JP4697478B2 - Mobile communication system, line management station, mobile communication base station and mobile station used therefor - Google Patents

Description

  The present invention receives an allocation of a reserved channel provided by a DAMA satellite communication system of a multiple channel access system upon request via a satellite, and allocates a frequency band of the reserved channel to a mobile communication base station and a mobile station. The present invention relates to a mobile communication system that performs communication, a line management station, a mobile communication base station, and a mobile station used therefor.

  In the satellite communication field, in the old days, a fixed-line communication between one-to-one satellite communication apparatuses is called a request-time channel assignment multiple access method (hereinafter referred to as “DAMA method”. Also, a DAMA satellite communication system is called this method. DAMA is an abbreviation of Demand Assignment Multiple Access.) In addition, communication by satellite mobile phones using CDMA or FDMA systems such as the Iridium Project was devised. Has been reached. The DAMA satellite communication system has a common communication system so that a plurality of slave stations can use satellite communication from the viewpoint of wide area and publicity, and a communication line is set up by a control station when a line assignment request is issued from the slave station. Is assigned, and immediately performs satellite communication between the slave stations. When the communication is completed, the communication line is released so that the assigned communication line can be used for satellite communication between the other slave stations. Generally, in the communication system of the DAMA satellite communication system, a common control line (for example, a line assignment request signal or a communication end signal) is transmitted and received between a plurality of slave stations and a control station. (Hereinafter referred to as “CSC line”) and an on-demand assignment communication line that is assigned upon request for communication between slave stations. In the on-demand allocation communication line, synchronous communication using continuous waves is generally performed, and communication between slave stations starts following a line allocation response from the control station to the line allocation request. A DAMA satellite communication system including a fixed communication line capable of receiving a predetermined line assignment in addition to such an on-demand assignment communication line can also be configured. It is disclosed.

  According to the DAMA satellite communication system described in Patent Document 1, when a DAMA control unit provided in a control station receives a line assignment request signal from an arbitrary calling station via a CSC line, it searches for a free communication line. Registering and registering a pair of communication lines that can communicate with each other between a pair of slave stations, as well as having a line assignment function based on the on-demand line assignment method by instructing the calling slave station via a CSC line When a line assignment request signal is received from either one of the slave stations, the communication line registered in the pair of slave stations is instructed to have a line assignment function based on a fixed line assignment method of the communication line. It is configured. With such a configuration, it is possible to provide a communication line based on the on-demand line assignment and a communication line based on the fixed assignment in the DAMA satellite communication system controlled by one control station.

Japanese Patent Laid-Open No. 10-327094

  As described above, in the conventional DAMA satellite communication system, although the communication line by the requested line assignment and the communication line fixedly registered in advance can coexist, the slave station receiving provision of the DAMA satellite communication system Must be compatible with the communication system of the CSC line and the communication line, and it is not possible to increase the scalability in terms of providing communication services to other satellite communication networks such as a mobile satellite communication network. was there. More specifically, for example, when a communication device mounted on a helicopter communicates with a base station on the ground via a satellite, in order to suppress the influence of blocking and reflection of transmission and reception waves by the rotor blades of the helicopter, The transmission wave from the helicopter is intermittently transmitted as a burst wave, and the transmission wave from the base station is transmitted by the time diversity method, and there is a problem that such communication cannot be performed in the DAMA satellite communication system. It was. A similar problem is that for other mobile communication systems that use a system that is different from the DAMA satellite communication system in the line control system and communication system, a separate satellite communication network system must be constructed. It is considered inefficient from the viewpoint of frequency use in communication, and how to effectively use a limited frequency band has been a problem.

  The present invention has been made in order to solve the above-described problems, and receives allocation of a reserved line provided by a DAMA satellite communication system of a multiple channel connection system upon request via a satellite. It is an object of the present invention to obtain a mobile communication system that performs mobile communication by assigning a frequency band to a mobile communication base station and a mobile station, and a line management station, a mobile communication base station, and a mobile station that are used therefor.

  The mobile communication system according to the first aspect of the present invention receives a reserved line assignment provided by a DAMA satellite communication system that provides a communication service via a satellite by a line management station, and transmits the frequency band of the reserved line to the mobile communication base. In a mobile communication system that allocates communication between a station and a mobile station and provides a communication service, the line management station communicates with a control station of the DAMA satellite communication system via a CSC line of the DAMA satellite communication system. A first DAMA communication unit that performs communication, a reservation terminal device that outputs a reservation request for requesting allocation of a reserved line to the first DAMA communication unit, and a frequency band of the reserved line that has been reserved. A line management device assigned to a communication line between the mobile station and the mobile station, and the mobile communication base station is assigned by the line management station. A mobile communication unit that communicates with the mobile station via the communication line, and a communication start command transmitted from the line management station at the communication start time of the reserved line. A first line control circuit that outputs a communication start signal to be transmitted to the mobile station, and the mobile station communicates with the mobile communication base station through a communication line assigned by the line management station. And a second line control circuit for starting transmission to the mobile communication base station based on receiving the communication start signal from the mobile communication base station. .

  The line management station according to the invention of claim 2 is assigned a reserved line provided by a DAMA satellite communication system that provides a communication service via a satellite, and assigns it to communication between a mobile communication base station and a mobile station. A first DAMA communication unit that communicates with a control station of the DAMA satellite communication system via a CSC line of the DAMA satellite communication system in a line management station of the mobile communication system that provides a communication service; A reservation terminal device that outputs a reservation request for requesting allocation of a reserved line to the DAMA communication unit of the network, a line management device that allocates a bandwidth of the reserved communication line to a communication line between the mobile communication base station and the mobile station, The line management apparatus generates a communication start command to be transmitted to the mobile communication base station at the communication start time of the reserved line.

