JP2001211192A - Transmission method, communication method, transmission device and communication system for data broadcast distribution - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide transmission method, communication method, transmission device and communication system for data broadcast distribution by which data transmission efficiency is enhanced while guaranteeing a high reliability in transmission data. SOLUTION: The methods, the device and the system are provided with a data packet generation process for successively generating data packets by using a primary station, a broadcast distribution process for successively transmitting each data packet to all N secondary stations via an outgoing line by broadcast distribution by using the primary station and a polling issuing process for transmitting a polling packet by individual communication by which the primary station inquires whether each secondary station has received each data packet by time difference to each secondary station via the outgoing line.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission method, a communication method, a transmission apparatus, and a data broadcasting method for simultaneously transmitting the same data from one primary station to a plurality of secondary stations via a line. It relates to a communication system.

[0002]

2. Description of the Related Art In general, when transmitting the same data from one primary station to a plurality of secondary stations, a connectionless protocol or a connection type protocol can be used.

[0003] The connectionless protocol means that the same data is unilaterally transmitted from one primary station to all the secondary stations on one line at the same time (broadcast distribution), and no data delivery confirmation is performed. Communication method. For example, UDP (User Datagram Protocol) is used for connectionless protocol.
ol) and the like, and there is an advantage that the line congestion and the load on the primary station are small during data broadcast distribution. However,
Since no data delivery confirmation is performed, there is also a drawback that it is suitable only for data broadcasting which does not require reliability.

On the other hand, the connection type protocol is
After establishing a connection from the next station to each of the secondary stations,
This is a communication method in which the same data is individually transmitted on each of the lines from the primary station to each of the secondary stations (lines corresponding to the total number of secondary stations) while confirming the delivery of data. For example, TCP (Transmis
sion control protocol), which has the advantage that high reliability can be ensured when broadcasting data. However, since data is individually transmitted from the primary station to each of the secondary stations, that is, the same data as the total number of secondary stations repeatedly flows on the line. There is a disadvantage that the communication time increases proportionately. When transmitting the same data divided into a plurality of packets from one primary station to each of the secondary stations, each time one or a plurality of packets are transmitted, Data delivery confirmation was performed independently for each connection. For this reason, when the total number of secondary stations increases, the load on the primary station for processing data delivery confirmation from each of the secondary stations increases, and packets for data delivery confirmation are transmitted on the line. There is a drawback that congestion is further increased and network throughput is reduced.

[0005]

In order to take advantage of the connectionless type protocol and the connection type protocol, first, the primary station to the secondary station respectively unilaterally store the same data on one line. A new first higher-level protocol that adds a function of broadcasting to a connection-type protocol can be considered. Next, a new second higher-level protocol that adds a function of confirming data delivery to the connectionless type protocol can be considered. However, in the new first higher-level protocol, the broadcast is performed on the connection-type protocol without the broadcast distribution function. Therefore, the same data is inevitably transmitted to each secondary station. It will be. As a result, there is a fundamental drawback that line congestion is increasingly caused and network throughput is reduced. That is, the first
In the upper protocol, the data transmission efficiency cannot be increased while guaranteeing high reliability of transmission data.
On the other hand, even in the new second upper layer protocol, every time one or a plurality of packets are transmitted, the delivery confirmation of the data is performed to all the secondary stations by the broadcast distribution.
When the total number of the secondary stations increases, the load on the primary station for processing the acknowledgment of data transmission from all of the secondary stations increases, and the packets for acknowledging the data transmission increase the congestion of the line. As a result, there is a disadvantage that the network throughput is reduced. Since this defect is not a fundamental defect, there is a problem that this defect must be improved by a protocol that improves the second higher-level protocol.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems in the prior art, and has been made in consideration of the above-mentioned problems. It is an object to provide a communication method, a transmission device, and a communication method.

[0007]

According to a first aspect of the present invention for solving the above-mentioned problems, a primary station divides data into blocks each having a predetermined length, and stores data including at least each of the data in this block area. A data packet producing process for sequentially producing packets;
A broadcast distribution step of sequentially transmitting each of the data packets to all of the secondary stations (N is a natural number of 2 or more) by broadcast distribution, and the primary station transmits the data packets via the downlink. A polling packet for asking whether each of the N secondary stations has received each of the data packets at a time difference from each of the N secondary stations by individual communication. And a polling issuing step.

Therefore, according to the data broadcasting transmission method of the first invention of the present application, the polling issuance process is performed not at every time when each data packet is sequentially transmitted by the broadcasting but at a time difference. . In other words,
The polling issue process is performed independently of the broadcast delivery process.
The polling issuance process is performed individually for each of the N secondary stations, but not for all of the N secondary stations. As a result, the line is not congested by the polling response packet from the secondary station that has received the polling packet to the primary station (including the reception state information indicating whether the secondary station has received the data packet). In addition, the reception confirmation processing load of the primary station does not concentrate at one time. Therefore, there is an advantage that the data transmission efficiency can be increased while guaranteeing high reliability of transmission data by the polling issuing process.

