JP4569486B2 - Superimposition communication terminal - Google Patents

Description

  The present invention relates to a communication terminal that performs superposition communication, and more particularly, to a channel setting technique for a signal to be superposed.

  Various multiplex communication techniques for multiplexing transmission data on one line are used. For example, techniques such as FDM (frequency division multiplexing), TDM (time division multiplexing), and CDM (code division multiplexing) are used.

  Conventionally, power lines have been used as infrastructure for multiplexing data. This is a so-called power line communication technology. The power line carrier communication has an advantage that a network can be efficiently constructed by using a power line wired in an office or a house.

  The following Patent Document 1 relates to a system that selects a transmission method according to a communication path or a communication state of a communication partner. In this system, the transmission method and communication state information are registered in a database corresponding to the destination address. And when a terminal communicates, the transmission method with a good communication state is selected with reference to the registered communication state.

JP 2004-248181 A

  In the communication terminal, various application programs using communication are executed. The application program performs communication processing with other terminals connected to the communication line using unicast, multicast, broadcast, or the like. In the case of unicast, important communication processing is frequently executed with a specific communication terminal. Alternatively, in a video conference system or the like, by using multicast, important work is smoothly advanced while reducing the burden on the line.

  However, signal multiplexing has limitations. When trying to execute highly important communication processing with a specific terminal by unicast, an empty signal channel may not be secured. Even when an application using multicast is to be executed, there is a waiting time if there is no available signal channel in the communication line. Or a communication error will occur. For example, when a large number of less important broadcast communications occur and a line is compressed, there is a problem that an important application using multicast does not operate.

  In Patent Document 1, an optimum communication method is determined for each transmission destination. However, even in this technology, the importance of the application is not taken into consideration. In other words, the optimum communication method corresponding to the transmission destination is determined, and basically, the idea is that communication that has occurred first uses an empty signal channel.

  In view of the above-described problems, an object of the present invention is to provide a superposition communication technique capable of allocating signal channels in a balanced manner to high priority applications.

In order to solve the above problem, the invention according to claim 1 is a terminal that transmits an IP packet by superimposing it on a transmission medium, and corresponds to a combination of an IP address system to which a destination IP address belongs and a destination IP address a management table which the signal channels are set, the transmission of IP packets by the communication application, before SL signal channel corresponding to the destination IP address belongs IP address system and the transmission destination IP address of the IP packet communication application sends said When registered in the management table, a registered signal channel is selected, and when a signal channel corresponding to the IP address system and the destination IP address is not registered in the management table, a default signal is selected. means for selecting a channel, selected signal channel The IP packet is superimposed on the transmission medium, characterized in that it comprises a means for transmitting.

According to a second aspect of the present invention, in the superimposed communication terminal according to the first aspect, a plurality of address systems selected from unicast, multicast and broadcast are registered in the management table as IP address systems. Features.

  The superimposed communication terminal of the present invention determines a signal channel according to the destination of the IP packet transmitted by the communication application when the IP packet is transmitted by the communication application. Thereby, it is possible to secure a signal channel for each application. For example, it is possible to operate such that a signal channel is reserved for an important application. Further, it is possible to solve the problem that the signal channel is compressed by unimportant communication and an important application does not operate.

  In addition, a signal channel is set for an address system such as a unicast IP address, a multicast IP address, and a broadcast IP address. Thereby, for example, it is possible to solve the problem that the bandwidth is compressed by unnecessary broadcast communication, and that an important application cannot use multicast.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a functional block diagram of a superimposed communication terminal 10 according to an embodiment of the present invention. The superimposed communication terminal 10 is connected to the power line 5 and is a communication terminal that transmits and receives an IP packet superimposed on the power line 5. For example, by using an existing power line network in an office and connecting the superimposed communication terminal 10 to this power line network, it is possible to greatly reduce the burden associated with network construction.

  The application control unit 11 included in the superimposed communication terminal 10 is a processing unit related to communication processing of an application program executed in the superimposed communication terminal 10. Therefore, the application control unit 11 is a part of the function of the application program executed on the CPU. The superimposition communication terminal 10 includes a CPU, a RAM, a hard disk, and the like, like a general personal computer, and can execute various application programs stored in the hard disk.

  Some application programs executed in the superimposed communication terminal 10 operate only locally, but some use communication processing. For example, in the case of an application program for a video conference system, the application is executed while transmitting and receiving video and audio data to and from many other terminals. Or if it is a WEB browser, a web content will be downloaded from the designated web server.

  As shown in the figure, the superimposed communication terminal 10 includes an IP packet transmission unit 12, a transmission signal channel control unit 13, a communication signal generation unit 14, and a superimposed communication control unit 15 as processing units related to transmission of IP packets. . In addition, a superimposition communication control unit 15, a reception signal channel control unit 16, a communication signal analysis unit 17, and an IP packet reception unit 18 are provided as processing units related to reception of IP packets.