According to a third aspect of the present invention, a mobile communication base station receives allocation of a reserved line provided by a DAMA satellite communication system that provides a communication service via a satellite by a line management station, and transmits a communication line from a frequency band of the reserved line. A first DAMA communication unit that performs communication with a control station of the DAMA satellite communication system through a CSC line of the DAMA satellite communication system in a mobile communication base station that receives communication and communicates with a mobile station A mobile communication unit that communicates with the mobile station via the assigned communication line by the line management station that receives the reserved line assignment by transmitting a reservation request for requesting the reserved line assignment , Transmitted from the communication unit to the mobile station based on a communication start command transmitted from the line management station at the communication start time of the reserved line It is obtained by a first line control circuit for outputting a communication start signal that.

The mobile station according to the invention of claim 4 receives allocation of a reserved line provided by a DAMA satellite communication system that provides a communication service via a satellite by the line management station, and receives the allocation of the communication line from the frequency band of the reserved line. In the mobile station that communicates with the mobile communication base station , the reservation is made by the first DAMA communication unit that communicates with the control station of the DAMA satellite communication system through the CSC line of the DAMA satellite communication system. A communication unit that communicates with the mobile communication base station via the assigned communication line by the line management station that receives the reserved line assignment by transmitting a reservation request for requesting line assignment ; The communication transmitted from the mobile communication base station based on the communication start command transmitted from the line management station at the communication start time of the reserved line. By receiving the start signal, in which a second line control circuit for starting the transmission to the mobile communication base station.

  According to a fifth aspect of the present invention, there is provided a mobile communication system in which a reserved line provided by a DAMA satellite communication system that provides a communication service via a satellite is assigned by a line management station, and a frequency band of the reserved line is received by a mobile communication base In a mobile communication system that allocates communication between a station and a mobile station and provides a communication service, the line management station communicates with a control station of the DAMA satellite communication system via a CSC line of the DAMA satellite communication system. A first DAMA communication unit that performs communication, and a reservation terminal device that outputs a reservation request for requesting allocation of a reserved line and a line allocation request for requesting allocation of a requested allocated line to the first DAMA communication unit; A line management device for allocating a reserved reserved frequency band to a communication line between the mobile communication base station and the mobile station; The mobile communication base station receives a request between the mobile communication unit that communicates with the mobile station through a communication line assigned by the line management station and a slave station of the DAMA satellite communication system. A second DAMA communication unit that performs communication through the allocated line, and a communication start that is transmitted from the mobile communication unit to the mobile station based on a communication start command transmitted from the line management station at the communication start time of the reserved line A first line control circuit for outputting a signal, wherein the mobile station communicates with the mobile communication base station via a communication line assigned by the line management station, and the mobile A second line control circuit for starting transmission to the mobile communication base station based on receiving the communication start signal from the mobile communication base station.

The mobile communication base station according to the invention of claim 6 receives allocation of a reserved line provided by a DAMA satellite communication system that provides a communication service via a satellite by the line management station, and from the frequency band of this reserved line, A first DAMA communication unit that performs communication with a control station of the DAMA satellite communication system through a CSC line of the DAMA satellite communication system in a mobile communication base station that receives communication and communicates with a mobile station A mobile communication unit that communicates with the mobile station via the assigned communication line by the line management station that receives the reserved line assignment by transmitting a reservation request for requesting the reserved line assignment the by first DAMA communication unit, by sending a line assignment request for requesting allocation of demand allocated line, demand split By the line management station that receives the assignment of the line, the request assignment has been the DAMA satellite communication system demand assignment access and a second DAMA communication unit that communicates with the slave station of the DAMA satellite communications system, A first line control circuit for outputting a communication start signal transmitted from the communication unit to the mobile station based on a communication start command transmitted from the line management station at a communication start time of the reserved line. is there.

  According to the first to fourth aspects of the present invention, the channel management station receives the reserved channel allocation of the DAMA satellite communication system, allocates the communication channel between the mobile communication base station and the mobile station, Communication between the mobile communication base station and the mobile station is performed based on the communication start command from the management station, so that the mobile station is not directly controlled from the DAMA satellite communication system, and the satellite communication is established. Can be made.

According to the invention of claim 5 or claim 6, in addition to the effects of the inventions of claims 1 to 4, the DAMA communication unit in which the mobile communication base station performs communication using the requested allocation line is provided. Therefore, the transmission signal transmitted from the mobile station can be transmitted to the slave station of the DAMA satellite communication system.

Embodiment 1

  A mobile communication system according to Embodiment 1 of the present invention will be described with reference to FIGS. 1 is a block diagram showing a configuration of a satellite communication system including a mobile communication system according to Embodiment 1 of the present invention. In FIG. 1, 1 is a control station that performs line control such as line assignment and release in a DAMA satellite communication system, 2 is a slave station of the DAMA satellite communication system, 3 is a communication satellite, 4 is a control station 1 and a plurality of slave stations 2 A CSC line for transmitting and receiving control signals in common with the mobile station 2, and a communication line 5 between the slave stations 2. 6 is a line management station for mobile communication, 7 is a mobile communication base station, and 8 is a mobile station. Examples of the mobile station 8 include a helicopter, an aircraft, a ship, and an automobile. 9 is a communication line for transmitting from the mobile communication base station 7 to the mobile station 8 via the communication satellite 3, and 10 is a communication line for transmitting from the mobile station 8 to the mobile communication base station 7 via the communication satellite 3.

