JP2008042253A - Mutlicast communication system and method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multicast communication system having good balance between a transmission quality and transmission efficiency. <P>SOLUTION: A transmitter side transmission apparatus 11 adds a transmission destination identifying code for identifying a transmission destination to which a normality response of reception should be returned to a transmission signal, and transmits the signal to receiver side transmission apparatuses 21-2n. Upon receiving the code, if the transmission destination identifying code of the reception signal is destined itself, the receiver side transmission apparatuses 21-2n each determine whether or not the reception signal is received, and return information about normal reception if reception determination is positive and information about a retransmission request if the reception determination is negative, as a response signal to the transmitter side transmission apparatus. In response to this, the transmitter side transmission apparatus 11 re-transmits a transmission signal. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a multicast communication system, and in particular, in multicast transmission in which the same data is transmitted to a plurality of transmission apparatuses among a plurality of transmission apparatuses, transmission with balanced transmission quality and transmission efficiency is performed. The present invention relates to a communication method and a program that can be used.

  In general, when the same information is transmitted from one transmission apparatus to a plurality of other transmission apparatuses, two methods are conceivable. In the first method, the same information is transmitted from a transmission apparatus on the transmission side to a plurality of transmission apparatuses on the reception side, but the transmission side transmission apparatus does not determine whether each reception side transmission apparatus has received normally. Is the method. In the second method, the same information is transmitted from a transmission device on the transmission side to a plurality of transmission devices on the reception side, and the transmission side transmission device determines whether or not each reception side transmission device has received normally by some method. It is a method to judge. The determination as to whether or not the reception is normal is made based on whether or not an acknowledgment signal or a retransmission request signal is returned from each receiving-side transmission apparatus.

Conventionally, various systems have been disclosed as multicast communication systems. For example, as described in Japanese Patent Laid-Open No. 11-150503 (Patent Document 1), when the same information data is transmitted to a large number of receiving side transmission devices, the communication band and the modulation method are changed for each receiving side transmission device, Some devices adjust the communication speed. Further, in JP 2000-196598 (Patent Document 2), the transmission apparatus on the transmission side adds the transmission destination 1 to be transferred next to the transmission apparatus on the reception side to the information data and transmits the information data. The receiving-side transmission apparatus discloses a relay-type multicast communication system in which a transfer destination 2 to be transferred next is added to information data and transmitted to the transfer destination 1.
Japanese Patent Laid-Open No. 11-150503 Japanese Unexamined Patent Publication No. 2000-196598

  However, in such a conventional method, there is a problem that the accuracy of whether or not it has been received and the processing load for response processing are excessively applied. More specifically, in the first method described above, high transmission efficiency can be realized, but it is unclear whether or not transmission has been performed normally. In the second method, high accuracy can be realized, but it takes time to receive responses from all receiving side transmission devices, the processing load on the transmission device increases, and the traffic load on the transmission path also increases. There was a drawback of doing.

  In view of such problems, the present invention enables a highly accurate transmission, further reduces the processing load of the transmission apparatus and realizes a high transmission efficiency, that is, a multicast communication system in which transmission quality and transmission efficiency are balanced. The purpose is to provide.

  According to the present invention, the transmission apparatus on the transmission side adds a transmission destination identification code for identifying the transmission destination to which the normality response of reception is to be transmitted to the transmission signal, and transmits the transmission signal to the plurality of transmission apparatuses on the reception side. When the transmission destination identification code of the received signal is addressed to itself, the transmission apparatus determines whether or not the received signal is received correctly. If the received determination is positive, the normal reception information is received. To the transmission device on the transmission side, and the transmission signal is retransmitted.

  More specifically, according to the present invention, in a multicast communication system that performs multicast transmission of transmission information data from a transmission-side transmission apparatus to a plurality of reception-side transmission apparatuses, the transmission-side transmission apparatus includes a plurality of reception-side transmission apparatuses. A transmission destination identification code adding means for adding a transmission destination identification code for identifying a transmission destination to which a normality response of reception should be returned to a transmission signal including transmission information data; and a transmission means for transmitting a transmission signal with a transmission destination added. The transmission destination identification code adding means changes the transmission destination for each transmission information data.

