JPH0541684A - Data distribution type transmission method - Google Patents

Abstract

(57) [Abstract] [Purpose] To obtain a data delivery type transmission system with low transmission cost per bit by reducing the idle time of the line. [Structure] Transmission data is classified into data for emergency transmission with high urgency and data for non-emergency transmission having low urgency, or permission from collection to transmission of the data for emergency transmission, S data for non-emergency transmission, and data It is divided into L data for non-urgent transmission that has a large time width and can be delivered regularly by reservation, and data with a low degree of urgency is a free time zone of the communication line where data with a higher degree of urgency is not transmitted. Use and deliver. [Effect] Data can be efficiently multiplexed with little free time, the utilization rate of the line is improved, and the transmission cost per bit can be significantly reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data delivery type transmission system for transmitting transmission request data from a plurality of users to one or a plurality of destinations designated by each user.

[0002]

2. Description of the Related Art Conventionally, a satellite communication system which shares a transmitting earth station, a communication satellite and a carrier wave by a data distribution type network using a communication satellite as a relay station is constructed as shown in FIG. In FIG. 9, A is a transmitting earth station that transmits data to the communication satellite 1, and an antenna 2, a transmitting device 3, a transmitting frequency converting device 4, which are sequentially connected,
It includes a modulator 5 and a buffer memory 6 for clock matching between the satellite line and the ground line.

Reference numeral 7 is a terminal device of the first user, 8 is a terminal device of the second user, 9 is a transmission signal transmitted from the transmitting earth station A, 11 is a reception dedicated station and a data terminal device of the user, 1
2 is a dedicated reception station and data terminal device of another user, and 13
Is a terrestrial line of the first user, 14 is a terrestrial line of the second user, and 20 is a switch for connecting the user terminal device and the transmitting earth station device A in a time zone designated by the user.

Next, the operation will be described. The terminal device 7 sends the requested data to the transmitting earth station A via the ground line 13 in response to the request from the user. At the transmitting earth station A, the transmitted data is stored in the buffer memory 6 via the switch 20 and converted into a satellite line clock, and then transmitted from the antenna 2 via the modulator 5, the transmission frequency converter 4 and the transmitter 3. It is transmitted to the satellite 1 as a transmission signal 9.

The transmitted signal is retransmitted to the earth via the communication satellite 1 and is received by all reception dedicated stations. The terminal device of the dedicated reception station detects the address addressed to itself in the header part of the received data, and sends the received data to the terminal device.
Since the other dedicated reception stations do not have headers addressed to themselves, the reception data is not captured by the terminal device and is discarded. The same is done for the second user.

[0006] In the above series of operations, since the first user and the second user send data independently, the timing of sending data overlaps, which may cause a collision at the entrance of the transmitting earth station A. In order to avoid this problem, the transmission time zone of the user is assigned in advance, the predetermined time zone is assigned by the switch 20, and the terminal devices 7 and 8 of the user and the transmission earth station A are connected to each other, so that the transmission earth time is increased by a plurality of users. Station A
It is possible to share.

FIG. 10 shows the above satellite communication system.
7 shows the temporal arrangement of the transmission signal 9 for transmitting the data from the two terminal devices 7, 8 from the transmitting earth station A, 71 and 72 are the transmission signals for transmitting the data transmitted from the terminal device 7, 81 and 82 Indicates a transmission signal for transmitting data transmitted from the terminal device 8.

The above description is for the case where the terminal device 7 or 8 independently broadcasts the data and sends out the data addressed to a specific reception dedicated station. Via terminal device 7 or 8
On the other hand, the same operation is performed when a data transmission request is made.

In the above description, a satellite communication system in a data distribution type network is used as a reception-only station for data transmission by a single-feed satellite line. It doesn't change.

[0010]

Since the conventional satellite communication system is configured as described above, in order to perform data transmission of a plurality of users, it is necessary to use two satellites based on the user's request.
Since it is necessary to allocate two time zones, in general, there is a free time T as shown in FIG. 10, it is difficult to increase the utilization time rate of the satellite line, and the repeater usage charge becomes relatively high, which leads to There was a problem that the competitiveness in terms of cost was inferior and it hindered the spread of satellite communication.

The present invention as set forth in claim 1 is made to solve the above-mentioned problems, and a plurality of users share a transmitting earth station equipment, a communication satellite used as a relay station, and a carrier frequency, It is an object of the present invention to obtain a satellite communication system that can maximize the utilization rate of satellite lines.

Further, the invention according to claim 2 overcomes the limit in improving the efficiency of the communication line and obtains a data delivery type transmission system capable of further improving the utilization time ratio of the communication line. The purpose is to

[0013]

A satellite communication system according to the invention as set forth in claim 1 stores data from a plurality of users.
When a request is issued, it is provided with a distinction between urgent and non-urgent, and as a data transmission processing means, it is equipped with a buffer memory that stores it separately for emergency transmission data and non-emergency transmission data. The data for extraction and non-emergency transmission is divided and extracted when the buffer memory storing the data for emergency transmission is empty, and a user identification signal, a destination, and a sequence number of data are added as a header to the head of each data. Data transmission processing means for transmitting data to the transmitting earth station is provided.

