JP2867937B2 - Mobile satellite communication equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile satellite communication device used for a mobile satellite communication system, and more particularly to a mobile satellite communication device that enables use of satellite communication indoors.

[0002]

2. Description of the Related Art A conventional mobile satellite communication apparatus will be described with reference to FIG. 4 showing a system diagram of a mobile satellite communication system.

[0003] This system comprises a base station 1, a plurality of mobile satellite communication devices 40-1 to 40-3 (hereinafter abbreviated as devices for simplicity), and a satellite 2.

The devices 40-1 to 40-3 are mobile satellite communication devices having the same configuration, and can be easily carried. Among them, for example, the device 40-1
This figure shows a configuration used outdoors and connected to a base station 1 via a satellite 2. In this case, the device 40-1
Even if the apparatus is moved to a mountain area, between buildings, or the like, communication can be performed within a range where the apparatus can see the satellite 2.

[0005] The device 40-2 is shown as being installed in a building such as a building. In this case, for example, communication is possible at a position where the satellite can be seen, such as near the window 21 provided in the building, because the signal is slightly attenuated to some extent.

[0006] On the other hand, the device 40-3 has a window 21 inside the building.
Since the satellite 2 is used at a location distant from the satellite, the satellite 2 cannot be seen through, and transmission of satellite communication transmission / reception signals becomes impossible.

In order to perform communication with the device 40-3,
It is necessary to move to a place such as a window where radio waves can reach like the device 40-2.

Documents describing the mobile satellite communication system described above include PTC '93 Proceedings, p. 835-p. 840, "Inmarsat-M
Portable MES "(INMARSAT-M POR
TABLE MES).

[0009]

As described above, in the conventional mobile satellite communication system, communication becomes impossible when there is an obstacle between the mobile satellite communication device and the satellite.

[0010] In particular, in a building such as a building, communication can be performed only in a limited place such as near a window, and even if the terminal can be moved as a mobile satellite communication terminal, it has a high degree of freedom. There was a problem that it was impossible to use.

[0011]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a mobile satellite communication terminal device installed in a building in which satellites cannot be seen, so that mobile terminals can freely use satellite communication. An object of the present invention is to provide a body satellite communication device.

Therefore, the mobile satellite communication apparatus of the present invention is provided as a dedicated indoor communication line in a mobile satellite communication apparatus that moves between indoors and outdoors via a satellite and transmits and receives data.
A detachable indoor unit comprising a first RF unit for transmitting and receiving a terrestrial radio line for enabling line-of- sight communication and a first antenna is attached to a common unit and connected to the outside by the terrestrial radio line. An indoor device for transmitting and receiving the transmitted signal, the indoor unit, and a detachable outdoor unit including a second RF unit and a second antenna for transmitting and receiving a satellite line, and attaching the terrestrial radio line to the To satellite line
Installed indoors with a relay device that converts in the RF band
Communication between the indoor device and a satellite earth station via a satellite
First communication means, the outdoor unit is attached to the common unit, and the outdoor device transmits and receives signals connected to the outside via a satellite line.
It has a second communication means for performing communication between earth stations .

[0013]

Next, a mobile satellite communication device according to the present invention will be described with reference to the drawings.

FIG. 1 is a system diagram of a mobile satellite communication system using the mobile satellite communication device of the present invention.

In FIG. 1, a mobile satellite communication apparatus according to the present invention is mainly connected directly to a subscriber terminal such as a telephone or a facsimile, and the signal is transmitted to a satellite line 11 or a terrestrial radio line 12.
There are mobile devices 3 and 4 that transmit using In addition, there are two types of relay devices 10 that convert signals transmitted and received between the satellite line 11 and the terrestrial wireless line 12.

