JP2003309505A - Satellite broadcasting system, terresrial transmitter, satellite relay device, broadcasting receiver, and satellite broadcasting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reliably receive a radio signal from a satellite not only by a fixed station but also by a mobile station without providing a large-scale facility even in a blind area unable to directly receive the radio signal from the satellite. <P>SOLUTION: A gap-filler GFa is disposed at a roof of a building, etc. to receive and amplify a broadcasting signal transmitted from a geo-stationary satellite SAT1, and to relay and transmit the broadcasting signal having the same frequency is as the broadcasting signal received from the geo-stationary satellite SAT1 to the blind area by using a directional antenna. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for transmitting information to a service area on the ground by using a broadcasting satellite or a communication satellite, and in particular, can reliably receive information even in a shadowed area such as a mountain or a building. The present invention relates to a satellite broadcasting system having a gap filler function and a gap filler device therefor.

[0002]

2. Description of the Related Art In recent years, various communication systems have been developed in response to an increase in communication needs and the development of communication technology. Among them, there are broadcasting satellites and satellite broadcasting systems using communication satellites. The advantage of the satellite broadcasting system is that it can provide information broadcasting service to a wide service area without constructing a large-scale infrastructure on the ground.

By the way, one of the problems of this type of system is a countermeasure against the shadow of a building which cannot receive a direct wave from a satellite. On the other hand, conventionally, for example, a common antenna with a large diameter is installed on the roof of a high-rise building or a steel tower, and the common antenna receives and amplifies the radio signal from the satellite, and the received radio signal is transmitted via a coaxial cable or an optical cable. Therefore, the information is delivered to the receiving device of each user behind the building.
By doing so, even a user who cannot receive the radio signal from the satellite, such as a building shade, can receive the transmission information from the satellite without exception.

[0004]

However, such joint reception equipment requires a large amount of work and cost because it is necessary to lay cables for all target users. Recently, it has been proposed to use a satellite broadcasting system to transmit information to mobile stations as well as fixed stations. In this case, if the user behind the building is a fixed station, it is possible to receive the information from the satellite by the above-mentioned joint reception facility. But,
Since it is not possible to lay a coaxial cable or an optical cable for a mobile station that is behind a building, it is not possible to receive information from satellites, and measures are urgently needed.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a fixed station in a shaded area of a building or the like where radio signals from satellites cannot be directly received without providing large-scale equipment. Another object of the present invention is to provide a satellite broadcasting system that not only enables mobile stations to receive signals reliably but also realizes an inexpensive and effective gap filler.

[0006]

In order to achieve the above object, a satellite broadcasting system of the present invention receives a broadcast signal relayed by a satellite, and broadcasts the received broadcast signal from the satellite within the service area. It is provided with a gap filler device that wirelessly transmits a signal to an area where the signal cannot be received.

By doing so, the radio signal from the satellite is retransmitted by radio to the shadow of the building after being received by the gap filler device. Therefore, it is not necessary to lay a coaxial cable or an optical cable for each user behind the building, so that it can be realized relatively easily and inexpensively. Also,
In the shadow of a building, not only fixed stations but also mobile stations can receive information from satellites. Further, since the radio signal is transmitted from the gap filler device at the same frequency, the user can receive the radio signal from the gap filler device only by having the receiving device for receiving the direct wave from the satellite.

Further, the gap filler device is characterized in that the directional antenna is used to wirelessly transmit the received broadcast signal to the area where the broadcast signal from the satellite cannot be received within the service area. There is. By doing so, it is possible to reduce the problem that the user in the area that can directly receive the radio signal from the satellite is interfered with by the radio signal retransmitted from the gap filler device.

When the satellite is a geostationary satellite placed in a geostationary orbit above the equator, it is preferable to wirelessly transmit the received broadcast signal from the gap filler device with directivity in the east and west directions. When a radio signal is transmitted from a geostationary satellite, which is generally placed in a geostationary orbit above the equator, radio waves are shaded on the north side of obstacles such as buildings on the ground. Therefore, for example, in an area where many buildings are lined up, such as an office district and a downtown area, if a radio signal is retransmitted from the gap filler device with directivity in the east-west direction, It is possible to effectively cover the shadow.

Further, at least one of the terrestrial broadcasting station and the satellite transmits the broadcast signal after the spread spectrum modulation with a predetermined spread code, and the gap filler device transmits the spread spectrum modulated broadcast signal from the satellite. Is received, and the received broadcast signal is wirelessly transmitted to the area within the service area where the broadcast signal from the satellite cannot be received.

By doing so, there is no fear of interference between the direct broadcast signal transmitted from the satellite and the relay broadcast signal transmitted by the gap filler device. For this reason,
Even if the receiver is located near the boundary between the area that can receive the direct broadcast signal from the satellite and the area that can receive the relay broadcast signal from the gap filler device, the reception quality is kept high without being affected by the interference. be able to.

On the other hand, the gap filler device of the present invention is a first device for receiving a broadcast signal transmitted from a satellite.
Antenna, a radio circuit unit for at least amplifying a broadcast signal received by the first antenna and outputting a transmission broadcast signal having the same frequency as the reception broadcast signal, and a radio circuit unit output from the radio circuit unit. A second antenna is provided for wirelessly transmitting a transmission broadcast signal to an area in which the broadcast signal from the satellite cannot be received within the service area.

By using such a gap filler device, as described above, each user behind the building can receive information from the satellite relatively easily and inexpensively without laying a coaxial cable or an optical cable. Moreover, not only the fixed station but also the mobile station can receive the information from the satellite. Further, since the relay broadcast signal to be transmitted to the building shade is transmitted at the same frequency as the direct broadcast signal from the satellite, the user only needs to have a receiving device to receive the direct wave from the satellite and the relay broadcast signal from the gap filler device. Signals can also be received.

Further, in another satellite broadcasting system of the present invention, the first and second satellites are arranged on the same satellite orbit at a predetermined distance from each other, and the same service is provided from the first and second satellites. The same broadcast signal is transmitted to the area in synchronization with each other.