  In the multicast communication system, the transmission-side transmission device and the plurality of reception-side transmission devices include a plurality of communication bands. The transmission-side transmission device further includes a second reception unit that receives a response signal, and an environment based on the received response signal. A communication environment grasping means for generating information data and grasping a communication environment from environment information data, and a communication band changing means for selecting a communication band suitable for the grasped communication environment from a plurality of communication bands, and transmitting means May be configured to perform transmission in a selected communication band.

  Further, the response signal may include a normal reception signal indicating that the reception signal has been normally received, or a retransmission request signal for requesting retransmission of the transmission signal with the destination added because the reception signal has not been normally received. .

  According to the present invention, a multicast communication method for performing multicast transmission of transmission information data from a transmission-side transmission device to a plurality of reception-side transmission devices is a transmission to which a normality response of reception is to be returned among the plurality of reception-side transmission devices. A first step of adding a destination identification code for identifying a destination to a transmission signal including transmission information data, and changing a transmission destination of a transmission destination added transmission signal to which a transmission destination identification code is added for each transmission information data And a second step of transmitting to a plurality of receiving side transmission apparatuses.

  Preferably, the method further includes a third step of receiving the destination-added transmission signal in any of the plurality of reception-side transmission apparatuses, and a first step of identifying a destination identification code of the received destination-added transmission signal. And a fifth step of transmitting a response signal to the received transmission destination added transmission signal to the transmission device when the transmission destination identification code is addressed to its own transmission device.

  The transmitting side transmission device and the plurality of receiving side transmission devices include a plurality of communication bands, and the method further includes a sixth step of receiving a response signal in the transmitting side transmission device, and environmental information data from the received response signal. And a seventh step of grasping the communication environment from the environment information data, an eighth step of selecting a communication band suitable for the grasped communication environment among a plurality of communication bands, and the selected communication band And a ninth step of performing transmission.

  According to the present invention, a communication method for multicast transmission of transmission information data from a transmission apparatus on the transmission side to a plurality of transmission apparatuses on the reception side can be realized in the form of a multicast communication program executed by a computer.

  According to the present invention, since the transmission apparatus on the transmission side can periodically receive responses from all the transmission apparatuses on the reception side, the communication rate, which is the amount of information transmitted per unit time, is reduced compared to the conventional method. Therefore, the transmission quality deviation can be reduced, and transmission with balanced transmission quality and transmission efficiency can be performed.

  The present invention is advantageously applied to the field of performing multicast transmission in which the same data is transmitted from a single transmission device to a plurality of transmission devices, such as a disaster report.

  Embodiments of a multicast communication system according to the present invention will now be described in detail with reference to the accompanying drawings. FIG. 1 is a conceptual block diagram showing an embodiment of a multicast communication system according to the present invention. The multicast communication system of the embodiment includes a transmission-side transmission device 11 and a plurality (n) of reception-side transmission devices 21 to 2n (n is a natural number), and the transmission-side transmission device 11 and a plurality of reception-side transmission devices 21 to 2n are connected by a wired or wireless transmission path. From the transmission device 11 on the transmission side, a transmission information sequence 31 having the configuration illustrated in FIG. 2 is transmitted to the transmission devices 21 to 2n on the reception side. The reception side transmission apparatuses 21 to 2n are configured to transmit a response signal to the transmission side transmission apparatus 11 according to the situation when receiving the transmission side transmission apparatuses 21 to 2n.

  For example, the system of the present embodiment is advantageously applied to a portable audio system that transmits information having high real-time characteristics such as music from a transmission source to a plurality of headphones. More specifically, the transmission-side transmission device 11 directs the transmission information sequence 31 including a series of music information No. 1 to No. m (m is a natural number) that occurs in time series to the reception-side transmission devices 21 to 2n. To send. In this embodiment, when each of the series of music information No. 1 to No. m is transmitted in order, the transmission side transmission device 11 sequentially selects one of the reception side transmission devices 21 to 2n, and The selected device is included in the transmission information as the destination. The reception-side transmission devices 21 to 2n receive transmission information all at once, but the reception-side transmission device that has identified its destination among them transmits a response signal to the transmission-side transmission device 11.