  The IP packet transmission unit 12 is a processing unit that creates an IP packet from transmission data created by the application control unit 11. The transmission signal channel control unit 13 is a processing unit that controls a signal channel for multiplexing the IP packet to be transmitted in accordance with the control of the application control unit 11. The communication signal generation unit 14 is a processing unit that generates a communication signal that modulates an IP packet in accordance with the signal channel set by the transmission signal channel control unit 13 and superimposes the IP packet on a power carrier wave.

  The superimposition communication control unit 15 receives the communication signal superimposed on the power carrier wave by superimposing the communication signal generated in the communication signal generation unit 14 on the power carrier wave and outputting the signal to the power line 5, Processing to separate and extract communication signals.

  The reception signal channel control unit 16 is a processing unit that demodulates the communication signal in accordance with the signal channel of the communication signal extracted by the superimposition communication control unit 15. The communication signal analysis unit 17 acquires protocol information, data length, error code, and the like from the demodulated communication signal, and analyzes the communication signal. The IP packet receiving unit 18 is a processing unit that restores and receives an IP packet according to the analysis result of the communication signal by the communication signal analyzing unit 17.

  The communication signal management unit 19 performs data read processing and update processing on the IP address management table 20. Table 1 shows an example of registered contents of the IP address management table 20.

  The IP address management table 20 includes three fields of “transmission destination”, “group”, and “signal channel”. The “transmission destination” field is an IP address system (or may be called IP address classification) designated as a transmission destination when the application program performs communication. For example, when the application program transmits an IP packet to a specific communication terminal, the “destination” is classified as unicast. When the application program transmits IP packets to a plurality of communication terminals in a specific group, the “destination” is classified as multicast. When the application program transmits IP packets to all communication terminals, the “transmission destination” is classified as broadcast. Others are registered as “destination”, which is the default classification.

  The “group” field is a field for specifying a specific group in multicast and broadcast. In this example, the IP address “224.0.1.1.1” or “224.0.1.2” is registered as the multicast. Also, the IP address “255.255.255.255”, “192.168.1.255”, or “192.168.2.255” is registered as a broadcast.

  FIG. 2 shows a multicast IP address system. Multicast is a class D address whose upper 4 bits are “1110”. The range of IP addresses that can be specified by class D is “224.0.1.0” to “239.255.255.255”. In Table 1, two multicast group IP addresses are registered from this range. For example, the application program for the video conference system sets a plurality of terminals that transmit IP packets (video, audio, etc.) using the multicast address “224.0.1.1”. In addition, the receiving terminal is also set to receive an IP packet in which the multicast address “224.0.1.1” is designated.

  In the broadcast, “255.255.255.255” is an IP address for transmitting an IP packet to all terminals. “192.168.1.255” is an IP address that transmits an IP packet to all terminals having a network address “192.168.1.0” (host address is lower 8 bits). 2.255 ”is an IP address that transmits an IP packet to all terminals having a network address“ 192.168.2.0 ”(host address is lower 8 bits).

  In the “signal channel” field, signal channels corresponding to each classification or each group are registered. Here, the signal channel is expressed using the signal channel parameter x and the function f, but in reality, the signal channel parameter x is registered in the IP address management table 20.

  There are various multiplexing methods. For example, there are FDM (frequency division multiplexing), TDM (time division multiplexing), CDM (code division multiplexing), and the like. When FDM is used as a multiplexing method, the signal channel constant f (x) is a frequency band assigned to a signal to be multiplexed. In the case of TDM, the signal channel constant f (x) is a signal to be multiplexed. In the case of CDM, the signal channel constant f (x) is a spreading code.

In the example shown in Table 1, the signal channel constant f (u) is set in the case of unicast, and the signal channel constants f (a) and f (b) are set in the case of multicast. In the case of broadcasting, signal channel constants f (z), f (c), and f (d) are set. Note that when information regarding the IP address of the transmission destination is not registered in the address management table 20 shown in Table 1, f (0) is used as the other (default) signal channel constant.

  The communication signal management unit 19 manages such an IP address management table 20. The IP address management table 20 is also managed by the other superimposed communication terminal 10 connected to the power line 5 with the same contents. For example, all the superimposed communication terminals 10 may manage the IP address management table 20 having the same contents by managing the IP address management table 20 serving as a master in the server and periodically referring to them.

  A flow of processing for generating a communication signal and setting a signal channel in the superimposed communication terminal 10 configured as described above will be described.

  FIG. 3 is a flowchart when a data packet is transmitted by the application program. When the application program is activated and transmission data is created by the application control unit 11, the IP packet transmission unit 12 generates an IP packet based on the transmission data (step S11).

  Next, the application control unit 11 provides the communication signal management unit 19 with information regarding the transmission destination to which the application program transmits the transmission data. The communication signal management unit 19 searches the IP address management table 20 based on the given transmission destination information, and provides the search result to the application control unit 11.

