JPH1127230A - Satellite broadcasting system and reception terminal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate promotion of multi channelization. SOLUTION: A desired channel signal is received by transmitting plural channel signals with different center frequencies to a stable satellite 30 from a transmission station 10 in a Ku band, sorting them by every center frequency at the stable satellite 30, circular-polarizing them into rightward and leftward circular polarized waves, transmitting to a service area as an S band channel and selecting channels at a reception terminal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a satellite broadcast suitable for providing a broadcast of video, audio, data, etc. to a desired service area using a geostationary satellite arranged in a geosynchronous orbit above the equator, for example. The present invention relates to a system and a receiving terminal.

[0002]

2. Description of the Related Art Recently, in the field of broadcasting systems,
2. Description of the Related Art Satellite broadcasting systems capable of serving a wide area have been developed, and diversification of broadcasting services has been achieved. In such a satellite broadcasting system, compared to conventional broadcasting systems, channel signals such as broadcast signals including video and audio can be relatively easily transmitted over a wide area without installing large-scale broadcasting facilities on the ground. It has the feature that it can be provided to a service area.

For example, as a satellite broadcasting system, BS
(Broadcasting Satellite) Broadcasting, CS (Communication
Satellite) broadcasting has been put to practical use. However, in the above-mentioned satellite broadcasting system, when the number of broadcast channels is increased in any of the systems, the output requirement of the relay-side power amplifier mounted on the satellite is accordingly increased, and thus the demand for the increase in the number of broadcast channels is required. Is difficult to perform.

[0004]

As described above, the conventional satellite broadcasting system has a problem that it is difficult to increase the number of broadcasting channels. The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a satellite broadcasting system and a receiving terminal that can easily and easily promote multi-channel.

[0005]

According to the present invention, a plurality of channel signals having different center frequencies are transmitted from a transmitting station to a satellite put into geosynchronous orbit, and the channel signals are transmitted from the satellite to a service area. A satellite broadcast system for receiving at a receiving terminal, wherein the satellite performs a polarization process on a channel signal received by the receiving antenna, and a signal receiving means for receiving a plurality of channel signals transmitted by the transmitting station. Classifying means for performing frequency conversion and classifying signals according to the frequency position, and a polarization setting means for amplifying each channel signal classified by the classifying means and setting each of the classifications to right-handed polarization or left-handed polarization. And a signal transmitting means for transmitting a channel signal whose polarization has been set by the polarization setting means, wherein the receiving terminal has a channel transmitted by the signal transmitting means. Receiving means for receiving a signal, a polarization processing means for performing polarization processing in accordance with a selected channel of the channel signal received by the reception means, and a channel signal subjected to polarization processing by the polarization processing means. And a channel selecting means for selecting a desired channel signal from among them.

According to the above configuration, since the signal processing sequence of the satellite is separated into a right-handed polarization system and a left-handed polarization system, the signal processing system is configured using a plurality of signal processing systems with low power efficiency.
Since the number of channels can be increased by using a signal processing system with low power efficiency, a request for increasing the number of channels can be easily realized.

Further, since the channel signal is separated into a right-handed polarization signal and a left-handed polarization signal and transmitted, only a signal of the same polarization is used as a signal interference source. By reducing interference noise power,
From this point, it is possible to promote multi-channel as much as possible.

Further, according to the present invention, a plurality of channel signals having different center frequencies are transmitted from a transmitting station to a satellite put into geosynchronous orbit, and the channel signals are transmitted from the satellite to a service area to receive the signals. A satellite broadcasting system for receiving at the transmitting station, the satellite receiving means for receiving a plurality of channel signals transmitted by the transmitting station, and the frequency conversion by performing a polarization process on the channel signal received by the receiving antenna. Classifying means for classifying signals according to their frequency positions, and amplifying each channel signal classified by the classifying means, and setting polarization setting means for setting vertical or horizontal polarization for each classification; Signal transmitting means for transmitting a channel signal whose polarization has been set by the setting means, wherein the receiving terminal receives the channel signal transmitted by the signal transmitting means. Receiving means for receiving the channel signal transmitted by the signal transmitting means, polarization processing means for performing polarization processing according to the selected channel of the channel signal received by the receiving means, Channel selecting means for selecting a desired channel signal from the channel signals subjected to the polarization processing by the means.

According to the above configuration, the signal processing sequence of the satellite is separated into a vertically polarized wave system and a horizontally polarized wave system, so that the signal processing system is configured using a plurality of signal processing systems with low power efficiency.
Since the number of channels can be increased by using a signal processing system with low power efficiency, a request for increasing the number of channels can be easily realized.