  FIG. 3 is a block diagram showing an example of the internal configuration of the transmission device 11 on the transmission side and the transmission device 21 on the reception side of the multicast communication system according to the present invention. The multicast communication system according to the present embodiment transmits transmission information 100 to be broadcast by adding a code for identifying a transmission destination, for example, the reception-side transmission device 21, and sequentially transmits this transmission destination to the reception-side transmission devices 21 to 2n. It changes so that it may transmit and it may be transmitted. When the receiving side transmission device, for example, 21 identifies the destination identification code of the received data and determines that it is addressed to itself, that is, to itself, it returns a response to the transmitting side transmission device 11. This response will be described in detail later. Further, when the transmission destination identification code of the received data is not addressed to itself, a normal process such as outputting the received data (100) without returning a response is performed. For example, if the received data is music information, it is reproduced and output. By doing so, the transmission-side transmission apparatus 11 can confirm the normality of transmission.

  Here, the term “destination” does not mean the destination to which the transmission information 100 is transmitted, but whether or not the transmitted transmission information 100 has been normally received among the receiving side transmission apparatuses 21 to 2n, or retransmission is necessary. It is used in the meaning of identification information that identifies the device that is the target of requesting the return of the normality response. This is because the transmission information 100 is transmitted toward all the receiving side transmission apparatuses 21 to 2n.

  The transmission apparatus 11 on the transmission side includes a data processing apparatus 110, which is a functional unit that receives information 100 to be transmitted and assembles it as a transmission signal 111. The transmission signal 111 is obtained by adding a transmission control signal to the information 100 and may be in a generally known format. The assembled transmission signal 111 is sent to the transmission destination identification code adding device 120. In the following description, the signal is specified by the reference numeral of the connecting line that appears.

  The transmission destination identification code adding device 120 has a function of adding a transmission destination identification code 122 (FIG. 4) to the transmission signal 111 to assemble a transmission destination added transmission signal 121 and transferring the transmission signal to the transmission device 130. The transmission destination identification code adding device 120 also performs destination management of the transmission destination added transmission signal 121 to be sent to the transmission device 130. In this destination management, a plurality of receiving side transmission devices 21 to 2n that perform transmission are managed in the order of transmission by a destination management table (not shown), and the destination transmission state is set for each receiving side transmission device and for each transmission signal. Is set to one of “not transmitted”, “sending”, or “sending completed”. By this destination management, it is possible to manage up to which receiving side transmission apparatus transmission of the destination is completed.

  Specifically, when the transmission destination identification code adding apparatus 120 sends a transmission destination added transmission signal 121 to a certain receiving side transmission apparatus, for example, 21, to the transmitting apparatus 130, transmission to the receiving side transmission apparatus 21 is performed. The status is changed from “not transmitted” to “sending”. The transmission apparatus 11 on the transmission side includes a reception apparatus 150. When the transmission destination identification code adding apparatus 120 receives the normal reception confirmation information 151 from the reception apparatus 150 as described later, the transmission state is changed from “transmitting” to “transmission”. Change to Completed. A specific configuration example of the transmission signal 111 and the destination-added transmission signal 121 is shown in detail in FIG. This will be described below whenever necessary.

  The transmission destination identification code adding device 120 further performs destination management as follows. In the destination management state, if any of the receiving side transmission devices 21 to 2n is “unsent” that does not include the destination in the broadcast data, one receiving side transmission device in the unsent state is set as the destination of the transmission data. Select one by one and set it as the destination. The transmitting device 130 transmits the data, and performs transmission processing while managing the destination until all the receiving-side transmission devices are in the “transmission complete” state in this way. Further, if there is data to be transmitted in the transmission information sequence 31, the above transmission operation is repeated.

  Returning to FIG. 3, the transmission device 130 is a functional unit that transmits the created transmission destination-added transmission signal 121 to the reception-side transmission devices 21 to 2n as the transmission signal 30. The transmission apparatus 11 also includes a transmission data storage device 140, which is a storage unit that stores the transmission destination added transmission signal 121 prior to transmission. The destination-added transmission signal 121 stored in the transmission data storage device 140 is used as the retransmission signal 31 when retransmission is necessary.

  Incidentally, the transmission-side transmission device 11 also includes a reception device 150, which is a reception circuit that receives a response signal 40 (described later) transmitted from the reception-side transmission device 21. As will be described in detail later, if the response signal 40 is the reception confirmation response signal 251, the reception device 150 recognizes that the transmission destination-added transmission signal 121 transmitted earlier is normally transmitted to the reception-side transmission device 21. Then, the normal reception confirmation information 151 is generated and sent to the transmission destination identification code adding device 120. As described above, the transmission destination identification code adding device 120 receives the normal reception confirmation information 151 and changes the destination transmission state included in the management data from “transmitting” to “transmission completed”.

