JPH06350604A - Earth station transmitter-receiver for satellite communication - Google Patents

Abstract

PURPOSE:To obtain the degree of freedom of revision of equipment configuration according to a transmission data quantity without increasing a scale of signal processing and the scale of the equipment and to facilitate the transportation and the installation after the transportation. CONSTITUTION:An antenna 11 and a transmitter-receiver 12 are used in common for access control sections and data interface sections. When transmission packet data Sd, Sf from external terminal equipments are received simultaneously, the access control sections 14a, 14b execute random access processing making re-transmission of data when plural transmission data are collided with each other. A signal distribution selector 17 selects any of the transmission packet data signals Sd, Sf from the access control sections 14a, 14b and gives the selected data to a MODEM 13. The transmission of the other transmission packet data signal of the transmission packet data signals Sd, Sf not selected is continued and made complete by the re-transmission by the random access processing of the access control section of the aborted data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an earth station transmitter / receiver for satellite communication which retransmits a plurality of packet data when they collide by random access processing.

[0002]

2. Description of the Related Art In recent satellite communication systems, a random access system may be adopted for data transmission in order to effectively use a microwave band, that is, an effective use of a radio wave which is a finite resource. For example, a micro earth station (V
SAT) is composed of a terrestrial center station and several hundred to several thousand peripheral stations, and the terrestrial center station and peripheral stations perform star-type packet data communication. In this case, a plurality of peripheral stations use the same frequency, and adopt a random access method that retransmits when a plurality of transmission data collide with each other to reduce the occupied frequency band.

FIG. 2 is a block diagram showing the configuration of a conventional earth station transceiver device for satellite communication. In FIG. 2, this earth station transmitter / receiver for satellite communication is a VSAT, and a parabolic type antenna 1 for emitting and receiving radio waves by setting an elevation angle and an azimuth at a ground central station, and a ground center through this antenna 1. Transceiver 2 which handles the transmission or reception to the station. Furthermore, this earth station transmitter / receiver for satellite communication demodulates data from the received signal from the transmitter / receiver 2, and modulates / demodulates 3 for modulating and transmitting the transmission data,
An access control unit 4 that performs random access control for efficiently using a microwave radio line in data transmission with the terrestrial center station, outputs a received packet data signal Sa, and is input from an external terminal device (not shown). The data interface unit 5 processes the transmission packet data signal Sb.

Next, the operation of this conventional configuration will be described. Radio waves in the broadcast mode from the ground central station are received by the antenna 1. The reception signal in the broadcast mode from the antenna 1 is demodulated by the transceiver 2 and the modulator / demodulator 3, the address is managed by the access control unit 4, and the demodulation data of the self-address is received by the data interface unit 5 via the reception packet data signal Sa. Is sent to an external terminal device (not shown).

A transmission packet data signal Sb from an external terminal device is also input to the access control unit 4 through the data interface unit 5. This access control unit 4
Then, a random access process of retransmitting when a plurality of transmission data collide is performed. The transmission data (transmission packet data signal Sb) from the access control unit 4 is modulated by the modulator / demodulator 3, and the modulated data is transmitted / received by the transceiver 2 and the antenna 1.
Is emitted as a radio wave.

In such a conventional earth station transmitter / receiver for satellite communication, the data interface unit 5 is processed by a physical interface and a logical interface with a data terminal. That is, since it requires protocol processing, it is usually composed of a microprocessor (MPU) and a memory. When this conventional single MPU is adopted, the number of physical interfaces with an external terminal device (not shown) that can be supported by the processing is limited due to its processing capacity. Therefore, it is necessary to improve the processing capability by performing parallel processing on a plurality of MPUs using a bus line, a dual port RAM, or the like. in this case,
The number of physical interfaces can be increased, but the device scale is increased.

Therefore, when a large number of physical interfaces are required at the same ground station site, that is, when a packet data signal having a larger amount of data is transmitted to and received from the ground central station, the configuration shown in FIG. 2 is used. It is necessary to install multiple earth station transceivers for satellite communication. In this case, the scale of the device is increased, the cost is increased, the transportation is troublesome, and a large installation place is required.

As a proposal for improvement of this kind, JP-A-2-09
The "satellite communication system" disclosed in Japanese Patent Laid-Open No. 0822, the "line control system" disclosed in Japanese Patent Laid-Open No. 63-166329, and the "forced wave stopping system" disclosed in Japanese Patent Laid-Open No. 63-062422. I can name it.

In the example of Japanese Patent Application Laid-Open No. Hei 2-090822, the master station broadcasts an inquiry packet of a certain slave station to all slave stations, and each slave station has the presence or absence of information matching the inquiry content or the information. The response packet expressing itself is returned to the inquiry station through the master station to enhance the detection and establishment of inquiry information and improve the service. JP-A-63-166
In the example of Japanese Patent No. 329, a dedicated access channel is assigned to a slave station with a high access line utilization rate, and a shared access channel is assigned to a slave station with a low access line utilization rate, thereby increasing the access line utilization rate. It is possible to accommodate a large number of slave stations with a low number of channels. In the example of Japanese Patent Laid-Open No. 63-062422, a baseband signal having a configuration different from that of the baseband signal used for modulation of a communication signal wave is used to forcibly stop the wave, and the reception system is made one. Eliminating the drop in utilization efficiency.

