Wireless communication system and control device

Abstract

Each wireless terminal will have a fixed communication console that it will communicate with. [Solution] A wireless communication system that communicates using the same frequency, comprising: a plurality of base stations capable of wireless communication with a plurality of wireless terminals; a control device connected to the plurality of base stations and controlling the transfer of data transmitted by the wireless communication; and a plurality of communication consoles connected to the control device and communicating with the wireless terminals via the base stations through the control device's line control, wherein the control device corrects the received field strength at the base station of the signal transmitted from the wireless terminal using a correction value determined by the combination of the wireless terminal and the base station, selects a base station to which the wireless terminal communicates based on the corrected received field strength, and transfers the data transmitted from the wireless terminal and via the selected base station to the communication console associated with the selected base station.

Description

Technical Field

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[0001] The present invention relates to a wireless communication system, and particularly to a function of controlling signals received by a plurality of base stations that communicate wirelessly with a wireless terminal.

Background Art

[0002] There is a wireless communication system that simultaneously receives a transmission signal from a wireless terminal at a plurality of base stations, and a line control device selects a base station with a strong received electric field strength, and outputs the communication data received by the selected base station to a communication desk.

[0003] As the background art in this technical field, there is the following prior art. Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2021-97307) discloses that a wireless line control device stores the transmission time from the wireless line control device for each of a plurality of connected base stations. When a base station receives a transmission signal from a mobile station, the base station sends the transmission signal to the wireless line control device. When the wireless line control device receives the transmission signal, the wireless line control device adjusts the transmission timing based on the transmission time to each base station and sends an instruction to the base stations to retransmit the transmission signal so that the instruction reaches all the base stations simultaneously. Thus, a wireless communication system in which the transmission signal is retransmitted simultaneously from all the base stations is described.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The wireless communication system using the SCPC (Single Channel Per Carrier) method described in Patent Document 1 often has the following two functions.

[0006] Function 1: When the line control unit notifies the communication console of the content transmitted from the wireless terminal, it switches the communication console to which the notification is sent depending on the base station that received it.

[0007] Function 2: Depending on the terrain where the base station is installed, the coverage area, and the use of the wireless link, the line control device corrects the received field strength (by adding or subtracting the received field strength, etc.) in order to prioritize the selection of a specific base station (by adding or subtracting the received field strength, it becomes possible to virtually expand or contract the coverage area of ​​the base station).

[0008] The two functions mentioned above allow for the logical expansion of the base station's coverage area and enable the use of a fixed communication console to handle communications from wireless terminals located within that coverage area. However, this system had the following challenges.

[0009] Problem 1: When a wireless terminal communicates with a communication console, the console used is determined by the base station used for communication. Therefore, if the base station's coverage area is widened, signals transmitted by wireless terminals near the boundary of adjacent coverage areas may be received by a specific base station, and the destination of these communications may be biased towards a specific communication console.

[0010] Problem 2: When communicating with wireless terminals near the boundary of adjacent coverage areas, the line control device may select a different base station each time the wireless terminal initiates a call, resulting in different communication consoles handling the call, which is inconvenient for the wireless terminal operators. [Means for solving the problem]

[0011] A representative example of the invention disclosed in this application is as follows: A wireless communication system that communicates using the same frequency, comprising: a plurality of base stations capable of wireless communication with a plurality of wireless terminals; a control device connected to the plurality of base stations and controlling the transfer of data transmitted by the wireless communication; and a plurality of communication consoles connected to the control device and communicating with the wireless terminals via the base stations through the control device's line control, wherein the control device corrects the received field strength at the base station of the signal transmitted from the wireless terminal using a correction value determined by the combination of the wireless terminal and the base station, selects a base station to which the wireless terminal communicates based on the corrected received field strength, and transfers the data transmitted from the wireless terminal and via the selected base station to a communication console associated with the selected base station.