  The receiving device 150 also has a function of sending the response signal 40 to the retransmission processing device 160 if the response signal 40 is the retransmission request signal 252. Based on a retransmission request signal 252 to be described later, the retransmission processing device 160 takes out the transmission destination added transmission signal 121, which is the transmission signal 30 transmitted earlier, from the transmission data storage device 140, and extracts it. The data is sent to the transmission device 130. The transmission device 130 also has a function of transmitting the transmission signal with the transmission destination added 121 as the transmission signal 30 to the reception-side transmission device 21 as a retransmission signal.

  The reception side transmission devices 21 to 2n may basically have the same configuration, and the reception side transmission device 21 will be described as an example. The reception-side transmission device 21 includes a reception device 210, which is a functional unit that receives the transmission destination added transmission signal 121 transmitted from the transmission device 130 of the transmission-side transmission device 11 as the reception signal 30. The receiving apparatus 210 also deletes the transmission control code from the transmission destination-added transmission signal 121 that is the reception signal 30, generates reception data 211, and sends this to the transmission destination code identification apparatus 220. A configuration example of the reception data 211 is shown in detail in FIG. The receiving device 210 also has a function of receiving the retransmission signal 31 described above.

  The transmission destination code identification device 220 has a function of determining whether or not the transmission destination identification code 122 present in the reception data 211 is the identification code of its own reception-side transmission device 21. If the determination result is NO, that is, if the transmission destination identification code 122 is not the identification code of its own receiving-side transmission device 21, it is determined that the transmission destination added transmission signal 121, which is the reception signal 30, is not addressed to itself, and the received data 211 is sent from the output 221 to the data processor 230 as it is. When the identification result is positive, that is, when the transmission destination identification code 122 is the identification code of its own reception-side transmission device 21, it is determined that the transmission destination added transmission signal 121 that is the reception signal 30 is addressed to itself. Received data 211 is sent to data processor 230.

  The data processing device 230 has a function of determining whether or not the information 100 present in the received data 211 is correctly received, that is, its normality. If it is determined that the data has been correctly received, it is determined that normal reception has been confirmed, and reception confirmation data 233 including a reception confirmation message 231 is generated and sent to the response processing device 250. That is, as a result, only the receiving side transmission apparatus designated as the transmission destination returns a response. The data processing device 230 also outputs the information 100 itself in the received data 211 from its output 100 and sends it to the subsequent device. On the other hand, if it is determined that the information 100 present in the received data 211 has not been received correctly, the data processing device 230 determines that the reception is abnormal, and requests retransmission of the transmission signal with the transmission destination added transmission signal 121 as a reception signal. Resend request data 234 including request message 232 is generated and sent to response processing device 250. In this case, the information 100 itself present in the received data 211 is not output from the output 100.

  Upon receiving the reception confirmation data 233, the response processing device 250 has a function of generating a reception confirmation response signal 251 including the reception confirmation data 233 and sending it to the transmission device 260. When receiving the retransmission request data 234, the response processing device 250 also has a function of generating a retransmission request signal 252 including the retransmission request data 234 and sending it to the transmission device 260. The reception confirmation data 233, the retransmission request data 234, the reception confirmation response signal 251 and the retransmission request signal 252 are illustrated in detail in FIG. The transmission device 260 is a transmission function unit that transmits the response signal 40 including the reception confirmation response signal 251 or the retransmission request signal 252 to the transmission device 11 on the transmission side.

