and wireless communication related to public services is performed. Conversely, when the public wireless communication network 10 is within range and the public wireless communication network 20 is out of range, the public wireless terminal 11 wirelessly connected to the public wireless communication network 10 is used to process incoming and outgoing communications, and wireless communication related to public services is performed.

(2) When both the reception electric fields received from the public wireless communication network 10 and the public wireless communication network 20 indicate reception electric fields within the communication range, the public wireless communication network 10 is selected as the preferred network, and the public wireless terminal 11 that is wirelessly connected to the selected public wireless communication network 10 is used to process incoming and outgoing communications, and wireless communication related to public services is performed.

(3) If both the reception electric fields received from the public wireless communication network 10 and the public wireless communication network 20 indicate reception electric fields outside the communication range, the business employee operating the public wireless terminal 21 is notified that neither the public wireless communication network 10 nor the public wireless communication network 20 is available, and the terminal is set not to process incoming and outgoing calls.

In the public wireless communication area expansion system 100 of this embodiment, the public wireless communication network 20 provided by the communication carrier is, as described above, for example, an LTE communication network, which is a communication network that supports wireless communication using the IP (Internet Protocol) protocol, and the control console 30 operated by a commander who issues commands regarding public services such as firefighting, disaster prevention, traffic, and defense also supports IP protocol communication. Therefore, as information regarding public services transmitted and received by wireless communication between the commander and the operator, not only voice data but also non-voice data information including still images, videos, documents, SMS (Short Message Service), etc. can be transmitted and received using the IP protocol.

In the above-mentioned embodiment, the public wireless terminal control application 21c implemented in the public wireless terminal 21 has a communication network selection means (i.e., a communication type selection control means) that selectively uses the two communication networks, the public wireless communication network 10 and the public wireless communication network 20, but the present invention is not limited to such a case. That is, it is sufficient to configure either the public wireless terminal 21 or the public wireless terminal 11 to have the communication network selection means (i.e., a communication type selection control means). In other words, in some cases, the public wireless terminal control application 11c implemented in the public wireless terminal 11, rather than the public wireless terminal 21, may have a communication network selection means (i.e., a communication type selection control means) that selectively uses the two communication networks, the public wireless communication network 10 and the public wireless communication network 20.

In such a case, whether the business employee uses the public wireless communication network 10 or the public wireless communication network 20, the business employee's call originating and receiving operations can be performed by using the public wireless terminal 11 (e.g., a portable mobile wireless communication device) in a manner different from the public wireless terminal 21 of the above-mentioned embodiment, to select a communication network. In other words, when the business employee wishes to use the public wireless communication network 10, the public wireless terminal control application 11c operates to perform call originating and receiving operations with the public wireless communication network 10 (SCPC communication network) via the SCPC communication control unit 11a, based on the results of the call originating and receiving operations of the public wireless terminal 11.

On the other hand, when attempting to use the public wireless communication network 20, the results of the call originating/receiving operation of the public wireless terminal 11 are transmitted to the Wi-Fi communication control unit 21b of the public wireless terminal 21 via the Wi-Fi communication control unit 11b by the operation of the public wireless terminal control application 11c, and the call originating/receiving operation with the public wireless communication network 20 (LTE communication network) is carried out via the LTE communication control unit 21a by the operation of the public wireless terminal control application 21c of the public wireless terminal 21.

(Explanation of Effects of the Embodiment)
As described above in detail, in this embodiment, the following effects can be obtained.

In other words, in the field of public safety such as firefighting, disaster prevention, transportation, and defense, if only the public wireless communication network 10 operated by a public organization as wireless equipment for its own infrastructure is used, as in the current technology, even if a worker moves out of communication range to an area where wireless communication is impossible, as long as he or she is within the communication range of the public wireless communication network 20, it is possible to obtain the effect that wireless communication related to public business can be performed. Therefore, it is possible to expand the wireless communication area related to public business without adding wireless equipment such as wireless base stations and wireless relay stations as the public wireless communication network 10.

Furthermore, a mechanism is adopted in which the decision as to which of the public wireless communication network 10 and the public wireless communication network 20 to use for wireless communication is automatically made based on the result of receiving electric field information from the wireless base station 15 and wireless base station 25 of the public wireless communication network 10 and the public wireless communication network 20, respectively, and determining whether the user is within or outside the communication range. Therefore, the worker does not need to perform any operations to make a decision regarding the selection of the communication network, and the wireless communication area can be expanded without compromising the convenience of being able to selectively use the two types of communication networks, the public wireless communication network 10 and the public wireless communication network 20.