[0012] Furthermore, in an example of a wireless communication system according to the present invention, the control device has reception level correction information in which a correction value of the reception level is recorded for each wireless terminal and each base station, reception level information in which the corrected reception field strength is temporarily recorded, and base station-specific destination communication console information in which the relationship between the base station and the destination communication console is recorded, and by referring to the reception level correction information, the received field strength at the base station of the signal transmitted from the wireless terminal is corrected and recorded in the reception level information, the base station with the highest corrected reception field strength recorded in the reception level information is selected as the base station with which the wireless terminal communicates, and the data transmitted from the wireless terminal and passed through the selected base station is transferred to the communication console associated with the selected base station.

[0013] Furthermore, in an example of the wireless communication system of the present invention, the control device compares the corrected received field strength of signals received by multiple base stations from the same wireless terminal, does not establish communication with base stations with low received field strength, establishes communication with base stations with high received field strength, and transfers data to a communication console associated with the base station with which communication has been established.

[0014] Furthermore, an example of the present invention is a control device that controls the transfer of data transmitted by wireless communication, and is connected to a plurality of base stations capable of wireless communication with a plurality of wireless terminals, and is connected to a plurality of communication consoles that communicate with the wireless terminals via the base stations through line control of the control device, corrects the received field strength at the base station of the signal transmitted from the wireless terminal using a correction value determined by the combination of the wireless terminal and the base station, selects a base station to which the wireless terminal communicates based on the corrected received field strength, and transfers the data transmitted from the wireless terminal and via the selected base station to the communication console associated with the selected base station. [Effects of the Invention]

[0015] According to one aspect of the present invention, the communication console that acts as the communication partner can be fixed for each wireless terminal. Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments. [Brief explanation of the drawing]

[0016] [Figure 1] This figure shows an example configuration of a wireless communication system according to an embodiment of the present invention. [Figure 2] This figure shows an example of the configuration of a reception level correction table according to an embodiment of the present invention. [Figure 3] This figure shows an example of the configuration of a reception level table according to an embodiment of the present invention. [Figure 4] This figure shows an example of the configuration of a reception level table according to an embodiment of the present invention. [Figure 5] This figure shows an example of the configuration of the communication console table for each base station according to an embodiment of the present invention. [Figure 6] This is a sequence diagram of the receiver sensitivity correction process according to an embodiment of the present invention. [Figure 7] This is a flowchart of the reception level correction process in Embodiment 1 of the present invention. [Figure 8] This is a flowchart of the audio sorting process in Embodiment 1 of the present invention. [Modes for carrying out the invention]

[0017] <Example 1> FIG. 1 is a diagram showing a configuration example of a wireless communication system according to an embodiment of the present invention.

[0018] The wireless communication system according to an embodiment of the present invention includes communication desks 1 and 2, a line control device 3, and base stations 4 and 5.

[0019] The communication desks 1 and 2 are installed, for example, at a command center, and communicate with wireless terminals 6 and 7 via the line control device 3 and the base stations 4 and 5. The line control device 3 is connected to the base stations 4 and 5 via a wireless or wired communication line (for example, an optical fiber network, a microwave line), and controls communication with the base stations 4 and 5. Further, the line control device 3 is connected to the communication desks 1 and 2 via a wired or wireless network, and controls communication with the communication desks 1 and 2. That is, the line control device 3 controls voice communication between the base stations 4 and 5 and the wireless terminals 6 and 7, such as setting and disconnecting a voice communication line. The communication desks 1 and 2 are associated with the base stations 4 and 5 in a one-to-one correspondence, and a wireless terminal that communicates with a specific base station communicates with the communication desk associated with the specific base station in, for example, a base station-by-base station connection destination communication desk table 120 (see FIG. 5).

[0020] The base stations 4 and 5 are installed at fixed locations on the ground and communicate with the wireless terminals 6 and 7 via a wireless communication line. A plurality of wireless terminals 6 and 7 exist within the coverage area of the base stations 4 and 5. The wireless terminals 6 and 7 communicate with the communication desks 1 and 2 via the base stations 4 and 5 and the line control device 3. Since the wireless terminals 6 and 7 move within the communication area of the base stations 4 and 5, the base station with which they communicate changes according to the position of the wireless terminals.