  Here, the operation of this embodiment will be described in detail with reference to FIGS. In these operation flow diagrams, the numbers in the circles are skip symbols. First, when transmission information, for example, transmission information data No. 1 in the transmission information sequence 31 occurs (step S, Y), the transmission apparatus 11 on the transmission side generates a transmission signal 111 from this transmission information (S2). Therefore, the transmission state of the destination management table of the receiving transmission apparatus 21 to be transmitted is checked, and it is determined whether or not the transmission destination of the apparatus 21 is “transmission complete” (S3). If it is in an “untransmitted” state (N), the process jumps to the next step S5 and adds the identification code of the receiving side transmission device 21 to the transmission signal 111 as a transmission destination identification code, and generates a transmission destination added transmission signal 121 (S5). In addition, the transmission state of the destination management table is changed from “not transmitted” to “sending”. If the transmission is completed in step S3 (Y), the process proceeds to the next step S4, and is changed to the next reception side transmission apparatus of the reception side transmission apparatus 21, which is the apparatus 22 in this embodiment (S4), and step S5. Then, the latter identification code is added as a transmission destination identification code to the transmission signal 111 to generate a transmission destination added transmission signal 121. Next, the transmission destination added transmission signal 121 is stored in the transmission data storage device 140 (S6). Thereafter, this transmission destination added transmission signal 121 is sent to the transmission device 130. The transmission device 130 transmits the destination-added transmission signal 121 to the reception-side transmission device 21 (S7).

  In the receiving-side transmission device 21, the receiving device 210 receives the destination-added transmission signal 121 as a reception signal 30 (S21). Next, the reception device 210 generates reception data 211 from the reception signal 30, and the transmission destination code identification device 220 compares the transmission destination identification code present in the reception data 211 with its own identification code to match. It is determined whether or not (S22). If the determination result is “no match”, it is determined that the received signal is not addressed to itself, and the received data 221 is simply output from the output 100 (S30). On the other hand, in the case of “match”, it is determined that the received signal is addressed to itself, that is, a request to return some response signal has been received, and the data processor 230 receives the information 100 present in the received data 211 normally. It is determined whether or not it has been done (S24). If it is determined that the reception is normal, the reception data 211 is sent to the subsequent apparatus as information 100 (S30), and the reception confirmation data 233 is sent to the response processing apparatus 250. In response to this, the response processing device 250 generates a normal reception confirmation signal 251 (S25), and the transmission device 260 generates a response signal 40 from the normal reception confirmation signal 251 and transmits it to the transmission apparatus 11 on the transmission side ( S27).

  If the data processing device 230 determines that the reception is abnormal in step S24, the response processing device 250 generates a retransmission request signal 252 (S26), and the transmission device 260 generates a response signal 40 from the retransmission request signal 252. (S28).

  Thus, the response signal 40 is sent to the transmission device 260 via the response processing device 250, and the transmission device 260 transmits the response signal 40 to the transmission device 11 on the transmission side (S29).

  The receiving device 150 of the transmitting side transmission device 11 receives such a response signal 40 and determines whether or not the response signal 40 is the retransmission request signal 252 (S8). If it is a retransmission request signal 252, the corresponding transmission destination added transmission signal 121, transmission information data No. 1 in the above example is extracted from the transmission data storage device 140 for retransmission (S10), transmission sequence control information, etc. Is changed and stored again in the transmission data storage device 140 (S6). Thereafter, the destination-added transmission signal 121 is retransmitted by the transmission device 130 to the reception-side transmission device 21 (S7). The other receiving side transmission apparatuses 22 to 2n discard the retransmitted signal, for example, No. 1 because it is the same as the signal received before. The subsequent processing is the same as the processing of the receiving side transmission device 21 described above.

  The transmission signal 30 may be configured to include an error correction code. By doing so, the receiving-side transmission devices 21 to 2n that have received the transmission information data in which the own station is not set as the transmission destination can perform error compensation at the own station when detecting an error. Further, in the system that handles the transmission information sequence 31 with high real-time characteristics, the number of retransmissions may be limited.

  If the response signal 40 is not the retransmission request signal 252 in step S8, that is, if the response signal 40 is a normal reception confirmation signal 251, the receiving device 150 assumes that the previous transmission has been normally performed to the receiving-side transmission device 21. Check. In response to this, the destination identification code adding device 120 changes the destination transmission state from “transmitting” to “transmission completed” (S9). This completes the destination transmission process to one of the receiving side transmission apparatuses 21 to 2n, for example, the apparatus 21. This destination transmission processing is performed in order for all the receiving side transmission apparatuses 21 to 2n until the destination management state in the transmission destination identification code adding apparatus 120 is set to “transmission complete” (S3). Such multicast transmission is repeated until transmission information does not occur (N) in step S1.