[0010]

In the examples of the above-mentioned conventional publications, the probability of inquiry information detection is increased. In addition, a shared access channel is assigned to a slave station with a low access line utilization rate, and a single reception system is used to prevent a decrease in frame utilization efficiency. However, these are large-scale processing and conventional single MP
It cannot be realized in U. Further, when transmitting a larger number of packet data signals, a large-scale physical interface is required, and it is similarly difficult to realize with a conventional single MPU. Therefore, there is a drawback that the device cannot be added or reduced according to the amount of transmission data, and it is difficult to use it for VSAT or the like that requires easy transportation and installation.

The present invention has been made in view of the above-mentioned circumstances, and it is possible to obtain the degree of freedom of changing the device configuration according to the amount of transmitted data without increasing the signal processing scale and the device scale. The purpose of the present invention is to provide an earth station transceiver device for satellite communication that facilitates transportation and installation after transportation.

[0012]

In order to achieve the above object, the present invention provides a single transmitting antenna and a transmitting antenna in a satellite communication earth station transmitting / receiving apparatus for transmitting packet data by random access processing. One transmitting means for transmitting data through, one modulating means for modulating input data and outputting to the transmitting means, and one signal for selecting and outputting any one of a plurality of modulated data from the modulating means. The selection means, a plurality of access control means for controlling the retransmission of the discarded transmission data by the random access processing when the transmission data discarded by the signal selection means and the plurality of transmission data collide, and the input transmission data To a plurality of access control means, and a plurality of data interfaces that perform processing for outputting the access control means to the plurality of access control means.

Further, according to the present invention, in a satellite communication earth station transmitting / receiving apparatus for transmitting packet data, one transmitting / receiving antenna, one transmitting / receiving means for transmitting / receiving data through the transmitting / receiving antenna, and the transmitting / receiving means are provided. Data demodulation is performed from the received signal, one modulation / demodulation means for modulating the data and outputting to the transmitting / receiving means, and the demodulation data from the modulation / demodulation means is branched and output, and any one of a plurality of modulation data is selected. And a plurality of access control means for outputting the demodulated data from the signal distribution and selection means, respectively, and for controlling the retransmission by random access processing when a plurality of transmission data collide. And a process of outputting the input transmission data to each of the plurality of access control means and outputting the demodulation data. Cormorant is configured to include a plurality of data interfaces.

Further, the apparatus is installed in a micro earth station, the transmission / reception target station is the earth central station, and the signal distribution / selection means distributes the data in the broadcast mode.

[0015]

The earth station transmitter / receiver for satellite communication according to the present invention having the above-described structure shares the antenna and the transmitter / receiver and selects any one of a plurality of modulated data. The transmission data collided and discarded is retransmitted by the random access process, so that the signal processing scale and the device scale do not increase. Furthermore, the degree of freedom in changing the device configuration according to the amount of transmitted data can be obtained, and transportation and installation after transportation are easy.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of an earth station transmitter / receiver for satellite communication according to the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of an embodiment of a satellite communication earth station transmitter / receiver of the present invention. In FIG. 1, this satellite communication earth station transmitter / receiver is an example of VSAT, and a parabolic antenna 11 for emitting and receiving radio waves by setting an elevation angle and an azimuth at a ground center station, and through this antenna 11. Transceiver 1 that handles transmission or reception to the ground central station
2 and a modulator / demodulator 13 that demodulates data from a reception signal in a broadcast mode from the transceiver 12 and that modulates and transmits transmission data (transmission packet data signals Sd and Sf).

Further, this earth station transmitter / receiver for satellite communication has an access control section 14a for performing random access control for efficiently using a microwave radio line for data transmission with the ground central station, and transmission data (received packet data signal). A data interface unit 15a for processing Sc and a transmission packet data signal Sd), and a modulator / demodulator 13
And a signal distribution selector 17 for branching and outputting the demodulated data in the broadcast mode from 1) and selecting one of the transmission data to be transmitted.

The satellite communication earth station transmitter / receiver is connected to a signal distribution selector 17, and an access controller 14b for performing random access control and transmission data (reception packet data signal Se and transmission packet data signal S).
and a data interface unit 15b for processing f). The signal distribution selector 17 includes an access control unit 14
One of the received packet data signals Sc and Se from a and 14b is selected and output to the modulator / demodulator 13. Further, the signal distribution selector 17 demodulates the radio wave in the broadcast mode from the ground central station through the antenna 11, the transceiver 12, and the modulator / demodulator 13, and outputs the demodulated data to both the access control units 14a and 14b at the same time.