[0021] The line control device 3 in this embodiment has the function of avoiding communication bias to a specific communication console and realizing the fixed destination base station in overreach areas where the coverage areas of multiple base stations overlap. For this reason, the line control device 3 controls the communication console of the communication partner to remain the same for each wireless terminal, in order to fix the base station used when transmissions from wireless terminals 6 and 7 are received by multiple base stations 4 and 5. For this reason, the line control device 3 corrects the received field strength according to the level correction value. The line control device 3 has a received level correction table 100 (Figure 2) in which the level correction value is recorded, received level tables 110 and 111 (Figures 3 and 4) in which the received field strength of the wireless terminal for each base station is recorded, and a base station-specific destination communication console table 120 (Figure 5) in which the relationship between the base station and the destination communication console is recorded.

[0022] [Received Level Correction Table] Figure 2 shows an example of the configuration of the reception level correction table 100 according to an embodiment of the present invention.

[0023] The reception level correction table 100 is provided in the line control device 3 and records the level correction value for each wireless terminal and each base station. The level correction value is the correction value for the received field strength in a combination of wireless terminal and base station, and is preferably determined by actual measurement or simulation. The correction value may be a fixed value or a variable value. For example, the correction value may be changed depending on the busyness of the communication console (by reducing the correction value of a base station connected to a busy communication console, the possibility of a wireless terminal being connected to that console is reduced). The correction value is added to the received field strength of the signal transmitted by the base station from the wireless terminal. If the correction value is a positive value, the received field strength of the signal transmitted from the wireless terminal that has passed through that base station is corrected to a high value, and the signal transmitted from that wireless terminal is preferentially routed through that base station to establish a line. On the other hand, if the correction value is a negative value, the received field strength of the signal transmitted from the wireless terminal that has passed through that base station is corrected to a low value, and the possibility of the signal transmitted from that wireless terminal being routed through another base station to establish a line increases.

[0024] [Received Level Table] Figures 3 and 4 show examples of the configuration of the receiving level tables 110 and 111 according to an embodiment of the present invention.

[0025] The reception level tables 110 and 111 are tables for each wireless terminal provided in the line control device 3, and temporarily record the received field strength before and after correction for each base station's wireless terminal. For example, in the reception level table 110 for wireless terminal A6 shown in Figure 3, the received field strength at base station A4 is 6 dBm, but after adding the correction value it becomes 16 dBm. The received field strength at base station B5 is 5 dBm, and since the correction value is 0, it remains at 5 dBm. Similarly, in the reception level table 111 for wireless terminal B7 shown in Figure 4, the received field strength at base station A4 is 6 dBm, and since the correction value is 0, it remains at 6 dBm. The received field strength at base station B5 is 5 dBm, but after adding the correction value it becomes 15 dBm. Note that the reception level tables 110 and 111 do not need to record the received field strength before correction, only the corrected received field strength. Also, the reception level tables 110 and 111 may consist of a single table recording the received field strength of all wireless terminals, rather than separate tables for each wireless terminal.

[0026] [Communication console table for each base station] Figure 5 shows an example of the configuration of the base station connection destination communication console table 120 in an embodiment of the present invention.

[0027] A base station-specific connection destination communication console table 120 is provided in the line control device 3 and records the relationship between base stations 4 and 5 and the connection destination communication consoles 1 and 2. Data transmitted from wireless terminals 6 and 7 and received by base stations 4 and 5 is forwarded to the connection destination communication consoles 1 and 2 recorded in the base station-specific connection destination communication console table 120, enabling communication between the wireless terminals 6 and 7 and the communication consoles 1 and 2 with the relationship recorded in the base station-specific connection destination communication console table 120.

[0028] [Sequence for receiver sensitivity correction in this system] Figure 6 is a sequence diagram of the receiver sensitivity correction process according to an embodiment of the present invention.

[0029] When the push-to-talk switch is operated, wireless terminal A6 transmits a call request that includes the caller ID, which is the terminal's identification number. The call request transmitted from wireless terminal A6, and the voice data transmitted in conjunction with that call request, are received by base stations A4 and B5 (S1, S3).

[0030] When base station B5 receives a call request, it transmits a connection request to the line control device 3, including the caller ID of radio terminal A6 and the received field strength (5 dBm) of the signal transmitted from radio terminal A6, along with the voice data (S1) received from radio terminal A6 (S2). When base station A4 receives a call request, it transmits a connection request to the line control device 3, including the caller ID of radio terminal A6 and the received field strength (6 dBm) of the signal transmitted from radio terminal A6, along with the voice data (S3) received from radio terminal A6 (S4).