In the data delivery type transmission method according to the invention described in claim 2, data for emergency transmission having a high degree of urgency for transmitting the transmission data when the transmission request is generated, is transmitted when the transmission request is generated, and is non-emergency as necessary. S-data for non-emergency transmission, which is divided into multiple levels depending on the degree, and L-data for non-emergency transmission, which has a large tolerance for the time from the collection of data to the transmission and which is regularly distributed by reservation. The data is divided and stored in the buffer memory, the emergency transmission data is given priority in accordance with the incoming order, and the non-emergency transmission S data is collectively or divided when the buffer memory storing the emergency transmission data is empty, For the non-emergency transmission L data, the buffer memory storing the emergency transmission data and the buffer memory storing the non-emergency transmission S data become empty at the same time. Extraction respectively at once or divided, after adding the user identification signal, the destination, the sequence number of the data as a header section, is intended to be delivered to the destination over a dedicated line which limited transmission in one direction.

[0015]

According to the first aspect of the invention, the data transmission processing means retrieves the emergency transmission data in the order of arrival and retrieves and transmits the non-emergency transmission data when the storage buffer memory for storing the emergency transmission data is empty. As a result, the data transmission efficiency is improved and the transmission cost can be significantly reduced.

The data transmission processing means in the invention according to claim 2 is for emergency transmission among the emergency transmission data, the non-emergency transmission S data, and the non-emergency transmission L data stored in the buffer memory. According to the order of arrival, the S data for non-emergency transmission and the L data for non-emergency transmission are batched or divided when the buffer memories accumulating data with higher urgency are all empty. In addition to limiting the transmission direction of the leased line to one direction, the data distribution type transmission system further improving the utilization time ratio of the communication line is realized.

[0017]

EXAMPLES Example 1. Embodiment 1 of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram showing an embodiment of the invention described in claim 1, and the same or corresponding parts as those of the conventional satellite communication system shown in FIG. There is. In FIG. 1, 6a is a buffer memory for storing emergency transmission data, and 6b is a buffer memory for storing non-emergency transmission data. Here, data for emergency transmission is data that is expected to be sent within the normal transmission time, and data for non-emergency transmission is data for file transfer that can be sent during the day, tens of minutes or hours. It is a search material etc. that is judged to be sufficient if it is obtained within. These urgent and non-urgent distinctions are given by the user before the user sends the data.

Further, 17 is the buffer memories 6a, 6
A buffer memory read interface unit for interfacing the read of data stored in b, a read address control unit 18 for giving a read address to the buffer memory read interface unit 17, and an interface 19 for writing data to the buffer memories 6a and 6b. A buffer memory write interface unit 21 is a write address control unit for giving a write address to the buffer memory write interface unit 19, and a reference numeral 22 is a buffer memory processor for controlling the read address control unit 18 and the write address control unit 21. is there. B is these buffer memory 6
a, 6b, buffer memory read interface unit 1
7, read address control unit 18, buffer memory write interface unit 19, write address control unit 2
1. Data transmission processing means including a buffer memory processor 22.

Here, in the transmission of the satellite communication system, in order to sufficiently use the frequency band of the communication satellite 1 which is a repeater, it is usual to multiplex and send signals having various bands or speeds. There are frequency division multiplex (FDM) and time division multiplex (TDM) as a method of realizing the same, and the effectiveness of the present invention is not changed by using either of them, but here, frequency multiplex, particularly pre-assignment, single・ Channel per carrier (Single Cha)
nnel Per Carrier (hereinafter referred to as SCPC)) is used. SCPC is the use of one carrier for one-channel signal transmission. As shown in FIG. 2, multiple carriers are arranged by arranging carrier waves having a frequency bandwidth corresponding to the transmission speed of a transmission signal at a predetermined interval. Do. In this case, in the pre-assignment system, the frequency of the carrier is assigned from the beginning such that channel 1 uses the carrier of f ₁ . When a large number of receiving stations are used in the data distribution type network as in the application example of the present invention, this method is taken as an example because the receiving stations are simpler and cheaper and the system configuration becomes easier if the frequency is fixed. FIG. 1 shows the one channel, and when the entire satellite repeater is used, n unit configurations of FIG. 1 may be arranged in parallel.