Further, the mobile unit can be detached from an outdoor unit or an indoor unit including an antenna and a high-frequency circuit unit, and the other units have a common configuration, and two types are provided depending on the type of the outdoor unit or the indoor unit. Divided into devices. That is, the mobile device 3 equipped with the outdoor unit for satellite communication (hereinafter, referred to as an outdoor device)
And a mobile device 4 (hereinafter referred to as an indoor device) equipped with an indoor unit for a terrestrial radio line.

The reason why the outdoor device 3 and the indoor device 4 are divided as described above is as follows.

The frequency band used for transmission and reception to and from the satellite 2 usually uses a microwave band or a quasi-microwave band and is a high frequency. In addition, QPSK (four-phase ratio modulator) and OQPS, which can efficiently use a wireless band and operate at a low C / N (carrier power to noise ratio), are also used as a modulation method.
K (offset QPSK) modulation or the like is selected.

On the other hand, a relatively low frequency band below the VHF band is used between the terrestrial radio line between the relay device 10 and the indoor device 4 in order to increase the directivity as much as possible. . Further, as a modulation method, for example, FSK modulation or FM modulation is used.

As described above, in order to use two lines having different purposes, the line is divided into an outdoor unit 3 and an indoor unit 4.

Here, the terrestrial radio line 12 is a line exclusively used for indoor communication, and refers to a radio line that enables non-line-of-sight communication using a relatively low frequency (for example, a VHF band frequency).

Using the mobile satellite communication apparatus described above, FIG.
Is configured.

That is, in the building 22 shown in FIG. 1, the relay device 10 is installed in a place where the satellite 2 can be seen, for example, near the window 21.

The repeater 10 includes an antenna (A) 5 for transmitting and receiving to and from the satellite 2 and a high-frequency circuit RF for a satellite line.
(A) An outdoor unit 20 composed of 7, an indoor unit 4 composed of an antenna (B) 6 for transmitting and receiving to and from the indoor device 4 via a terrestrial radio line, a radio frequency circuit RF (B) 8 for a terrestrial radio line, and a satellite line. And a conversion unit 9 for mutually converting the signal with the terrestrial radio line.

Further, inside the building 22, an indoor unit 30 including an antenna (B) 6 and an RF (B) 8 is provided so that transmission and reception can be performed by the relay device 10 and the terrestrial radio line 12.
The indoor device 4 including the common unit 15 is installed.

On the other hand, outdoors, an indoor unit 20 comprising an antenna (A) 5 and an RF (A) 7 which can be transmitted and received by the satellite 2 and the satellite line 11 and an outdoor device 3 comprising a common unit 15 are installed. ing.

Next, specific operations of these mobile satellite devices will be described.

First, the relay device 10 will be described below.

In the present invention, in order to use satellite communication indoors, the relay device 10 is provided at a position where the satellite 2 can be seen.

The relay device 10 includes a satellite communication antenna (A) 5 for satellite communication and an RF (A) 7 for satellite communication, and an antenna (B) 6 and an R (ground communication) antenna for terrestrial radio communication.
F (B) 8 and a converter 9 for converting these signals.

The present device uses these two antennas to
For example, when receiving a reception signal from the satellite 2, the antenna (A) 5 directly receives the satellite line 11 through the window 21,
After the signal is converted to the terrestrial line 12 by the converter 9, the signal is transmitted to the indoor unit 4 using the antenna (B). As a result, even if the indoor device 4 is installed in a place where the satellite 2 cannot be seen at all, it is possible to transmit and receive to and from the satellite 2 via the relay device 10.

Next, a specific configuration of the indoor unit 4 will be described.

As described above, the indoor unit 4 includes the indoor unit 30 in which the indoor antenna (B) 6 for the terrestrial radio line 12 and the RF (B) 8 are combined, and the common unit 15.

Here, the RF (B) 8 is connected to the terrestrial radio line 12.
It has a function of frequency conversion of a high frequency signal for use.

The common unit 15 has a modulation / demodulation function, a baseband processing function, and the like.