A second invention of the present application provides a data packet producing process in which a primary station divides data into blocks each having a predetermined length, and sequentially produces data packets including at least each of the data in the block area. The primary station sends W (W is 0 or more) from the first data packet among the data packets to all N secondary stations (N is a natural number of 2 or more) via the downlink. Is a natural number,
The initial value of W is M, which is a natural number of 1 or more. )), Wherein each of the N secondary stations transmits W data packets on the downlink.
Broadcast receiving step of receiving each of the data packets described above, and the primary station transmits polling packets to the respective N secondary stations with a time lag by individual communication via the downlink. Polling issuing process,
N of each of the secondary stations receives the polling packet on the downlink, and receives the polling packet to the primary station via the uplink, from the latest received data packet to the immediately preceding data packet. A polling response step of transmitting, by multiple access, a polling response packet including at least reception status information as to whether or not the M data packets have been received, and the primary station receiving each of the polling response packets on the uplink. , N to determine whether there are any data packets not received by any of the N secondary stations and whether there are data packets received by all of the N secondary stations. And if there is any data packet that has not been received by any of the N secondary stations in the reception management process, A re-broadcasting process in which a primary station retransmits by broadcast to all of the N secondary stations via the downlink, and the broadcast reception in which this data packet is used as the W data packet. A priority polling issuing step in which the primary station preferentially transmits a polling packet by individual communication to the secondary station that has not received the data packet via the downlink, and And a polling response step of performing a secondary station not receiving as the N secondary station, and returning to the reception management step. In the reception management step, all of the N secondary stations receive data. If the data packet is present, the broadcast distribution step of performing the number of data packets as the W, the broadcast receiving step of performing the number of data packets as the W, Serial polling issued process, the and a polling response process, a communication method of data broadcasting, characterized in that return to the reception management process.

Therefore, according to the data broadcasting communication method of the second invention of the present application, the polling issuance process is performed not at every time when each data packet is sequentially transmitted by the broadcast but at a time difference. . In other words,
The polling issue process is performed independently of the broadcast delivery process.
The polling issuance process is performed individually for each of the N secondary stations, but not for all of the N secondary stations. Thus, in the polling response process, the uplink is not congested by the polling response packet. In addition, the reception confirmation processing load of the primary station does not concentrate at one time. Therefore, there is an advantage that the data transmission efficiency can be increased while guaranteeing high reliability of transmission data by the polling issuing process.

Further, according to the data broadcasting communication method of the second invention of the present application, any one of the N secondary stations receives data in the reception management process of managing the reception status of the secondary station. If there is no data packet, a re-broadcasting process and a priority polling issuing process are provided. Therefore, in the reception management process, it can be preferentially managed whether or not the secondary station has received the retransmitted data packet. Here, if it is determined that all of the N secondary stations have received the same data packet as the retransmitted data packet, a new data packet will be transmitted by broadcast in the broadcast distribution process. . In other words, since the primary station can immediately transmit a data packet to the secondary station,
There is an advantage that data transmission efficiency can be further increased.

According to a third invention of the present application, in the communication method for data broadcasting of the second invention of the present application, the polling issuing step includes the step of: A communication method for data broadcasting, wherein at least one or more data packets are transmitted every time a data packet of M is transmitted on the downlink as a reference.

Therefore, according to the communication method for data broadcasting of the third invention of the present application, there is an advantage of the second invention of the present application, and every time M data packets are transmitted, the N secondary stations receive the data. Since all of them receive at least one or more polling packets, each time M data packets are transmitted, the reception management process determines whether there are any data packets that are received by all N secondary stations. Can be managed. Here, when there is a data packet that is received by all of the N secondary stations, a new data packet is transmitted by the broadcast distribution in the broadcast distribution process.
In other words, since the primary station can transmit data packets to the secondary station, there is an advantage that data transmission efficiency can be further increased.

According to a fourth invention of the present application, in the communication method for data broadcasting according to the second invention of the present application or the third invention of the present application, the polling issuance step is performed when the reception management step includes the second of N. When there is the data packet that is received by all of the next stations, the last data packet among the data packets is the latest received data packet when the polling packet is received.
This is a data broadcasting communication method characterized by performing preferential transmission to the next station.

Therefore, according to the communication method for data broadcasting of the fourth invention of the present application, there are advantages of the second invention of the present application or the third invention of the present application, and N secondary stations in the reception management process. Is the secondary station of the second station, that is, the last station of the data packet which is the latest received data packet when the polling packet is received, that is, the secondary station of N The polling packet is preferentially transmitted to the secondary station whose reception confirmation is the latest among the stations. As a result, the reception status information of the secondary station that has received the polling packet is updated, so that the data packet is retransmitted,
A new data packet will be transmitted. In other words, since the primary station can transmit (retransmit) the data packet to the secondary station, there is an advantage that the data transmission efficiency can be further increased.

According to a fifth aspect of the present invention, there is provided a communication method of data broadcast distribution according to any one of the second to the fourth aspects of the present invention, wherein the broadcast receiving step comprises the first M A data broadcasting communication method characterized by transmitting one data packet to a tertiary station sequentially from the first data packet every time a new data packet is received after receiving a data packet.

Therefore, according to the communication method for data broadcasting of the fifth invention of the present application, there is provided any one of the advantages of the second invention of the present application to the fourth invention of the present application, and the communication from the primary station is also possible. When the data packet is received, all of the N secondary stations can transmit the same data packet at the same timing. In other words, there is an advantage that the primary station can control the transmission of data packets from the secondary station to the tertiary station.

According to a sixth aspect of the present invention, there is provided a data packet generating means for dividing data into blocks each having a predetermined length, and sequentially generating data packets including at least each of the data in the block area; Through N
, And broadcast means for sequentially transmitting each of the data packets to all of the receiving devices (N is a natural number of 2 or more) by broadcast, and N via the downlink.
Polling issuing means for transmitting a polling packet by individual communication for inquiring whether or not each of the N receiving devices has received each of the data packets at a time difference with respect to each of the receiving devices. A data broadcasting transmission device characterized by having:

Therefore, according to the data broadcasting transmission apparatus (primary station) of the sixth invention of the present application, the polling issuing means performs the time lag instead of each time when each data packet is sequentially transmitted by the broadcasting. Is performed. In other words, the polling issuing means is performed independently of the broadcast distribution means. Further, the polling issuing means is performed not for all of the N receiving apparatuses (secondary stations) but for each of one receiving apparatus (secondary station). As a result, the receiving apparatus (secondary station) that has received the polling packet transmits the data broadcast transmission apparatus (1).
The line is not congested by the polling response packet to the next station). In addition, the reception confirmation processing load of the transmission apparatus (primary station) for data broadcasting does not concentrate at one time. Therefore, there is an advantage that the data transmission efficiency can be increased while ensuring high reliability of transmission data by the polling issuing means.