Next, the operation will be described. The terminal device 7 of the first user sends the requested data to the data transmission processing means B via the ground line 13. In the data transmission processing means B, when the buffer memory write interface unit 19 receives the transmitted data, it gives an incoming interrupt instruction to the write address control unit 21, and at the same time, the buffer address is given by the write address control unit 21. The data received by the write interface unit 19 is written in the buffer memory 6a or 6b. In this case, the data sent from the terminal device 7 of the first user is classified into emergency transmission data and non-emergency transmission data,
Since the identification codes are attached to each, the emergency transmission data is stored in the buffer memory 6a, the non-emergency transmission data is stored in the buffer memory 6b, and the write address control unit 21 controls by the buffer memory processor 22 respectively. It is classified and written in the order of arrival.

The emergency transmission data stored in the buffer memory 6a is read out via the buffer memory read interface unit 17 according to an instruction from the read address control unit 18. At this time, the user identification signal generated by the buffer memory processor 22 is added to the header portion of the data. On the other hand, the data classified as the non-emergency transmission data is written in the buffer memory 6b in the order of arrival by the control of the write address control unit 21 according to the instruction of the processor 22. The stored non-emergency transmission data is divided into packets of an appropriate length according to an instruction from the read address control unit 18 when the buffer memory 6a storing the emergency transmission data becomes empty, and the buffer memory read interface unit 17 Be read via. At this time, the user identification signal generated by the buffer memory processor 22 is added to the header portion of the data as in the case of the emergency transmission data. If the emergency transmission data is written to the buffer memory 6a while the non-emergency transmission data is being read and sent to the modulator 5, the buffer memory processor 22 reads the non-emergency data read stop instruction. The address control unit 18 is instructed to read the address control unit 18 to preferentially read the emergency transmission data written in the buffer memory 6a.

The data read from the buffer memory 6a or 6b and having the user identification signal and the destination added to the header section is passed through the modulator 5, the transmission frequency converter 4, the transmitter 3 and the antenna 2. The transmission signal 9 is transmitted to the communication satellite 1. When the communication satellite 1 receives the transmission signal 9, it retransmits it toward the earth, and this signal is received by all the dedicated reception stations. The dedicated reception station detects the user identification signal in the header part of the received data and the address addressed to the own station and captures it in the terminal device. The other dedicated receiving station discards the received data unless an address signal addressed to itself is detected. The station that has received the non-emergency data stores the data in the memory of the terminal device in the order of arrival and receives the data until all the data are collected. In the case of the second user, the same operation as the first user is performed. The number of users may increase.

FIG. 3 is a diagram showing a temporal arrangement of user data sent as the transmission signal 9. In FIG. 3, (a) shows a case of a conventional satellite communication system in which no distinction is made between emergency transmission data and non-emergency transmission data, and an idle time occurs in the temporal arrangement of transmission signals. (B) is an example of the satellite communication system according to the first embodiment, in which the non-emergency transmission data is inserted and transmitted by utilizing the idle time for transmitting the emergency transmission data,
We show that efficient transmission with almost no free time is possible. In the first embodiment, the user terminal device 7,
8 shows the case of broadcast distribution of data independently sent from 8 and data distribution to a specific reception dedicated station, but from the reception dedicated station 11 or 12 to the terminal device 7 or 8 via a land line, for example. The same applies when making a data distribution request.

Example 2. Next, a second embodiment of the present invention will be described. FIG. 4 is a configuration diagram showing an embodiment of the invention described in claim 2, and the same portions as those in FIG. 1 are denoted by the same reference numerals to avoid redundant description. In FIG. 4, 6b and 6c are buffer memories for separately storing S data for non-urgent transmission and L data for non-urgent transmission, which will be described later, and 23 and 24 are terminal devices 7 and 8 of the user and buffer memories. It is a ground line which is connected to the write interface unit 19 and is used particularly for transmitting the L data for non-emergency transmission.

Here, in the distribution system according to the second embodiment, still images such as faxes and various CADs are used.
Data, such as data distribution of floppy disk and laser disk, and file transfer, all data that is unidirectionally distributed from one location to another desired location are handled. In this embodiment, the data is handled as follows. Classify into three types according to urgency.

[0026]

[Table 1]

In particular, L data for non-urgent transmission is a large amount of data such as CAD data, high-definition still image, file update of computer, and the time from data collection to transmission at the transmitting station is acceptable, for example, half a day or one day. The feature is that the data has a wide range and can be expected to be delivered regularly by reservation. Since this reservation-based data generally has a large amount of data, data for emergency transmission and S for non-emergency transmission are used.
Compared to the case of data, a higher speed is required for the communication line, and there is a risk of blocking the line for a long time. In that case, it is necessary to input via another ground line 23, 24. As one method, it is possible to call the data from the transmitting station side when the user side has the data.