  Next, the lines assigned by FIG. 2 will be described. FIG. 2 is a schematic diagram showing frequency allocation in the satellite communication system according to the first embodiment. FIG. 2A shows a line assigned in the DAMA satellite communication system. Control signals between the control station 1 and the plurality of slave stations 2 are transmitted / received through a predetermined CSC line 4, and transmission from the slave station 2 to the control station 1 is an uplink CSC line (frequency f 1), Transmission from 1 to the slave station 2 is performed on the downstream CSC line (f2). The slave station 2 transmits a line assignment request signal for requesting communication line assignment to the control station 1 via the uplink CSC line 4, searches for a free line in the control station 1, and assigns the communication line 5 between the slave stations. The line information of the assigned communication line 5 is transmitted from the control station 1 to the slave station 2 as a line assignment response signal via the downlink CSC line 4. The communication line 5 assigned here is a request-time assignment line, and is a communication line having the frequencies f3, f4, f5, and f6 shown in FIG. In order to perform two-way communication between slave stations, f3 and f4 are assigned as a pair of communication lines. Communication is immediately started between the assigned slave stations. Further, in the DAMA satellite communication system, it is possible to reserve a line in advance and use a reserved line in which the reserved communication line is exclusively used among the slave stations for a predetermined period. f8 is a reserved line. A slave station 2 that wants a reserved line applies to the control station 1 for a reservation specifying a communication start time and a communication end time via the CSC line 4, and the control station 1 determines whether there is a line to be allocated as a reserved line. If there is a free line, a reservation is accepted, and the reserved line is secured for use by the slave station between the designated communication start time and communication end time. Reserved lines such as f7 and f8 may be unidirectional, or may be divided into two so that bidirectional communication can be performed in the band B.

  Next, a description will be given of a case where the mobile communication system requests the DAMA satellite communication system to assign a communication line and performs mobile communication on the assigned communication line. An application for the reserved line (f7, f8, etc.) in FIG. The reservation line assignment application is made through the CSC line 4 of the DAMA satellite communication system. Upon receiving the reserved line assignment, the line management station 6 creates a communication line by freely dividing the use band B as shown in FIG. In FIG. 2B, f9 and f11 are lines with a narrow bandwidth and a low communication speed, and f10 and f12 are lines with a wide bandwidth and a high communication speed. Depending on the use of mobile communication, when communication between the mobile station 8 and the mobile communication base station 7 is considered, bidirectional communication at the same speed and bidirectional communication at a different speed are used. There is. Bidirectional communication at different speeds is also called so-called asymmetric communication. In mobile communication using a helicopter as shown in FIG. 1, video / audio and control signals captured from a helicopter (mobile 8) are transmitted to the mobile communication base station 7. When a voice / control signal is transmitted from the mobile communication base station 7 to the helicopter (mobile 8), the line from the mobile 8 to the mobile communication base station 7 has a wide bandwidth and mobile communication. If the line from the base station 7 to the mobile unit 8 is a narrow band, the line can be used more efficiently. In this case, f9 in FIG. 2B is assigned as a transmission line from the mobile communication base station 7 to the helicopter (mobile 8), f10 is assigned as a transmission line from the mobile 8 to the mobile communication base station 7, and f11 and f12 is assigned as a communication line between another helicopter (mobile unit 8) and the mobile communication base station 7.

  Also, the line management station 6 can assign a plurality of reserved lines and assign a wider band to communication between a larger number of mobile stations 8 and mobile communication base stations 7. In FIG. 2 (c), the line management station 6 receives allocation of reserved lines of f7 and f8, and secures a 2 × B communication band, and more mobile communication lines are allocated to this communication band. Is.

  Next, the configuration of the control station 1, the slave station 2, the line management station 6, the mobile communication base station 7, and the mobile station 8 will be described with reference to FIGS. FIG. 3 is a functional block diagram showing the configuration of the control station 1. In FIG. 3, 11 is an error correction coding circuit that performs error correction coding on a voice signal and data signal to be transmitted, 12 is a frame generation circuit that frames a transmission signal that has been error correction coded, and 13 is a frame generation circuit 12. A communication line modulator 14 that modulates a framed transmission signal, and a transmitter 14 that amplifies the transmission signal modulated by the communication line modulator 13. The transmission signal is transmitted to the communication satellite 3 through the antenna duplexer 15 and the antenna 16. On the other hand, the received signal is input to the receiver 17 via the antenna 16 and the antenna duplexer 15 and amplified with low noise. 18 is a communication line demodulator that demodulates the received signal, 19 is a frame processing circuit that deframes the demodulated received signal, and 20 is error correction decoding that performs error correction decoding on the deframed received signal data string. The error correction decoding circuit 20 outputs a voice signal and a data signal. If the audio signal is compression-encoded, further expansion processing is performed. Reference numeral 21 denotes a line assignment control device that receives a line assignment request signal from the slave station 2 and searches for a free communication line and assigns communication lines (requested assignment line and reserved line). The control signal from the line allocation control device 21 is modulated by the CSC line modulator 22 and output to the transmitter 14, transmitted to the communication satellite 3 via the antenna duplexer 15 and the antenna 16, and received from the slave station 2 that receives it. The control signal is input to the receiver 17 through the antenna 16 and the antenna duplexer 15, demodulated by the CSC line demodulator 23, and input to the line allocation control device 21.