In the seventh invention of the present application, a primary station for transmitting data on the downlink and N secondary stations for receiving the data on the downlink (N is a natural number of 2 or more). Wherein the primary station divides the data into blocks each having a predetermined length, and sequentially creates data packets including at least each of the data in the block area. Data packet generating means, and from the first data packet of the data packets to W
(W is a natural number equal to or greater than 0, and the initial value of W is M, which is a natural number equal to or greater than 1). 2
Each of the next stations has broadcast receiving means for receiving each of the data packets of W on the downlink, and the primary station communicates with each of the N secondary stations via the downlink. A polling issuing means for transmitting a polling packet by individual communication with a time lag therebetween, wherein each of the N secondary stations receives the polling packet on the downlink and transmits the polling packet via the uplink. Polling for transmitting, by multiple access, a polling response packet including at least reception status information as to whether or not the data packet of the latest M has been received from the latest data packet received at the time of receiving the polling packet to the primary station. Responding means, wherein the primary station receives each of the polling response packets on the uplink,
And receiving management means for managing whether there is a data packet which is not received by any of said secondary stations and whether there is a data packet which is received by all of said N secondary stations. If any of the N secondary stations has not received the data packet in the reception management means, the primary station transmits the data packet to the N via the downlink.
, And re-broadcasting means for re-transmitting to all of the secondary stations by broadcasting, wherein each of the N secondary stations performs this data packet as the W data packet. Priority polling issuing means for preferentially transmitting a polling packet by individual communication to the secondary station from which the primary station has not received the data packet via the downlink. The apparatus further comprises the polling response means for performing a secondary station which has not received a packet as the N secondary stations, and the reception management means, wherein the reception management means receives all of the N secondary stations. The primary station has the broadcasting means for performing the number of data packets as the W when there are any of the data packets, and each of the N secondary stations has The primary station has the polling issuing means, each of the N secondary stations has the polling response means, and the primary station has A communication system for data broadcast distribution, characterized by having the reception management means.

Therefore, according to the communication system for data broadcasting of the seventh invention of the present application, the polling issuing means is performed not every time data packets are sequentially transmitted by the broadcasting but with a time difference. . In other words,
The polling issuing means is performed independently of the broadcast distribution means.
Also, the polling issuing means is performed individually for each of the N secondary stations, but not for all the secondary stations. This prevents the polling response means from congesting the uplink line due to the polling response packet. In addition, the reception confirmation processing load of the primary station does not concentrate at one time. Therefore, there is an advantage that the data transmission efficiency can be increased while ensuring high reliability of transmission data by the polling issuing means.

Further, according to the communication system for data broadcasting of the seventh aspect of the present invention, the reception management means for managing the reception status of the secondary station receives any one of the N secondary stations. In the case where there is no data packet, it has re-broadcast distribution means and priority polling issuing means. Therefore, the reception management means can preferentially manage whether or not the secondary station has received the retransmitted data packet. Here, if all of the N secondary stations have received the same data packet as the retransmitted data packet, a new data packet will be transmitted by the broadcast distribution by the broadcast distribution means. . In other words, since the primary station can immediately transmit a data packet to the secondary station,
There is an advantage that data transmission efficiency can be further increased.

According to an eighth aspect of the present invention, in the data broadcasting communication system according to the seventh aspect of the present invention, the polling issuing means includes a first data packet among the data packets in the broadcast communication means. A data broadcast communication method characterized in that at least one or more data packets are transmitted each time M data packets are transmitted on the downlink as a reference.

Therefore, according to the communication system for data broadcasting of the eighth invention of the present application, there is an advantage of the seventh invention of the present application, and every time when M data packets are transmitted, N secondary stations receive the data. Since all receive at least one or more polling packets, each time M data packets are transmitted, the reception management means determines whether there is a data packet that is received by all of the N secondary stations. Can be managed. Here, when there is a data packet that is received by all of the N secondary stations, a new data packet is transmitted by the broadcast distribution by the broadcast distribution means.
In other words, since the primary station can transmit data packets to the secondary station, there is an advantage that data transmission efficiency can be further increased.

According to a ninth invention of the present application, in the communication system for data broadcast distribution according to the seventh invention of the present application or the eighth invention of the present application, the polling issuance unit is configured so that the reception management unit uses When there is the data packet that is received by all of the next stations, the last data packet among the data packets is the latest received data packet when the polling packet is received.
This is a data broadcast communication method characterized by preferential transmission to the next station.

Therefore, according to the communication system for data broadcasting of the ninth invention of the present application, there are advantages of the seventh invention of the present application or the eighth invention of the present application, and the reception management means has N secondary stations. Is the secondary station of the second station, that is, the last station of the data packet which is the latest received data packet when the polling packet is received, that is, the secondary station of N The polling packet is preferentially transmitted to the secondary station whose reception confirmation is the latest among the stations. As a result, the reception status information of the secondary station that has received the polling packet is updated, so that the data packet is retransmitted,
A new data packet will be transmitted. In other words, since the primary station can transmit (retransmit) the data packet to the secondary station, there is an advantage that the data transmission efficiency can be further increased.