By doing so, the same broadcast signal is sent from the two satellites having different positions to the users in the service area. Therefore, for example, a station located in an area where the broadcast signal from one satellite cannot be directly received, such as in the shade of a building, can receive the broadcast signal from the other satellite. It is possible to obtain the same effect as in the case where the gap filler device described in 1 is provided.

Further, when a spare aircraft is arranged on the same orbit, this spare aircraft is used as the second satellite. In this way, it is not necessary to launch a new satellite for countermeasures against building shadows, etc., and an inexpensive system can be provided.

Further, in the satellite broadcasting system of the present invention, in the satellite, the broadcasting signal transmitted from the terrestrial broadcasting station is converted into first and second broadcasting signals having different frequencies, and the signals are wirelessly transmitted. The device receives the second broadcast signal transmitted from the satellite, converts the second broadcast signal into a third broadcast signal having the same frequency as the first broadcast signal, and outputs the third broadcast signal. Is wirelessly transmitted to the area where the first broadcast signal from the satellite cannot be received within the service area.

By doing so, in the gap filler device, the frequency of the second broadcast signal received from the satellite and the frequency of the third broadcast signal transmitted by the device are different, so that the received wave of the transmitted wave is different. It is possible to easily prevent wraparound.

Further, it is preferable that the broadcast receiving device has means for receiving and synthesizing the first broadcast signal transmitted from the satellite and the third broadcast signal transmitted by the gap filler device, respectively. With this configuration, the broadcast receiving device can receive higher quality when it is in a place where both the first broadcast signal from the satellite and the third broadcast signal from the gap filler device can be received. Become.

Further, in the satellite conversion means, the broadcast signal transmitted from the terrestrial broadcasting station is converted into a first broadcast signal in the S band and a second broadcast signal in a high frequency region beyond the S band, and the first broadcast signal is transmitted. A signal may be transmitted as a signal for the broadcast receiving device, and the second broadcast signal may be transmitted as a signal for the gap filler device.

In this way, since the broadcast receiving apparatus only needs to receive the S-band broadcast signal, it is possible to receive the signal with simple equipment without using a large antenna such as a parabolic antenna. For this reason, the user can use a small-sized and inexpensive broadcast receiving device, and can receive a broadcast with inexpensive equipment without sacrificing portability. On the other hand, in the gap filler device, for example, a broadcast signal in the Ku or Ka band is received, so a receiving facility having a parabolic antenna is required, and a frequency conversion function from the Ku or Ka band to the S band is required. However, since the gap filler device is a part of the equipment of the system, it does not burden the user and does not cause a big problem.

Further, the satellite broadcasting system of the present invention includes a terrestrial network transmitting means for transmitting a second broadcasting signal having the same content as the first broadcasting signal transmitted from the terrestrial broadcasting station to the satellite through the terrestrial network, and The second broadcast signal transmitted by the terrestrial network transmission means is received, the received second broadcast signal is converted into a third broadcast signal in the same frequency band as the broadcast signal transmitted by the satellite, and the third broadcast signal is converted into the third broadcast signal. And a gap filler device for wirelessly transmitting the broadcast signal of No. 3 to the area in which the broadcast signal from the satellite cannot be received in the service area.

Further, the gap filler device of the present invention is
Terrestrial network receiving means for receiving from the terrestrial broadcasting station a second broadcasting signal having the same content as the broadcasting signal transmitted from the terrestrial broadcasting station to the satellite, and received by the terrestrial network receiving means. In the service area, a conversion unit that converts the generated second broadcast signal into a third broadcast signal in the same frequency band as the broadcast signal transmitted by the satellite, and the third broadcast signal obtained by the conversion unit And a transmission means for wirelessly transmitting a broadcast signal from the satellite to an area where the satellite cannot be received.

By using such a system and the gap filler device, even if the gap filler device cannot be installed in a place where the direct broadcasting signal from the satellite can be received due to the location conditions, the broadcasting signal from the satellite cannot be directly received. It is possible to reliably cover the dead area.

Further, the gap filler device is provided with a satellite receiving means for receiving the broadcast signal transmitted from the satellite and a second broadcast signal having the same content as the broadcast signal transmitted by the terrestrial broadcast station to the satellite. Terrestrial network receiving means for receiving via the upper network, and converting the second broadcast signal received by the terrestrial network receiving means into a third broadcast signal in the same frequency band as the broadcast signal transmitted from the satellite. To convert the satellite from the satellite within the service area by selecting one of the converting means, the broadcast signal received by the satellite receiving means, and the third broadcast signal obtained by the converting means. And a selective transmission unit for wirelessly transmitting a broadcast signal to an unreceivable area.

In this way, one gap filler device has a function of receiving and relaying a broadcast signal from a satellite, and a function of receiving and relaying a broadcast signal sent via the ground network. Each of them can have its own, so that you only have to prepare one gap filler device,
Each of the above functions can be selectively used according to the installation conditions of the gap filler device.

Further, in the selective transmitting means, it is judged whether or not the satellite receiving means receives a broadcast signal of a predetermined level or more. If it is judged that the broadcasting signal is received, the broadcast signal received by the satellite receiving means. Is selected and wirelessly transmitted to the unreceivable area. On the other hand, if it is determined that the signal is not received, the third broadcast signal obtained by the converting means is wirelessly transmitted to the unreceivable area.

In this way, each function can be automatically selected according to whether or not the broadcast signal from the satellite can be directly received, and the work such as maintenance setting can be facilitated.

Further, the satellite broadcasting system of the present invention comprises, in addition to the gap filler device, a monitoring device connected to the gap filler device via a communication line. Monitor information transmitting means for generating the monitor information representing the monitor information and transmitting the monitor information to the monitoring device via the communication line, and the monitor device has a monitor transmitted from the gap filler device via the communication line. It is characterized by further comprising means for receiving information and performing a predetermined process for monitoring the operating state of the gap filler device based on the received monitor information.

With such a system, the operating state of the gap filler device can be centrally managed at, for example, a monitoring center, and thus a quick response to a failure can be achieved.