[0031] When the line control device 3 receives a connection request from the first-arriving base station B5, it calculates the corrected received electric field strength from the received electric field strength received by base station B5 and records the corrected value in the received level table 110 (S11).

[0032] Refer to Figure 7 to explain the details of the reception level correction process (S11).

[0033] The line control device 3 acquires the received field strength (5 dBm) at base station B5 from the signal transmitted from wireless terminal A6 and records 5 dBm in the uncorrected level of the received level table 110 (S111). Next, the line control device 3 refers to the received level correction table 100 and acquires the correction value for the combination of wireless terminal A6 and base station B5 (S112), and adds the acquired correction value to the actual received field strength to correct the received field strength (S113). According to the received level correction table 100, the correction value for the combination of wireless terminal A and base station B is 0, so the corrected received field strength for wireless terminal A6 at base station B5 is the same as the actual received field strength, 5 dBm. Then, the line control device 3 records the corrected received field strength of 5 dBm in the corrected level of the received level table 110 (S114).

[0034] Furthermore, when the line control device 3 receives a connection request from the subsequent base station A4, it calculates the corrected received field strength from the received field strength received by base station A4 and records the corrected value in the received level table 110 (S12). The received level correction process (S12) is the same as the received level correction process in step S11 (Figure 7), although the base station and communication console handled are different.

[0035] Specifically, the line control device 3 obtains the received field strength (6 dBm) at base station A4 from the signal transmitted from wireless terminal A6 and records 6 dBm in the uncorrected level of the received level table 110 (S111). Next, the line control device 3 refers to the received level correction table 100 and obtains the correction value for the combination of wireless terminal A6 and base station A4 (S112), and adds the obtained correction value to the actual received field strength to correct the received field strength (S113). According to the received level correction table 100, the correction value for the combination of wireless terminal A and base station A is +10, so the corrected received field strength for wireless terminal A6 at base station A4 becomes 16 dBm. Then, the line control device 3 records the corrected received field strength of 16 dBm in the corrected level of the received level table 110 (S114).

[0036] Then, the line control device 3 selects base station A4, which has the maximum corrected level (16 dBm) among the corrected levels in the received level table 110, and selects the communication console A1 corresponding to base station A4 (S13).

[0037] Refer to Figure 8 to explain the details of the audio sorting process (S13).

[0038] The line control device 3 selects base station A4 from the corrected levels in the reception level table 110, which has the maximum corrected level (16 dBm), and obtains the corrected received field strength of the selected base station A4 from the reception level table 110 (S131). The line control device 3 refers to the base station destination communication console table 120 and obtains the destination communication console A1 corresponding to the selected base station A4 from the base station destination communication console table 120 (S132). Then, the line control device 3 establishes a line between the selected base station A4 and the line control device 3, and a line between the communication console A1 and the line control device 3, and transmits the voice data transmitted from base station A4 to the communication console A1 (S133).

[0039] Through the above process, the line control device 3 transfers the voice data transmitted from the wireless terminal A6 and received via the base station A4 to the communication console A1 via the established line (S5), enabling voice communication between the wireless terminal A6, the base station A4, and the communication console A1.

[0040] Similarly, when the transmit switch is operated, wireless terminal B7 transmits a call request including the call number, which is the terminal's identification number. The call request transmitted from wireless terminal B7 and the voice data transmitted thereafter are received by base stations A4 and B5 (S6, S8).

[0041] When base station B5 receives a call request, it transmits a connection request to the line control device 3 (S7) including the caller ID of radio terminal B7 and the received field strength (5 dBm) of the signal transmitted from radio terminal B7, as well as the voice data (S6) received from radio terminal B7. When base station A4 receives a call request, it transmits a connection request to the line control device 3 (S9) including the caller ID of radio terminal B7 and the received field strength (6 dBm) of the signal transmitted from radio terminal B7, as well as the voice data (S8) received from radio terminal B7.

