JP2012004792A - Mobile radio system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mobile radio system which can automatically set a communication path having a strong electric field and excellent clarity.SOLUTION: A mobile radio system comprises: a fixed station 1 which is fixedly installed at a prescribed place; a mobile station 9 having a vehicle and for performing communication with the fixed station 1 in a communication service area; an A relay station 4 and a B relay station 7 for relaying communication between the fixed station 1 and the mobile station 9. The fixed station 1 adds a tone signal respectively specifying the A relay station 4 and the B relay station 7 to a voice signal to be transmitted by the fixed station 1, and transmits the resultant signal to the A relay station 4 and the B relay station 7. A relay station, which has received the tone signal specifying the own station, adds this tone signal to the voice signal, and transmits the resultant signal to the mobile station 9. The mobile station 9, which has responded to this voice signal within a prescribed time period, transmits a voice signal after adding a specifying signal specifying a responding partner relay station to the voice signal, and performs communication between the fixed station 1 and the mobile station 9 through this relay station regarding communication after this.

Description

  The present invention relates to a mobile radio system, and more particularly to a mobile radio system that designates a relay station having a strong electric field strength and performs communication between a fixed station and a mobile station via the relay station.

In a conventional mobile radio system, in order to secure a wide service area, a plurality of radio relay stations (hereinafter simply referred to as relay stations) are arranged, for example, on a mountain, and different FM waves are used for transmission and reception 2 Communication between a radio fixed station (hereinafter, simply referred to as a fixed station) and a mobile station is performed using a frequency relay system.
FIG. 8 is a diagram showing a configuration example of a conventional mobile radio system. In this figure, in order to simplify the description, a fixed station is assumed to be one place, a relay station is assumed to be two places (A, B), and a mobile station is assumed to be one place. Also, the reception levels from the relay stations 54 and 57 are set so that the A relay station 54 is higher than the B relay station 57 in order to prevent reception failure due to cross modulation (that is, the A relay station 4 is B has higher priority than relay station B). As a result, when the fixed station 51 receives from the A relay station 54 and the B relay station 57 at the same time, the signal of the A relay station 54 having a high reception level is demodulated by the masking effect. When communication is performed between the fixed station 51 and the mobile station 59 under such conditions, for example, the radio wave relayed from the A relay station 54 is obstructed by the obstacle (mountain) 55 and the received electric field is low. The radio waves transmitted to the mobile station 59 and relayed from the B relay station 57 are not disturbed anywhere and the received electric field is higher than that of the A relay station 54 and the mobile station is in a state of good clarity. (This state changes depending on the location of the mobile station 59). As a result, the mobile station 59 demodulates the radio wave from the B relay station 57 due to the masking effect.

Next, when voice is transmitted from the mobile station 59 to the fixed station 51, the radio wave (F1) emitted from the mobile station 59 is transmitted to the A relay station 54 and the B relay station 57, and from the A relay station 54 to the B relay. The electric field having a stronger electric field than the station 57 is transmitted to the fixed station 51. As a result, the radio wave of the A relay station 54 is automatically demodulated due to the masking effect, and as a result, communication with poor clarity is performed. That is, there is a case where the clarity is good in the communication from the fixed station 51 to the mobile station 59, but the clarity is poor in the communication from the mobile station 59 to the fixed station 51.
In order to solve this problem, Patent Document 1 includes a tone squelch control circuit in a plurality of relay station radio apparatuses of a single speech path system, and particularly eliminates interference interference from channel selection communication of a fixed station. A relay station selection circuit based on a tone signal suitable for use in a circuit is disclosed.

Utility Model Application Notice 2-1974

However, in the conventional technique disclosed in Patent Document 1, it is necessary for the mobile radio station to select and determine which radio relay station is in the service area, and in the service area other than the selected radio relay station There is a problem that a wireless call cannot be made if there is a mobile radio station.
The present invention has been made in view of such a problem, and when transmitting a voice signal from a fixed station, a specific signal identifying each relay station is added and transmitted, and the relay station selected by the masking effect is transmitted. A mobile station that has received an audio signal with a specific signal automatically sets a communication line with high electric field strength and good clarity by adding the specific signal to the audio signal and transmitting it. An object of the present invention is to provide a mobile radio system capable of