According to a tenth aspect of the present invention, in the communication system for data broadcast distribution according to any one of the seventh to ninth aspects of the present invention, the broadcast receiving means comprises: This is a data broadcast communication method characterized by transmitting one data packet to a tertiary station sequentially from the first data packet every time a new data packet is received after receiving a data packet.

Therefore, according to the communication system for data broadcasting of the tenth invention of the present application, any one of the advantages of the seventh invention of the present application to the ninth invention of the present application can be obtained, and at the same time, the communication from the primary station can be performed. When the data packet is received, all of the N secondary stations can transmit the same data packet at the same timing. In other words, there is an advantage that the primary station can control the transmission of data packets from the secondary station to the tertiary station.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A transmission method, a communication method, a transmission device, and a communication system for data broadcasting according to an embodiment of the present invention will be described below with reference to the drawings.

First, a transmission method, a communication method, a transmission device (primary station), and a communication system (primary station, secondary station) of data broadcast distribution according to an embodiment of the present invention are shown in FIGS. This will be described with reference to FIG. FIG. 1 is a configuration diagram showing a communication system (primary station, secondary station) for data broadcast distribution according to an embodiment of the present invention.
FIG. 2A is a configuration diagram illustrating a primary station, and FIG. 2B is a diagram illustrating an example of a reception record table of the primary station. FIG. 3A is a configuration diagram illustrating a secondary station, and FIG. 3B is a diagram illustrating an example of a reception record table of the secondary station. FIG. 4A shows a format of a data packet transmitted from the primary station to the secondary station. FIG. 4B shows a format of a polling packet transmitted from the primary station to the secondary station. FIG. 4 (3) is a diagram showing 2
FIG. 7 is a diagram illustrating a format of a polling response packet transmitted from the next station to the primary station.

First, as shown in FIG. 1, the communication system of data broadcast distribution includes a primary station P1 for transmitting data on the downlink by packet communication and an N for receiving downlink data by packet communication. Secondary stations S1 to SN (N is 2
These are natural numbers above. ). Data on the downlink from the primary station P1 to all N secondary stations (S1 to SN) is transmitted by broadcast distribution, while each of the N secondary stations (S1, S2,..., SN). From primary station P
Data on the uplink to 1 is transmitted by multiple access. Here, the broadcast distribution is a primary station P of one.
This means that the same data is transmitted simultaneously to all of the secondary stations 1 to N (S1 to SN). Multiple access means that all of the N secondary stations (S1 to SN) share the uplink and each of the N secondary stations (S1, S2,..., S
N) means transmitting data to the primary station P1. The multiple access includes, for example, TDMA (Time Division Multiple Access). Note that, with reference to FIG. 1, all the N secondary stations (receiving antennas) from the primary station (transmitting antenna).
The down link to is wireless, but may be wired. Also, the uplink may be wireless or wired. For example, a satellite line (wireless) can be used for both the down line and the up line. Further, for example, so-called non-target satellite communication in which the downlink is a satellite link (wireless) and the uplink is a telephone link (wired) can be used. Note that the primary station has N
It is assumed that all the secondary stations are registered in advance. Also,
The maximum number of packets (window size) that can be transmitted from the primary station without waiting for confirmation of reception from the secondary station is M (M is a natural number of 1 or more). Here, the value of M is determined by the primary station according to the line congestion situation. For example, when the line is congested, the value of M is increased.

[Roles and Structure of Primary Station] The primary station (transmitting apparatus for data broadcasting) performs data transmission and polling (transmission / reception confirmation request) to the secondary station (receiving apparatus). Also,
As shown in FIG. 2A, the primary station is a CPU (Central Processing Unit) that controls the operation of each device.
1, a memory 2 for storing information, a data buffer 3 for storing data to be transmitted, a communication device 5 for communicating with a secondary station, and an input device for inputting transmission data 4 is provided. For example, both the primary station and the secondary station are broadcasting stations that transmit and receive programs and the like. A tertiary station described later is also a broadcast station, for example. In the memory 2, an area for storing each of the four pieces of information is created by the CPU 1. Specifically, these four pieces of information are information of the reception record table 6 of the primary station, information of the window pointer 7, information of the window counter 9, and information of the polling pointer 8.

As shown in FIG. 2 (2), the information in the reception record table 6 of the primary station is divided into 2M areas.
This area corresponds to the packet number and is 0 to 2M-
1 is identified. As the information of the polling pointer 8, the packet number of the data packet transmitted immediately before the polling is recorded for each secondary station. Therefore,
The information of the polling pointer 8 is updated every time the primary station performs polling. The information of the window pointer 7 records the packet number of the oldest data packet among the data packets that have already been transmitted and are waiting for reception confirmation (data packets waiting for reception confirmation). The window counter 9 stores the window size M in advance. In other words, assuming that the value of the window counter 9 is W, the initial value of W is M. Here, W is a natural number of 0 or more.

The primary station decreases the value W of the window counter 9 by one each time one new data packet is transmitted. On the other hand, when it is confirmed that a certain data packet has been received by all of the N secondary stations, the primary station increases the value W of the window counter 9 by one. No new data packet is transmitted when the value W of the window counter 9 is 0. The information in the reception record table 6 of the primary station is updated by the result of the polling response from the secondary station. On the basis of the updated information in the reception record table 6, the primary station performs a process of retransmitting the data packet required by the secondary station and increasing the value W of the window counter.

[Roles and Structure of Secondary Station] Secondary Station (Receiver)
Receives data from the primary station (transmitter for data broadcasting). The secondary station is identified by a unique number (secondary station number). Also, as shown in FIG. 3A, the secondary station includes a CPU 11 for controlling the operation of each device, a memory 12 for storing information, and a communication for performing communication between the primary station. The device 14 is provided. In addition, 2
When it is necessary to output the data transmitted to the next station to the third station, the secondary station is configured by adding an output device 13 for outputting to the third station. CP inside the memory 12
U11 creates an area for storing each of the three pieces of information. Here, specifically, these three pieces of information, information of the reception record table 15 of the secondary station, information of the reception pointer 17, and the read pointer 16
Information.