Next, the operation will be described. The transmission request data from the user is sent from the terminal devices 7 and 8 to the data transmission processing means B via the ground lines 13 and 14 or 23 and 24 according to the respective protocols. In the data transmission processing means B, the data is given an incoming interrupt instruction to the write address control section 21 via the buffer memory write interface section 19, and at the same time, the instruction from the write address control section 21 causes the buffer memory 6a,
It is written in either 6b or 6c. In this case, the data sent from the terminal device 7, 8 of the user is classified into the emergency transmission data, the non-emergency transmission S data, and the non-emergency transmission L data, and the identification code is attached to each of them. The data is classified into the buffer memory 6a, the non-urgent transmission S data is classified into the buffer memory 6b, the non-urgent transmission L data is classified into the buffer memory 6c, and the write address control unit 21 controls the buffer memory processor 22 to classify the data. And written in the order of arrival.

The emergency transmission data stored in the buffer memory 6a is read out via the buffer memory read interface unit 17 according to an instruction from the read address control unit 18. At this time, the user identification signal and the destination generated by the buffer memory processor 22 are added to the header portion of the data. On the other hand, the non-emergency transmission S data stored in the buffer memory 6b passes through the buffer memory read interface unit 17 according to an instruction from the read address control unit 18 when the buffer memory 6a storing the emergency transmission data becomes empty. Read out. At this time, the user identification signal generated by the buffer memory processor 22 and the destination are added to the header portion of the data as in the case of the emergency transmission data. If the emergency transmission data is written to the buffer memory 6a while the non-emergency transmission S data is being read and sent to the modulator 5, the buffer memory processor 22 stops reading the non-emergency transmission S data. The read address control unit 18 is instructed to instruct the read address control unit 18 to preferentially read the written emergency transmission data. When the buffer memory 6a becomes empty again, an instruction to start reading the non-emergency transmission S data is given by the above procedure, and the above procedure is repeated until a series of non-emergency transmission S data is read.

The non-emergency transmission L data stored in the buffer memory 6c is the same when the buffer memory 6a storing the emergency transmission data and the buffer memory 6b storing the non-emergency transmission S data become empty at the same time. , Is read out via the buffer memory read interface 17 according to an instruction from the read address control unit 18. At this time, the user identification signal and the destination generated by the buffer memory processor 22 are added to the header portion of the data. If data is written to either the buffer memory 6a or 6b while the non-emergency transmission L data is being read and sent to the modulator 5, the buffer memory processor 2
Reference numeral 2 instructs the read address control unit 18 to stop reading the L data for non-urgent transmission, and reads the written data with priority. Again, the buffer memory 6a,
When 6b are emptied at the same time, it is instructed to start reading the non-emergency transmission data L, and the above procedure is repeated until a series of non-emergency transmission L data is read.

The data read out from the buffer memories 6a, 6b or 6c and having the user identification signal and the destination added to the header section pass through the modulator 5, the transmission frequency converter 4, the transmitter 3 and the antenna 2. , Transmitted signal 9
Is sent to the communication satellite 1 through a satellite line which is a dedicated line. The communication satellite 1 retransmits the received signal toward the earth, and this signal is received by all the dedicated reception stations.
The user ID number of the received data at the corresponding receiving station,
Detects the destination addressed to your own station and captures the data. Since the other dedicated receiving station does not detect the destination signal addressed to itself, the received data is discarded. Further, the station requesting the non-emergency transmission S data or the non-emergency transmission L data stores the data in the memory in the reception dedicated station in the order of arrival when the data is divided, and when the series of data is collected. The reception is completed. The data fetched by the dedicated reception station is sent to the receiving side terminal under the required interface conditions according to the protocol of the terminal used.

FIG. 5 is an explanatory diagram showing the temporal arrangement of user data sent to a satellite line, that is, the time distribution of transmission request data assuming the state of use of the line.
FIG. 5A shows the case where only the emergency transmission data is used, B shows the case where the emergency transmission data and the non-emergency transmission S data are distinguished, and FIG. 5C shows the case where the non-emergency transmission L data is further added. .. As described above, in the second embodiment, the case where the pre-assignment SCPC is used is shown. This is sent in parallel and randomly from the limited n users as shown in FIG. 6 and stored in the buffer memory. It means that the output data is sent through an output line with a constant line capacity (transmission speed).

Here, when urgency is required for data transmission, the capacity of the output line (transmission speed) must be made larger than the capacity of the input line (transmission speed) in response to the peak of traffic. .. Actually, the line capacity cannot be arbitrarily selected, so the capacity of the output line (for example, 64 kb / se
The number of users will be determined in consideration of traffic according to c). FIG. 5A shows the “time distribution of transmission request data” and the “line usage state” in such a state. If the user is mainly a company, the time distribution of the transmission request data will be sparse after 9 o'clock to 10 o'clock in the morning, around the beginning and after hours of the afternoon, as in normal communication services. Is considered to be the average pattern. The actual traffic distribution is more complicated, but in this figure it is normalized by the line capacity for simplicity. Since there is a slight time delay due to emergency transmission, the usage status of the line is almost equal to the time distribution.