  As described above, the transmission-side transmission device 11 can periodically receive responses from all the reception-side transmission devices 21 to 2n. Therefore, as compared with the conventional method, information can be reliably transmitted without reducing the communication rate, which is the information transmission amount per unit time. In this way, the deviation in transmission quality can be reduced, and transmission in which transmission quality and transmission efficiency are balanced can be performed.

  The present invention is of course not limited to the portable audio system as in the embodiment described, but is advantageously applied to any communication system that multicasts highly real-time information. Further, the number of destinations included in one piece of transmission information, for example, No. 1, is not limited to one, and may be plural. Further, this destination may be generated randomly or in a predetermined order, instead of being shifted in order.

  Now, with reference to FIG. 7, another embodiment of the multicast communication system according to the present invention will be described in detail. FIG. 7 is a block diagram showing a configuration example of the transmitting side transmission device 11a and the receiving side transmission device 21a of the multicast communication system according to this embodiment. Components that are slightly different from those of the embodiment shown in FIG. The basic overall configuration may be the same as the embodiment shown in FIG. In the following description, similar elements are designated by the same reference numerals, and overlapping descriptions are avoided.

  In the multicast communication system of this embodiment, the receiving side transmission device 21a has a function of grasping the communication environment. When receiving the reception signal 30, the reception-side transmission device 21a reports the grasped reception environment to the transmission-side transmission device 11a as a response thereto. The transmission apparatus 11a on the transmission side has a plurality of usable communication bands, and receives information 100 to be broadcast by periodically or temporarily changing the band used for communication based on the report of the reception environment. It transmits toward the side transmission device 21a. By doing so, the transmission apparatus 11a can adaptively select a band having a good communication state and perform transmission.

  The transmission device 11a of the present embodiment includes a communication band changing device 170 and a communication environment information storage device 180 in addition to the same functional units as the components of the transmission device 11 shown in FIG. The communication band changing device 170 has a function of changing the frequency band used for communication periodically or temporarily. The communication environment storage device 180 is a storage unit that stores a later-described reception confirmation response signal 251a and a retransmission request signal 252a, which are response signals 40 received from the reception-side transmission device 21a.

  The communication band changing device 170 also indicates a communication environment indicating the communication environment such as the number of transmission packets, the number of occurrences and the probability of retransmission from the reception confirmation response signal 251a and the retransmission request signal 252a stored in the communication environment storage device 180. It also has a function of generating information 171 and storing it in the communication environment storage device 180. The communication band changing device 170 also grasps the state of the communication environment from the communication environment information 171 and uses the communication environment information 171 to select a band with a good communication state from a plurality of communication bands. The optimum communication band information 101 (FIG. 8) indicating the band is generated and stored in the communication environment storage device 180. The optimum communication band information 101 is also sent to the transmission destination identification code adding device 120a.

  The transmission destination identification code adding device 120a has a function of incorporating the optimum communication bandwidth information 101 into the transmission destination added transmission signal 121a and sending the transmission destination added transmission signal 121a incorporating the optimum communication bandwidth information 101 to the transmission device 130a. have. The transmission device 130a reads the optimum communication band information 101 existing in the transmission signal with destination added 121a, and has a function of a band that has been used so far among a plurality of communication bands based on the optimum communication band information 101. The transmission function is changed from the transmission function to a transmission function having a function corresponding to this favorable band, and the transmission signal 30 is transmitted to the reception-side transmission device 21a.

  The transmitting side transmission device 11a has a receiving device 150a. The receiving device 150a has a function capable of receiving a plurality of communication bands, and has a function of receiving a response signal 40, which will be described later, transmitted from the receiving-side transmission device 21a. The reception device 150a receives the response signal 40 transmitted from the reception-side transmission device 21a using a band corresponding to the optimum communication band, and stores the response signal 40 in the communication environment storage device 180.

  By the way, the receiving-side transmission device 21a includes a receiving device 210a, which has a function capable of receiving even a plurality of communication bands. The receiving device 210a receives the transmission signal 30, which is the transmission signal with the transmission destination added 121a, transmitted from the transmitting device 130a of the transmitting-side transmission device 11a using a good band with a receiving function corresponding to the good band. It has the function to do. The reception device 210a generates reception data 211a from the received signal 30 and sends it to the transmission destination code identification device 220.