The following methods can be considered as the monitoring method of the monitor information. That is, in the first method, the monitoring device transmits a monitor information transmission request to the gap filler device via the communication line periodically or when necessary, and the monitor information is accumulated in the gap filler device. Each time a transmission request arrives from the monitoring device, the previously stored monitor information is read and transmitted to the monitoring device. With this method, even if there are many gap filler devices, the monitor information of these gap filler devices can be efficiently collected in the monitoring center.

In the second method, in the gap filler device, the operating state of the device itself is monitored, and when it is detected that the operating state of the device itself is abnormal, the monitor information indicating the content is provided to the communication line. Is transmitted to the monitoring device via the. According to this method, when a failure occurs in the gap filler device, the information can be notified to the immediate monitoring center.

Further, in the gap filler device, when it is detected that an abnormality occurs in the operating state of the device itself, message information to that effect is generated and the message information is broadcast in the area covered by the device itself. You may make it transmit to a receiver. In this way, when the gap filler device cannot receive a broadcast signal from a satellite, for example, or when its own device fails and relay broadcasting cannot be performed, a message to that effect is sent to the broadcast receiving device. Can be displayed. As a result, the user can clearly know the reason why reception is not possible.

The satellite broadcasting system of the present invention further includes, in addition to the gap filler device, a monitor receiving device having a function of receiving the received broadcast signal transmitted from the gap filler device in the unreceivable area, and the monitor receiving device. And a monitoring device connected to the device via a communication line. And in the gap filler device,
It generates monitor information indicating the operating state of its own device and wirelessly transmits it by including this monitor information in the received broadcast signal, and the monitor receiver receives the relay broadcast signal transmitted from the gap filler device and outputs it. While extracting the monitor information from, to detect the reception state of the relay broadcast signal, so that the detection information of the reception state and the extracted monitor information is transmitted to the monitoring device via a communication line, the monitoring device, Monitor information and detection information transmitted from the monitor receiver via the communication line are received, and predetermined processing for monitoring the operating state of the gap filler device is performed based on the received monitor information and detection information. It is characterized by having done.

In such a system, the receiving condition of the broadcast signal from the gap filler device can be directly observed by installing the monitor receiving device at an arbitrary position in the blind area. Can be sent to the monitoring center together with the monitor information sent by the gap filler device itself. For this reason, it is possible to perform monitoring that is more realistic.

[0036]

BEST MODE FOR CARRYING OUT THE INVENTION (First Embodiment) This satellite broadcasting system comprises a plurality of terrestrial broadcasting stations (VSAT) BC1, B1.
C2 or feeder link station, geostationary satellite SAT1,
It is equipped with satellite tracking and control station STCC.

The terrestrial broadcasting station (VSAT) BC1, BC2 or the feeder link station stores the program information created and edited by each broadcasting company in the Ka band (26.5-40 GH).
z) or Ku band (12.5-18 GHz) to the geostationary satellite SAT1 via the upstream transmission path.

The geostationary satellite SAT1 includes, for example, an antenna for Ka band or Ku band having a diameter of 2.5 m class and an S band having a diameter of 15 m class (for example, 2.6 G).
Hz) antenna. Then, the broadcasting signal multiplexed and transmitted from each of the broadcasting stations (VSAT) BC1 and BC2 or the feeder link station is received and amplified by the above Ka or Ku band antenna and then converted into an S band signal. Then, the converted broadcast signal is transmitted from the S-band antenna to the service area via the S-band downlink transmission path. The geostationary satellite SAT
The caliber of the antenna for upstream transmission mounted in 1 may be smaller than 2.5 m class, and the caliber of the S-band antenna is not limited to 15 m class and may be 8 m class.

The satellite tracking and control station STCC monitors and controls the operating state of the geostationary satellite SAT1.

In the service area, for example, a broadcast receiving device (not shown) fixedly installed in an office or home,
An in-vehicle or portable mobile broadcast receiving device MS receives a broadcast signal transmitted from the geostationary satellite SAT1 to an S band down transmission path. In the downlink transmission line of the S band, a plurality of channels having a transmission rate of 64 to 256 Kbps / channel are multiplexed at a maximum of 900 channels. Further, when transmitting a video signal through each channel, MPEG4 (moving picture e) is used as a video encoding method.
xperts group 4) is used.

By the way, in the system of the first embodiment, the gap filler device GFa is provided on the roof of a high-rise building or the like.
Has been installed. The gap filler device GFa receives and amplifies the broadcast signal from the geostationary satellite SAT1 and then amplifies it in an area such as a building where the broadcast signal from the geostationary satellite SAT1 cannot be received while keeping the received broadcast signal at the same frequency. For example, it is configured as follows.

FIG. 2 is a circuit block diagram showing the configuration. That is, the broadcast signal transmitted from the geostationary satellite SAT1 is received by the receiving antenna 11 and then input to the input filter 12, where only a predetermined transmission band is selected and then amplified by the low noise amplifier 13. Then, the amplified broadcast signal is amplified by the power amplifier 14 and further band-limited by the output filter 15 to a predetermined transmission band.
It is transmitted to the blind area where the direct wave from T1 does not reach. Here, a directional antenna is used as the output antenna 16, which limits the transmission range of the broadcast signal to a dead area where the direct wave from the geostationary satellite SAT1 cannot be received.

With such a configuration, broadcast signals transmitted from a plurality of broadcasting stations BC1, BC2 or feeder link stations are sent to the geostationary satellite SAT1 via the Ka or Ku band upstream transmission path, This geostationary satellite SA
The signal is transmitted from T1 to the service area via the down transmission path of the S band, and is received by the broadcast receiving device MS existing in the service area. At this time, the geostationary satellite SAT1 is equipped with an antenna for S-band with a large diameter of 15 m class, and since the S-band has the property that it is not easily affected by rain attenuation, each broadcasting receiver MS broadcasts. The signal is received with a sufficiently high received field strength. Therefore, the broadcast receiving device MS can receive the broadcast signal by using a small rod antenna or a flat antenna.

However, geostationary satellite S
The broadcast receiving device MS located in the blind area where the direct wave from the AT1 cannot be received cannot directly receive the broadcast signal. However, the broadcast signal transmitted from the geostationary satellite SAT1 is received by the gap filler device GFa, and then relayed to the blind area behind the building. For this reason, the broadcast receiving device M in the shadow of the building
Also in S, it is possible to receive the broadcast signal.