In order to solve the above-mentioned problems, the present invention provides a fixed station, a mobile station having mobile means and communicating with the fixed station within a communication service area, the fixed station, and the mobile A relay station that relays communication with a station, and a mobile radio system using a two-frequency relay system that uses different frequencies at the time of transmission and reception at each station, wherein the fixed station Fixed station transmission / reception means for performing modulation / demodulation of radio communication by two frequencies, fixed station specific signal addition means for adding a specific signal for specifying each relay station to a voice signal to be transmitted, and reception via the fixed station transmission / reception means Fixed station identifying signal identifying means for identifying which relay station is the specific signal included in the received signal, and the relay station is a relay station transmitting / receiving means for performing modulation / demodulation of wireless communication by the two frequencies, Relay station Relay station specific signal adding means for adding a specific signal to be specified to the audio signal received from the fixed station, and whether the specific signal included in the received signal received via the relay station transmitting / receiving means is the specific signal of the own station Relay station specifying signal identifying means for identifying the mobile station, the mobile station responding after receiving radio waves by the mobile station transmitting / receiving means and mobile station transmitting / receiving means for performing modulation / demodulation of wireless communication by the two frequencies Response time measuring means for measuring the time until, mobile station specifying signal adding means for adding a specific signal for specifying each relay station to the voice signal, and the received signal received via the mobile station transmitting / receiving means And a specific signal detecting means for detecting the specific signal.
When transmitting from a fixed station for the first time, since the mobile radio station does not know which radio relay station is in the service area, it transmits by adding specific signals of all the relay stations. The relay station includes relay station specific signal identifying means for determining whether or not the signal is a specific signal of the local station. When the local station is identified, the relay station adds the specific signal to the voice signal and transmits it to the mobile station. In addition, since mobile stations often communicate while moving, the communication environment often changes constantly. Therefore, there are cases where the radio waves of one relay station are received, and radio waves from a plurality of relay stations are received. In the former case, if a response is made, the received relay station specific signal is added to the audio signal. In the latter case, since one relay station is selected due to the masking effect, the specific signal is added to the audio signal. As a result, the fixed station, the relay station, and the mobile station can establish a communication route based on the specific signal.

In a second aspect of the present invention, when the mobile station receives radio waves from one relay station and communicates with the fixed station, the fixed station specifies the relay station in an audio signal transmitted from the fixed station. Is added to the relay station, and the relay station identified by the relay station specific signal identifying means as the specific signal that identifies the local station adds the specific signal to the voice signal to the mobile station. The mobile station that has transmitted and received the radio wave, when detecting the specific signal by the specific signal detecting means, adds the detected specific signal as it is to the voice signal and transmits it to the relay station.
The fixed station may select one relay station and relay the relay station to establish communication with the mobile station. In such a case, the fixed station adds only the specific signal of the relay station to be selected to the voice signal and transmits it. When the relay station receives the radio wave, if it is a specific signal of its own station, the relay station adds the specific signal to the voice signal and transmits it to the mobile station. The received mobile station adds the specific signal as it is to the voice signal and transmits it to the relay station. As a result, communication with the mobile station can be established via the relay station selected by the fixed station.

According to a third aspect of the present invention, when the mobile station receives radio waves from a plurality of relay stations and communicates with the fixed station, the fixed station identifies the plurality of relay stations in an audio signal transmitted from the fixed station. Each relay station identified as a specific signal for identifying its own station by the relay station specific signal identifying means adds the specific signal to the voice signal. Then, the mobile station that has transmitted to the mobile station and received the radio wave adds the specific signal related to the radio wave demodulated by the masking effect to the voice signal as it is and transmits it to the relay station.
When the mobile station receives radio waves from a plurality of relay stations, it works to demodulate the radio waves with the strongest received electric field due to the masking effect. Therefore, the mobile station does not need to identify the specific signal, and transmits the received specific signal as it is added to the voice signal. Thereby, the transmission operation of the mobile station can be automatically established by the masking effect.

According to a fourth aspect of the present invention, when the mobile station receives radio waves from a plurality of relay stations and the mobile station responds to the audio signal within a predetermined time, the specific signal related to the radio wave demodulated by the masking effect is used as it is. It is added to the voice signal and transmitted to the relay station.
When radio waves are received from a plurality of relay stations, the radio waves from one relay station are demodulated due to the masking effect. Therefore, when a mobile station called from a fixed station by the radio wave responds by voice within a predetermined time, it is necessary to fix it by the communication route. Therefore, in the present invention, the specific signal received from the responding relay station is added as it is and transmitted. As a result, communication can be performed while maintaining a good communication state.