Further, since the channel signal is separated into a vertically polarized signal and a vertically polarized signal and transmitted, only a signal of the same polarization is used as a signal interference source. By reducing noise power,
From this point, it is possible to promote multi-channel as much as possible.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a schematic configuration of a satellite broadcasting system according to an embodiment of the present invention. For example, a transmitting station 10 disposed on the ground and a stationary station above the equator based on a command signal from a satellite control station 20, for example. A geostationary satellite 30 that is deployed in orbit with its attitude controlled.

The transmitting station 10 in FIG.
Although only one station is described, a plurality of stations may be provided. The geostationary satellite 20 transmits, for example, a Ku band transmitted from the transmitting station 10 via an uplink transmission path.
The reception antenna 31 receives a channel signal such as a broadcast signal, converts the frequency to an S band, and transmits the signal to a predetermined service area on the ground from a transmission antenna 32 having a diameter of, for example, 8 m via a downlink transmission path. In the service area, a channel signal transmitted from the geostationary satellite 30 is transmitted to a receiving terminal 50 (see FIG. 4), such as a mobile receiving terminal mounted on a mobile object, a mobile receiving terminal, or a fixed receiving terminal provided on a ground building. To receive.

That is, when the transmitting station 10 receives programs 1 to N from a program provider, for example, the transmitting station 10 converts the programs 1 to N into adders 101 to N as shown in FIG.
10N. To the adders 101 to 10N, on the receiving terminal side, spreading codes corresponding to selection numbers (so-called channel numbers) for selecting the signals are input from spreading code generators 111 to 11N. Each of the programs 1 to N is added to the synthesizer 1
Output to 2.

The synthesizer 12 has a well-known CDMA (Code div).
A multiplexed channel signal is generated by ision multtiple access (code division multiple access) and output to the modulator 13. The modulator 13 performs, for example, spread spectrum modulation on the input channel signal and outputs the signal to the transmitter 14. The transmitter 14 converts the frequency of the input channel signal in the Ku band so that the center frequencies thereof become F1 and F2, and transmits the signal to the geostationary satellite 30 via the uplink transmission line via the antenna 15.

For example, channel signals (CH1 to CH
8), the channel signals (CH1, CH3, CH5, CH7, CH8) are set to the center frequency F1, and the channel signals (CH2, CH2) are set as shown in FIG.
4, CH6) is set to the center frequency F2.

The receiving antenna 31 of the geostationary satellite 30 is connected to the receiving feed element 33, and outputs a received channel signal to the receiving feed element 33. The receiving power supply element 33 is connected to, for example, a polarizer 34, which converts the frequency of the input channel signals (CH 1 to CH 8) and outputs the converted signal to the polarizer 34. A feeder link receiver 35 is connected to the polarizer 34, and sets the input channel signal to, for example, circular polarization and outputs the signal to the feed link receiver 35.

A band filter 36 is connected to the feeder receiver 35, and converts the frequency of the input circularly polarized channel signal into, for example, an S band, and outputs the signal to the band filter 36. The input terminals of the first and second power amplifiers 37a and 37b are connected to the bandpass filter 36, and the channel signals (CH1, CH3, CH5, CH7, CH7) of the center frequency F1 among the input channel signals.
8) is output to the first power amplifier 37a, and the center frequency F
2 channel signals (CH2, CH4, CH6)
To the power amplifier 37b.

A right-handed polarizer 38a is connected to the first power amplifier 37a, and receives the input channel signals (CH1, CH1).
CH3, CH5, CH7, and CH8) are power-amplified and output to the right-handed polarizer 38a. A transmission feed element 39 is connected to the right-handed polarizer 38a, and the input channel signal (C
H1, CH3, CH5, CH7, and CH8) are converted into right-handed circularly polarized waves and output to the transmission feed element 39.

A left-handed polarizer 28b is connected to the second power amplifier 37b, and the input channel signal (CH
2, CH4, CH6) to power amplify the right-handed polarizer 38b
Output to The transmission feed element 39 is connected to the right-handed polarizer 38b, and the input channel signals (CH2, C
H4, CH6) to the left-handed circularly polarized wave and transmit the power feed element 3
9 is output.

The transmitting power supply element 39 is connected to the transmitting antenna 3
2 and input channel signals (CH1, CH
3, CH5, CH7, CH8) and channel signal (C
H2, CH4, and CH6) are transmitted to a predetermined service area via a downlink transmission path.