  4 is a functional block diagram showing the configuration of the slave station 2. In FIG. 4, reference numeral 24 denotes a line assignment request signal to be transmitted to the control station 1, and the communication line is set based on the line assignment response signal from the control station 1. A line control circuit to be set, 25 is a CSC line modulator for modulating a control signal to be transmitted, and 26 is a CSC line demodulator for demodulating a received control signal. In FIG. 4, parts and circuits denoted by the same reference numerals as those in FIG. 3 are equivalent to or equivalent to those parts and circuits in FIG.

  Control signal transmission / reception between the control station 1 and the slave station 2 is performed by the CSC line 4, but the control signal transmitted from the control station 1 is transmitted as a continuous wave, and the control signal transmitted from the slave station 2 is It is transmitted as a burst wave. Therefore, the CSC line modulator 22 of the control station 1 in FIG. 3 modulates and transmits a continuous wave, and the CSC line demodulator 23 demodulates a burst wave. In FIG. 4, the CSC line modulator 25 of the slave station 2 modulates and transmits a burst wave, and the CSC line demodulator 26 demodulates a continuous wave.

  Next, the configuration of the line management station 6 and the mobile communication base station 7 will be described with reference to FIG. FIG. 5 is a functional block diagram showing configurations of the line management station 6 and the mobile communication base station 7. In the line management station 6 shown in FIG. 5, 27 is a reservation terminal device for applying for a reserved line, 28 is a DAMA communication unit for communicating with a DAMA satellite communication system via a CSC line, and 29 is a control for a reservation application signal and the like. A control signal processing circuit that generates a signal, 30 is a CSC line modulator that burst modulates a control signal to be transmitted, and 31 is a CSC line demodulator that demodulates the received control signal as a continuous wave. The control signal processing circuit 29 outputs necessary information (for example, reservation status information and reservation completion notification) based on the received control signal. A transmitter 32 amplifies the control signal, and a transmission signal output from the transmitter 32 is transmitted to the communication satellite 3 via the antenna duplexer 33 and the antenna 34. Reference numeral 35 denotes a receiver that amplifies the received signal received via the antenna 34 and the antenna duplexer 33 with low noise. The control signal received by the receiver 35 is input to the CSC line demodulator 31. Reference numeral 36 denotes a line management device that allocates a frequency band of a communication line reserved by the reservation terminal device 27 to a mobile unit. In the mobile communication base station 7, reference numeral 37 denotes a line that controls its own line to perform communication with the mobile station 8 based on the communication line assignment and communication start command by the line management device 36 of the line management station 6. A control circuit 38 is a mobile communication unit that communicates with the mobile station 8. In the mobile communication unit 38, 39 is a multiplexing circuit that multiplexes a voice / data signal to be transmitted and a control signal, 40 is an error correction coding circuit that performs error correction coding on the multiplexed transmission signal, and 41 is a transmission. A frame generation circuit for framing the signal, 42 is a diversity data generation circuit for converting the transmission signal into diversity data for time diversity reception in the mobile station 8, and 43 is a modulator for modulating the transmission signal as a continuous wave. The time diversity of the transmission signal from the mobile base station 7 is effective when the mobile body is a helicopter. Although the format of the transmission signal will be described later, the diversity data generation circuit 42 is not necessary in such mobile communication that does not require diversity. A demodulator 44 demodulates a received signal transmitted from the mobile station 8 and received via the communication satellite 3. The received signal demodulated by the demodulator 44 is subjected to frame processing by the frame processing circuit 45 and the error correction decoding circuit 46. And error correction decoding. A separation circuit 47 separates the video / audio signal and the control response signal. The control response signal is input to the line control circuit 37. A transmission signal from the mobile communication unit 38 is transmitted to the communication satellite 3 via the transmitter 48, the antenna duplexer 49 and the antenna 50, and a signal transmitted from the mobile station 8 and received via the communication satellite 3 is the antenna 50, The signal is input to the mobile communication unit 38 via the antenna duplexer 49 and the receiver 51. Signals transmitted / received to / from the mobile station 8 are video, audio, data signals, etc., and are appropriately determined according to the use of the mobile communication system.

  Next, the configuration of the mobile station 8 will be described with reference to FIG. FIG. 6 is a functional block diagram showing the configuration of the mobile station 8. In FIG. 6, 52 is a multiplexing circuit that multiplexes the video / audio signal and control response signal transmitted from the mobile station 8, 53 is an error correction coding circuit that performs error correction coding of the transmission signal, and 54 is a frame that transmits the transmission signal. This is a frame generation circuit to be converted. A burst generation circuit 55 generates a burst signal from the framed transmission signal, and a modulator 56 modulates the burst signal. When the mobile station 8 is a helicopter, the transmission path between the communication device mounted on the helicopter body (under the rotor blade) and the communication satellite 3 is intermittently interrupted by the rotation of the rotor blade. Reference numeral 57 denotes a transmission timing generation circuit that receives the transmission wave cut-off timing by the rotor blades, generates a transmission timing signal indicating a period of no cut-off, and outputs the transmission timing signal to the burst generation circuit 55 and the modulator 56. The transmission signal is amplified by the transmitter 58 and transmitted to the communication satellite 3 via the antenna duplexer 59 and the antenna 60, and the reception signal is received via the antenna 60 and the antenna duplexer 59. Amplified. A diversity combining circuit 62 performs diversity combining on the received signal. The demodulated reception signal is demodulated by the demodulator 63, and frame processing and error correction decoding are performed by the frame processing circuit 64 and the error correction decoding circuit 65. Reference numeral 66 denotes a separation circuit that separates the control signal and the voice / data signal included in the received signal, and the control signal is output to the line control circuit 67. The multiplexing circuit 52, the error correction coding circuit 53, the frame generation circuit 54, the burst generation circuit 55, the modulator 56, the transmission timing generation circuit 57, the diversity combining circuit 62, the demodulator 63, the frame processing circuit 64, the error correction. A communication unit 68 is configured by the decoding circuit 65 and the separation circuit 66.