5. The mobile station according to claim 5, wherein when the mobile station does not respond to the voice signal within a predetermined time, the mobile station adds a specific signal specifying each relay station to the voice signal and transmits the voice signal. And
If the mobile station does not respond to the audio signal within a predetermined time, it is determined that the communication is different from the response to the call, for example, the call of another radio station, etc. Is added to the audio signal. Thereby, communication with other radio stations (for example, other mobile stations) can be performed quickly.

According to a sixth aspect of the present invention, the specific signal is a tone signal composed of a frequency different from the frequency band of the audio signal.
The audio signal is performed in the 500 Hz to 3 kHz band. Therefore, the outside of the band can be used as the band of the control signal. In the present invention, the specific signal is a tone signal composed of a frequency different from the frequency band of the audio signal. Thereby, a circuit for identifying each specific signal can be simplified.

According to the present invention, there are cases where radio waves from one relay station are received or radio waves from a plurality of relay stations are received. In the former case, if a response is made, the received relay station specific signal is added to the audio signal. In the latter case, since one relay station is selected due to the masking effect, the specific signal is added to the audio signal. As a result, the fixed station, the relay station, and the mobile station can establish a communication route based on the specific signal.
The fixed station may select one relay station and relay the relay station to establish communication with the mobile station. In such a case, the fixed station adds only the specific signal of the relay station to be selected to the voice signal and transmits it. When the relay station receives the radio wave, if it is a specific signal of its own station, the relay station adds the specific signal to the voice signal and transmits it to the mobile station. The received mobile station adds the specific signal as it is to the voice signal and transmits it to the relay station, so that communication with the mobile station can be established via the relay station selected by the fixed station.
Further, when the mobile station receives radio waves from a plurality of relay stations, it works to demodulate the radio wave having the strongest received electric field by the masking effect. Therefore, the mobile station does not need to identify a specific signal and transmits the received specific signal as it is added to the voice signal, so that the transmission operation of the mobile station can be automatically established by the masking effect.
Further, since the specific signal received from the responding relay station is added as it is and transmitted, communication can be performed while maintaining a good communication state.
Further, since the specific signal is a tone signal composed of a frequency different from the frequency band of the audio signal, a circuit for identifying each specific signal can be simplified.

It is a figure which shows the structural example of the mobile radio system which concerns on embodiment of this invention. It is a functional block diagram explaining the function of the fixed station of this invention. It is a functional block diagram explaining the function of the relay station of this invention. It is a functional block diagram explaining the function of the mobile station of this invention. (A) is a sequence diagram when the mobile station receives radio waves from one relay station, and (b) is a sequence diagram when the mobile station receives radio waves from a plurality of relay stations. (A) is a sequence diagram when the mobile station receives radio waves from a plurality of relay stations, and responds at a certain time. (B) is a response when the mobile station receives radio waves from a plurality of relay stations at a certain time. It is a sequence diagram when not. It is a flowchart explaining operation | movement of this invention. It is a figure which shows the structural example of the conventional mobile radio system.

  Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings. However, the components, types, combinations, shapes, relative arrangements, and the like described in this embodiment are merely illustrative examples and not intended to limit the scope of the present invention only unless otherwise specified. .

  FIG. 1 is a diagram illustrating a configuration example of a mobile radio system according to an embodiment of the present invention. In this figure, in order to simplify the description, a fixed station is assumed to be one place, a relay station is assumed to be two places (A, B), and a mobile station is assumed to be one place. The mobile radio system 100 includes a fixed station 1 fixedly installed at a predetermined location, a mobile station 9 having a vehicle (moving means) and communicating with the fixed station 1 in a communication service area, A relay station 4 and B relay station 7 that relay communication between the fixed station 1 and the mobile station 9, and use different frequencies (F1, F2) at the time of transmission and reception at each station. In the mobile radio system 100 using the frequency relay system, the fixed station 1 adds a tone signal (specific signal) for specifying each of the A relay station 4 and the B relay station 7 to the audio signal transmitted from the fixed station 1. The relay station that has transmitted to the A relay station 4 and the B relay station 7 and has received the tone signal for identifying its own station adds the tone signal to the voice signal and transmits it to the mobile station 9. The mobile station 9 that responded within the time specified a relay station as a response partner. By sending a tone signal by adding the audio signal to, the subsequent communication is performed between a fixed station 1 and the mobile station 9 via the relay station. In this embodiment, the transmission signal of the fixed station 1 is performed at the frequency F1, and the A relay station 4 and the B relay station 7 convert F1 received from the fixed station 1 into F2 and transmit it to the mobile station 9, and the mobile station 9 receives F2 and converts it to F1 at the time of transmission and transmits it to A relay station 4 and B relay station 7. At A relay station 4 and B relay station 7, F1 is converted to F2 and transmitted to fixed station 1. . If the mobile station 9 does not respond to the audio signal within a predetermined time (for example, within 10 seconds), the mobile station 9 adds a tone signal for identifying the respective relay stations 4 and 7 to the audio signal. To send.