As shown in FIG. 3 (2), the information in the reception record table 15 of the secondary station is divided into 2M areas.
It is identified by the number M-1. In addition, the information in the reception record table 15 of the secondary station records the data packet reception status (either received or unreceived) of the own station and the received data packet. As the information of the reception pointer 17, the latest one among the packet numbers of the received data packets is recorded. The read pointer 16
Is always smaller than the value recorded in the information of the reception pointer 17 by M. Here, when the secondary station has the output device 13, the value of the information of the read pointer 16 is the packet number of the data packet output immediately before to the tertiary station.

Upon receiving the data packet from the primary station, the secondary station updates the information in the reception record table 15 according to the result. Here, when the secondary station includes the output device 13, a new data packet is output according to the result of receiving the data packet. Further, when the secondary station receives polling from the primary station, the value recorded in the information of the reception pointer 17 and the reception state of the M data packets immediately before this value (including the packet at the position of the reception pointer) are set to 1
Send to the next station.

[Packet Format] There are three types of packet formats used for communication between the primary station and the secondary station, as shown in FIGS. The areas of the symbols H and T described in FIG. 4 are areas where network-specific information and the like necessary for performing communication between the primary station and the secondary station are stored. As shown in FIG. 4A, the data packet (primary station → secondary station) includes a packet number, data of a block area, and a checksum. As shown in FIG. 4 (2), the polling packet (primary station → secondary station) includes one or more secondary station numbers to be polled and a checksum. As shown in FIG. 4 (3), the polling response packet (secondary station → primary station) includes a value of a reception pointer, a reception state of M data packets, and a checksum.

Next, the operation of the data broadcast transmission method, communication method, transmitting apparatus (primary station), and communication system (primary station, secondary station) of the embodiment of the present invention will be described. Description will be made with reference to FIGS. 4 to 9 as necessary. FIG. 5 is a diagram for explaining whether a data packet received by the secondary station is a retransmitted packet or a newly transmitted data packet. FIG. 6 is a flowchart of the data transmission operation of the primary station. FIG. 7 is a flowchart of the polling issuing operation of the primary station. FIG. 8 is a flowchart of the data reception operation of the secondary station. FIG. 9 is a flowchart of the polling response operation of the secondary station.

(Data Creation) As described above, the maximum number of packets (window size) that the primary station can transmit without waiting for confirmation of reception from the secondary station is M (M is a natural number of 1 or more). . The primary station divides the data to be transmitted into blocks of a predetermined length (for example, 188 bytes), and uses a packet number from 0 to 2M-1 based on the data of the first block in the data of this block area. Each of the data in the area is identified sequentially. That is, the data of the 2Mth block area from the data of the first block area is identified by the packet numbers of 0, 1, 2, 3,..., 2M-2, and 2M-1. .., 2M−2, 2M−1 again from the data of the first block area to the data of the 2M + 1th block area and thereafter.
Is identified by the packet number. That is, the packet number is calculated by so-called modulo 2M, and the above-described packet number and the packet number described later are also calculated by modulo 2M. Next, as shown in FIG. 4A, the primary station sequentially creates a data packet including at least a packet number, data of a block area identified by the packet number, and a checksum.

(Data Transmission) The data packets produced as described above are transmitted one by one for each data packet by the primary station. First, the primary station checks the value W recorded in the information of the window counter 9, and if the value is larger than 0, the primary station can continuously transmit data packets by W. Therefore, the primary station sequentially transmits the data packets of W from the first data packet among the data packets to all of the N secondary stations by broadcast distribution via the downlink.

(Data reception) On the other hand, each of the N secondary stations receives each of the W data packets on the downlink, and the data in the block area of this data packet and the packet corresponding to this data are received. Get the number and the checksum. Here, by detecting the checksum from the received data packet, the secondary station can confirm that there is no error in the data and packet number of the block area inside the received data packet. Subsequently, each time the secondary station receives a data packet, it makes a retransmission determination on the data packet. Here, the retransmission determination refers to determining whether the data packet has been transmitted once or is new data from the packet number in the data packet. As shown in FIG. 5, the definitions of retransmission data and new data are as follows.

When the packet number is one of the value recorded in the information of the read pointer 16 plus the value recorded in the information of the reception pointer 17, the data packet is retransmission data. On the other hand, the packet number is read from the value +1 recorded in the information of the reception pointer 17 + 1
The data packet is new data when it is any of the values recorded in the information of No. 6.

As a result of the retransmission determination, if the data packet received by the secondary station is retransmitted data, the data in the block area inside the data packet has been received or has been previously received and has been previously failed. Whether or not it is necessary is searched by the information of the reception record table 15 of the secondary station. As a result, when it is necessary to take in the data this time, the data of the block area inside the received data packet is recorded in the information of the reception record table 15 of the secondary station, and the flag of the data packet reception state is set to “received”. change.
At this time, since the data packet is retransmission data, the value recorded in the information of the reception pointer 17 is not changed. If it is necessary to take in the data this time, the secondary station discards the data packet.

As a result of the retransmission determination, if the data packet received by the secondary station is new data, the data packet received in the area corresponding to the packet number in the information of the reception record table 15 of the secondary station The data of the internal block area is recorded, and the flag of the data packet reception state is changed to “received”. At this time, since the data packet is new data, the value recorded in the information of the reception pointer 17 is changed to the value of the packet number of this data packet. Normally, the secondary station normally receives data packets from the primary station one by one, so the value recorded in the information of the reception pointer 17 increases by one. Therefore, if the value recorded in the information of the reception pointer 17 after the change is different from the value recorded in the information of the reception pointer 17 before the change by two or more, it means that a data packet between them could not be received. Therefore, "not received" is recorded in the data packet reception state flag of the dropped data packet.