  The operations of the line management station 6, the mobile communication base station 7 and the mobile station 8 configured as described above will be described with reference to FIG. FIG. 7 is a processing sequence diagram showing the flow of channel control processing by the channel management station 6, the mobile communication base station 7 and the mobile station 8. In FIG. 7, the reservation terminal device 27 of the line management station 6 sends a reservation status inquiry request to the line management device 36 in step S 1, and the line management device 36 sends this request to the DAMA communication unit 28. Based on this request, the DAMA communication unit 28 generates a reservation status inquiry signal that is a control signal, and transmits it through the CSC line 4 in step S2. The reservation status inquiry signal is a signal including a control code indicating a reservation status inquiry and the station number of the line management station. When the control station 1 receives the reservation status inquiry signal through the CSC line 4, the line allocation control device 21 creates reservation status data for the reserved line (for example, data describing the presence / absence of reservation for each reserved line for one week). A response signal is generated. The reservation status response signal includes a control code indicating a response to a reservation status inquiry, a station number of the line management station, and reservation status data. In step S3, the control station 1 transmits a reservation status response signal through the CSC line 4. When receiving the reservation status response signal, the DAMA communication unit 28 of the line management station 6 sends the reservation status data included in this signal to the line management device 36 in step S4, and the line management device 36 sends the reservation status data to the reservation terminal device. To 27. The reservation terminal device 27 displays the reservation status data on a screen or the like, and if there is a reservation input by the operator, a reservation request is generated and sent to the line management device 36 in step S5. The line management device 36 sends the reservation request to the DAMA communication. The DAMA communication unit 28 generates a reservation request signal and transmits it through the CSC line 4 in step S6. The reservation request signal is a signal including a control code indicating a reservation request, a station number of the line management station, a reserved line number, and a description indicating a communication start / end time. When the control station 1 receives the reservation request signal via the CSC line 4, the line allocation control device 21 performs reservation processing by associating and storing the number of the reserved line, the station number, and the communication start / end time. When the reservation process is completed, the line allocation control device 21 generates a reservation notification signal. This reservation notification signal includes a control code indicating that it is a reservation notification signal and a station number of the line management station. In step S7, the control station 1 transmits a reservation notification signal through the CSC line 4. When the DAMA communication unit 28 of the line management station 6 receives the reservation notification signal, it sends a reservation notification to the line management device 36 in step S8, and the line management device 36 sends this notification to the reservation terminal device 27. The reservation terminal device 27 displays on the screen or the like that the reservation has been completed. The line management device 36 performs allocation processing for the communication lines 9 and 10 for mobile communication within the reserved frequency band based on the reserved line number. It is assumed that the relationship between the reserved line number and the frequency band is known in the line management device 36. The communication lines 9 and 10 are, for example, a line having a center frequency f9 as a transmission line from the mobile communication base station 7 to the mobile station 8 and a mobile communication base station 7 from the mobile station 8 as shown in FIG. A line having a center frequency f10 is assigned to the transmission line to the. After the communication line allocation processing, the line management device 36 sends a line setting command to the mobile communication base station 7 and the mobile station 8 in step S9, and the mobile communication base station 7 and the mobile station 8 set the line. A setting confirmation notification indicating that the setting has been completed is sent to the line management device 36 in step S10. The line setting command is a command including the mobile station number and communication line information (center frequency, bandwidth), and the setting confirmation notification includes the mobile station number and a control code indicating confirmation. The notification is transmitted and received between the mobile communication base station 7 and the mobile station 8 and the line management station 6 via a ground network such as a public line network or the Internet or a dedicated line.

  When the communication start time is reached, the control station 1 of the DAMA satellite communication system generates a start notification signal instructing the start of communication on the reserved line, and transmits it via the CSC line 4 in step S11. The DAMA communication unit 28 of the line management station 6 receives the start notification signal and sends the start notification to the line management device 36 in step S12. The line management device 36 generates a communication start command including a control code instructing the start of communication based on the start notification, and sends it to the mobile communication base station 7 in step S13. This communication start command, a start confirmation notification described later, a communication end command, and an end confirmation notification are transmitted and received between the mobile communication base station 7 and the line management station 6 through a ground network or a dedicated line. When the mobile communication base station 7 receives the communication start command, the line control circuit 37 generates a communication start signal including a control code for instructing the mobile station 8 to start communication. In step S14, communication via the communication satellite 3 is performed. A communication start signal is transmitted to the mobile station 8 via the line 9. The mobile station 8 shifts the reception system circuit to the operating state before the communication start time, receives the communication start signal, generates a start confirmation signal including a control code indicating that the communication start signal has been received, and in step S15, The data is transmitted to the mobile communication base station 7 via the communication line 10 via the communication satellite 3. Upon receipt of the start confirmation signal, the mobile communication base station 7 generates a start confirmation notification including a control code indicating that confirmation of the start of communication with the mobile station 8 has been taken. In step S16, the mobile communication base station 7 The data is sent to the line management device 36. Thereafter, communication via the communication satellite 3 is performed between the mobile communication base station 7 and the mobile station 8 using the communication lines 9 and 10.