  That is, in the present embodiment, when communication is not performed using only the masking effect, a tone signal for specifying each relay station is given to each of the relay stations 4 and 7 and an audio signal is transmitted from the fixed station 1 Adds a tone signal for identifying the respective relay stations 4 and 7 (for example, the relay station 4 has a tone signal of 100 Hz and the relay station 7 has a tone signal of 200 Hz) to the voice signal and transmits it to the relay station. When each relay station detects the tone signal of its own station, it adds the tone signal to the audio signal, converts the frequency from F1 to F2, and transmits it to the mobile station 9. For example, when the mobile station 9 responds to a radio wave from the relay station 4, the tone signal added to the radio wave is added to the voice signal as it is and transmitted to the relay station 4. As a result, only one identified relay station 4 relays the audio signal and transmits it to the fixed station 1. The fixed station 1 detects the tone signal of the relay station 4 and fixes the tone signal so as to communicate with the relay station 4 in subsequent communications. Thereby, the mobile station 9 responding to the fixed station 1 can communicate with the specific relay station 4.

FIG. 2 is a functional block diagram illustrating functions of the fixed station of the present invention.
The fixed station 1 transmits a transmission / reception unit (fixed station transmission / reception means) 11 that performs modulation / demodulation of wireless communication by two frequencies (F1, F2) and a tone signal (specific signal) that specifies each of the relay stations 4 and 7. A tone signal adding circuit (fixed station specific signal adding means) 13 for adding to the audio signal and a tone signal identifying unit (fixed) for identifying which relay station is the tone signal included in the received signal received via the transmitting / receiving unit 11 (Station identification signal identifying means) 12 and a control unit 14 for controlling each unit. The transmitter / receiver 11 includes an antenna 2.
That is, at the time of transmission, the control unit 14 adds a tone signal for identifying all the relay stations to the audio signal to be transmitted by the tone signal addition circuit 13 and modulates it by the transmission / reception unit 11 at the frequency F1 from the antenna 2. Send. At the time of reception, the radio wave of frequency F2 received from the antenna 2 is demodulated by the transmission / reception unit 11 and identified by the tone signal identification unit 12 to determine which relay station transmitted the tone signal. Also, the audio signal is input to the control unit 14 by another route. In subsequent communications, the tone signal of the identified relay station is added to the voice signal to be transmitted, modulated by the transmitter / receiver 11 at the frequency F1, and transmitted from the antenna 2 to the relay station.

FIG. 3 is a functional block diagram illustrating functions of the relay station of the present invention. The relay station 4 (7) receives from the fixed station 1 a transmission / reception unit (relay station transmission / reception means) 15 that performs modulation / demodulation of wireless communication by two frequencies (F1, F2) and a tone signal (specific signal) that specifies the relay station. A tone signal adding circuit (relay station specific signal adding means) 17 for adding to the received audio signal and a tone for identifying whether or not the tone signal included in the received signal received via the transmitting / receiving unit 15 is the tone signal of the own station. A signal identification unit (relay station specific signal identification unit) 16 and a control unit 19 that controls each unit are configured. The audio signal is input to the control unit 19 by another route. The transmitter / receiver 15 includes an antenna 3 (6).
That is, at the time of reception, the radio wave of the frequency F1 received from the antenna 3 is demodulated by the transmission / reception unit 15 and the tone signal is identified by the tone signal identification unit 16 to identify whether it is the tone signal of the own station. . The audio signal is input to the control unit 14 by another route. At the time of transmission, when the control unit 19 recognizes that the own station is called by the tone signal identification unit 16, the tone signal adding circuit 17 converts the tone signal for specifying the relay station of the own station into an audio signal to be transmitted. In addition, the signal is modulated by the transmitter / receiver 15 at the frequency F2 and transmitted from the antenna 3.