  The reception-side transmission device 21a has a data processing device 230a, which is the same functional unit as that of the embodiment shown in FIG. 3, but is included in the reception data 211a with respect to the reception confirmation message 231a or the retransmission request message 232a. It also has a function of generating reception confirmation data 233a or retransmission request data 234a, respectively, by adding the optimum communication band information 101.

  The receiving side transmission device 21a has a response processing device 250a, which receives the reception confirmation data 233a to which the optimum communication band information 101 is added or the retransmission request data 234a, and receives each of which the optimum communication band information 101 is added. This is a functional unit that generates a retransmission request signal 252a to which the confirmation response signal 251a or the optimum communication band information 101 is added and sends it to the transmitter 260a. The destination-added transmission signal 121a, the reception data 211a, the reception confirmation data 233a, the retransmission request data 234a, the reception confirmation response signal 251a, and the retransmission request signal 252a to which the optimum communication band information 101 is added are shown in detail in FIG. Yes.

  Upon receiving the reception confirmation response signal 251a to which the optimum communication band information 101 is added or the retransmission request signal 252a to which the optimum communication band information 101 is added, the transmission device 260a receives the optimum communication at present based on the optimum communication band information 101. It has a function of grasping the band and transmitting the reception confirmation response signal 25a1 or the retransmission request signal 252a as the response signal 40 to the transmission apparatus 11a using the transmission function corresponding to the grasped optimum communication band. Yes.

  In this embodiment, the other receiving side transmission apparatus is not shown, but it is needless to say that the receiving side transmission apparatus is configured in the same manner as the receiving side transmission apparatus 21a.

  Here, the operation of this embodiment will be described with reference to FIG. 9, FIG. 10, and FIG. The operation flow of this embodiment differs from the operation flow shown in FIGS. 5 and 6 in the following points. The same operation steps are denoted by the same reference numerals, and redundant description is avoided.

  After transmitting the response signal 40 to the transmission device 11a in step S29 (FIG. 10), the reception device 150a of the transmission device 11a transmits the response signal received from the reception device 21a in step S8a (FIG. 11). 40 is stored in the communication environment storage device 180 as environment data. Next, the communication band changing device 710 generates the communication environment information 171 based on this environment data, further generates the optimal communication band information 101, and stores the optimal communication band information 101 in the communication environment storage device 180 (S8b ). Further, the transmission destination identification code adding device 120a adds the optimum communication band information 101 to the transmission destination added transmission signal 121a that is the transmission signal 30 (step S5a in FIG. 9).

  In the transmission device 11a, the transmission device 130a stores the transmission destination added transmission signal 121a in the transmission data storage device 140a (step S6 in FIG. 9), as in the embodiment shown in FIG. In S6a, the transmission device 130a selects and transmits a transmission function having the optimum communication band based on the optimum communication band information 101.

  In the receiving-side transmission device 21a, the response processing device 251 generates the response signal 40 in step S27 or S28 (FIG. 10). Thereafter, in step S27a, the transmission device 260a is based on the optimum communication band information 101. The transmission function having the optimum communication band is selected and transmitted.

  Other operations, for example, after the transmission processing to the receiving side transmission device 21a is completed, for all other receiving side transmission devices, until the destination management state in the transmission destination identification code adding device 120a is set to transmission complete, The same destination transmission processing in order (S3) may be the same.

  Thus, in the present embodiment, transmission / reception can be performed using a band corresponding to the optimum communication band. Therefore, the same effect as the embodiment shown in FIG. 3 can be obtained, transmission errors are reduced, and the number of retransmissions is reduced, so that transmission efficiency is further improved.

1 is a conceptual block diagram illustrating an embodiment of a multicast communication system according to the present invention. It is a figure which shows the example of the transmission information sequence used with the multicast communication system shown in FIG. It is a functional block diagram which shows the structural example of the transmission apparatus in the Example shown in FIG. It is a figure which shows the structural example of the data and signal in the Example. It is a flowchart which shows the operation | movement flow in the Example. It is a flowchart which shows the operation | movement flow in the Example. It is a functional block diagram similar to FIG. 3 which shows the example of a structure of the other Example of the transmission apparatus in the multicast communication system by this invention. FIG. 8 is a diagram similar to FIG. 4, showing a configuration example of data and signals in the embodiment shown in FIG. 7. It is a flowchart which shows the operation | movement flow in the Example shown in FIG. It is a flowchart which shows the operation | movement flow in the Example. It is a flowchart which shows the operation | movement flow in the Example.