On the other hand, the receiving terminal 50 for receiving the channel signals (CH1 to CH8) from the geostationary satellite 30 is provided with a receiving antenna 51 corresponding to the transmitting antenna 32 of the geostationary satellite 30 as shown in FIG. The channel signals (CH1 to CH8) thus output are output to the receiving and feeding element 52. A right-handed polarizer 53a and a left-handed polarizer 53b are connected to the receiving feed element 52, and output terminals of the right-handed polarizer 53a and the left-handed polarizer 53b are connected to a receiver 55 via a switch 54. Connected to.

The switch 54 is connected to, for example, a switching operator (not shown), and the user (user) operates the switching operator (not shown) to switch one of the right-handed polarizer 53a and the left-handed polarizer 53b. Is selected, a switching signal is input. Here, the switch 54 selects one of the right-handed polarizer 53a and the left-handed polarizer 53b according to the switching signal,
Channel signals (CH1, CH3, CH5, CH) input to the right-handed polarizer 53a or the left-handed polarizer 53b
7, CH8) or channel signal (CH2, CH2)
4, CH6) to the receiver 55.

The receiver 55 is, for example, as shown in FIG.
A wireless circuit 55a is provided corresponding to the switch 54. The wireless circuit 55a is provided with a despreading circuit 5 via a demodulator 55b.
5c is connected. Accordingly, the radio circuit 55a transmits the channel signals (CH1, CH3, CH5, CH7, CH
8) or channel signal (CH2, CH4, CH
When 6) is input, the frequency is converted and output to the demodulator 55b.

The demodulator 55b demodulates the input channel signal (CH1, CH3, CH5, CH7, CH8) or the channel signal (CH2, CH4, CH6) and outputs it to the despreading circuit 55c. A control circuit 55d for channel selection is connected to the despreading circuit 55c, and the input channel signals (CH1, CH3, CH5, CH
7, CH8) or channel signal (CH2, CH2)
4, CH6) are subjected to despreading processing, separated based on the channel setting signal input to the control circuit 55d, and output to a display unit (not shown) at the subsequent stage.

The channel setting signal is set by, for example, a switching operation of a channel setting operator (not shown) by a user. As described above, the satellite broadcasting system transmits a plurality of channel signals having different center frequencies from the transmitting station 10 to the geostationary satellite 30 in the Ku band, and classifies each center frequency by the geostationary satellite 30 to the right-handed or It is configured such that the signal is converted to left-handed polarization, transmitted as an S-band channel signal to the service area, and the receiving terminal 50 selects a channel, thereby receiving a desired channel signal.

According to this, the signal processing unit of the geostationary satellite 30 is separated into a right-handed polarization system and a left-handed polarization system,
Since a configuration using a plurality of signal processing systems with low power efficiency is used, the number of channels can be increased by using a signal processing system with low power efficiency. Therefore, a request for multi-channel can be easily realized.

The channel signals (CH1 to CH8)
Is separated into a right-handed polarization signal and a left-handed polarization signal and transmitted, so that only the signal of the same polarization is used as a signal interference source, and interference noise power can be reduced as compared with the number of channels. Thus, from this point, the promotion of multi-channeling can be promoted as much as possible.

For example, in the case of channel signals (CH1 to CH8) that have been subjected to multiplexing processing by the CDMA system, channel signals other than the same-polarized channel signal (for example, right In the case of polarization, the left-handed polarized channel signal) acts as interference noise power. Therefore, as the number of channel signals transmitted from the geostationary satellite is increased, the interference noise power is increased and required. It is difficult to secure the power ratio C / N. However, by subjecting the transmitted channel signal, which is a feature of the present invention, to reverse-polarization, the interference noise power can be reduced as described above, and multi-channel can be promoted.

Specifically, when the antenna axis ratio between the geostationary satellite 30 and the receiving terminal is about 2 dB / 3 dB, the isolation for the anti-rotational polarization can be secured to 10 dB or more. The interference noise power can be reduced by 55% compared to using only If the desired transmission power can be secured, the channel capacity can be set to about 1.8 times.

In the above-described embodiment, a case has been described where the channel signal is set to be circularly polarized and is rotated to right-handed or left-handed polarization. However, the present invention is not limited to this. It is also possible to adopt a configuration in which the polarization is changed to polarization or horizontal polarization, and substantially the same effect is expected.

Further, in the above-described embodiment, the case has been described where the modulation scheme is such that modulation is performed using a spreading code and multiplexing is performed using the CDMA scheme. However, the present invention is not limited to this. Alternatively, the present invention can be applied to a multiplex system. Therefore, it is needless to say that the present invention is not limited to the above-described embodiment, and that various modifications can be made without departing from the scope of the present invention.