As a result, when transmitting a voice or data signal from the indoor unit 4 to the base station 1, first, the common unit 15 uses the modulation / demodulation method (B) for the terrestrial radio line.
Is output. Next, the modulated signal is R
After being converted to the carrier frequency (B) by the F (B) 8, it is transmitted to the relay device 10 by the antenna (B) 6.
The relay device 10 receives a transmission signal having a carrier frequency (B) modulated by the modulation / demodulation method (B) by an antenna (B) 6.

When receiving the signal from the indoor unit 4, the converter 9 changes the carrier frequency (B) to the carrier frequency (A) which is a carrier wave for satellite communication, and the modulation / demodulation method (B) to the modulation / demodulation method for satellite communication. The data is converted into the modulation / demodulation method (A).

The output signal of the converter 9 is transmitted by the antenna (A) 5, which is a satellite communication antenna, to the satellite 2 using the carrier frequency (A) and the modulation / demodulation method (A) via the satellite line 11.

On the other hand, when the signal is received by the indoor unit 4,
A modulated signal according to the modulation / demodulation method (A) is received by the relay device 10 from the satellite 2 at the carrier frequency (A). The signal received by the relay device 10 is converted into a signal of a carrier frequency (B) for the terrestrial line and a modulation and demodulation method (B), and transmitted to the indoor device 4.

The indoor unit 4 receives a signal from the relay device 10 and outputs a received signal.

Next, a case where the mobile satellite communication device of the present invention is used as an outdoor device 3 will be described.

As the outdoor device 3, an outdoor unit 20 equipped with a satellite communication antenna (A) 5 is used so that a satellite communication line can be used.

As described above, except for the mobile unit other than the outdoor unit 20 or 30, the common unit 15 has the same configuration regardless of whether it is an outdoor unit or an indoor unit.

In the above-described configuration, the case where the modulation and demodulation method of the present apparatus is different between the radio line and the satellite line has been described.

However, in order to simplify the device configuration,
However, the present invention is not limited to this, and the modulation and demodulation method may be the same for the wireless line and the satellite line.

Next, a specific configuration of the mobile satellite communication device of the present invention will be described in detail.

FIGS. 2A to 2D are basic structural elements of the mobile satellite communication apparatus of the present invention, and are diagrams showing a conversion unit.

That is, these figures show exchange units necessary for the outdoor unit 3, the indoor unit 4, and the relay unit 1. Here, FIG. 2A illustrates a common unit 15 having a function of performing modulation / demodulation processing in the IF band and a baseband signal processing function of interfacing with an external terminal device and performing signal processing.
Is represented. FIG. 2B shows a converter 9 having a function of converting the carrier frequencies (A) and (B) and a function of converting the modulation and demodulation methods (A) and (B). Further, FIG. 2C shows an exchange unit (outdoor unit) 20 in which an antenna unit I5 and an RF unit I7 for transmitting and receiving to and from the satellite at the transmission / reception frequency (A) are integrated. FIG.
(D) is composed of an exchange unit (indoor unit) 30 including an antenna (B) 6 for transmitting and receiving at an indoor transmission / reception frequency (B) and an RF (B) 8.

Here, the common unit 15 includes the outdoor unit 20.
And the indoor unit 30 are attached together, and only one of them is selectively connected. In this case, the connection of the two signals is connected using a coaxial cable or a coaxial connector.

Further, both the outdoor unit 20 and the indoor unit 30 can be attached to the conversion unit 9 at the same time.

FIGS. 3A to 3C show FIGS. 2A to 2D.
FIG. 3 is a diagram showing that a mobile satellite communication device of the present invention can be configured using the switching unit shown in FIG.

FIGS. 3A and 3B are diagrams showing a case where an indoor unit 4 and an outdoor unit 3 are configured by attaching an indoor unit 30 and an outdoor unit 20 to the common unit 15, respectively.

FIG. 3C shows a configuration in which both the outdoor unit 20 and the indoor unit 30 are attached to the conversion unit 9 to form the relay device 10.