Next, FIG. 5B shows a case in which S data for non-urgent transmission which allows a slight delay is added. In this case, delay of non-emergency S data transmission is allowed,
Non-emergency transmission S data may be input by exceeding the capacity of the output line, and the line usage status can be transmitted with less idle time and more efficient than when only emergency transmission data is used as shown in the figure. Is. However, as long as only data to be transmitted when a transmission request occurs, such as data for emergency transmission and S data for non-emergency transmission, traffic concentration in a specific time zone cannot be avoided, and if the output line capacity is adjusted to this, The vacant time in the intermediate time zone still remains considerably as shown in FIG. In addition, when the fluctuation of traffic due to transmission is expected, the idle time rate becomes even larger.

FIG. 5C shows a case where, in addition to the above-mentioned data for emergency transmission and S data for non-emergency transmission, L data for non-emergency transmission, which can be expected to be periodically delivered by reservation as described above, is newly added. Is. This non-emergency L data is a large amount of data, and in this case, the line for emergency transmission data and the line for non-emergency transmission S may block the line for a long time, so use a higher speed line separately. The data is input to the buffer memory separately from the emergency transmission data and the non-emergency transmission S data. As another method, it is possible to call the data from the transmission side when the user side has the data. In this way, the storage status of FIG. 5C shows the pattern of the non-emergency transmission L data that is separately captured from the emergency transmission data and the non-emergency transmission S data. By newly adding the L data for non-urgent transmission, the idle time of the line is remarkably filled and the utilization time ratio of the line can be sufficiently increased. How much you can improve efficiency depends on the fluctuation rate of daily traffic. In the second embodiment, the most general case is that the urgency level of data is three levels. However, the non-emergency S data level may be omitted depending on the user's request, and vice versa. Therefore, the idea is the same even if the number of non-emergency S data is increased.

Further, in the second embodiment, the transmission according to the connection procedure according to the protocol determined by the used terminal device is performed between the transmission terminals ← → the data transmission processing means and the reception dedicated station ←.
→ The data is transmitted between the receiving terminals, and the dedicated line section by the satellite line between the transmitting earth station and the receiving dedicated station is one-way data transmission. The fact that the leased line is unidirectional in this way substantially improves the efficiency of data transmission by eliminating the procedure of setting / releasing the communication path each time communication is performed, and at the same time, using the above-mentioned data transmission processing means. Therefore, it is suitable for directly transmitting a data signal string sent out with almost no gap. In this system, if it is necessary to send back a signal such as delivery confirmation or resend request from the receiving side to the transmitting side, a separate terrestrial line is used.

Further, the example of FIG. 4 is a case where the receiving side terminal device is connected to a public line and a private line in the receiving dedicated station or in the same premises, but when the receiving terminal is away from the receiving dedicated station Naturally, a public line will be connected between them. Further, although the case where the satellite line is used as the dedicated line has been described with reference to FIG. 4, even if the terrestrial dedicated line limited to one-way transmission is used, the distribution system operates exactly the same as the above embodiment. The same effect can be obtained.

Example 3. The second embodiment described with reference to FIG. 4 is a case where the pre-assignment SCPC is used in order to make the price of the dedicated reception station placed on the user side as low as possible so that it is widely used by small users. For this reason, it is necessary to pack traffic with fluctuations from a large number of users in one line, which naturally limits the improvement of the average utilization time ratio of lines. In order to further increase the average utilization time ratio of this line, the second line that sends out the surplus data when it is judged that one line cannot send the data within the specified time Need to be provided.

FIG. 7 is a block diagram of a system of such an embodiment, and most of it is the same as that of FIG. 4 and duplicated description will not be repeated. In the figure, 4a, 5a and 4
Reference numerals b and 5b are a frequency conversion device and a modulation device for producing carrier waves of different frequencies, and 25 is a transmission route selection processor for monitoring the transmission status of the transmission routes of two systems and selecting the transmission route. Reference numerals 9 and 10 denote transmission signals transmitted from the transmitting earth station A via the frequency converter and the modulators 4a, 5a and 4b, 5b. FIG. 8 is an explanatory diagram showing the frequency spectrum of the repeater of the communication satellite 1. In the figure, 41 is the bandwidth of the repeater (communication satellite 1), and 42 and 43 are frequency converters 4a and 4b and modulators, respectively. 3 shows the carrier spectrum of the transmission signals 9, 10 transmitted from the transmitting earth station A via the devices 5a and 5b.

Next, the operation will be described. The data for emergency transmission, the S data for non-emergency transmission, and the L data for non-emergency transmission are classified according to their urgency levels in advance, and the data transmitted from the user's terminal device to the data transmission processing means via the ground line is , Is temporarily stored in any of the buffer memories 6a, 6b, 6c, and is then sent to the transmitting earth station A by a prescribed procedure in accordance with the order of urgency. This procedure is based on the second embodiment shown in FIG. As already described.