[0032]

As described above in detail, according to the present invention, it is possible to provide a satellite broadcasting system and a receiving terminal which can easily and easily promote multi-channel.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a satellite broadcasting system according to an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a transmitting station in FIG. 1;

FIG. 3 is a diagram showing a configuration of the geostationary satellite in FIG. 1;

FIG. 4 is a diagram showing a receiving terminal according to one embodiment of the present invention;

FIG. 5 is a diagram showing a receiver of the receiving terminal of FIG. 4;

[Explanation of symbols]

 10 ... Transmission station. 101 to 10N: Adder. 111-11N... Spreading code generator. 12 ... Synthesizer. 13 ... Modulator. 14 ... Transmitter. 15 ... An antenna. 20 satellite control station. 30 ... geostationary satellite. 31 ... receiving antenna. 32 ... Transmission antenna. 33 ... Reception feed element. 34 ... Polarizer. 35 ... Feeder link receiver. 36 ... Band filter. 37a, 37b: first and second power amplifiers. 38a, 38b: right-handed and left-handed polarizers. 39 ... Transmission feeding element. 50 ... Reception terminal. 51 ... Reception antenna. 52 ... Receiving feed element. 53a, 53b: right-handed and left-handed polarizers. 54 ... Switch. 55 ... Receiver. 55a ... Wireless circuit. 55b demodulation circuit. 55c: despreading circuit. 55d: control circuit

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Nozomi Fujimori 1st location of Komukai Toshiba-cho, Saiwai-ku, Kawasaki-shi, Kanagawa Prefecture Inside the Toshiba Komukai Plant (72) Inventor Hideo Kikuchi Toshiba Komukai-shi, Kawasaki-shi, Kanagawa No. 1 town Inside the Toshiba Komukai Plant

Claims (6)

[Claims] 1. A plurality of channel signals having different center frequencies are transmitted from a transmitting station to a satellite put into a geosynchronous orbit, and the channel signals are transmitted from the satellite to a service area and received by a receiving terminal. A broadcasting system, wherein the satellite is a signal receiving unit that receives a plurality of channel signals transmitted by the transmitting station; and a polarization processing is performed on the channel signal received by the reception antenna to perform frequency conversion, and the frequency position is changed. Classifying means for classifying signals according to the following; and amplifying each channel signal classified by the classifying means, and setting a right-handed polarization or a left-handed polarization for each classification; and a polarization setting means. Signal transmitting means for transmitting a channel signal for which polarization has been set, wherein the receiving terminal receives the channel signal transmitted by the signal transmitting means. A polarization processing unit for performing polarization processing according to the selected channel of the channel signal received by the reception unit; and a desired channel signal from the channel signals subjected to polarization processing by the polarization processing unit. A satellite broadcasting system comprising: a channel selecting unit for selecting. 2. A plurality of channel signals having different center frequencies are transmitted from a transmitting station to a satellite put into geosynchronous orbit, and the channel signals are transmitted from the satellite to a service area and received by a receiving terminal. A broadcasting system, wherein the satellite is a signal receiving unit that receives a plurality of channel signals transmitted by the transmitting station; and a polarization processing is performed on the channel signal received by the reception antenna to perform frequency conversion, and the frequency position is changed. Classification means for classifying signals according to the following, polarization setting means for amplifying each channel signal classified by the classification means, and setting vertical polarization or horizontal polarization for each classification, and polarization by this polarization setting means Signal transmitting means for transmitting a channel signal for which a wave is set, wherein the receiving terminal receives the channel signal transmitted by the signal transmitting means. Receiving means for receiving the channel signal transmitted by the signal transmitting means; polarization processing means for performing polarization processing according to the selected channel of the channel signal received by the receiving means; A channel selecting means for selecting a desired channel signal from the channel signals subjected to the wave processing. 3. The satellite broadcasting system according to claim 1, wherein the channel signal is multiplexed by code division multiple access for each channel. 4. Receiving means for receiving a plurality of channel signals subjected to right-handed or left-handed polarization processing, and receiving means for subjecting the channel signals received by the receiving means to rotation-polarization processing according to the selected channel. And a channel selecting means for outputting to the receiving terminal. 5. A receiving means for receiving a plurality of channel signals subjected to vertical or horizontal polarization processing, and a polarization processing means for subjecting the channel signals received by the receiving means to polarization processing according to a selected channel. And a channel selecting means for selecting a desired channel signal from the channel signals subjected to the polarization processing by the polarization processing means. 6. The receiving terminal according to claim 4, wherein the channel signal is multiplexed by code division multiple access for each channel.