Further, since the value of the information of the read pointer 16 is always smaller than the value of the information of the receive pointer 17 by M, the information of the read pointer 16 is also changed. When the secondary station has the output device 13, the secondary station changes the value of the read pointer 16 before the change from the value +1 recorded in the information of the read pointer 16 before the change to the read pointer 1 after the change.
Data packets corresponding to the values recorded in the information No. 6 are output to the tertiary station in ascending order of packet number.
In other words, the secondary station outputs one data packet to the tertiary station sequentially from the first data packet every time a new data packet is received after receiving the first M data packets. This allows the secondary station to output the same data packet at the same timing when the data packet is received from the primary station. That is, there is an advantage that the primary station can control the output of the data packet from the secondary station to the tertiary station.

The secondary station transfers the data of the data packet from the value +1 recorded in the information of the read pointer 16 before the change to the value recorded in the information of the read pointer 16 after the change to the secondary station. From the information in the reception record table 15, and resets the data packet reception state flag to "not received". (In other words, when the secondary station is provided with the output device 13, the data of the data packet output from the secondary station to the tertiary station is deleted from the information in the reception record table 15 of the secondary station. Resets the packet reception status flag to "not received".

(Polling) The primary station places a time difference with respect to each of the N secondary stations via the downlink, and sets N 2
A polling packet for asking whether each of the following stations has received each of the data packets is transmitted by individual communication. At this time, the polling is performed not at every time when each data packet is sequentially transmitted by the broadcast distribution but at a time difference. In other words, polling is performed independently of data transmission. Polling is performed individually for each of the N secondary stations, but not for all the secondary stations. As a result, the line is not congested by the polling response packet from the secondary station that has received the polling packet to the primary station (including the reception state information indicating whether the secondary station has received the data packet). In addition, the reception confirmation processing load of the primary station does not concentrate at one time. Therefore, there is an advantage that the data transmission efficiency can be increased while guaranteeing high reliability of transmission data by the polling issuing process.

The schedule for when and to which secondary station polling is performed is controlled by the primary station. After transmitting the polling packet, the primary station updates the information of the polling pointer 8 corresponding to the secondary station that performs polling. Therefore, at the time of data transmission by the primary station, at least one or more polling can be performed each time M data packets are transmitted on the downlink with reference to the first data packet among the data packets. In other words, every time M data packets are transmitted, all of the N secondary stations receive at least one or more polling packets. From the information in the recording table 6, N of 2
It is possible to manage whether or not there is a data packet that is received by all of the next stations. Here, if there is a data packet that is received by all of the N secondary stations, the primary station can transmit a new data packet to the secondary station. There is the advantage that it can be higher.

After transmitting the data packet by the value W recorded in the information of the window counter 9, the primary station transmits
From the information in the reception record table 6, if there is a data packet that has been received by all of the N secondary stations, the primary station determines the last data packet among these data packets as the most recently received polling packet. Priority polling can be performed for a secondary station that is a data packet received late. (In other words, the window counter 9
When the value W recorded in the information of the polling pointer 8 is 0 (a state in which a new data packet cannot be transmitted), a value smaller than the value recorded in the information of the window pointer 7 is recorded in the information of the polling pointer 8. Can be preferentially polled. As a result, the reception status information (information of the polling pointer 8) of the secondary station that has received this polling packet is updated, so that the primary station can perform data transmission from the information of the reception record table 6. This has the advantage that the data transmission efficiency can be further increased.

If the primary station does not receive a polling response within a predetermined time after transmitting the polling packet, the primary station re-issues the polling packet. If no response is obtained after repeating the polling a certain number of times, the secondary station is determined to be faulty and is thereafter excluded from transmission targets.

(Polling Response) Each of the secondary stations receives a polling packet on the downlink, and receives the polling packet to the primary station via the uplink, starting from the latest received data packet and immediately preceding the data packet. A polling response packet including at least a data packet reception state flag and a packet number corresponding to the M data packet is transmitted by multiple access. On the other hand, the primary station receives the polling response packet on the uplink and records the flag of the data packet reception state of M data packets from the secondary station in the information of the reception record table 6 of the primary station. . As a result of the polling, the packet number of the value recorded in the information of the window pointer 7 of the primary station is recorded in the information of the window counter 9 when all of the N secondary stations become “received”. Value W is increased by one. Also, the primary station updates the information of the window pointer 7 in which the packet number of the oldest data packet among the data packets that have already been transmitted and are waiting for reception confirmation (reception confirmation waiting data packet) is recorded. Incidentally, if the value recorded in the information of the reception pointer 17 of the secondary station is smaller than the value recorded in the information of the window pointer 7 of the primary station, the secondary station becomes Since the reception of all data packets has failed, the information in the reception status table 6 of the primary station is not updated.

(Retransmission of data packet) If there is a data packet which has not been received by any of the N secondary stations from the information in the reception record table 6, the primary station transmits this data packet to the downlink. , And re-transmit by broadcast to all of the N secondary stations. (In other words, even though the values recorded in the information of all the polling pointers 8 are later than the values recorded in the information of the window pointer 7, the values correspond to the values recorded in the information of the window pointer 7. If the flag of the data packet reception status of the data packet is “not received” at any of the secondary stations, it means that the secondary station could not receive the data packet, and the primary station retransmits the data packet. The primary station simultaneously retransmits the data packet,
A polling packet is preferentially transmitted to the secondary station which has not received this data packet via the downlink by individual communication.