FIG. 4 is a functional block diagram illustrating functions of the mobile station of the present invention. The mobile station 9 includes a transmission / reception unit (mobile station transmission / reception means) 20 that performs modulation / demodulation of radio communication using two frequencies (F1, F2), and a response that measures the time from reception of a radio wave by the transmission / reception unit 20 until response Time counting means 23, tone signal adding circuit (mobile station specifying signal adding means) 22 for adding a tone signal (specific signal) specifying each relay station to the audio signal, and the received signal received via transmitting / receiving unit 20 A tone signal detection unit (specific signal detection means) 21 that detects the included tone signal and a control unit 24 that controls each unit are configured. The transmission / reception unit 20 includes an antenna 8.
That is, at the time of reception, the radio wave of the frequency F2 received from the antenna 8 is demodulated by the transmission / reception unit 20, and the tone signal identification unit 21 identifies the tone signal. At this time, the control unit 24 starts the response time counting means 23 and checks whether or not to respond to the received radio wave. When the response is made within the time, the received tone signal is added as it is to the audio signal to be transmitted by the tone signal adding circuit 22, and is modulated by the transmitting / receiving unit 20 at the frequency F1 and transmitted from the antenna 8. When not responding within the time, the tone signals of all the relay stations are added to the audio signal to be transmitted by the tone signal adding circuit 22, modulated by the transmitting / receiving unit 20 at the frequency F1, and transmitted from the antenna 8.

  Thus, when transmitting from the fixed station 1 for the first time, since it is not known which relay station is selected, the tone signals of all the relay stations 4 and 7 are added and transmitted. Each of the relay stations 4 and 7 includes a tone signal identification unit 16 that identifies whether or not the tone signal is the own station. When the own station is selected, the tone signal is added to the voice signal and the mobile station 9 Send. In addition, since the mobile station 9 often communicates while moving, the communication environment always changes. Therefore, there are cases where the radio waves of one relay station are received, and radio waves from a plurality of relay stations are received. In the former case, if the response is made, the received relay station tone signal is added to the audio signal. In the latter case, one relay station is selected due to the masking effect (demodulates the radio wave having the strongest reception electric field), and therefore a tone signal specifying the relay station is added to the audio signal. When a radio wave is received and a response is made within a predetermined time, a tone signal received from the responding relay station is added as it is and transmitted. If no response is made within a predetermined time, it is considered that the other radio station is called, and the tone signals of all the relay stations are added and transmitted. Thereby, the fixed station 1, the relay stations 4 and 7, and the mobile station 9 can establish a communication route based on the tone signal.

  FIG. 5A is a sequence diagram when the mobile station receives radio waves from one relay station. In this case, for example, in order to select the A relay station 4, the fixed station 1 adds a tone signal a for identifying the A relay station 4 to the audio signal and transmits the sound signal at the frequency F1. The radio wave is simultaneously transmitted to the A relay station 4 and the B relay station 7, but the B relay station 7 does not respond because the tone signal b is not added, and only the A relay station 4 responds. Then, the tone signal a is added to the audio signal from the A relay station 4 and transmitted to the mobile station 9 at the frequency F2. Since the mobile station 9 has received radio waves from one relay station, the tone signal a is directly added to the voice signal and transmitted to the A relay station 4 and the B relay station 7 at the same time at the frequency F1. The A relay station 4 and the B relay station 7 that have received the radio wave identify the tone signal and the A relay station 4 responds, but the B relay station 7 does not respond. As a result, the tone signal a is added from the A relay station 4 to the audio signal and transmitted to the fixed station 1 at the frequency F2.

  FIG. 5B is a sequence diagram when the mobile station receives radio waves from a plurality of relay stations. In this case, the fixed station 1 adds a tone signal a and a tone signal b that specify the A relay station 4 and the B relay station 7 to the audio signal and transmits the audio signal at the frequency F1. The radio waves are simultaneously transmitted to the A relay station 4 and the B relay station 7, and both the A relay station 4 and the B relay station 7 respond. Then, the A relay station 4 adds the tone signal a to the voice and transmits it to the mobile station 9 at frequency F2, and the B relay station 7 adds the tone signal b to the voice and transmits it to the mobile station 9 at frequency F2. . In the mobile station 9, for example, if the B relay station 7 is demodulated due to the masking effect, the tone signal b is added to the audio signal and transmitted to the A relay station 4 and the B relay station 7 simultaneously at the frequency F1. The A relay station 4 and the B relay station 7 that have received the radio wave identify the tone signal and the B relay station 7 responds, but the A relay station 4 does not respond. As a result, the tone signal b is added from the B relay station 7 to the audio signal and transmitted to the fixed station 1 at the frequency F2.