[0042] When the line control device 3 receives a connection request from the first-arriving base station B5, it calculates the corrected received field strength from the received field strength received by base station B5 and records the corrected value in the received level table 111 (S14). The received level correction process (S14) is the same as the received level correction process in step S11 (Figure 7), although the base station and communication console being handled are different.

[0043] Specifically, the line control device 3 obtains the received field strength (5 dBm) at base station B5 from the signal transmitted from wireless terminal B7 and records 5 dBm in the uncorrected level of the received level table 111 (S111). Next, the line control device 3 refers to the received level correction table 100 and obtains the correction value for the combination of wireless terminal B7 and base station B5 (S112), and adds the obtained correction value to the actual received field strength to correct the received field strength (S113). According to the received level correction table 100, the correction value for the combination of wireless terminal B and base station B is +10, so the corrected received field strength for wireless terminal A6 at base station A4 becomes 15 dBm. Then, the line control device 3 records the corrected received field strength of 15 dBm in the corrected level of the received level table 111 (S114).

[0044] Furthermore, when the line control device 3 receives a connection request from the subsequent base station A4, it calculates the corrected received field strength from the received field strength received by base station A4 and records the corrected value in the received level table 111 (S15). The received level correction process (S15) is the same as the received level correction process in step S11 (Figure 7), although the base station and communication console handled are different.

[0045] Specifically, the line control device 3 obtains the received field strength (6 dBm) at base station A4 from the signal transmitted from wireless terminal B7 and records 6 dBm in the uncorrected level of the received level table 111 (S111). Next, the line control device 3 refers to the received level correction table 100 and obtains the correction value for the combination of wireless terminal B7 and base station A4 (S112), and adds the obtained correction value to the actual received field strength to correct the received field strength (S113). According to the received level correction table 100, the correction value for the combination of wireless terminal B and base station A is 0, so the corrected received field strength for wireless terminal A6 at base station A4 is the same as the actual received field strength, 6 dBm. Then, the line control device 3 records the corrected received field strength of 6 dBm in the corrected level of the received level table 111 (S114).

[0046] Then, the line control device 3 selects base station B5, which has the maximum corrected level (15 dBm) among the corrected levels in the reception level table 111, and selects the communication console B2 corresponding to base station B5 (S16). The voice distribution process (S16) is the same as the voice distribution process in step S13 (Figure 8), although the base station and communication console being handled are different.

[0047] Specifically, the line control device 3 selects base station B5, which has the maximum corrected level (15 dBm) among the corrected levels in the received level table 111, and obtains the corrected received field strength of the selected base station B5 from the received level table 110 (S131). The line control device 3 refers to the base station destination communication console table 120 and obtains the destination communication console B2 corresponding to the selected base station B5 from the base station destination communication console table 120 (S132). Then, the line control device 3 establishes a line between the selected base station B5 and the line control device 3, and a line between the communication console B2 and the line control device 3, and transmits the voice data transmitted from base station B5 to the communication console B2 (S133).

[0048] Through the above process, the line control device 3 transfers the voice data transmitted from the wireless terminal B7 and received via the base station B5 to the communication console B2 via the established line (S5), enabling voice communication between the wireless terminal B7, the base station B5, and the communication console B2.

[0049] In the reception sensitivity correction process described above, voice distribution processing is performed after receiving connection requests from multiple base stations. However, voice distribution processing may also be performed each time a connection request is received from a base station. In this case, if the received field strength received by the later-arriving base station is greater than the received field strength received by the earlier-arriving base station, the connection established by the connection request from the earlier-arriving base station should be disconnected, a connection should be established by the connection request from the later-arriving base station, and the voice data should be transferred to the communication console.

[0050] [effect] According to the wireless communication system of the embodiment of the present invention, a base station to be preferentially selected for each wireless terminal is determined by specifying a reception level correction value table. That is, when a call is initiated from a wireless terminal, the base station to be used is determined by the received field strength after reception level correction processing, so the possibility of connection with a communication console corresponding to a base station that has been corrected to increase the received field strength is improved, and it is possible to determine which base station to preferentially communicate with the wireless terminal from among the base stations that simultaneously receive the signal transmitted from the wireless terminal, and the communication console that will be the communication partner for each wireless terminal can be fixed.