(At the end of transmission) If the secondary station has an output device 13, the primary station has transmitted all the data to be transmitted, and then has read the pointer 16 in the memory 12 of the secondary station. In order to output all data remaining after the value recorded in the information, M dummy data packets containing no data are transmitted.

(Operation Example) FIG. 10 is a time chart showing an operation example of a transmission method, a communication method, a transmission device, and a communication method of data broadcast distribution according to the embodiment of the present invention. Note that FIG.
, The total number N of secondary stations is 3, and the window size M is 4. First, the primary station window pointer 7
Has no value, but becomes zero when data packet 0 (packet number 0) is transmitted. First, the primary station P1 transmits data packets (packets) by the number of window counters W (M = 4). Here, it is assumed that the secondary station S2 has failed to receive the packet of the number 1. Since the value of the window counter W becomes 0 when the primary station P1 transmits packets 0 to 3, no new data can be transmitted, and the result of the polling is awaited. When all polls for the secondary stations S1 to S3 are returned, the reception of packet 0 is confirmed, and the value W of the window counter increases by one, so that the value W of the window counter of the primary station P1 is set to packet 1. . As a result, the packet 4 is newly transmitted, and the value of the window counter W becomes 0 again. The primary station P1 checks the reception confirmation table, and the secondary station S2 determines that the packet 1
Packet 1 is retransmitted. After the retransmission of the packet 1, the primary station P1 polls the secondary station S2. As a result of the polling response, the acknowledgment of the packet 1 is completed, and the subsequent packet 5 is transmitted.

Next, the primary station P1 polls the last data packet among the data packets when there are data packets (packet 0 and packet 1) received by all three secondary stations. When the packet (packet 1) is received, the polling packet is preferentially transmitted to the secondary station (S1) which is the latest received data packet. In other words, the primary station P1 preferentially transmits the polling packet to the secondary station S1 whose reception confirmation is the latest among the three secondary stations. This allows
Since the reception status information of the secondary station S1 that has received this polling packet is updated, a new data packet (packet 2) is transmitted.

In the configuration of the embodiment, for example, the primary station, the secondary station, and the tertiary station are broadcast stations that transmit and receive programs and the like.
Network) can also be a computer that sends and receives files and the like. In this case, one computer (primary station) is replaced by a plurality of other computers (secondary stations).
, And each of the other computers (secondary station) receiving the file outputs the file to another computer (tertiary station). Here, a file is a collection of data having a meaningful unit in order for a computer to perform some processing. Therefore, in order for data transmitted by one computer (primary station) to be a file, one computer (1
The importance of transmitting the same data packet at the same timing to all of the plurality of computers (secondary stations) at the timing of receiving the data packet from the next station is low. That is, the computer (secondary station) that has received the file can immediately output the file each time the file is received.

[0058]

As described above, according to the present invention, the primary station divides data into blocks each having a predetermined length, and sequentially generates data packets including at least each of the data in the block area. Broadcast, wherein the primary station sequentially transmits each of the data packets by broadcast to all N secondary stations (N is a natural number of 2 or more) via the downlink. A distribution process, and whether each of the N secondary stations has received each of the data packets at a time lag from the N secondary stations via the downlink. And a polling issuing step of transmitting a polling packet by individual communication. Thus, according to the present invention, the polling issuance process is performed at a time lag, rather than each time a data packet is sequentially transmitted by broadcast. In other words, the polling issuance process is performed independently of the broadcast distribution process. The polling issuance process is performed individually for each of the N secondary stations, but not for all of the N secondary stations. As a result, the line is not congested by the polling response packet from the secondary station that has received the polling packet to the primary station (including the reception state information indicating whether the secondary station has received the data packet). In addition, the reception confirmation processing load of the primary station does not concentrate at one time. Therefore, there is an effect that the data transmission efficiency can be increased while ensuring high reliability of transmission data by the polling issuing process.

[Brief description of the drawings]

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

FIG. 2A is a configuration diagram showing a primary station, and FIG.
(2) is a diagram showing an example of a reception record table of the primary station.

FIG. 3A is a configuration diagram illustrating a secondary station, and FIG.
(2) is a diagram showing an example of a reception record table of the secondary station.

FIG. 4 (1) is a diagram showing one format of a data packet transmitted from a primary station to a secondary station, and FIG. 4 (2) is a polling transmitted from the primary station to the secondary station. FIG. 4C is a diagram showing one format of a packet, and FIG. 4C is a diagram showing one format of a polling response packet transmitted from the secondary station to the primary station.

FIG. 5 is a diagram for explaining whether a data packet received by a secondary station is a retransmitted packet or a newly transmitted data packet.

FIG. 6 is a flowchart of a data transmission operation of the primary station.

FIG. 7 is a flowchart of the polling issuing operation of the primary station.

FIG. 8 is a flowchart of a data reception operation of the secondary station.

FIG. 9 is a flowchart of a polling response operation of a secondary station.

FIG. 10 is a time chart of an operation example according to the embodiment of the present invention.