  When the communication end time is reached, the control station 1 of the DAMA satellite communication system generates an end notification signal instructing the end of communication on the reserved line, and transmits it through the CSC line 4 in step S17. The DAMA communication unit 28 of the line management station 6 receives the end notification signal and sends the end notification to the line management device 36 in step S18. The line management device 36 generates a communication end command including a control code instructing the end of communication based on the end notification, and sends it to the mobile communication base station 7 in step S19. When the mobile communication base station 7 receives the communication end command, the line control circuit 37 generates a communication end signal including a control code for instructing the mobile station 8 to end the communication. In step S20, communication via the communication satellite 3 is performed. A communication end signal is transmitted to the mobile station 8 via the line 9. The mobile station 8 receives the communication end signal, generates an end confirmation signal including a control code indicating that the communication end signal has been received, and in step S21, the mobile communication base 10 uses the communication line 10 via the communication satellite 3. Transmit to station 7. After this transmission, the mobile station 8 turns off the transmission system circuit and the reception system circuit to open the line. When the mobile communication base station 7 receives the end confirmation signal, the mobile communication base station 7 turns off the transmission system circuit and the reception system circuit to open the line, and sends a control code indicating that the communication end with the mobile station 8 has been confirmed. An end confirmation notification is generated and sent to the line management apparatus 36 of the line management station 6 in step S22.

  Signals transmitted and received in communication between the mobile communication base station 7 and the mobile station 8 via the communication satellite 3 will be described based on FIGS. 8 and 9 by taking as an example a case where the mobile is a helicopter. FIG. 8 is a schematic diagram showing signals transmitted from the mobile station 8 to the mobile communication base station 7 via the communication satellite 3. In FIG. 8, stage A is a framed transmission signal generated by the frame generation circuit 54 of the mobile station 8 and is composed of a synchronization word (SYNC) and transmission data subjected to error correction coding. The B stage is a bursted transmission signal generated by the burst generation circuit 55, and the A stage framed transmission signal is cut out by the cutoff start timing in the transmission timing signal shown in the C stage, and is used for reception pull-in. Preamble is added to the head. Stage C represents the timing at which the rotor blades of the helicopter block the communication path between the installed communication device and the communication satellite, and the blocking period and the period during which transmission is possible without interruption are repeated. The burst transmission signal shown in the B stage is transmitted to the communication satellite 3 in the transmittable period shown in the C stage. FIG. 9 is a schematic diagram showing signals transmitted from the mobile communication base station 7 to the mobile station 8 via the communication satellite 3. 9 is a framed transmission signal generated by the frame generation circuit 41 of the mobile communication base station 7, and includes a synchronization word (SYNC) and transmission data subjected to error correction coding. The diversity data generation circuit 42 blocks the framed transmission signal into D (i) and D (i + 1) as shown below the D stage, and adds N blocks before to generate diversity data shown at the E stage. To do. The diversity data shown in the E stage is transmitted as a continuous wave, and the diversity combining circuit 62 of the mobile station 8 combines the received signal and the delay signal for N blocks. Although the rotor blades intermittently cut off the communication path between the communication device mounted on the mobile body and the communication satellite 3, the reception loss at the mobile station can be reduced by performing diversity reception as described above. .

  As described above, in the mobile communication system according to the communication system shown in the first embodiment, the line management station 6 receives the reserved line assignment of the DAMA satellite communication system, and the mobile communication system in the reserved line band. By assigning a communication line for use, satellite communication in the frequency band of the DAMA satellite communication system can be performed between the mobile communication base station and the mobile station. In addition, this mobile communication system can establish communication without the mobile station or mobile communication base station receiving direct control from the DAMA satellite communication system, and without having a CSC line modem. Therefore, the applicability to mobile communication having a communication method peculiar to mobile communication such as burst transmission / reception and diversity transmission / reception is high, and an increase in the scale of the communication device can be suppressed.

Embodiment 2

  A mobile communication system according to Embodiment 2 of the present invention will be described with reference to FIGS. FIG. 10 is a block diagram showing the configuration of a satellite communication system including a mobile communication system according to Embodiment 2 of the present invention. In FIG. 10, reference numeral 69 denotes a communication line between the mobile communication base station 7 and the slave station 2. 10, parts and circuits denoted by the same reference numerals as those in FIG. 1 are the same as or correspond to those parts and circuits in FIG. In the second embodiment, in addition to the mobile communication system described in the first embodiment, satellite communication between the mobile communication base station 7 and the slave station 2 of the DAMA satellite communication system can be performed. is there. The line management station 6 requests the control station 1 to assign a communication line, and notifies the mobile communication base station 7 of the assigned communication line. Upon receiving this notification, the mobile communication base station 7 communicates with the slave station 2 via the communication line 69.