[0051] In particular, it can suppress fluctuations in the communication console that wireless terminals communicate with near the boundary of the base station's coverage area, and improve the likelihood that a specific wireless terminal will prioritize using a specific base station and communicate with a specific communication console. Furthermore, it can improve the bias of calls to specific communication consoles by allowing each wireless terminal to prioritize using a specific base station, without the communication consoles that wireless terminals communicate with near the boundary of the base station's coverage area being biased towards a specific communication console. In addition, it can control wireless terminals to connect to the same communication console, suppressing connections to different communication consoles with each operation of the transmit switch in overreach areas.

[0052] It should be noted that the present invention is not limited to the embodiments described above, but includes various modifications and equivalent configurations within the spirit of the attached claims. For example, the embodiments described above are described in detail for the purpose of clearly illustrating the present invention, and the present invention is not necessarily limited to having all the described configurations. Furthermore, some of the configurations of one embodiment may be replaced with those of another embodiment. Furthermore, configurations of other embodiments may be added to the configuration of one embodiment. Furthermore, some of the configurations of each embodiment may be added, deleted, or replaced with those of other embodiments.

[0053] Furthermore, each of the aforementioned configurations, functions, processing units, and processing means may be implemented in hardware, for example, by designing them as integrated circuits, or they may be implemented in software by having a processor interpret and execute programs that realize each function.

[0054] Information such as programs, tables, and files that implement each function can be stored in memory, hard disks, SSDs (Solid State Drives), or other storage media such as IC cards, SD cards, and DVDs.

[0055] Furthermore, the control lines and information lines shown are those deemed necessary for explanation purposes and do not necessarily represent all control lines and information lines required for implementation. In reality, it can be assumed that almost all components are interconnected. [Explanation of symbols]

[0056] 1, 2. Communication console 3. Circuit control device 4, 5 base station 6, 7 Wireless terminals

Claims

1. A wireless communication system that communicates using the same frequency, Multiple base stations capable of wireless communication with multiple wireless terminals, A control device connected to the plurality of base stations and controlling the transfer of data transmitted by wireless communication, The system comprises multiple communication consoles connected to the control device, which communicate with the wireless terminal via the base station through the control device's line control, The control device is Using a correction value determined by the combination of the wireless terminal and the base station, the received electric field strength at the base station of the signal transmitted from the wireless terminal is corrected. Based on the corrected received electric field strength, the wireless terminal selects a base station to communicate with. A wireless communication system characterized by transferring data transmitted from the wireless terminal and via the selected base station to a communication console associated with the selected base station.

2. A wireless communication system according to claim 1, The control device is The system includes reception level correction information in which a correction value for the reception level is recorded for each wireless terminal and each base station, reception level information in which the corrected reception field strength is temporarily recorded, and base station-specific connection destination communication console information in which the relationship between the base station and the connection destination communication console is recorded. The received electric field strength at the base station of the signal transmitted from the wireless terminal is corrected by referring to the received level correction information, and recorded in the received level information. The base station with the highest corrected received electric field strength recorded in the reception level information is selected as the base station with which the wireless terminal communicates. A wireless communication system characterized by transferring data transmitted from the wireless terminal and via the selected base station to a communication console associated with the selected base station.

3. A wireless communication system according to claim 1, The control device is Multiple base stations compare the corrected received electric field strength of signals received from the same wireless terminal. Communication is not established with base stations with low received field strength. Establish communication with a base station with a high received electric field strength, A wireless communication system characterized by transferring data to a communication console associated with a base station where communication has been established.

4. A control device that controls the transfer of data transmitted via wireless communication, It is connected to multiple base stations capable of wireless communication with multiple wireless terminals. The control device's line control connects to multiple communication consoles that communicate with the wireless terminal via the base station. Using a correction value determined by the combination of the wireless terminal and the base station, the received electric field strength at the base station of the signal transmitted from the wireless terminal is corrected. Based on the corrected received electric field strength, the wireless terminal selects a base station to communicate with. A control device characterized by transferring data transmitted from the wireless terminal and via the selected base station to a communication console associated with the selected base station.

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