[Explanation of symbols]

 P1 Primary station S1 to SN Secondary station 1, 11 CPU 2, 12 Memory 3 Data buffer 4 Input device 5, 14 Communication device 6, 15 Reception record table 7 Window pointer 8 Polling pointer 9 Window counter 13 Output device 16 Read pointer 17 Receive pointer

Claims (10)

[Claims] 1. A data packet producing step in which a primary station divides data into blocks of a predetermined length and sequentially produces data packets including at least each of the data in the block area; A broadcast distribution step of sequentially transmitting each of the data packets to all N secondary stations (N is a natural number equal to or greater than 2) via a downlink, and the primary station; A polling packet asking whether each of the N secondary stations has received each of the data packets at a time difference from each of the N secondary stations via the downlink. And a polling issuing step of transmitting by individual communication. 2. A data packet producing step in which a primary station divides data into blocks each having a predetermined length, and sequentially produces data packets including at least each of the data in the block area; For all of the N secondary stations (N is a natural number of 2 or more) through the downlink, W (W is a natural number of 0 or more, and W The value is M which is a natural number of 1 or more.) Broadcast distribution process of sequentially transmitting the data packets by broadcast distribution, and wherein each of the N secondary stations has the data packet of W on the downlink. And a polling process in which the primary station transmits a polling packet via the downlink to each of the N secondary stations at a time difference by individual communication. The issuance process; and the data received latest when each of the N secondary stations receives the polling packet on the downlink and receives the polling packet to the primary station via the uplink. A polling response step of transmitting, by multiple access, a polling response packet including at least reception status information as to whether or not the data packet of the immediately preceding M has been received from the packet; Each receives and manages whether there are any data packets not received by any of the N secondary stations and whether there are data packets received by all of the N secondary stations. A receiving management step, and when there is the data packet not received by any of the N secondary stations in the receiving managing step, A re-broadcasting process in which the primary station retransmits a packet to all of the N secondary stations via the downlink by broadcasting, and performing the data packet as the W data packet. A broadcast receiving step, a priority polling issuing step in which the primary station preferentially transmits a polling packet by individual communication to the secondary station not receiving the data packet via the downlink, And a polling response step of performing a secondary station that has not received a data packet as the N secondary stations, and returning to the reception management step, wherein all of the N secondary stations are N in the reception management step. When there is the data packet being received, the broadcasting step in which the number of data packets is set to W, and the broadcasting in which the number of data packets is set to W, A receiving step, and the polling issuing process, and a said polling response process, a method of communicating data broadcasting, characterized in that return to the reception management process. 3. The polling issuance step includes performing at least one or more transmissions each time an M data packet is transmitted on the downlink with reference to a head data packet among the data packets in the broadcast communication step. 3. The communication method for data broadcast distribution according to claim 2, wherein: 4. The polling issuance step includes the step of polling the last data packet among the data packets when all of the N secondary stations have the data packet in the reception management step. 4. The data broadcast communication method according to claim 2, wherein priority is given to a secondary station which is the data packet received latest when a packet is received. 5. In the broadcast receiving step, after receiving the first M data packets, each time a new data packet is received, one data packet is sequentially transmitted from the first data packet to the tertiary station. The communication method for data broadcast distribution according to any one of claims 2 to 4, wherein the communication is performed. 6. A data packet generating means for dividing data into blocks each having a predetermined length, and sequentially generating data packets including at least each of the data in the block area, and N receiving devices via a downlink. (N is a natural number of 2 or more) to all of the data packets, and to each of the N receiving devices via the downlink to sequentially transmit each of the data packets by broadcast. Polling issuing means for transmitting a polling packet by individual communication for inquiring whether or not each of the N receiving devices has received each of the data packets at a time difference. Transmission device for data broadcasting. 7. A data broadcasting system comprising: a primary station for transmitting data on a downlink; and N secondary stations (N is a natural number of 2 or more) for receiving the downlink data. A communication system, wherein the primary station divides the data into blocks each having a predetermined length, and sequentially creates data packets including at least each of the data in the block area; W (W is a natural number equal to or greater than 0, and the initial value of W is M, which is a natural number equal to or greater than 1, from the first data packet of the data packets to all of the N secondary stations via a line. )), Wherein each of the N secondary stations receives each of the W data packets on the downlink line by a broadcast distribution means for sequentially transmitting the data packets by the broadcast distribution. Has receiving means The primary station has polling issuing means for transmitting polling packets by individual communication with a time difference to each of the N secondary stations via the downlink, Each of the stations receives the polling packet on the downlink, and receives the polling packet for the primary station via the uplink, and transmits the M data packet immediately before the latest received data packet. Has polling response means for transmitting by multiple access a polling response packet including at least reception status information of whether or not has been received, the primary station receives each of the polling response packets on the uplink, Whether there are any data packets not received by any of the N secondary stations and the data received by all of the N secondary stations Receiving management means for managing whether or not there is a packet, and if the reception management means has any of the data packets which have not been received by any of the N secondary stations, the primary station transmits the data packet. And re-broadcasting means for re-transmitting all of the N secondary stations by broadcast over the downlink, and each of the N secondary stations transmits this data packet to the W Having the broadcast receiving means for performing data packet transmission, wherein the primary station preferentially transmits a polling packet to the secondary station which has not received the data packet via the downlink by individual communication. Priority polling issuing means, the polling response means for performing a secondary station which has not received the data packet as the N secondary stations, and the reception management means; In the case where there is the data packet received by all of the N secondary stations, the primary station has the broadcast distribution means for performing the number of data packets as the W, and the N Each of the next stations has the broadcast receiving means for setting the number of data packets as W, the primary station has the polling issuing means,
Wherein each of the secondary stations has the polling response means and the primary station has the reception management means. 8. The polling issuing means performs at least one or more transmissions each time an M data packet is transmitted on the downlink with respect to a head data packet of the data packets in the broadcast communication means. 8. The communication method for data broadcast distribution according to claim 7, wherein: 9. The polling issuing means, when there is the data packet which is received by all of the N secondary stations in the reception management means, and polls the last data packet among the data packets. 9. The data broadcast communication method according to claim 7, wherein priority is given to a secondary station which is the data packet received latest when receiving a packet. 10. The broadcast receiving means transmits one data packet to the tertiary station sequentially from the first data packet every time a new data packet is received after receiving the first M data packet. The communication system for data broadcast distribution according to any one of claims 7 to 9, wherein: