Simulated Signal Output Device for Mobile Satellite Communication

Abstract

To provide a signal attenuation device in mobile satellite communication that enables simulation of a moving environment of a mobile satellite communication system even if the mobile satellite communication system does not move.SOLUTION: A simulation signal output device for mobile satellite communication is a simulation signal output device for simulating a mobile satellite communication system that outputs a simulated simulation signal that can be received from a satellite by a mobile body moving on a first movement path at a first movement speed, characterized by including output means for outputting a time-series simulation signal reflecting the first movement speed and attenuation caused by a shield that shields the signal from the satellite while moving on the first movement path.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a simulation signal output device for mobile satellite communication.

Background Art

[0002] In the field of satellite communication, especially as a Ka (K-above) band satellite communication system, for ESIM (Earth Station in Motion), 19.7 - 20.2 GHz and 29.5 - 30.0 GHz, which had been assigned to fixed satellite communication in the World Radiocommunication Conference, were recognized as frequency bands for ESIM. Subsequently, 17.7 - 19.7 GHz and 27.5 - 29.5 GHz were additionally recognized as frequency bands for ESIM. Because of these, the attention to Ka band mobile satellite communication has been increasing. For this reason, a congestion control algorithm for satellite lines as disclosed in Non-Patent Document 1 has been attracting attention.

[0003] In the disclosed technology of Non-Patent Document 1, a congestion control algorithm for satellite lines that can cope with the properties peculiar to satellite lines such as long delay time and packet loss due to bit error is disclosed.

Prior Art Documents

Non-Patent Documents

[0004]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] On the one hand, a mobile satellite communication system, particularly a land mobile satellite communication system, conducts satellite communication while moving. For this reason, it is affected by obstacles such as artificial objects and buildings, and communication interruptions frequently occur. There is a problem that such a phenomenon cannot be avoided and it has an adverse effect on data communication. Also, even if the given physical line bandwidth is wide, there is a problem that the throughput of TCP (Transmission Control Protocol) does not increase. In order to solve these problems, it is necessary to improve the efficiency of data communication by using an emulator or simulator that simulates a mobile satellite communication system while it is moving.

[0006] However, in Non-Patent Document 1, communication interruptions due to obstacles that occur when a mobile satellite communication system moves are not considered, and a fixed earth station such as VSAT (Very Small Aperture Terminal) is assumed. In a mobile satellite communication system, it is very difficult to run on a road where there are no obstacles at all. The congestion control algorithm for satellite lines, TCP accelerator, and the effect of optimizing the line based on the simulation results of the satellite communication network in Non-Patent Document 1 and the like are limited because communication interruptions due to obstacles are not considered. Also, variations in the duration of communication interruptions due to changes in the moving speed of the mobile satellite communication system and the type of obstacle, and the complexity of the interlock control that occurs each time are also problems.

[0007] The present invention has been derived to solve the above-described problems, and an object is to provide a simulated signal output device for mobile satellite communication that can simulate a received signal that a mobile body can receive in a mobile satellite communication system even when the mobile body is not moving.

Means for Solving the Problem

[0008] The simulated signal output device for mobile satellite communication according to the first invention is In a simulated signal output device for simulating a mobile satellite communication system that outputs a simulated simulated signal that a mobile body moving along a first movement path at a first movement speed can receive from a satellite, attenuation by an obstacle that shields the signal from the satellite while the mobile body moves along the first movement path, and a time-series simulated signal reflecting the first movement speed are referred to, and attenuation means for attenuating a newly received first evaluation signal is provided. characterized by.

[0009] The simulated signal output device for mobile satellite communication according to the second invention isIn the first invention, simulation signal generation means for generating the simulation signal is further provided based on position information regarding the position of an obstacle that shields the signal from the satellite while the mobile body moves along the first movement path and the first movement speed. is characterized by.

[0010] The analog signal output device for mobile satellite communication according to the third invention In a simulated signal output device for simulating a mobile satellite communication system that outputs a simulated simulated signal that a mobile body moving along a first movement path at a first movement speed can receive from a satellite, output means for outputting a time-series simulated signal reflecting the first movement speed and attenuation by an obstacle that shields the signal from the satellite while the mobile body moves along the first movement path is provided, and shielding information regarding the type and / or width of the obstacle and an attenuation pattern regarding the attenuation pattern of the signal by the obstacle are associated with each other, storage means for storing an attenuation model having the shielding information as an input and the attenuation pattern as an output, shielding information acquisition means for acquiring the shielding information of the obstacle that shields the signal from the satellite while the mobile body moves along the first movement path, and simulation signal generation means for generating a simulation signal from the attenuation pattern output by inputting the shielding information acquired by the shielding information acquisition means into the attenuation model stored by the storage means are further provided. is characterized by the following.