During this process, the traffic requested by some users increases, and any one of the amounts of data being stored in the buffer memories 6a, 6b, and 6c exceeds a predetermined fixed amount within a prescribed time. If the buffer memory processor 22 receives an instruction of an empty route from the transmission route selection processor 25, the buffer memory processor 22 designates the data in the buffer memory in units of users on a first-come-first-served basis via the buffer memory read interface unit 17 each time. The data is sent to the route. When the amount of accumulated data in the buffer memory becomes less than a certain amount, the transmission from another route is stopped and the original transmission by one route is resumed. If the amount of remaining data in the buffer memory exceeds a certain amount due to a sudden increase in traffic at the same time in two or more buffer memories, the data in the buffer memory accommodating data with a high degree of urgency is transmitted first. To do.

Here, there are various ways to determine the fixed amount that determines the start of two-wave transmission, but the simplest example is shown below. Considering the urgency specified in the buffer memory, the remaining time allowed for the transmission of accumulated data shall be α hours, the transmission rate of the line that sends out the data shall be 64 kb / s, and input within α hours at the higher urgency level. Assuming that the amount of data that is supposed to be D is D, the constant amount K is as follows.

K = α × 3600 × 64 kb-D

The signal sent back to the ground via the communication satellite 1 is received by all dedicated reception stations. The dedicated reception station incorporated in this system has a function of receiving two carrier waves at the same time, and monitors the identification signal in the header section to identify the own station, and only when the data addressed to the own station is detected, the terminal device The data is taken in and the data not addressed to the own station is discarded. In this way, by allocating one extra carrier wave and using another two routes at the same time when necessary, the average utilization time ratio of the original line can be increased to the point where a certain amount of overflow is allowed even with fluctuating traffic. It is possible to improve.

In the above description, an example of two-wave transmission in which one normal carrier is added with another backup carrier for rapid traffic increase, but the degree of traffic overflow is too frequent. If not, it is also possible to set a common spare carrier for N regular carriers.

[0046]

As described above, according to the invention described in claim 1, there is a buffer memory for storing data separately for emergency transmission data and non-emergency transmission data, and the emergency transmission data is received. In accordance with the order, the non-emergency transmission data is taken out when the buffer memory storing the emergency transmission data is empty, and the header portion according to the user identification signal, the destination, and the sequence number of the data is added to the beginning of the data to transmit the data to the earth. Since the data transmission processing means for transmitting to the station is provided, it is possible to efficiently multiplex the data to be placed on the carrier of the transmitting earth station in a state where the idle time is small, and the transmission cost per bit is greatly increased. It is possible to lower it.

According to the second aspect of the invention, the data for emergency transmission for transmitting the transmission data when the transmission request occurs and the S data for non-emergency transmission, and the allowance of the time from the collection of the data to the transmission It is divided into L data for non-emergency transmission, which has a wide range and can be delivered regularly by reservation, and low urgency data uses the free time of the leased line where higher urgency data is not transmitted. Since the dedicated line is configured to be used only for one-way transmission, it is possible to further reduce the free time of the dedicated line, significantly improving the utilization rate of the dedicated line, and This has the effect of further reducing the transmission cost per hit. Further, since the effect of the present invention is not influenced by the property of the transmission line, it is obvious that the present invention can be applied to the data distribution system having the ground line as well as the satellite line.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing frequency allocation in SCPC.

FIG. 3 is an explanatory diagram showing a temporal arrangement of transmission signals of the above embodiment.

FIG. 4 is a configuration diagram showing a second embodiment of the present invention.

FIG. 5 is an explanatory diagram showing a temporal arrangement of transmission signals in the above embodiment.

FIG. 6 is an explanatory diagram schematically showing a relationship between an input line and an output line of a buffer memory.

FIG. 7 is a configuration diagram showing a third embodiment of the present invention.

FIG. 8 is an explanatory diagram showing a frequency spectrum of a repeater in the above embodiment.

FIG. 9 is a block diagram showing a satellite communication system in a conventional data distribution network.

FIG. 10 is a block diagram showing a satellite communication system in a distribution type network of a conventional system.

[Explanation of symbols]

 1 Communication Satellite 6a Buffer Memory 6b Buffer Memory 6c Buffer Memory A Transmission Earth Station B Data Transmission Processing Means

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[Procedure amendment]

[Submission date] April 28, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 2

[Correction method] Change

[Correction content]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0021

[Correction method] Change

[Correction content]