  FIG. 6A is a sequence diagram when the mobile station responds to a certain time when receiving radio waves from a plurality of relay stations. In this case, the fixed station 1 adds a tone signal a and a tone signal b that specify the A relay station 4 and the B relay station 7 to the audio signal and transmits the audio signal at the frequency F1. The radio waves are simultaneously transmitted to the A relay station 4 and the B relay station 7, and both the A relay station 4 and the B relay station 7 respond. The A relay station 4 adds the tone signal a to the audio signal and transmits it to the mobile station 9 at frequency F2, and the B relay station 7 adds the tone signal b to the audio signal and transmits it to the mobile station 9 at frequency F2. Is done. In the mobile station 9, for example, if the B relay station 7 is demodulated due to the masking effect, when the mobile station 9 responds to the radio wave within a certain time, the tone signal b is added to the voice signal to add the A relay station 4 and the B relay station 7 At the same time at frequency F1. The A relay station 4 and the B relay station 7 that have received the radio wave identify the tone signal and the B relay station 7 responds, but the A relay station 4 does not respond. As a result, the tone signal b is added from the B relay station 7 to the audio signal and transmitted to the fixed station 1 at the frequency F2.

  FIG. 6B is a sequence diagram in the case where the mobile station does not respond in a certain time when receiving radio waves from a plurality of relay stations. In this case, the fixed station 1 adds a tone signal a and a tone b signal that specify the A relay station 4 and the B relay station 7 to the audio signal and transmits the audio signal at the frequency F1. The radio waves are simultaneously transmitted to the A relay station 4 and the B relay station 7, and both the A relay station 4 and the B relay station 7 respond. The A relay station 4 adds the tone signal a to the audio signal and transmits it to the mobile station 9 at frequency F2, and the B relay station 7 adds the tone signal b to the audio signal and transmits it to the mobile station 9 at frequency F2. Is done. In the mobile station 9, for example, if the B relay station 7 is demodulated due to the masking effect, the tone signal a and the tone signal b are added to the voice signal and the A relay station 4 and Simultaneously transmit to the B relay station 7 at the frequency F1. The A relay station 4 and the B relay station 7 that have received the radio wave identify the tone signal, and both the A relay station 4 and the B relay station 7 respond. As a result, the tone signal a and tone signal b are added to the audio signal from the A relay station 4 and the B relay station 7 and transmitted to the fixed station 1 at the frequency F2.

  FIG. 7 is a flowchart for explaining the operation of the present invention. The fixed station 1 adds a tone signal a and a tone signal b that specify the A relay station 4 and the B relay station 7 to the audio signal, and transmits it at the frequency F1 (S1). The radio waves are simultaneously transmitted to the A relay station 4 and the B relay station 7, and both the A relay station 4 and the B relay station 7 respond (Y in S4, Y in S9). Then, the tone signal a is added to the voice signal from the A relay station 4 and transmitted to the mobile station 9 at the frequency F2 (S5), and the tone signal b is added to the voice signal from the B relay station 7 and the frequency is sent to the mobile station 9. It is transmitted by F2 (S10). When the mobile station 9 receives the radio wave (Y in S14), it checks whether or not it has responded within a certain time (S16), and if it does not respond within a certain time (Y in S15), the voice signal includes the tone signal a and b is added (S19), the frequency is converted from F2 to F1, and transmitted to the A relay station 4 and the B relay station 7 (S18). If there is a response within a predetermined time in step S16 (Y in S16), the tone signal of the responding relay station is added to the audio signal (S17), the frequency is converted from F2 to F1, and the A relay stations 4 and B are converted. It transmits to the relay station 7 (S18). The A relay station 4 and B relay station 7 that have received the radio wave identify the tone signal (S6, S11), and if the tone signal a and the tone signal b are added in step S19, the A relay station 4 and Both B relay stations 7 respond. As a result, the tone signal a and tone signal b are added to the audio signal from the A relay station 4 and the B relay station 7 and transmitted to the fixed station 1 at the frequency F2. On the other hand, when the tone signal of the relay station that responded in step S17 is added, one of the relay stations responds, adds the tone signal of the relay station to the audio signal, and transmits it to the fixed station 1 at the frequency F2. (S7, S12). The fixed station 1 fixes the received tone signal and performs subsequent communication (S3).