At this time, the gap filler device GF
The frequency of the broadcast signal relayed from a
It is set to be the same as the broadcast signal sent from AT1.
Therefore, even if the broadcast receiving device MS is behind the building,
The broadcast signal from the gap filler device GFa can be received as long as the reception device receives the broadcast signal from the geostationary satellite SAT1 without using a special reception device.

Moreover, a directional antenna is used to transmit a broadcast signal from the gap filler device GFa to a blind area behind the building by limiting the broadcast range.
Therefore, although the frequency of the signal transmitted from the gap filler device GFa is set to be the same as the frequency of the signal transmitted from the geostationary satellite SAT1, the geostationary satellite SAT1 transmits signals in the vicinity of the blind area, which is the shadow of the building. There is little concern that the transmission signal of the gap filler device GFa interferes with the signal, which allows the broadcast receiving device MS to receive the broadcast signal with high quality regardless of the area.

(Second Embodiment) Generally, when a radio signal is transmitted from a geostationary satellite placed on a geostationary orbit above the equator, radio waves are shaded on the north side of an obstacle such as a building on the ground. In the second embodiment of the present invention, attention is paid to this point, and in an area where a large number of buildings are lined up, a gap filler device is provided with directivity in the east-west direction to relay and transmit a broadcast signal. is there.

FIG. 3 and FIG. 4 are diagrams for explaining this embodiment. That is, in a place where buildings are forested along a road such as a downtown area or an office district, a blind area in which radio signals from the geostationary satellite SAT1 cannot be directly received on the north side of these buildings is shaded in FIG. As shown in, it is formed in a band shape in the east-west direction.

Therefore, in this embodiment, the gap filler device GFb is installed at a position where the broadcast signal from the geostationary satellite SAT1 can be directly received, such as a large intersection. As the installation means, for example, the pillar 4 on the pavement
5 is erected, and the gap filler device G is mounted on the pillar 45.
This is done by fixing Fb.

The gap filler device GFb is a main body 4 containing a transmission / reception circuit section such as a low noise amplifier and a power amplifier.
2, the antenna 41 for receiving the broadcast signal from the geostationary satellite SAT is attached to the upper part of the main body 42,
Retransmission antennas 43 and 44 are attached to two opposite side surfaces of the main body 42, respectively. The directions of the retransmitted antennas 43 and 44 are set so that the transmission direction of the retransmitted radio signal is east-west.

If existing pillars such as a road sign pillar, a signal pillar, and a telephone pole installed on a sidewalk can be used, the dedicated pillar 45 is not provided and the above existing pillars are not provided. A gap filler device GFb may be installed in the.

As described above, according to the present embodiment, the broadcast signal sent from the geostationary satellite SAT1 is received and amplified by the gap filler device GFb, and then transmitted from the relay transmission antennas 43 and 44 to FIGS. As shown, it is transmitted with directivity in the east-west direction. Therefore, it is possible to effectively cover the gap area where the broadcast signal from the geostationary satellite SAT1 cannot be directly received by installing a small number of gap filler devices.

The gap filler device GFb is not necessarily limited to the one in which the satellite receiving antenna 41 and the retransmitting antennas 43 and 44 are integrally attached to the main body 42. For example, the main body 42 to which the antenna 41 for satellite reception is attached is installed at a place where the signal from the geostationary satellite SAT1 can be received more reliably, such as the roof of a building, and the antennas 43 and 44 for relay transmission are provided at the intersection. It is attached to a pole for a sign, a pole for a traffic signal, a telephone pole, etc., which are installed in, and the main body 42 and the antennas 43 and 44 of the retransmit credit are connected via a coaxial cable. By doing so, the connection between the main body 42 and the antennas 43 and 44 for retransmission is slightly complicated, but it is possible to provide a gap filler device having high reception performance. In addition,
As the antennas 43 and 44, small patch antennas can be used.

To cover a wide band-shaped dead area, for example, as shown in FIG. 5, a gap filler device GFc is installed at a high place such as the roof of a building, and the roof has directivity to the dead area. It is good to send with. FIG. 5 shows a case in which a blind area of several tens of kilometers to several kilometers is covered by this configuration.

Depending on the shape of the dead area, for example, as shown in FIG.
Fd may be installed so that the gap filler device GFd may relay the broadcast signal using an omnidirectional antenna. By doing so, it is possible to cover a wide range of circular insensitive areas.

(Third Embodiment) In the third embodiment of the present invention, a plurality of channel signals transmitted from a terrestrial broadcasting station to satellites are multiplexed by a CDM (Code Division Multiplex) system, and a gap filler device is provided. This is to amplify the above-mentioned CDM multiplex broadcast signal that has arrived via a satellite and relay it to a gap area such as a building shadow.

FIG. 7 is a circuit block diagram showing the structure of the transmitting section in the terrestrial broadcasting stations BC1 and BC2. Broadcast signals of a plurality of programs (N programs in the figure) edited by a circuit (not shown) are input to the modulators 51 to 5n, respectively. In each of these modulators 51 to 5n, the broadcast signal is spread-spectrum modulated by different spreading codes generated from the spreading code generators 61 to 6n. The broadcast signals spread-spectrum-modulated by the modulators 51 to 5n are combined by the combiner 71 into a single-system multiplex broadcast signal, and then input to the modulator 72. In this modulator 72,
The multiple broadcast signal is further modulated by a digital modulation method such as QPSK or QAM method. The modulated multiplexed broadcast signal is frequency-converted by the transmitter 73 into a Ka or Ku band radio signal, further amplified to a predetermined transmission power, and then transmitted from the antenna 74 to the geostationary satellite.

The geostationary satellites are the above-mentioned terrestrial broadcasting stations BC1 and BC.
2 or the CDM multiplex broadcast signal transmitted from the feeder link station is frequency-converted to the S band and amplified to a predetermined power level, and then transmitted to the ground service area.

The gap filler device receives the CDM multiplex broadcast signal transmitted from the geostationary satellite, amplifies this received signal to the transmission power level for the gap filler, and transmits it to the blind area.