The emergency transmission data stored in the buffer memory 6a is read out via the buffer memory read interface unit 17 according to an instruction from the read address control unit 18. At this time, the user identification signal generated by the buffer memory processor 22, the destination, and the sequence number of the data
No. is added to the header part of the data. On the other hand, the data discriminated as the non-emergency transmission data is written in the buffer memory 6b by the write address control unit 2 according to the instruction of the processor 22.
It is written in the order of arrival by the control of 1. The stored non-emergency transmission data is read out by the read address control unit 1 when the buffer memory 6a storing the emergency transmission data becomes empty.
According to the instruction of 8, the packet is divided into packets of an appropriate length and is read out via the buffer memory read interface unit 17. At this time, as in the case of the emergency transmission data, the user identification signal generated by the buffer memory processor 22 , the destination, and the sequence number of the data are added to the header portion of the data. The non-emergency transmission data is read and the modulator 5
If the emergency transmission data is written in the buffer memory 6a while being sent to the buffer memory 6a, the buffer memory processor 22 gives an instruction to stop reading the non-emergency data to the read address control unit 18, and the buffer memory 6a
The read address control unit 18 is instructed to preferentially read the emergency transmission data written in a.

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] 0022

[Correction method] Change

[Correction content]

The user identification signal 1 and the destination and the sequence number of the data read from the buffer memory 6a or 6b.
The data in which the signal is added to the header portion is transmitted to the communication satellite 1 as a transmission signal 9 via the modulation device 5, the transmission frequency conversion device 4, the transmission device 3, and the antenna 2. When the communication satellite 1 receives the transmission signal 9, it retransmits it toward the earth, and this signal is received by all the dedicated reception stations.
The dedicated reception station detects the user identification signal in the header part of the received data and the address addressed to the own station and captures it in the terminal device. The other dedicated receiving station discards the received data unless an address signal addressed to itself is detected. The station that has received the non-emergency data stores the data in the memory of the terminal device in the order of arrival and receives the data until all the data are collected. In the case of the second user, the same operation as the first user is performed. The number of users may increase.

[Procedure amendment 4]

[Document name to be amended] Statement

[Name of item to be corrected] 0029

[Correction method] Change

[Correction content]

The emergency transmission data stored in the buffer memory 6a is read out via the buffer memory read interface unit 17 according to an instruction from the read address control unit 18. At this time, the user identification signal generated by the buffer memory processor 22 , the destination , and the sequence number of the data
No. is added to the header part of the data. On the other hand, the non-emergency transmission S data stored in the buffer memory 6b passes through the buffer memory read interface unit 17 according to an instruction from the read address control unit 18 when the buffer memory 6a storing the emergency transmission data becomes empty. Read out. At this time, the user identification signal generated by the buffer memory processor 22, as in the case of the emergency transmission data ,
The destination and the sequence number of the data are added to the header of the data. If the emergency transmission data is written to the buffer memory 6a while the non-emergency transmission S data is being read and sent to the modulator 5, the buffer memory processor 2
Reference numeral 2 instructs the read address control unit 18 to stop reading the non-emergency transmission S data, and instructs the read address control unit 18 to preferentially read the written emergency transmission data. When the buffer memory 6a becomes empty again, an instruction to start reading the non-emergency transmission S data is given by the above procedure, and the above procedure is repeated until a series of non-emergency transmission S data is read.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Name of item to be corrected] 0030

[Correction method] Change

[Correction content]

The non-emergency transmission L data stored in the buffer memory 6c is the same when the buffer memory 6a storing the emergency transmission data and the buffer memory 6b storing the non-emergency transmission S data become empty at the same time. , Is read out via the buffer memory read interface 17 according to an instruction from the read address control unit 18. At this time, the user identification signal, the destination , and the data sequence number generated by the buffer memory processor 22 are added to the header portion of the data. While the L data for non-urgent transmission is being read and being sent to the modulator 5, the buffer memory 6a or 6b
When data is written to any of the above, the buffer memory processor 22 gives an instruction to stop the read of the non-emergency transmission L data to the read address control unit 18, and reads the written data with priority. When the buffer memories 6a and 6b are simultaneously emptied again, the start of reading the non-emergency transmission data L is instructed, and the above procedure is repeated until a series of non-emergency transmission L data is read.

[Procedure Amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0031

[Correction method] Change

[Correction content]

The sequence number of the user identification signal, the destination , and the data read from the buffer memory 6a, 6b or 6c.
The data in which the signal is added to the header section is transmitted to the communication satellite 1 through the modulator 5, the transmission frequency converter 4, the transmitter 3 and the antenna 2, and as a transmission signal 9 through a satellite line which is a dedicated line. Sent out. The communication satellite 1 retransmits the received signal toward the earth, and this signal is received by all the dedicated reception stations. The corresponding dedicated reception station detects the user identification number of the received data and the destination addressed to itself, and captures the data. Since the other dedicated receiving station does not detect the destination signal addressed to itself, the received data is discarded. Also it station that requested the S data or non-urgent transmission L data for non-emergency transmission, stores data in the order of arrival if the data is divided into the memory of the receive-only station, the gathered set of data The data
The reception is completed when the order number is confirmed . The data fetched by the dedicated reception station is sent to the receiving side terminal under the required interface conditions according to the protocol of the terminal used.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0034