  In the above description, the case where the fixed station 1 and the mobile station 9 communicate by relaying the relay stations 4 and 7 has been described. However, the mobile station 9 and another mobile station relay the relay stations 4 and 7. The present invention can also be applied to the case of communicating with each other.

1 fixed station, 2 fixed station antenna, 3 A relay station antenna, 4 A relay station, 5 obstacle, 6 B relay station antenna, 7 B relay station, 8 mobile station antenna, 9 mobile station, 11 fixed station transceiver, 12 fixed station tone signal identification unit, 13 fixed station tone signal addition circuit, 14 fixed station control unit, 15 relay station transmission / reception unit, 16 relay station tone signal identification unit, 17 relay station tone signal addition circuit, 19 relay station control unit, DESCRIPTION OF SYMBOLS 20 Mobile station transmission / reception part, 21 Tone signal detection part, 22 Mobile station tone signal addition circuit, 23 Response time measuring means, 24 Mobile station control part, 100 Mobile radio system

Claims (6)

A fixed station, a mobile station that has mobile means and communicates with the fixed station in a communication service area, and a relay station that relays communication between the fixed station and the mobile station, A mobile radio system using a two-frequency relay system that uses different frequencies at the time of transmission and reception at each station,
The fixed station includes fixed station transmission / reception means for performing modulation / demodulation of radio communication by the two frequencies, fixed station specific signal addition means for adding a specific signal for specifying each relay station, and the fixed station transmission / reception. Fixed station specific signal identifying means for identifying which relay station is the specific signal included in the received signal received via the means,
The relay station is a relay station transmission / reception means for performing modulation / demodulation of the radio communication by the two frequencies, a relay station specifying signal adding means for adding a specific signal for specifying the relay station to an audio signal received from the fixed station, Relay station specifying signal identifying means for identifying whether or not the specific signal included in the received signal received via the relay station transmitting / receiving means is a specific signal of the own station,
The mobile station includes a mobile station transmission / reception means for performing modulation / demodulation of radio communication by the two frequencies, a response time counting means for measuring a time from reception of a radio wave by the mobile station transmission / reception means to a response, and each relay station A mobile station specific signal adding means for adding a specific signal for specifying a voice signal, a specific signal detecting means for detecting the specific signal included in the received signal received via the mobile station transmitting / receiving means,
A mobile radio system comprising: When the mobile station receives radio waves from one relay station and communicates with the fixed station,
The fixed station is a specific signal for adding a specific signal for specifying the relay station to a voice signal transmitted from the fixed station, transmitting the signal to the relay station, and specifying the own station by the relay station specific signal identifying unit. When the mobile station that has received the radio wave detects the specific signal by the specific signal detector, the relay station that has identified the specific signal is added to the voice signal and transmitted to the mobile station. The mobile radio system according to claim 1, wherein is added to the voice signal as it is and transmitted to the relay station. When the mobile station receives radio waves from a plurality of relay stations and communicates with the fixed station,
The fixed station adds a plurality of specific signals for specifying the plurality of relay stations to the audio signal transmitted from the fixed station, transmits the signals to the relay station, and specifies the own station by the relay station specific signal identifying means. Each relay station identified as a specific signal to be transmitted adds the specific signal to the voice signal and transmits it to the mobile station, and the mobile station that has received the radio wave specifies the specific radio wave demodulated by the masking effect. The mobile radio system according to claim 1, wherein the signal is added to the voice signal as it is and transmitted to the relay station.   When the mobile station receives radio waves from a plurality of relay stations and the mobile station responds to the audio signal within a predetermined time, the specific signal related to the radio wave demodulated by the masking effect is added to the audio signal as it is. The mobile radio system according to claim 1, wherein the mobile radio system transmits to the relay station.   2. If the mobile station does not respond to the voice signal within a predetermined time, the mobile station adds a specific signal for specifying each relay station to the voice signal and transmits it. The mobile radio system described in 1.   The mobile radio system according to any one of claims 1 to 5, wherein the specific signal is a tone signal composed of a frequency different from a frequency band of the audio signal.

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