Other Embodiments of the Invention
In the above-described embodiment, a case has been described in which workers engaged in public work at actual sites have two types of wireless terminals for wireless communication: a public wireless terminal 11 (portable/vehicle-mounted mobile wireless communication device) and a public wireless terminal 21 (smartphone, mobile phone terminal, tablet terminal, etc.), and the public wireless terminal 11 and the public wireless terminal 21 are locally connected via Wi-Fi wireless communication, and the public wireless communication network 20 has been described using an LTE network, but the present invention is not limited to such a case.

For example, Bluetooth (registered trademark) may be used instead of Wi-Fi as a means for making a local connection, and instead of wireless communication such as Wi-Fi, the public wireless terminal 11 and the public wireless terminal 21 may be connected by wire using a wired cable such as a USB cable or a LAN cable. Furthermore, the public wireless communication network 20 may use a fifth generation mobile communication system (5G) instead of an LTE network.

Furthermore, as shown in FIG. 6, the public wireless terminal 11 and the public wireless terminal 21 may be configured as an integrated mobile wireless terminal 40 housed in the same housing. FIG. 6 is a terminal configuration diagram showing an example of the configuration of an integrated mobile wireless terminal 40 in which the public wireless terminal 11 and the public wireless terminal 21 shown in FIG. 1 are housed in the same housing.

The mobile wireless terminal 40 shown in FIG. 6 shows an example in which a public wireless communication panel 41 for performing operations related to public wireless communication is mounted on the front side of the housing, and a public wireless communication panel 42 for performing operations related to public wireless communication is mounted on the back side of the housing. The public wireless communication panel 41 is provided with a liquid crystal panel 41a and operation keys 41b similar to those of current portable wireless communication devices, and the public wireless communication panel 42 is provided with a liquid crystal panel 42a and operation buttons 42b similar to those of a smartphone, for example.

The housing includes integrated implementation means for both wireless terminals: a public wireless terminal 11 that wirelessly connects to a public wireless communication network 10 that is installed independently for public business, and a public wireless terminal 21 that wirelessly connects to a public wireless communication network 20 that provides public wireless communication services.

Specifically, the implementation means includes at least a public communication control unit, such as an SCPC communication control unit, which performs wireless communication with the public wireless communication network 10, a public communication control unit, such as an LTE communication control unit, which performs wireless communication with the public wireless communication network 20, and a communication network selection unit that selects one of the two communication networks, the public wireless communication network 10 and the public wireless communication network 20, and connects to the selected communication network. In other words, the communication network selection unit selects one of the public wireless communication network 10 and the public wireless communication network 20 depending on the state of the receiving electric field received from both the public wireless communication network 10 and the public wireless communication network 20, and sets the state to perform wireless communication for public business by wirelessly connecting to the selected communication network.

The above describes the configuration of a preferred embodiment of the present invention. However, please note that such an embodiment is merely an example of the present invention and does not limit the present invention in any way. Those skilled in the art will easily understand that various modifications and alterations are possible according to specific applications without departing from the gist of the present invention.

10 Public wireless communication network 11 Public wireless terminal 11a SCPC communication control unit 11b Wi-Fi communication control unit 11c Public wireless terminal control application 15 Wireless base station 20 Public wireless communication network 21 Public wireless terminal 21a LTE communication control unit 21b Wi-Fi communication control unit 21c Public wireless terminal control application 25 Wireless base station 30 Control console 40 Mobile wireless terminal 41 Public wireless communication panel 41a Liquid crystal panel 41b Operation key 42 Public wireless communication panel 42a Liquid crystal panel 42b Operation button 100 Public wireless communication area expansion system

Claims (1)

A mobile radio terminal operated by a public service worker,
The implementation means of both a public wireless terminal that wirelessly connects to a public wireless communication network that is independently installed for the public service and a public wireless terminal that wirelessly connects to a public wireless communication network that provides a public wireless communication service are integrated and implemented in one housing;
A public wireless terminal is provided on one side of the device, and a public wireless terminal is provided on the other side of the device,
The implementation means includes:
a public communication control means for performing wireless communication with the public wireless communication network;
a public communication control means for performing wireless communication with the public wireless communication network;
a communication network selection means for selecting either the public wireless communication network or the public wireless communication network according to the state of reception electric fields received from both the public wireless communication network and the public wireless communication network, and for wirelessly connecting to the selected communication network to set the state of performing wireless communication for the public service;
A mobile radio terminal comprising:

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