[Correction method] Change

[Correction content]

Next, FIG. 5B shows a case in which S data for non-urgent transmission which allows a slight delay is added. In this case, delay of non-emergency S data transmission is allowed,
Non-emergency transmission S data may be input by exceeding the capacity of the output line, and the line usage status can be transmitted with less idle time and more efficient than when only emergency transmission data is used as shown in the figure. Is. However, as long as only data to be transmitted when a transmission request occurs, such as data for emergency transmission and S data for non-emergency transmission, traffic concentration in a specific time zone cannot be avoided, and if the output line capacity is adjusted to this, The vacant time in the intermediate time zone still remains considerably as shown in FIG. In addition , the vacant time rate becomes even larger when the fluctuation of traffic depending on the transmission date is expected.

[Procedure Amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0036

[Correction method] Change

[Correction content]

Further, in Examples 1 and 2,
Transmission according to the connection procedure according to the protocol determined by the terminal device used is performed between the transmitting terminals ← → between the data transmission processing means and the receiving dedicated station ← → between the receiving terminals, and is dedicated by the satellite line between the transmitting earth station → the receiving dedicated station. The line section is a one-way data transmission. The fact that the leased line is unidirectional in this way substantially improves the efficiency of data transmission by eliminating the procedure of setting / releasing the communication path each time communication is performed, and at the same time, using the above-mentioned data transmission processing means. hand,
It is suitable for directly transmitting a data signal stream sent with almost no gap. In this system, if it is necessary to send back a signal such as delivery confirmation or resend request from the receiving side to the transmitting side, a separate terrestrial line is used.

[Procedure Amendment 9]

[Document name to be amended] Statement

[Name of item to be corrected] 0037

[Correction method] Change

[Correction content]

Further, although the example of FIGS . 1 and 4 is a case where the receiving side terminal device is a connection between a public line and a private line within the receiving dedicated station or the same premises, the receiving terminal is located in a place away from the receiving dedicated station. Of course, at some point, a public line will be connected between them. Further, although the case where the satellite line is used as the dedicated line has been described with reference to FIG. 4, even if the terrestrial dedicated line limited to one-way transmission is used, the distribution system operates exactly the same as the above embodiment. The same effect can be obtained.

[Procedure Amendment 10]

[Document name to be amended] Statement

[Item name to be corrected] 0040

[Correction method] Change

[Correction content]

Next, the operation will be described. Data that is classified in advance into emergency transmission data, non-emergency transmission S data, or non-emergency transmission L data according to the degree of urgency, and is sent from the user's terminal device to the data transmission processing means via the ground line. Is once buffer memory 6a, 6b, 6c
Stored in one of the above, and then sent to the transmitting earth station A by a prescribed procedure according to the order of urgency. This procedure is as already described based on the second embodiment shown in FIG.

Claims (2)

[Claims] 1. A satellite communication system using a data distribution network for collecting transmission request data from a plurality of users and transferring the data to a plurality of receiving earth stations by using a transmitting earth station and a communication satellite as a relay station. The transmission data from the user is classified into the emergency transmission data and the non-emergency transmission data according to the request from the user, and the data is urgently or non-emergencyly as the transmission processing means for processing the data from the plurality of users. A buffer memory for storing the data separately, the emergency transmission data is preferentially taken out in accordance with the order of arrival, and the non-emergency transmission data is divided when the buffer memory storing the emergency transmission data is empty. A user identification signal, a destination, and a data sequence number are added as a header to the head of each data and transferred to the transmitting earth station. A satellite communication system comprising means. 2. Transmission request data from a plurality of users,
In the data delivery type transmission method in which the data is transferred to one or more destinations designated by each user, the user side transmits the transmission data in the same manner as the emergency transmission data having a high degree of urgency to be transmitted when the transmission request occurs. It is sent at the time of occurrence, and S data for non-urgent transmission is divided into multiple stages depending on the degree of non-urgentness, and there is a large allowance for the time from the collection of data to the transmission, and it is regularly reserved. And L data for non-emergency transmission to be distributed to
An identification code is added to each and transferred to the data transmission processing means, and the transmission data received by the data transmission processing means is subjected to the emergency transmission data, the non-emergency transmission S data, and the non-emergency transmission according to the identification code. A buffer memory in which credit L data is classified and stored in corresponding buffer memories, the emergency transmission data is preferentially taken out in accordance with the order of arrival, and the non-emergency transmission S data is storing the emergency transmission data. When it is empty, the L-data for non-emergency transmission is taken out collectively or in a divided manner, and the buffer memory storing the data for emergency transmission and the buffer storing the S data for non-urgent transmission become empty at the same time. When you take it, you can take it out in batches or in pieces,
A data delivery type transmission method characterized in that a user identification number, a destination, and a data sequence number are added to the head of each data as a header part, and then the data is delivered to the destination through a dedicated line limited to one direction. ..