Next, the operation of the configuration of this embodiment will be described. In the case of reception, first, the radio wave in the broadcast mode from the ground central station is received by the antenna 11. The reception signal in the broadcast mode from the antenna 11 is demodulated through the transceiver 12 and the modulator / demodulator 13. This demodulated data is divided into two by the signal distribution selector 17, and is input to the access control units 14a and 14b, respectively. Access control unit 1
4a manages the address in the demodulated data,
The demodulated data corresponding to the self-address is sent to the external terminal device (not shown) as the received packet data signal Sc through the data interface unit 15a. The access control unit 14b also manages the address in the demodulated data, the demodulated data corresponding to the self-address is processed by the data interface unit 15b, and the received packet data signal Se is sent to an external terminal device (not shown). To be done.

In the case of transmission, a transmission packet data signal Sd and a transmission packet data signal S from an external terminal device
f are the data interface units 15a and 15b, respectively.
Are input simultaneously or at different times. The transmission packet data signal Sd is input to the access control unit 14a through the data interface unit 15a. The access control unit 14a performs a random access process of retransmitting when a plurality of transmission data collide. Further, the transmission packet data signal Sf is input to the access control unit 14b through the data interface unit 15b. The access control unit 14b performs a random access process of retransmitting when a plurality of transmission data collide.

In this case, the transmission packet data signal Sd,
When Sf is input at the same time, the signal distribution selector 17 selects either one and supplies it to the modulator / demodulator 13. This other non-selected transmission packet data signal Sd,
The processing of Sf is performed by the access control unit 14a on the discarded side.
(14b) uses the same frequency and is retransmitted by a random access process that retransmits when a plurality of transmission data collide. That is, the communication for data transmission is continued by the normal retransmission processing, and the transmission packet data signal S
The transmission of d and Sf is completed. Although the transmission of the two transmission packet data signals Sd and Sf has been described in this embodiment, the transmission of the transmission packet data signals of three or more can be completed by the same process.

In this way, by dividing a plurality of received packet data signals, selecting one of the transmitted packet data signals, and retransmitting the discarded transmitted packet data signals by random access processing,
Physical interfaces other than the antenna 11 and the transmitter / receiver 12 can be realized with a simple configuration using a conventional single MPU. Further, since the antenna 11 and the transmission / reception device 12 can be shared, even when performing a large amount of data transmission, a plurality of devices including the antenna and the transmission / reception device are carried as described above, and at the site, etc. Easy to install.

The number of physical interfaces required for the earth station having such a configuration differs depending on the station.
In the SAT system, even a small number of stations that require 5 ports or more can add only the communication control device B. In addition, at the time of initial installation, it is sufficient to install only the communication control devices A and B for the time being, and then connect the communication control devices B by adding them as needed, and construct a system with a high degree of freedom of configuration change with a small initial investment. Is possible.

[0024]

As described above, the earth station transmitter / receiver for satellite communication of the present invention shares the antenna and the transmitter / receiver and selects any one of a plurality of modulated data.
At this time, the discarded transmission data and the transmission data discarded due to collision of the plurality of transmission data are retransmitted by the random access process, and therefore the signal processing scale and the device scale do not increase. Further, there is an effect that the degree of freedom of changing the device configuration according to the amount of transmission data can be obtained, and that transportation and installation after transportation can be facilitated.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of an earth station transceiver device for satellite communication of the present invention.

FIG. 2 is a block diagram showing a configuration of a conventional earth station transceiver device for satellite communication.

[Explanation of symbols]

 12 transceiver 13 modulator / demodulator 14a, 14b access controller 15a, 15b data interface 17 signal distribution selector Sd, Sf transmission packet data signal Sc, Se reception packet data signal

Claims (3)

[Claims] 1. A satellite communication earth station transmitter / receiver for transmitting packet data by random access processing, comprising: one transmitting antenna; one transmitting means for transmitting data through the transmitting antenna; and input data. One modulating means for performing modulation and outputting to the transmitting means, one signal selecting means for selecting and outputting any of a plurality of modulated data from the modulating means, and transmission discarded by the signal selecting means A plurality of access control means for controlling the retransmission of the discarded transmission data by random access processing when the data and the plurality of transmission data collide, and a processing for outputting the input transmission data to each of the plurality of access control means An earth station transmitter / receiver for satellite communication, which comprises a plurality of data interfaces for performing. 2. A satellite communication earth station transmitter / receiver for transmitting packet data by random access processing, comprising: one transmitting / receiving antenna; one transmitting / receiving means for transmitting / receiving data through the transmitting / receiving antenna; and the transmitting / receiving means. Data demodulation from the received signal from, the modulation and demodulation means to modulate the data and output to the transmitting and receiving means, and the demodulation data from the modulation and demodulation means is branched and output, and a plurality of modulation data of One signal distribution selecting unit that selects and outputs any one of them, outputs the demodulated data from the signal distribution selecting unit, and performs control to retransmit by random access processing when a plurality of transmission data collide. It outputs a plurality of access control means and input transmission data to each of the plurality of access control means. An earth station transceiver device for satellite communication, comprising: a plurality of data interfaces that perform processing of outputting demodulated data. 3. A satellite communication, characterized in that the device is installed in a micro earth station, a transmission / reception target station is an earth central station, and a signal distribution selecting means distributes data in a broadcast mode. Earth station transceiver.