Therefore, in order to connect to the satellite 2 from indoors, it is clear that one indoor unit 30 and two outdoor units 20 should be prepared in addition to the conversion unit 9 and the common unit 15.

Similarly, when used only outdoors, at least one common unit 15 and at least one outdoor unit 20 may be prepared.

Although the outdoor device 3 described above is intended for outdoor use, it can be naturally used indoors when the satellite can be seen near windows and the like. Similarly, the indoor device and the relay device have been described for use indoors, but can be used outdoors.

[0057]

As described above, the mobile satellite communication apparatus according to the present invention combines an outdoor unit and a common part into an outdoor apparatus when used outdoors, and converts between an outdoor unit and an indoor unit when used indoors. A relay device is configured by attaching the relay unit to a relay unit, and further connected to the relay device. The indoor unit and the common unit are combined and used as an indoor device. As a result, the indoor device has an effect that it can sufficiently exhibit portability as a mobile device.

The combination of the indoor unit, the outdoor unit, the common unit, and the conversion unit can cope with both the relay device and the indoor / outdoor device, so that there is an effect that a highly flexible device can be provided.

[Brief description of the drawings]

FIG. 1 is a system diagram showing an embodiment of a mobile satellite system using a mobile satellite communication device of the present invention.

FIG. 2 is a diagram showing an exchange unit of the present invention.

FIG. 3 is a diagram showing that an indoor device, an outdoor device, and a relay device are configured using the exchange unit of FIG. 2;

FIG. 4 is a system diagram showing a conventional mobile satellite system.

[Explanation of symbols]

 Reference Signs List 1 base station 2 satellite 3 mobile satellite communication device (outdoor device) 4 mobile satellite communication device (indoor device) 5 antenna (A) 6 antenna (B) 7 RF (A) 8 RF (B) 9 conversion unit 10 relay Apparatus 11 Satellite line 12 Terrestrial radio line 15 Common part 20 Outdoor unit 21 Window 22 Building 30 Indoor unit 40 Mobile satellite communication device

Claims (6)

(57) [Claims] 1. A mobile satellite communication apparatus for transmitting / receiving indoors / outdoors via a satellite, wherein the mobile satellite communication apparatus is provided as a dedicated line for indoor communication and enables line-of-sight communication.
A detachable indoor unit comprising a first RF unit for transmitting and receiving a terrestrial radio line and a first antenna is attached to a common unit, and an indoor unit for transmitting and receiving signals connected to the outside via the terrestrial radio line. An indoor unit and a second RF for transmitting and receiving satellite links
A detachable outdoor unit comprising a unit and a second antenna is attached, and provided indoors by a relay device that converts the terrestrial radio line into the satellite line in the RF band.
Communication between the indoor equipment and the satellite earth station via the satellite.
Cormorant first communication means, said mounting outdoor unit to the common unit, before the outdoor unit for transmitting and receiving a signal connected to the external at the satellite line
Communication between the satellite earth station via outdoor equipment and satellite
A mobile satellite communication device comprising second communication means . 2. The indoor unit and the outdoor unit both have a structure that can be mechanically attached to and detached from the common unit.
2. The mobile satellite communication device according to claim 1, wherein one of the common units is selectively attached. 3. The mobile satellite communication device according to claim 1, wherein the relay device attaches both the indoor unit and the outdoor unit to a conversion unit and is installed at a position where the satellite can be seen. . 4. The mobile satellite communication device according to claim 1, wherein the common unit has a function of modulating and demodulating a transmission / reception signal of the indoor unit or the outdoor unit and a baseband processing function. 5. The conversion unit has a function of mutually converting a transmission / reception frequency of a terrestrial radio line used for an indoor unit and a transmission / reception frequency of a satellite line used for an outdoor unit. Item 4. The mobile satellite communication device according to item 3. 6. The mobile satellite communication device according to claim 1, wherein the terrestrial radio line uses a low frequency band equal to or lower than a VHF band.