On the other hand, the broadcast receiving device MS is constructed as follows. FIG. 8 is a circuit block diagram showing the configuration of the broadcast receiving device MS. In the figure, a CDM multiplex broadcast signal transmitted from a geostationary satellite and a gap filler device is received by an antenna 21 and then input to a receiver 22. The receiver 22 receives and reproduces the broadcast signal corresponding to the channel designated by the user among the CDM multiplex broadcast signals by the RAKE reception system, and inputs the reproduced reception signal to the audio / video separation circuit unit 23.

The audio / video separation circuit section 23 separates the reproduced reception signal into audio data, video data, and additional data such as text data, and inputs the separated received audio data to the audio decoder 24. The received video signal is input to the video decoder 26, and the additional data is input to the additional data decoder 28. Audio decoder 24
Decodes the received voice data to reproduce a voice signal,
This audio signal is output from the speaker 25 in a loud voice. Further, the video decoder 26 decodes the received video data by, for example, the MPEG4 system, and supplies the decoded video signal to the liquid crystal display 27 for display. Further, the additional data decoder 28 decodes the additional data such as text data and causes the decoded data thus decoded to be displayed on the liquid crystal display 27 together with the video signal.

By the way, the receiver 22 is constructed as follows. FIG. 9 is a circuit block diagram showing the configuration. That is, the CDM multiplex broadcast signal coming from the geostationary satellite and the gap filler device is first down-converted by the radio circuit 28 from the radio frequency to the baseband frequency. Then, the received baseband signal is digitized by an analog / digital converter (A / D) 29 at a predetermined sampling period, and then, a search receiver 30 and three digital data demodulators 31, 3 are provided.
2 and 33 respectively.

The search receiver 30 is connected to the terrestrial broadcasting station BC1,
It receives and demodulates the pilot signal transmitted from BC2, and basically each digital data demodulator 3 described below.
It has the same configuration as 1, 32, 33.

The data demodulators 31, 32, and 33 RAKE the broadcast signal corresponding to the channel designated by the user from the CDM multiplex broadcast signal coming from the geostationary satellite or the CDM multiplex broadcast signal coming from the gap filler device.
It is demodulated by the receiving method.

That is, the data demodulators 31, 32, 33
Generates an original clock based on the sampling clock of the A / D converter 29 and operates independently of each other by the original clock.
A clock tracking unit and a data demodulation unit are provided. Of these, the data demodulation unit is the phase compensation unit 311, 321, 33.
1, multipliers 312, 322, 332, PN code generators 313, 323, 333, and accumulators 314.
324 and 334.

In the phase compensators 311, 321, 331,
Phase compensation of the received signal is performed for path diversity. In the multipliers 312, 322, 332, the received signals output from the phase compensating units 311, 321, 331 are multiplied by the PN code corresponding to the designated channel generated by the PN code generators 313, 323, 333, As a result, spectrum despreading of the received signal is performed.
The accumulators 314, 324, 334 integrate the despread received signals output from the multipliers 312, 322, 332, and the integrated outputs are input to the symbol combiner 34, respectively.

The symbol synthesizer 34 synthesizes the integrated outputs of the received signals output from the digital data demodulators 31, 32 and 33 to reproduce a data component, and reproduces the reproduced data component as shown in FIG. It is supplied to the video separation unit 23.

The control section 35 is provided with a microcomputer as a main control section, and is provided with a path position detecting means and a PN code generation control means as control functions related to RAKE reception. The path position detecting means determines the geostationary satellite SA from the pilot signal received by the search receiver 2.
The path positions of the signal coming from T and the signal coming from the gap filler device are respectively detected. The PN code generation control means obtains an optimum PN address value based on the detection result of the path position, and uses this PN address value as the PN code generator 313 of the three digital data demodulators 31, 32, 33. To 323,333. Then, by this, the chip phase of the PN code generated from each PN code generator 313, 323, 333 is variably controlled.

By using the broadcast receiving device MS having such a configuration, the CDM multiplex broadcast signal sent from the geostationary satellite and the CDM multiplex broadcast signal retransmitted from the gap filler device are received as if the multipath signal is received. Each of them can be received, reproduced and combined as described above. That is, it is possible to perform path diversity reception of the CDM multiplex broadcast signal transmitted from the geostationary satellite and the CDM multiplex broadcast signal relay-transmitted from the gap filler device. Therefore, even if the broadcast receiving device MS is located in an area that can receive both the CDM multiplex broadcast signal from the geostationary satellite and the relay transmission signal from the gap filler device, the broadcast receiving device MS does not cause interference between the two signals and is of high quality. Can be received.

Further, according to the present embodiment, there is no need to worry about interference due to the same frequency between the CDM multiplex broadcast signal from the geostationary satellite and the relay transmission signal from the gap filler device. It is not necessary to strictly adjust the directivity of the signal to be transmitted, which makes it possible to easily install the gap filler device.

(Fourth Embodiment) In the fourth embodiment of the present invention, two geostationary satellites composed of the main unit and a standby unit launched on the same geostationary orbit are separated by a predetermined interval. By arranging and transmitting the same broadcast signal from these geostationary satellites to the service area in synchronization with each other, even the broadcast receiving device MS in the area where the broadcast signal from this unit cannot be received from the standby unit. It is designed to receive broadcast signals.

FIG. 10 is a schematic configuration diagram of a satellite broadcasting system according to this embodiment. In the figure, two geostationary satellites SATa and SATb are arranged on the geostationary orbit at a predetermined distance. Each of the geostationary satellites SATa, S
One of the ATb's functions as the main unit and the other as the standby unit. Even when the unit is functioning normally, the standby unit does not put the standby unit in the standby state and transmits the same broadcast signal as the unit. There is.

With such a configuration, for example, as shown in FIG. 7, a mobile station MS in an area where the broadcast signal RSa from the main unit SATa cannot be received due to a building or the like receives the broadcast signal RSb from the standby unit SATb. can do. On the contrary, the broadcast signal RS from the standby device SATb
The mobile station MS located in an area where b cannot be received is
It is possible to receive the broadcast signal RSa from Ta. Therefore, according to the present embodiment, it is possible to eliminate the gap area without installing the gap filler device on the ground. Moreover, in the present embodiment, since the gap filler effect is realized by using the existing standby machine, there is an advantage that it is not necessary to launch a new satellite and can be realized at low cost.

(Fifth Embodiment) In the fifth embodiment of the present invention, a broadcast signal transmitted by a terrestrial broadcasting station or a feeder link station is broadcasted by a first satellite for a broadcasting receiving apparatus having different frequencies in a geostationary satellite. The signal and the second broadcast signal for the gap filler device after frequency conversion and transmission,
The gap filler device receives the second broadcast signal, converts the second broadcast signal into a broadcast signal having the same frequency as the first broadcast signal, and then relays the signal to the blind area.

FIG. 11 is a schematic configuration diagram of the satellite broadcasting system according to the present embodiment. FIG. 12 shows the structure of the transponder mounted on the geostationary satellite SAT2 of this system, and FIG. 13 shows the structure of the gap filler device.

In the transponder of the geostationary satellite SAT2,
The Ku band upstream broadcast signal UL (frequency fua) transmitted from the terrestrial broadcasting station BC is received by the receiving antenna 81, is then amplified by the low noise amplifier 82, and is then distributed by the signal distributor 83.
Entered in. The signal distributor 83 distributes the upstream broadcast signal into two systems.

The broadcast signal of one system is converted by the first frequency converter 84 into a radio frequency signal of S band (frequency f
s) is frequency-converted to the transmission power level necessary for reception by the broadcast receiving device of the fixed station or mobile station MS by the first power amplifier 86, and then from the transmission antenna 88 for the S band to the first transmission power level. The downlink broadcast signal DLa is transmitted to the ground service area.

On the other hand, the broadcast signal of the other system to which the signal is distributed is frequency-converted by the second frequency converter 85 into a radio frequency signal (frequency fub) of Ku band, and then the second frequency converter 85 is subjected to the second frequency conversion.
The power amplifier 87 of the amplifier Amplifies the power to the level required for the gap filler device GFe to receive, and then K
It is transmitted as the second downlink broadcast signal DLb from the u-band transmission antenna 89. The second downlink broadcast signal DLb and the uplink broadcast signal UL are both transmitted in the Ku band, but their frequencies are different. For example, the frequency fub of the second downlink broadcast signal DLb is 14 GHz.
In addition, the frequency fua of the upstream broadcast signal UL is 12 GHz.
Is set to.

On the other hand, in the gap filler device GFe, the second broadcast signal DL transmitted from the geostationary satellite SAT2.
b is received by the antenna 91 and then the low noise amplifier 92
And is input to the frequency converter 93. In the frequency converter 93, the received second downlink broadcast signal is converted into an S-band radio frequency signal (frequency fs), that is, the first downlink broadcast signal DLa transmitted by the geostationary satellite SAT2 to the broadcast receiving device. The frequency is converted into a radio frequency signal having the same frequency. Then, the broadcast signal frequency-converted to the S band is amplified by the power amplifier 94 to a transmission power level corresponding to the size of the gap filler cover area GE, and thereafter, from the transmission antenna 95 as a relay broadcast signal DLg. Area GE
Sent to.

Due to this structure, the geostationary satellite SA
Since the frequency of the downlink broadcast signal DLb coming from T2 is different from the frequency of the relay broadcast signal DLg transmitted to the gap filler cover area GE, the gap filler device GFe transmits to the reception antenna of the transmission relay broadcast signal DLg. It is possible to easily prevent wraparound, and thereby to realize isolation between input and output easily and surely.

(Sixth Embodiment) In the sixth embodiment of the present invention, a second broadcast signal having the same content as an upstream broadcast signal transmitted from a terrestrial broadcast station to a geostationary satellite is transmitted via a terrestrial network to a gap. A relay broadcast signal, which is the same as the downlink broadcast signal transmitted from the geostationary satellite to the broadcast receiving device, is generated based on the second broadcast signal transmitted to the filler device and transmitted through the ground network in the gap filler device. Then, this is transmitted to the blind area.

FIG. 14 is a circuit block diagram showing the structure. A terrestrial broadcasting station (not shown) generates a second broadcasting signal having the same content as the upstream broadcasting signal transmitted by itself to the geostationary satellite and configured in a signal format for wired transmission,
This is transmitted to the gap filler device GFf via a terrestrial public network NW such as an ISDN network.

Upon receiving the second broadcast signal from the terrestrial broadcasting station by the modem, the gap filler device GFf changes the signal format of the second broadcast signal from the cable transmission format to the satellite broadcast in the signal conversion device 101. Convert to the signal format of. Then, the satellite converter broadcast signal is frequency-converted into an S-band radio frequency signal by the frequency converter 102, and the power amplifier 103 is further used.
After amplifying to a transmission power level corresponding to the size of the blind area, the transmission antenna 10 is used as a relay broadcast signal.
Send from 4 to a blind area such as the shadow of a building.

With such a configuration, even if the gap filler device cannot be installed in a place where the downlink broadcast signal from the geostationary satellite can be received, the broadcast signal can be reliably broadcast to the blind area.

The above gap filler device GFf
In addition to the circuit for receiving a broadcast signal via the terrestrial public network NW to generate a relay broadcast signal, a downlink broadcast signal from a geostationary satellite as shown in FIG. A conversion circuit is provided. Then, the broadcast signal generated by each of the circuits may be selected and transmitted to the blind area according to the installation condition of the gap filler device.

Further, a circuit for determining the reception quality of the downlink broadcast signal from the geostationary satellite is further provided, and when the determination circuit determines that the downlink broadcast signal is received with a predetermined reception quality, the geostationary satellite The relay broadcast signal generated on the basis of the downlink broadcast signal from is transmitted to the blind area, and when it is determined that the predetermined reception quality cannot be obtained, the relay broadcast signal is transmitted via the terrestrial public network NW. The relay broadcast signal generated based on the second broadcast signal may be selected and transmitted to the blind area.

(Seventh Embodiment) In a seventh embodiment of the present invention, the gap filler device is provided with a function of generating monitor information indicating the operating state of the device itself and transmitting the monitor information to the monitor center. The monitor center monitors the operating state of the gap filler device based on the monitor information.

FIG. 15 shows a first example of the system according to this embodiment. In the figure, the gap filler device GFg detects elements indicating the operating state of itself such as the reception level of the downlink broadcast signal and the transmission level of the relay broadcast signal at regular time intervals, and stores them in the memory as information based on these. accumulate.

On the other hand, the monitor center MCa generates a monitor information transmission request periodically or at an arbitrary timing, and sends this transmission request to the gap filler device GFg via the ground network NW. Then, the gap filler device GFg reads the monitor information from the memory and transmits it to the monitor center MCa via the ground network NW. At this time, the monitor information transmitted to the monitor center MCa may be only the latest monitor information, but all the monitor information accumulated from the previous transmission timing to the current transmission timing may be transmitted. Good.

That is, the monitor center MCa collects monitor information from a plurality of gap filler devices scattered in the service area by the polling method, and displays or prints out the collected monitor information. At the same time, based on the contents of the monitor information, it is determined whether the operating state of the gap filler device is normal, and the determination result is displayed.

With such a configuration, the operating state of each gap filler device GFg can be centrally managed at the monitor center MCa, and efficient maintenance can be performed. Further, since the monitor information is collected by the polling method, it is possible to efficiently collect the monitor information of a large number of gap filler devices.

FIG. 16 shows a second example of the system according to this embodiment. In the figure, each gap filler device GFh and the monitor center MCb are connected via a satellite communication line. Then, the gap filler device GFh reads the monitor information from the memory and converts the monitor information into a signal format for satellite communication each time a monitor information transmission request is received from the monitor center MCb via the satellite communication line. After that, the data is transmitted to the monitor center MCb via the satellite communication line.

According to this structure, since the monitor information can be collected from each gap filler device by utilizing the existing satellite communication line of the geostationary satellite, the communication line using the ground network NW can be eliminated. .

In each of the examples described above, the monitor information of the gap filler devices GFg and GFh is stored in the monitor center M.
The case of collecting by polling from Ca and MCb has been described. However, in addition to the collection function by this polling, the gap filler devices GFg, GFh are provided with a self-determination function of the operating state, and when an abnormal operation is detected, the gap filler devices GFg, GFh call the monitor centers MCa, MCb. Then, the monitor information relating to the abnormality may be notified to the monitor centers MCa and MCb.

By doing so, the monitor center can immediately know that an operation abnormality has occurred in the gap filler device, and as a result, it is possible to take a quicker recovery action.

Further, the gap filler device GFg, G
When an abnormal reception of a broadcast signal from a satellite or an abnormal operation of the gap filler devices GFg and GFh itself occurs in Fh, a message to that effect is sent to the monitor centers MCa and MCb.
May be notified and transmitted to the broadcast receiving device existing in the blind area. At this time, as the message to be notified to each broadcast receiving device, a text message or a voice message such as “the reception condition from the satellite is getting worse. Please wait for a while” is used.

FIG. 17 shows a third example of the system according to this embodiment. In the figure, when the gap filler device GFi generates and transmits a relay broadcast signal based on a downlink broadcast signal coming from a geostationary satellite, the gap filler device GFi multiplexes monitor information indicating the operation state of its own device with the relay broadcast signal. And send it to the blind area. As the multiplexing method, the FDM method or the CDM method can be used.

The monitor receiver MR is arranged at an arbitrary position of the dead area, for example, at a position corresponding to the edge of the area. The monitor receiver MR may be a handy type carried by a maintenance person, a vehicle mounted type, or a fixedly installed type. The monitor receiver MR is the gap filler device GFi.
The relay broadcast signal transmitted from the receiver is received, the monitor information is separated and extracted, and the reception level of the relay broadcast signal is detected. Then, the detection data of the reception level is included in the monitor information, and the monitor information is transmitted to the monitor center MCc via a mobile communication network INW such as a cellular radio telephone system or PHS.

With this configuration, it is possible to transmit the detection data of the reception level measured by the monitor receiver MR to the monitor center MCc together with the monitor information generated by the gap filler device. For this reason,
The monitor center MCc can determine not only the operating state of the gap filler device itself, but also the compatibility between the transmission level and the actual reception level in the dead area.

The present invention is not limited to the above embodiments. For example, by using a method of installing a gap filler device on the ground to cover a blind area and a method of covering a blind area using two geostationary satellites, an area that cannot be covered by each other You may make it cover each other.

In each of the above embodiments, the satellite broadcasting system using the geostationary satellite is taken as an example, and the broadcast signal sent from the geostationary satellite is received by the gap filler device and retransmitted to the broadcast receiving device MS. However, the present invention is not limited to this, and in an interactive satellite broadcasting system, for example, the signal transmitted from the broadcast receiving device MS to the satellite may be relayed by the gap filler device and transmitted to the satellite.

Further, in the above-described embodiment, the case where the dead area generated in the shadow of the building is covered has been described as an example.
The present invention can be similarly applied to the case of covering a gap area caused by another structure such as a steel tower or a natural object such as a mountain or a cliff.

Furthermore, the present invention can be applied to the case of covering a blind area in a room. For example, install a small indoor gap filler device (repeater) at a position where it can directly receive downlink broadcast signals from satellites, such as at a window, and then send a relay broadcast signal from this repeater to the room and receive it at the receiver. Let In this case, the receiving device may be connected to the repeater via a coaxial cable or the like, and the received downlink broadcast signal may be transmitted to the receiving device via the coaxial cable. The repeater may be installed on the roof or roof of a building or house.

Besides, the configuration and installation place of the gap filler device, the type and configuration of the broadcast receiving device MS, the type of satellite,
The types of signals transmitted from satellites, their transmission systems, and the like can be modified in various ways without departing from the scope of the present invention.

[0105]

As described above in detail, according to the present invention,
A gap filler device is provided, and by this gap filler device, the broadcast signal relayed by the satellite is received, and the received broadcast signal is transmitted from the satellite to an area where the broadcast signal from the satellite cannot be received within the service area. By wirelessly transmitting at the same frequency as the broadcast signal that is used, in a blind area where the radio signal from the satellite cannot be directly received, such as in the shadow of a building, there is no need to install large-scale equipment, and not only fixed stations but also mobile stations. It is possible to provide a satellite broadcasting system and a gap filler device therefor capable of surely receiving even the MS and thereby realizing an inexpensive and effective gap filler.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a first embodiment of a satellite broadcasting system having a gap filler function according to the present invention.

FIG. 2 is a circuit block diagram showing a configuration of a gap filler device used in the system shown in FIG.

FIG. 3 is a plan view for explaining a second embodiment of the satellite broadcasting system according to the present invention.

FIG. 4 is a front view for explaining a second embodiment of the satellite broadcasting system according to the present invention.

FIG. 5 is a diagram showing another example of the second embodiment of the satellite broadcasting system according to the present invention.

FIG. 6 is a diagram showing another example of the second embodiment of the satellite broadcasting system according to the present invention.

FIG. 7 is a circuit block diagram showing a configuration of a transmission unit of a terrestrial broadcasting station used in a third embodiment of a satellite broadcasting system having a gap filler function according to the present invention.

FIG. 8 is a circuit block diagram showing a configuration of a broadcast receiving apparatus used in a third embodiment of a satellite broadcast system having a gap filler function according to the present invention.

9 is a circuit block diagram showing a configuration of a receiver of the broadcast receiving apparatus shown in FIG.

FIG. 10 is a schematic configuration diagram showing a fourth embodiment of a satellite broadcasting system having a gap filler function according to the present invention.

FIG. 11 is a schematic configuration diagram showing a fifth embodiment of a satellite broadcasting system having a gap filler function according to the present invention.

12 is a circuit block diagram showing a configuration of a transponder of a geostationary satellite used in the system shown in FIG.

13 is a circuit block diagram showing a configuration of a gap filler device used in the system shown in FIG.

FIG. 14 is a schematic configuration diagram showing a sixth embodiment of a satellite broadcasting system having a gap filler function according to the present invention.

FIG. 15 is a first part of a seventh embodiment of a satellite broadcasting system having a gap filler function according to the present invention.
2 is a schematic configuration diagram showing an embodiment of FIG.

FIG. 16 is a second part of the seventh embodiment of the satellite broadcasting system having the gap filler function according to the present invention.
2 is a schematic configuration diagram showing an embodiment of FIG.

FIG. 17 is a third part of the seventh embodiment of the satellite broadcasting system having the gap filler function according to the present invention.
2 is a schematic configuration diagram showing an embodiment of FIG.

[Explanation of symbols]

BC, BC1, BC2 ... Terrestrial broadcasting station (VSAT) SAT1, SAT2, SATa, SATb ... Geostationary satellite MS ... Mobile station MR ... Monitor receivers GFa-GFi ... Gap filler devices MCa-MCc ... Monitor center NW ... Terrestrial public network INW ... Mobile communication network 11, 41, 81, 91 ... Satellite receiving antenna 12 ... Input filter 13, 82, 92 ... Low noise amplifier 14, 86, 87, 94, 103 ... Power amplifier 15 ... Output filter 16, 43 , 44, 88, 89, 95, 104 ... Transmitting antenna 42 ... Gap filler device main body 45 ... Gap filler device fixing column 20 ... Control unit 21 ... Fixed station or mobile station receiving antenna 22 ... Receiver 23 ... Audio / video separation circuit section 24 ... Audio decoder 25 ... Speaker 26 ... Video decoder 27 ... Liquid crystal display 2 8 ... Radio circuit 29 ... Analog / digital converter (A / D) 30 ... Search receiver 31, 32, 33 ... Digital data demodulator 34 ... Symbol combiner 35 ... Control unit 36 ... Additional data decoder 311, 321, 331 ... phase compensator 312, 322, 332 ... multiplier 313, 323, 333 ... PN code generator 314, 324, 334 ... accumulator 84, 85, 93, 102 ... frequency converter 101 ... signal converter

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hideo Kikuchi             1-1 Shibaura, Minato-ku, Tokyo Co., Ltd.             Toshiba headquarters office (72) Inventor Yoichi Koishi             1st Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa             Ceremony Company Toshiba Komukai Factory (72) Inventor Yu Oka             1-1 Shibaura, Minato-ku, Tokyo Co., Ltd.             Toshiba headquarters office F-term (reference) 5K067 AA22 EE02 EE06 EE07 EE10                 5K072 AA01 AA22 AA29 BB03 BB04                       BB14 BB22 BB27 CC02 CC33                       DD02 DD04 DD17 GG01 GG14

Claims (6)

[Claims] 1. A pair of satellites, which are arranged on the same orbit at a predetermined distance from each other and transmit the same broadcast signal toward the same service area in synchronization with each other, and to each of the pair of satellites. A satellite broadcasting system comprising: a terrestrial transmission device for transmitting a broadcast signal to the satellite; and a broadcast receiving device for receiving at least one of the broadcast signals respectively transmitted from the pair of satellites in the service area. . 2. The satellite broadcasting system according to claim 1, wherein one of the pair of satellites is a standby unit for the other satellite. 3. The terrestrial transmitter used in the satellite broadcasting system according to claim 1, further comprising first and second transmitters for simultaneously transmitting the broadcast signal to each of the pair of satellites. A terrestrial transmitter characterized by. 4. The satellite-mounted relay device used in the satellite broadcasting system according to claim 1, wherein the broadcast receiving device receives a broadcast signal transmitted from the terrestrial transmitting device, and the received broadcast signal. A satellite relay device, comprising: a synchronizing device for synchronizing each other with the other satellite; and a transmitting device for sending the broadcast signal synchronized by the synchronizing device toward the service area. 5. The broadcast receiving device used in the satellite broadcasting system according to claim 1, wherein the antenna is for receiving at least one of broadcast signals transmitted from each of the pair of satellites in the service area. And a signal processing device that extracts and reproduces a broadcast signal from a received signal of the antenna. 6. A satellite broadcast characterized by arranging a pair of satellites on the same orbit at a predetermined distance from each other and transmitting the same broadcast signals to the same service area in synchronization with each other. Method.