Explanation of symbols

11, 11a Transmission side transmission equipment
21-2n, 21a Receiver side transmission equipment
110, 110a Data processing device
120, 120a Destination identification code adding device
130, 130a Transmitter
140, 140a Transmission data storage device
160, 160a Retransmission processing device
170 Communication band changing device
180 Communication environment storage device
210, 210a receiver
220 Destination code identification device
230, 230a Data processing device
250, 250a Response processing device
260, 260a Transmitter

Claims (10)

In a multicast communication system that performs multicast transmission of transmission information data from a transmission apparatus on the transmission side to a plurality of transmission apparatuses on the reception side, the transmission apparatus on the transmission side includes:
A transmission destination identification code adding means for adding a transmission destination identification code for identifying a transmission destination to which a normality response of reception is to be returned among the plurality of reception side transmission devices to a transmission signal including the transmission information data;
Transmitting means for transmitting the destination-added transmission signal,
The multicast communication system, wherein the transmission destination identification code adding means changes the transmission destination for each transmission information data. The system according to claim 1, wherein the transmission device on the receiving side is
First receiving means for receiving the destination-added transmission signal from the transmission-side transmission device;
Transmission destination identification means for identifying the transmission destination identification code of the received transmission destination added transmission signal;
A multicast communication system, comprising: a reception response transmission unit configured to transmit a response signal to the received transmission signal with the transmission destination added to the transmission apparatus on the transmission side when the transmission destination identification code is addressed to itself.   3. The system according to claim 2, wherein the response signal is a normal reception signal indicating that the received transmission destination added transmission signal is normally received, and the received transmission destination added transmission signal is normally received. A multicast communication system comprising any one of retransmission request signals for requesting retransmission of the transmission signal with the destination added. The system according to claim 1, wherein the transmission-side transmission device and the plurality of reception-side transmission devices include a plurality of communication bands, and the transmission-side transmission device further includes:
Second receiving means for receiving the response signal;
Communication environment grasping means for generating environment information data from the received response signal and grasping a communication environment from the environment information data;
Communication band changing means for selecting a communication band suitable for the grasped communication environment from the plurality of communication bands,
The multicast communication system, wherein the transmission means performs transmission in the selected communication band.   5. The multicast communication system according to claim 4, wherein the environment information data includes at least one of the number of transmitted packets, the number of retransmissions, and the occurrence probability of retransmission. In a multicast communication method for performing multicast transmission of transmission information data from a transmission-side transmission device to a plurality of reception-side transmission devices, the method includes:
A first step of adding a transmission destination identification code for identifying a transmission destination identification code for identifying a transmission destination to which a reception normality response is to be returned among the plurality of reception side transmission apparatuses to a transmission signal including the transmission information data When,
And a second step of transmitting the transmission destination added transmission signal to which the transmission destination identification code is added for each transmission information data to the plurality of receiving side transmission devices. Multicast communication method. The method of claim 6, further comprising:
A third step of receiving the destination-added transmission signal in the plurality of reception-side transmission devices;
A fourth step of identifying the destination identification code of the received destination-added transmission signal;
A fifth step of transmitting a response signal to the received transmission destination-added transmission signal to the transmission-side transmission device in the transmission-side transmission device addressed to the transmission destination identification code among the plurality of reception-side transmission devices; A multicast communication method comprising:   8. The method according to claim 7, wherein the response signal is a normal reception signal indicating that the received transmission destination added transmission signal is normally received, and the received transmission destination added transmission signal is normally received. A multicast communication method characterized by including any one of retransmission request signals for requesting retransmission of the transmission signal with the transmission destination added. 7. The method according to claim 6, wherein the transmission side transmission apparatus and the plurality of reception side transmission apparatuses include a plurality of communication bands, and the method further includes:
A third step of receiving the response signal in the transmission-side transmission device;
A fourth step of generating environmental information data from the received response signal and grasping a communication environment from the environmental information data;
A fifth step of selecting a communication band suitable for the grasped communication environment from the plurality of communication bands;
And a sixth step of performing transmission in the selected communication band. 10. The method according to claim 9, wherein the environment information data includes at least one of the number of transmission packets, the number of retransmissions, and the probability of occurrence of retransmission.

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