[0011] The analog signal output device for mobile satellite communication according to the fourth invention In a simulated signal output device for simulating a mobile satellite communication system that outputs a simulated simulated signal that a mobile body moving along a first moving path at a first moving speed can receive from a satellite, there is provided output means for outputting a time-series simulated signal reflecting the first moving speed and the attenuation by an obstacle that shields the signal from the satellite when moving along the first moving path; storage means for storing a data table in which attenuation patterns regarding the attenuation pattern for each position on the first moving path are associated with each other; running time acquisition means for acquiring the running time of the mobile body; current position calculation means for obtaining a virtual current position on the first moving path based on the running time acquired by the running time acquisition means and the first moving speed; attenuation pattern selection means for referring to the data table stored by the storage means and selecting the attenuation pattern for a position corresponding to the virtual current position calculated by the current position calculation means; and further comprising simulated signal generation means for generating a simulated signal from the selected attenuation pattern by the attenuation pattern selection means is characterized by the following.

[0012] The analog signal output device for mobile satellite communication according to the fifth invention In the first invention, there are further provided storage means for storing an attenuation model in which obstacle information regarding the type and / or width of an obstacle and an attenuation pattern regarding the signal attenuation pattern by the obstacle are associated with each other, with the input being the obstacle information and the output being the attenuation pattern; obstacle information acquisition means for acquiring the obstacle information of an obstacle that shields the signal from the satellite when the mobile body moves along the first moving path; and simulated signal generation means for generating a simulated signal from the attenuation pattern output by inputting the obstacle information acquired by the obstacle information acquisition means into the attenuation model stored by the storage means is characterized by the following.

[0013] The analog signal output device for mobile satellite communication according to the sixth invention is an analog signal output device for simulating a mobile satellite communication system that outputs an analog analog signal that a mobile body moving along a first moving path at a first moving speed can receive from a satellite. In the analog signal output device, a second attenuation means for attenuating a second evaluation signal to be newly transmitted is provided by referring to a time-series analog signal in which the first moving speed and the attenuation by a shielding object that shields a signal from the satellite when moving along the first moving path are reflected, and a transmission antenna for transmitting the second evaluation signal attenuated by the second attenuation means.

Advantages of the Invention

[0014] According to the first to sixth inventions, the analog signal output device for mobile satellite communication outputs a time-series analog signal in which the first moving speed and the attenuation by a shielding object that shields a signal from the satellite when moving along the first moving path are reflected. As a result, in a mobile satellite communication system, it becomes possible to simulate and output a received signal attenuated by a shielding object. For this reason, the attenuation by a shielding object in a mobile satellite communication system can be simulated without moving the mobile body. In addition, the attenuation by a shielding object in a mobile satellite communication system can be simulated in a laboratory, and it becomes possible to examine the influence of communication interruption due to a shielding object that occurs while the mobile satellite communication system is moving and to examine a congestion control algorithm accordingly. Further, according to the first invention, the simulated signal output device for mobile satellite communication refers to the simulated signal and attenuates the newly received first evaluation signal. As a result, it becomes possible to reflect the attenuation amount in the simulated signal in the first evaluation signal. Therefore, it becomes possible to output an evaluation signal reflecting the attenuation amount in the mobile satellite communication system

[0015] In particular 、According to the second invention, the analog signal output device for mobile satellite communication is Based on the position information and the first moving speed, a simulation signal is generated. Thereby, it becomes possible to simulate a simulation signal based on the position of the shielding object and the speed of the moving object. For this reason, it becomes possible to simulate the received signals of a mobile satellite communication system with more diverse patterns.

[0016] In particular, according to the third invention, the analog signal output device for mobile satellite communication is A simulation signal is generated from the attenuation pattern output by inputting shielding object information into the attenuation model. Thereby, it becomes possible to generate a simulation signal that reflects the attenuation that varies depending on the type and size of the shielding object. For this reason, it becomes possible to simulate the received signals of a mobile satellite communication system with more diverse patterns.

[0017] In particular, according to the fourth invention, the analog signal output device for mobile satellite communication is Refer to the data table, select the attenuation pattern for the position corresponding to the virtual current position, and generate a simulation signal from the selected attenuation pattern. Thereby, a simulation signal can be generated according to the virtual position. For this reason, it becomes possible to generate a simulation signal suitable for the environment of the virtual position, and it becomes possible to more accurately simulate the received signal in the mobile satellite communication system.

[0018] In particular, according to the fifth invention, the analog signal output device for mobile satellite communication is A simulation signal is generated from the attenuation pattern output by inputting shielding object information into the attenuation model. Thereby, it becomes possible to generate a simulation signal that reflects the attenuation that varies depending on the type and size of the shielding object. For this reason, it becomes possible to simulate the received signals of a mobile satellite communication system with more diverse patterns.

[0019] In particular, according to the sixth invention, the analog signal output device for mobile satellite communication refers to the analog signal, attenuates the second evaluation signal to be newly transmitted, and transmits the attenuated second evaluation signal. As a result, it becomes possible to attenuate the evaluation signal to be transmitted, and it becomes possible to attenuate the evaluation signals to be individually transmitted and received by the ODU (Out Door Unit) and the IDU (In Door Unit). Thereby, for example, when a communication interruption occurs, it becomes possible to examine the influence on data communication by the interlock, which is a function of stopping transmission.

Brief Description of Drawings

[0020]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

[0021] (First Embodiment) Hereinafter, a simulated signal output device 1 according to a first embodiment to which the present invention is applied will be described in detail with reference to the drawings.

[0022] The simulated signal output device 1 simulates a reception signal that a moving object 53 can receive from a satellite 52 in a mobile satellite communication system 100 as shown in FIG. 1, for example.

[0023] The mobile satellite communication system 100 is a communication system including, for example, a gateway station 51, a satellite 52 that transmits and receives signals to and from the gateway station 51, and a moving object 53 that transmits and receives signals to and from the satellite 52.

[0024] The gateway station 51 plays a role as a so-called base station, serves as a wireless access point between devices in a wireless communication network, and serves as an interface between a public communication network such as the Internet. That is, the gateway station 51 serves as a relay means for enabling a device to transmit and receive signals to and from a public communication network such as the Internet via the gateway station 51.

[0025] The satellite 52 orbits in a geostationary orbit (GEO: Geostationary Earth Orbit) which is an Earth - orbiting orbit with an orbital period matching the Earth's rotation period, or it can fly in a low - Earth orbit (LEO: Low Earth Orbit), a medium - Earth orbit (MEO: Medium Earth Orbit) that rotates independently of the Earth's rotation period, or even in deep space, etc. This satellite 52 can be launched for any purpose. Also, this satellite 52 is not limited to those orbiting GEO, LEO, or MEO, but is a concept that includes any other satellite flying in space.

[0026] The mobile object 53 is a moving object capable of communicating with the satellite 52. For example, the mobile object 53 can be a car equipped with an antenna, a bus, an airplane, a ship, etc. In the mobile satellite communication system 100, the mobile object 53 communicates with the satellite 52 and transmits and receives signals attenuated by the shielding object 54.

[0027] The shielding object 54 is a building such as a house, a building, a utility pole, a mercury lamp, or a natural object such as a tree or a mountain that shields and attenuates the communication signal between the satellite 52 and the mobile object 53 in the mobile satellite communication system 100.

[0028] Figure 2 shows, in the mobile satellite communication system 100, the received signal received by the mobile body 53 when the mobile body 53 moves along the moving path 60 at a set moving speed, and the correspondence between the positions of the mercury lamp 61 and the utility pole 62 on the moving path 60. The graph shown in the lower part of Figure 2 indicates the data transfer rate (Bits / s) of the received signal received by the mobile body 53 with respect to time (s). In the mobile satellite communication system 100, the signal received by the mobile body 53 moving along the moving path 60 from the satellite 52 is interrupted and attenuated, for example, by the mercury lamp 61 or the utility pole 62 on the moving path 60. As a result, the received power of the received signal received by the mobile body 53 from the satellite 52 is attenuated. Along with this attenuation of the received power, the data transfer rate of the received signal also attenuates. In the graph shown in the lower part of Figure 2, which converts the attenuation of the data transfer rate of this received signal into the time axis, it is shown that the data transfer rate of the received signal received by the mobile body 53 attenuates when passing through the positions of the mercury lamp 61 or the utility pole 62 on the moving path 60. This is because the received power of the received signal received by the mobile body 53 from the satellite 52 is attenuated by the mercury lamp 61 or the utility pole 62 on the moving path 60. Also, the attenuation pattern of the received signal received by the mobile body 53 varies depending on, for example, the type and width of the shielding object 54 (such as the mercury lamp 61, the utility pole 62, etc.). For example, the attenuation pattern when the mobile body 53 passes through the mercury lamp 61 and the attenuation pattern when the mobile body 53 passes through the utility pole 62 are different from each other.

[0029] The attenuation pattern referred to here indicates the attenuation pattern of the received signal received by the mobile body 53 when attenuated by the influence of the shielding object 54. The attenuation pattern includes the attenuation amount indicating the magnitude of the signal attenuation. Also, the attenuation pattern includes the attenuation width, which is the difference between the distance at which the signal starts to attenuate and the distance at which the signal finishes attenuating.

[0030] The analog signal output device 1 of the first embodiment to which the present invention is applied outputs an analog signal that simulates the received signal received by the mobile body 53 moving along an arbitrarily set first moving path at an arbitrarily set first moving speed from the satellite 52 in this mobile satellite communication system 100 and that is actually attenuated by the influence of the shielding object 54.

[0031] The graph in FIG. 3 is an example of a graph showing the attenuation amount (dB) of the actual received signal received by the moving body 53 moving along the first moving path at the first moving speed with respect to the distance (m), and the attenuation amount (dB) of the simulated signal simulating this received signal. The simulated signal is a signal that is simulated based on the received signal received by the moving body 53 moving along the first moving path at the first moving speed from the satellite 52. The simulated signal is a time-series signal that reflects the first moving speed and the attenuation by the shielding object 54 that shields the signal from the satellite 52 when moving along the first moving path. Further, the simulated signal may be a signal respectively associated with each position on the first moving path. Further, the simulated signal may be a signal that reflects the attenuation by the above-described shielding object, the moving speed of the moving body 53, and the attenuation due to the line margin.

[0032] FIG. 4(a) is an overall schematic diagram of the simulated signal output device 1 according to the first embodiment to which the present invention is applied. The simulated signal output device 1 is mounted on, for example, the moving body 53, but is not limited thereto, and may be installed in a stationary state indoors.

[0033] The simulated signal output device 1 is connected to, for example, the ODU 11 and the IDU 14. The simulated signal output device 1 includes a first stepless attenuator 13 and a second stepless attenuator 15 connected to the IDU 14 and the ODU 11, and an attenuation control unit 17 connected to the first stepless attenuator 13 and the second stepless attenuator 15.

[0034] The ODU11 includes a receiving antenna for receiving a first evaluation signal and a transmitting antenna for transmitting a second evaluation signal. The ODU11 may receive the first evaluation signal from, for example, the satellite 52, but it is not limited to this, and it may also receive the first evaluation signal from the satellite 52. Also, the ODU11 may transmit the second evaluation signal to, for example, the satellite 52, but it is not limited to this, and it may also transmit the second evaluation signal to the satellite 52. The ODU11 outputs, for example, the first evaluation signal received by the receiving antenna to the first stepless attenuator 13. The evaluation signal is a time-series signal to be attenuated. The first evaluation signal is the evaluation signal received by the ODU11. The second evaluation signal is the evaluation signal transmitted by the ODU11.

[0035] The IDU14 is, for example, a modem for modulating and demodulating signals transmitted and received with the evaluation device 19. The IDU14 outputs, for example, data extracted from the demodulated first evaluation signal attenuated by the first stepless attenuator 13 to the evaluation device 19. Also, the IDU14 generates, for example, a second evaluation signal and outputs the generated second evaluation signal to the second stepless attenuator 15.

[0036] The first stepless attenuator 13 is an attenuator that attenuates the first evaluation signal input from the ODU11 based on the attenuation control signal output from the attenuation control unit 17. The first stepless attenuator 13 outputs the attenuated first evaluation signal to the IDU14.

[0037] The second stepless attenuator 15 is an attenuator that attenuates the second evaluation signal output from the IDU14 based on the attenuation control signal output from the attenuation control unit 17. The second stepless attenuator 15 outputs the second evaluation signal to the ODU11.

[0038] The attenuation control unit 17 controls the attenuation in the first stepless attenuator 13 and the second stepless attenuator 15. For example, the attenuation control unit 17 generates an attenuation control signal and outputs the generated attenuation control signal to the first stepless attenuator 13 and the second stepless attenuator 15.

[0039] The evaluation device 19 is a device that evaluates the evaluation signal attenuated by the analog signal output device 1. The evaluation device 19 may, for example, in the mobile satellite communication system 100, compare and evaluate the received signal actually received by the mobile body 53 with the evaluation signal attenuated under the control of the attenuation control unit 17.

[0040] As shown in FIG. 4(b), the attenuation control unit 17 includes an acquisition unit 171, a generation unit 172, an output unit 173, and a storage unit 174 that are connected to each other. Each function in these attenuation control units 17 may be realized by software.

[0041] The acquisition unit 171 acquires various information input from the user by a keyboard or the like.

[0042] The generation unit 172 generates various information such as an analog signal and an attenuation control signal.

[0043] The storage unit 174 stores the various information acquired by the acquisition unit 171 and the various information generated by the generation unit 172.

[0044] The output unit 173 outputs the analog signal stored in the storage unit 174 to the first stepless attenuator 13 and the second stepless attenuator 15.

[0045] Next, the operation of outputting the analog signal in this embodiment will be described.

[0046] First, the ODU 11 receives the first evaluation signal from the satellite 52. The ODU 11 outputs the received first evaluation signal to the first stepless attenuator 13.

[0047] The generation unit 172 in the attenuation control unit 17 refers to the analog signal and generates an attenuation control signal. The output unit 173 outputs the generated attenuation control signal to the first stepless attenuator 13.

[0048] Next, the first stepless attenuator 13 attenuates the first evaluation signal based on the attenuation control signal. In such a case, the first stepless attenuator 13 can attenuate the first evaluation signal by reflecting the attenuation by the shielding object. Thereby, it becomes possible to reflect the attenuation amount in the analog signal in the first evaluation signal. The first stepless attenuator 13 outputs the attenuated first evaluation signal to the IDU 14.

[0049] The IDU 14 outputs the data extracted from the demodulated first evaluation signal sent from the first stepless attenuator 13 to the evaluation device 19. The evaluation device 19 to which the data extracted from the demodulated first evaluation signal is output from the IDU 14 evaluates the first evaluation signal.

[0050] Also, the IDU 14 may generate a second evaluation signal different from the first evaluation signal. In such a case, the IDU 14 outputs the generated second evaluation signal to the second stepless attenuator 15.

[0051] Next, the second stepless attenuator 15 attenuates the second evaluation signal input from the IDU 14 based on the attenuation control signal input from the attenuation control unit 17.

[0052] Next, the second stepless attenuator 15 outputs the second evaluation signal to the ODU 11, and the ODU 11 transmits the second evaluation signal to the satellite 52. Thereby, the second evaluation signal to be transmitted and the received first evaluation signal can be individually attenuated for transmission and reception. Thereby, for example, when a communication interruption occurs, it is also possible to consider the influence on data communication by the interlock, which is a function of stopping transmission.

[0053] As a result, in the mobile satellite communication system 100, it becomes possible to simulate and output a received signal attenuated by the shielding object 54. For this reason, the attenuation by the shielding object 54 in the mobile satellite communication system 100 can be simulated without moving the mobile object 53. Further, the attenuation by the shielding object 54 in the mobile satellite communication system 100 can be simulated in a laboratory, and it becomes possible to examine the influence of communication interruption due to the shielding object 54 generated while the mobile satellite communication system 100 is moving and to examine a congestion control algorithm corresponding thereto.

[0054] (Second Embodiment) Hereinafter, the simulation signal output device 1 according to the second embodiment to which the present invention is applied will be described in detail.

[0055] FIG. 5 is an overall schematic diagram of the simulation signal output device 1 according to the second embodiment to which the present invention is applied. The simulation signal output device 1 outputs a simulation signal. The simulation signal output device 1 may be provided indoors such as in a laboratory. The simulation signal output device 1 includes a mobile object simulation unit 4, a satellite simulation unit 3 connected to the mobile object simulation unit 4, and a gateway station simulation unit 2 connected to the satellite simulation unit 3.

[0056] The mobile object simulation unit 4 simulates the mobile object 53 that communicates with the satellite 52 in the mobile satellite communication system 100. The mobile object simulation unit 4 outputs a simulated simulation signal that the mobile object 53 can receive from the satellite 52 to the satellite simulation unit 3 and the evaluation device 19a.

[0057] The evaluation device 19a evaluates data extracted from the demodulated simulation signal output from the mobile object simulation unit 4.

[0058] The mobile object simulation unit 4 includes an attenuation control unit 17, a modem 41, and a modem 43 connected to the attenuation control unit 17.

[0059] The attenuation control unit 17 outputs a simulation signal to the modem 41 and the modem 43.

[0060] The modem 41 modulates and demodulates the signals transmitted and received with the satellite simulation unit 3. The modem 41 outputs the analog signal output from the attenuation control unit 17 to the satellite simulation unit 3.

[0061] The modem 43 modulates and demodulates the signals transmitted and received with the evaluation device 19a. The modem 43 outputs the data extracted from the demodulated analog signal output from the attenuation control unit 17 to the evaluation device 19a.

[0062] The satellite simulation unit 3 simulates the satellite 52 that communicates with the gateway station 51 and the mobile body 53 in the mobile satellite communication system 100, for example. The satellite simulation unit 3 delays, for example, the analog signal output from the mobile body simulation unit 4, and outputs the delayed analog signal to the gateway station simulation unit 2. The satellite simulation unit 3 includes a delay device unit 31 for delaying the signal.

[0063] The delay device unit 31 is a delay circuit that delays the signal. The delay device unit 31 delays, for example, the analog signal output from the modem 41. The delay device unit 31 outputs the delayed analog signal to the gateway station simulation unit 2.

[0064] The gateway station simulation unit 2 simulates the gateway station 51 that communicates with the satellite 52 in the mobile satellite communication system 100. The gateway station simulation unit 2 outputs an analog signal from the satellite simulation unit 3. Further, the gateway station simulation unit 2 includes a modem 21 and a modem 22 connected to the modem 21.

[0065] The modem 22 modulates and demodulates the signals transmitted and received with the satellite simulation unit 3. The modem 22 outputs, for example, the analog signal output from the satellite simulation unit 3 to the modem 21.

[0066] The modem 21 is a transceiver for modulating and demodulating the signals transmitted and received with the evaluation device 19b. The modem 21 outputs the data extracted from the demodulated analog signal output from the modem 22 to the evaluation device 19b.

[0067] The external device 19b of the evaluation device evaluates the data extracted from the demodulated analog signal output from the gateway station simulation unit 2.

[0068] Next, the operation of outputting the analog signal in the present embodiment to the evaluation device 19a and the evaluation device 19b will be described.

[0069] First, the attenuation control unit 17 outputs the analog signal to the modem 41 or the modem 43. In such a case, the attenuation control unit 17 may output the analog signal itself stored in the storage unit 174. Thereby, the attenuation due to the shielding object 54 in the mobile satellite communication system 100 can be simulated without moving the mobile body 53.

[0070] Next, the analog signal output device 1 outputs the analog signal to the evaluation device 19a and the evaluation device 19b. The modem 41 output with the analog signal from the attenuation control unit 17 outputs the analog signal to the delay device unit 31. The delay device unit 31 output with the analog signal delays the analog signal. Thereby, in the mobile satellite communication system 100, the delay generated when transmitting a signal from the mobile body 53 to the gateway station 51 via the satellite 52 can be simulated.

[0071] Next, the delay device unit 31 outputs the delayed analog signal to the modem 22. The modem 22 output with the analog signal outputs the data extracted from the demodulated analog signal via the modem 21 to the evaluation device 19b. Thereby, in the mobile satellite communication system 100, the signal transmitted from the mobile body 53 via the satellite 52 to the gateway station 51 can be simulated.

[0072] Also, the modem 43 outputs the data extracted from the demodulated analog signal output to the evaluation device 19a. Thereby, the evaluation device 19a can evaluate the data extracted from the demodulated analog signal output by the mobile body simulation unit 4.

[0073] (Third Embodiment) Hereinafter, the analog signal output device 1 according to the third embodiment to which the present invention is applied will be described in detail. The third embodiment is different from the first and second embodiments in that the generation unit 172 generates an analog signal in the first and second embodiments.

[0074] An example of the operation of generating an analog signal in this embodiment will be described. The operation of generating an analog signal in this embodiment first acquires position information and a first moving speed. Next, an analog signal is generated based on the position information and the first moving speed. Each process will be described in detail below.

[0075] First, the attenuation control unit 17 acquires position information regarding the position of the shielding object 54 that shields the signal from the satellite 52 while the moving object 53 moves along the first moving path, and the first moving speed of the moving object 53. In such a case, the acquisition unit 171 may acquire the position information of the shielding object 54 and the first moving speed input from the user who requests the evaluation of the evaluation signal.

[0076] The position information of the shielding object 54 is information regarding the position of the shielding object 54 that shields the signal from the satellite 52 while the moving object 53 moves along the first moving path. The position information of the shielding object 54 and the first moving speed may be parameters arbitrarily set by the above-described user. Further, the position information of the shielding object 54 and the first moving speed may use parameters actually acquired in the mobile satellite communication system 100.

[0077] Next, the generation unit 172 generates an analog signal based on the position information of the shielding object 54 acquired by the acquisition unit 171 and the first moving speed. In such a case, it is converted into a time-series signal based on each position information and the first moving speed. The generation unit 172 calculates the time when the moving object 53 passes each shielding object 54 from the position information of the shielding object 54 and the first moving speed. Then, a preset attenuation pattern for each shielding object 54 is read out, and an analog signal reflecting the attenuation pattern in the time-series signal is generated.

[0078] (Fourth Embodiment) Hereinafter, the analog signal output device 1 of the fourth embodiment to which the present invention is applied will be described in detail. The fourth embodiment is different from the third embodiment in that an analog signal is generated from an attenuation pattern output by inputting shielding information regarding the shielding object 54 into an attenuation model.

[0079] Next, an example of the operation of generating an analog signal in this embodiment will be described. The operation of generating an analog signal in this embodiment is to prepare an attenuation model in advance, input the newly acquired shielding information into this attenuation model, output the attenuation pattern as a search solution, and generate an analog signal from the attenuation pattern obtained as this search solution.

[0080] The shielding information is information regarding the type and / or width of the shielding object 54. Further, the shielding information may be information regarding, for example, the type or model number of the shielding object 54, the width of the shielding object, the line margin, the interlock by the shielding object, etc.

[0081] The attenuation model is a model that consists of a plurality of data in which the shielding information and the attenuation pattern are associated with each other, with the input being the shielding information and the output being the attenuation pattern as a search solution. The attenuation model may be a table in which the shielding information and the attenuation pattern are uniquely associated with each other as shown in Table 1. The operation of generating an analog signal will be described in detail below.

Table 1

[0082] First, prepare an attenuation model in which the shielding information regarding the type and / or width of the shielding object 54 and the attenuation pattern are associated with each other, with the input being the shielding information and the output being the attenuation pattern as a search solution, and store it in advance in the storage unit 174. In such a case, in the mobile satellite communication system 100, the shielding information of the shielding object 54 on the actual moving path and the attenuation pattern of the received signal received by the mobile object 53 moving on the moving path may be respectively acquired as the input and output of the attenuation model.

[0083] FIG. 6 is a graph showing measured values (Measured) and calculated values (Calculated) of the attenuation amount (dB) of a signal with a frequency of 18.9 GHz received by the mobile body 53 with respect to the distance (mm) from the center of the antenna of the mobile body 53 to the utility pole 62 when the mobile body 53 equipped with a vehicle-mounted station antenna with an aperture diameter of 65 cm passes through the utility pole 62 with a diameter of 350 mm while tracking the satellite 52 in the mobile satellite communication system 100. The calculated value here is the value of the attenuation amount (dB) calculated by an equation approximated to the measured value. As shown in FIG. 6, a calculated value corresponding to the measured value of the signal received by the mobile body 53 moving along the actually acquired movement path may be stored as an attenuation pattern of the output of the attenuation model. In such a case, the shielding object information of the utility pole 62 may be used as an input to the attenuation model, and the calculated value may be used as an output of the attenuation pattern.

[0084] After preparing the attenuation model in this way, the acquisition unit 171 acquires shielding object information. The acquisition unit 171 may be configured to receive an input of shielding object information by a user who actually performs analysis using the evaluation device 19.

[0085] Next, the generation unit 172 outputs an attenuation pattern by inputting the shielding object information acquired by the acquisition unit 171 into the attenuation model stored by the storage unit 174. In such a case, when the acquisition unit 171 acquires the shielding object information B, an attenuation pattern B associated with the shielding object information B corresponding to the input in the attenuation model in Table 1 may be output.

[0086] Next, the generation unit 172 generates a simulated signal from the output attenuation pattern. As a result, it becomes possible to generate a simulated signal that reflects the attenuation that varies depending on the type and size of the shielding object 54. Therefore, it becomes possible to simulate reception signals of mobile satellite communication systems with more diverse patterns.

[0087] (Fifth Embodiment) Hereinafter, the analog signal output device 1 to which the fifth embodiment of the present invention is applied will be described in detail. The fifth embodiment is different from the fourth embodiment in that it refers to a data table and generates an analog signal for a position corresponding to a virtual current position.

[0088] The operation of generating an analog signal in this embodiment will be described. The storage unit 174 stores in advance a data table in which attenuation patterns for each position on the first moving path are associated with each other. Table 2 shows an example of the data table, which is a table in which attenuation patterns for each position on the first moving path are associated with each other. The data table is a table in which each position assigned every 1 m from the starting point, shielding object information, and an attenuation pattern are uniquely associated with each other. However, it is not essential that the shielding object information be associated with this data table, and it may be a table in which only the position and the attenuation pattern are associated with each other.

Table 2

[0089] After preparing such a data table, the acquisition unit 171 acquires the first moving speed and the traveling time of the moving body 53. At this time, the acquisition unit 171 obtains a virtual current position on the first moving path based on the traveling time and the first moving speed. The generation unit 172 refers to the data table stored in the storage unit 174, selects an attenuation pattern for a position corresponding to the virtual current position, and generates an analog signal from the selected attenuation pattern. For example, if the virtual current position is "2 m from the starting point", the attenuation pattern B associated with this becomes the search solution.

[0090] As another example of the data table, as shown in FIG. 7, shielding object information at a distance on the moving path and an attenuation pattern of a received signal received by the moving body 53 moving on the above-described moving path at the distance may be prepared. The lower part of FIG. 7 is a graph showing the attenuation amount (dB) of the signal with respect to the position (distance) from the starting point.

[0091] In Fig. 7, the shielding object information of the utility pole 62a is associated with the position (distance) from the starting point at 1 m, and the shielding object information of the utility pole 62b is associated with the position (distance) from the starting point at 3 m.

[0092] In the process of creating this data table, when newly obtaining the shielding object information and the attenuation amount of the received signal, these are associated with each other. For example, as shown in Fig. 7, when the shielding object information of the utility pole 62a and the attenuation pattern of the received signal are obtained at the position (distance) of 1 m from the starting point, these are associated with each other, and when the shielding object information of the utility pole 62b and the attenuation pattern of the received signal are obtained at the position (distance) of 3 m from the starting point, a data table is created by associating these with each other.

[0093] Next, the acquisition unit 171 acquires the travel time of the moving body 53.

[0094] Next, the acquisition unit 171 obtains a virtual current position on the first movement path based on the acquired travel time and the first movement speed. In such a case, the acquisition unit 171 may obtain, for example, the virtual current position on the first movement path from the product of the travel time and the first movement speed.

[0095] Next, the generation unit 172 refers to the data table stored by the storage unit 174 and selects an attenuation pattern for the position corresponding to the virtual current position obtained by the acquisition unit 171. In such a case, for example, when the position corresponding to the virtual current position by the acquisition unit 171 is 3 m from the starting point, referring to the data table in Fig. 7, an attenuation pattern of the simulated signal for the current position 3 m from the starting point is selected.

[0096] Next, the generation unit 172 generates a simulated signal according to the selected attenuation pattern. Thereby, a simulated signal can be generated according to the virtual position.

[0097] Although embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. Such novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalent scope thereof.

Explanation of Reference Numerals

[0098] 1 Analog signal output device 2 Gateway station simulation unit 3 Satellite simulation unit 4 Mobile body simulation unit 11 ODU 13 First stepless attenuator 14 IDU 15 Second stepless attenuator 17 Attenuation control unit 19 Evaluation device 21 Modem 22 Modem 31 Delay device unit 41 Modem 43 Modem 100 Mobile satellite communication system 51 Gateway station 52 Satellite 53 Mobile body 54 Shielding object 60 Movement path 61 Mercury lamp 62 Utility pole 171 Acquisition unit 172 Generation unit 173 Output unit 174 Storage unit

Claims

1. In a simulated signal output device for simulating a mobile satellite communication system that outputs a simulated signal that a mobile body moving along a first movement path at a first movement speed can receive from a satellite, attenuation means for referring to a time-series simulated signal reflecting the first movement speed and attenuation by an obstacle that shields the signal from the satellite while the mobile body moves along the first movement path, and attenuating a newly received first evaluation signal is provided. A simulated signal output device for mobile satellite communication, characterized by the above.

2. The simulated signal output device for mobile satellite communication according to claim 1, further comprising simulated signal generation means for generating the simulated signal based on position information regarding the position of an obstacle that shields the signal from the satellite while the mobile body moves along the first movement path and the first movement speed.

3. In a simulated signal output device for simulating a mobile satellite communication system that outputs a simulated signal that a mobile body moving along a first movement path at a first movement speed can receive from a satellite, output means for outputting a time-series simulated signal reflecting the first movement speed and attenuation by an obstacle that shields the signal from the satellite while the mobile body moves along the first movement path is provided, storage means for storing an attenuation model in which obstacle information regarding the type and / or width of the obstacle and an attenuation pattern regarding the attenuation pattern of the signal by the obstacle are associated with each other, with the input being the obstacle information and the output being the attenuation pattern, obstacle information acquisition means for acquiring the obstacle information of an obstacle that shields the signal from the satellite while the mobile body moves along the first movement path, and simulated signal generation means for generating a simulated signal from the attenuation pattern output by inputting the obstacle information acquired by the obstacle information acquisition means into the attenuation model stored by the storage means is further provided. A simulated signal output device for mobile satellite communication, characterized by the above.

4. In a simulated signal output device for simulating a mobile satellite communication system that outputs a simulated signal that a mobile body moving along a first movement path at a first movement speed can receive from a satellite, output means for outputting a time-series simulated signal reflecting the first movement speed and attenuation by an obstacle that shields the signal from the satellite while the mobile body moves along the first movement path is provided, Storage means for storing a data table in which attenuation patterns related to the attenuation patterns for each position on the above-described first movement path are associated with each other; Travel time acquisition means for acquiring the travel time of the above-described moving body; Current position calculation means for obtaining a virtual current position on the first movement path based on the travel time acquired by the above-described travel time acquisition means and the above-described first movement speed; Attenuation pattern selection means for referring to the data table stored by the above-described storage means and selecting the attenuation pattern for the position corresponding to the virtual current position calculated by the above-described current position calculation means; Further comprising simulation signal generation means for generating a simulation signal from the selected attenuation pattern by the above-described attenuation pattern selection means A simulation signal output device for mobile satellite communication, characterized in that.

5. Storage means for storing an attenuation model in which shielding object information regarding the type and / or width of the shielding object and an attenuation pattern regarding the attenuation pattern of the signal by the shielding object are associated with each other, with the input being the shielding object information and the output being the attenuation pattern; Shielding object information acquisition means for acquiring the shielding object information of the shielding object that shields the signal from the satellite when the above-described moving body moves on the above-described first movement path; Further comprising simulation signal generation means for generating a simulation signal from the attenuation pattern output by inputting the shielding object information acquired by the above-described shielding object information acquisition means into the attenuation model stored by the above-described storage means The simulation signal output device for mobile satellite communication according to claim 1, characterized in that.

6. In a simulation signal output device for simulating a mobile satellite communication system that outputs a simulated simulation signal that a moving body moving on a first movement path at a first movement speed can receive from a satellite, Second attenuation means for referring to a time-series simulation signal reflecting the above-described first movement speed and the attenuation by a shielding object that shields the signal from the satellite when moving on the above-described first movement path, and attenuating a second evaluation signal to be newly transmitted; Comprising a transmission antenna for transmitting the second evaluation signal attenuated by the above-described second attenuation means A simulation signal output device for mobile satellite communication, characterized in that.

Images