  FIG. 11 is a functional block diagram showing configurations of the line management station 6 and the mobile communication base station 7 according to the second embodiment. In FIG. 11, reference numeral 70 denotes a DAMA communication unit that is provided in the mobile communication base station 7 and performs transmission / reception through a communication line assigned by the DAMA satellite communication system. The error correction circuit 11, frame generation circuit 12, communication line modulator 13, communication line demodulator 18, frame processing circuit 19, and error correction decoding circuit 20 in the DAMA communication unit 70 are the same as those shown in FIG. It is the same or equivalent. Also, in FIG. 11, components and circuits denoted by the same reference numerals as those in FIG. 5 are the same as or correspond to the components or circuits in FIG. 5.

  The line management station 6 uses the line management station number recognized from the DAMA satellite communication system when applying for the reserved line to the DAMA satellite communication system. In addition to this, the line management station 6 acquires another slave station number. It shall be. The reservation terminal device 27 of the line management station 6 sends the request to the line management device 36 when the request for obtaining the requested allocated line is inputted by the operator, and the line management device 36 sends the request to the control signal processing circuit 29. Send a request. The control signal processing circuit 29 generates a line assignment request signal that is a control signal of the DAMA satellite communication system, and the line assignment request signal is transmitted through the CSC line modulator 30, the transmitter 32, and the antenna 34 through the CSC line 4. . The line assignment request signal includes a control code, a local station number (the above-mentioned slave station number), and a partner slave station number. The control station 1 receives the line assignment request signal via the CSC line 4, searches the idle line by the line assignment control device 21, and assigns the requested assignment line. Two communication lines, for example, f3 and f4 shown in FIG. 2 (a) are assigned to the requested assignment line so that two-way communication between the slave stations is possible. The line assignment control device 21 generates a line assignment response signal including a control code, line information (center frequency, bandwidth, etc.) of the assigned on-demand assignment line, and a slave station number. The line assignment response signal is transmitted via the CSC line modulator 22, the transmitter 14, and the antenna 16 of the control station 1 shown in FIG. When the line management station 6 receives the line assignment response signal via the CSC line 4, the control signal processing circuit 29 reads the information on the assigned line at the time of request, and the information is sent to the line management device 36 and the reservation terminal device 27. Is transmitted. The line management device 36 generates a line assignment notification including the line information of the requested assignment line and sends it to the mobile communication base station 7 through a terrestrial network such as a public line network or the Internet or a dedicated line. When the mobile communication base station 7 receives the line assignment notification, the line control circuit 37 sets the transmission line and the reception line of the DAMA communication unit 70 based on the line information of the requested assignment line.

  At the same time as the requested allocation line is set, mobile satellite communication between the mobile communication base station 7 and the mobile station 8 is established after receiving the allocation of the reserved line as in the first embodiment. It shall be. The mobile communication base station 7 receives the video / audio signal from the mobile station 8 and outputs it from the demultiplexing circuit 47, and the video / audio signal output from the demultiplexing circuit 47 is sent to the DAMA communication unit 69. Is input to, subjected to processing such as error correction coding and framing, transmitted via the transmitter 48 and the antenna 50, and received by the partner slave station which has been assigned the requested allocation line. As described above, the video / audio signal transmitted from the mobile station 8 can be relayed and transmitted not only to the mobile communication base station 7 but also to a slave station of the DAMA satellite communication system. Furthermore, the mobile communication base station 7, it is not necessary to transmit / receive control signals of the DAMA satellite communication system via the CSC line, and an increase in the circuit scale of the mobile communication base station can be suppressed. In addition to the above-described line assignment request signal and line assignment response signal, the line management station 6 controls a health check signal for confirming the operation status of the slave station, a line end signal for ending the use of the requested assignment line, and the like. Instead of the mobile communication base station 7, the signal is transmitted / received to / from the control station 1 via the CSC line, the response content is requested to the mobile communication base station 7 as appropriate, and the response signal is transmitted via the CSC line 4. Further, if the requested allocation line transmitted from the mobile communication base station 7 is a broadcast transmission line, the video / audio signals from the mobile station 8 can be received by the plurality of slave stations 2.

It is a block diagram showing the structure of the satellite communication system containing the mobile communication system which concerns on Embodiment 1 of this invention. It is a schematic diagram which shows the frequency allocation in the satellite communication system which concerns on Embodiment 1 of this invention. It is a functional block diagram showing the structure of the control station which concerns on Embodiment 1 of this invention. It is a functional block diagram showing the structure of the sub_station | mobile_unit which concerns on Embodiment 1 of this invention. It is a functional block diagram which shows the structure of the line management station and mobile communication base station which concern on Embodiment 1 of this invention. It is a functional block diagram which shows the structure of the mobile station which concerns on Embodiment 1 of this invention. It is a process sequence diagram which shows the flow of the line control process by the line management station, mobile communication base station, and mobile station which concern on Embodiment 1 of this invention. It is a schematic diagram showing the signal transmitted to a mobile communication base station via a communication satellite from a mobile station. 4 is a schematic diagram showing signals transmitted from mobile communication base station 7 to mobile station 8 via communication satellite 3. FIG. It is a block diagram showing the structure of the satellite communication system containing the mobile communication system which concerns on Embodiment 2 of this invention. It is a functional block diagram which shows the structure of the line management station and mobile communication base station which concern on Embodiment 2 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Control station 2 Slave station 3 Communication satellite 4 CSC line 5 Communication line 6 Line management station 7 Mobile communication base station 8 Mobile station 9, 10 Communication line 21 Line allocation control device 24 Line control circuit (inside slave station)
27 Reservation terminal device 28 DAMA communication part (in the line management station)
36 Line management device 37 Line control circuit (in mobile communication base station)
38 Mobile communication section 67 Line control circuit (inside mobile station)
68 communication section 69 communication line 70 DAMA communication section (in mobile communication base station)

Claims (6)

  The line management station receives an allocation of a reserved line provided by a DAMA satellite communication system that provides a communication service via a satellite, and allocates the frequency band of the reserved line to communication between the mobile communication base station and the mobile station. In the mobile communication system that provides the service, the line management station includes a first DAMA communication unit that performs communication with the control station of the DAMA satellite communication system via a CSC line of the DAMA satellite communication system, A reservation terminal device that outputs a reservation request for requesting allocation of a reserved line to one DAMA communication unit, and line management for allocating a frequency band of the reserved reserved line to a communication line between the mobile communication base station and the mobile station And the mobile communication base station communicates with the mobile station through a communication line assigned by the line management station. And a communication start signal to be transmitted from the mobile communication unit to the mobile station based on a communication start command transmitted from the line management station at a communication start time of the reserved line. The mobile station includes a communication unit that communicates with the mobile communication base station through a communication line assigned by the line management station, and a communication unit that receives communication from the mobile communication base station. A mobile communication system comprising: a second line control circuit that starts transmission to the mobile communication base station based on receiving the communication start signal.   Line management of a mobile communication system that receives a reserved line provided by a DAMA satellite communication system that provides a communication service via a satellite and assigns it to a communication between a mobile communication base station and a mobile station to provide a communication service The station requests a first DAMA communication unit for communicating with the control station of the DAMA satellite communication system via the CSC line of the DAMA satellite communication system, and requests the first DAMA communication unit to allocate a reserved line. A reservation terminal device for outputting a reservation request; and a line management device for allocating a reserved communication line bandwidth to a communication line between the mobile communication base station and the mobile station. A line management station that generates a communication start command to be transmitted to the mobile communication base station at a communication start time. A mobile station that receives a reserved line assignment provided by a DAMA satellite communication system that provides a communication service via a satellite and communicates with a mobile station by receiving a communication line assignment from the frequency band of the reserved line. In the body communication base station, the first DAMA communication unit that performs communication with the control station of the DAMA satellite communication system through the CSC line of the DAMA satellite communication system transmits a reservation request for requesting the allocation of the reserved line. The mobile communication unit that communicates with the mobile station through the assigned communication line by the line management station that receives the reserved line assignment from the line management station at the communication start time of the reserved line. First line control for outputting a communication start signal transmitted from the communication unit to the mobile station based on a transmitted communication start command Mobile communication base stations, characterized in that a road. The line management station receives a reserved line assignment provided by a DAMA satellite communication system that provides a communication service via a satellite, and communicates with a mobile communication base station by receiving a communication line assignment from the frequency band of the reserved line. The first DAMA communication unit that performs communication with the control station of the DAMA satellite communication system through the CSC line of the DAMA satellite communication system transmits a reservation request that requests allocation of the reserved line. A communication unit that communicates with the mobile communication base station via the assigned communication line by the line management station that receives the reserved line assignment, and the line management station at the communication start time of the reserved line. By receiving a communication start signal transmitted from the mobile communication base station based on the communication start command transmitted from Mobile station, characterized in that a second line control circuit for starting the transmission to the serial mobile communication base station.   The line management station receives an allocation of a reserved line provided by a DAMA satellite communication system that provides a communication service via a satellite, and allocates the frequency band of the reserved line to communication between the mobile communication base station and the mobile station. In the mobile communication system that provides the service, the line management station includes a first DAMA communication unit that performs communication with the control station of the DAMA satellite communication system via a CSC line of the DAMA satellite communication system, A reservation terminal device for outputting a reservation request for requesting allocation of a reserved line and a request for allocation of an allocated line upon request to a DAMA communication unit, and a frequency band of the reserved line for reservation in the mobile communication A line management device assigned to a communication line between the base station and the mobile station, and the mobile communication base station is connected to the line management station. A mobile communication unit that communicates with the mobile station via a communication line assigned to the mobile station, and a second DAMA communication unit that communicates with the slave station of the DAMA satellite communication system via the requested allocation line. And a first line control circuit for outputting a communication start signal to be transmitted from the mobile communication unit to the mobile station based on a communication start command transmitted from the line management station at the communication start time of the reserved line. And the mobile station receives a communication unit that communicates with the mobile communication base station via a communication line assigned by the line management station, and the communication start signal from the mobile communication base station. And a second circuit control circuit for starting transmission to the mobile communication base station based on the above. A mobile station that receives a reserved line assignment provided by a DAMA satellite communication system that provides a communication service via a satellite and communicates with a mobile station by receiving a communication line assignment from the frequency band of the reserved line. In the body communication base station, the first DAMA communication unit that performs communication with the control station of the DAMA satellite communication system through the CSC line of the DAMA satellite communication system transmits a reservation request for requesting the allocation of the reserved line. Accordingly, the line management station that receives the reserved line assignment causes the mobile communication unit that communicates with the mobile station via the assigned communication line , and the on-demand assigned line by the first DAMA communication unit. by sending a line assignment request for requesting assignment to the line control station receiving an allocation of demand allocated line Ri, the request assignment has been the DAMA satellite communication system demand assignment access and a second DAMA communication unit that communicates with the slave station of the DAMA satellite communications system, said the communication start time of the reservation line A mobile communication base station comprising: a first line control circuit that outputs a communication start signal transmitted from the communication unit to the mobile station based on a communication start command transmitted from a line management station.

Images