  As a result of the search, when the transmission destination of the IP packet by the application program is registered in the IP address management table 20 (YES in step S12), the application control unit 11 is registered in the IP address management table 20. The signal channel parameter x is given to the transmission signal channel controller 13. The transmission signal channel controller 13 calculates a signal channel constant f (x) using the given signal channel parameter x and function f (step S13). On the other hand, if it is not registered in the address management table 20 (NO in step S12), the application control unit 11 gives the signal channel parameter “0” to the transmission signal channel control unit 13. The transmission signal channel control unit 13 calculates a default signal channel constant f (0) using the given signal channel parameter “0” and the function f (step S14).

  When the transmission signal channel controller 13 calculates the signal channel constant f (x), the communication signal generator 14 modulates the IP packet data according to the signal channel constant f (x) to generate a communication signal. (Step S15). Then, the superimposition communication control unit 15 multiplexes the communication signal generated by the communication signal generation unit 14 with the signal channel specified by the signal channel constant f (x) and sends it out (step S16).

  As described above, when the application program transmits an IP packet, it checks whether or not the destination IP address is registered in the IP address management table 20, and if it is registered, the reserved signal I try to use the channel. In addition, when not registered, a reserved default signal channel is used. For example, when a group IP address that is not registered by multicast is designated, a default signal channel is used.

  FIG. 4 is a flowchart for setting a signal channel for receiving an IP packet. The application control unit 11 checks whether or not the change processing of the IP address management table 20 has been performed by the communication signal management unit 19 (step S21). Refers to a changed or newly added record. Then, a signal channel constant f (x) is calculated based on the signal channel parameter x relating to the transmission destination that has been changed or newly added (step S22).

  Then, it is checked whether or not the content of the change in the IP address management table 20 is a new record addition (step S23). If the record is a new addition, the received signal channel control unit 16 calculates the calculated signal channel constant. The signal channel detection unit corresponding to f (x) is activated (step S24). Accordingly, the reception signal channel control unit 16 can demodulate the communication signal corresponding to the record newly added to the IP address management table 20. That is, the signal channel detection unit sets the filter operable to demodulate the communication signal multiplexed on the newly added signal channel.

  On the other hand, when the change content of the IP address management table 20 is not a new record addition, that is, a change of a registered record (NO in step S23), the reception signal channel control unit 16 has already started. Is reset as a signal channel detector corresponding to the calculated signal channel constant f (x) (step S25). Accordingly, the reception signal channel control unit 16 can demodulate the communication signal corresponding to the record changed in the IP address management table 20.

  Next, the flow of reception channel setting processing in conjunction with the activation of the application program will be described with reference to FIG. In the superimposed communication terminal 10, an application program for performing communication processing is started (step S31). Then, the application control unit 11 checks whether or not the IP address or IP address system used by the application program for communication processing is registered in the IP address management table 20 (step S32). Acquires the signal channel parameter x from the IP address management table 20, and calculates the signal channel constant f (x) based on the parameter (step S33). Then, the reception signal channel control unit 16 activates a signal channel detection unit corresponding to the calculated signal channel constant f (x) (step S36). Thereby, the application program can demodulate the communication signal received by superimposition communication.

  On the other hand, if the IP address or IP address system used by the application program for communication processing is not registered in the IP address management table 20 (NO in step S32), the application control unit 11 default parameter “0”. The signal channel constant f (0) is calculated based on (Step S34). Then, the reception signal channel control unit 16 checks whether or not the signal channel detection unit corresponding to the calculated default signal channel constant f (0) has already been activated (step S35). Activates a default signal channel detector corresponding to the calculated signal channel constant f (0) (step S36). Thereby, the application program can demodulate the communication signal received by superimposition communication. If the default signal channel detection unit has already been activated (YES in step S35), the process ends.

  For example, it is assumed that the application program is an application for a video conference system. When a video conference application program is started in each superimposed communication terminal 10 participating in the conference, each superimposed communication terminal 10 receives a multicast IP packet including video and audio from other terminals. Therefore, in order to operate as a receiving terminal, each superimposition communication terminal 10 executes the processing shown in FIG. 5 to activate the signal channel detection unit corresponding to the application and prepare for reception.

  As described above, in the superimposed communication terminal 10 according to the present embodiment, the signal channel for performing power line carrier communication is determined based on the IP address or the IP address system determined by the application program. The correspondence between the IP address or IP address system and the signal channel is reserved in advance by the IP address management table 20. As a result, for example, it is possible to avoid a situation in which there are no free signal channels for performing multicast communication because a large number of terminals 10 performing power line carrier communication have performed many unicast communications. . Alternatively, it is possible to solve the problem that a bandwidth is compressed by broadcast communication and an important application causes an execution error.

  As described above, multicast is used for applications that distribute audio and video such as video conferencing and surveillance systems. If the bandwidth is occupied by other unicast communication or broadcast communication, these applications will not operate smoothly. In this regard, in the superposition communication system using the superposition communication terminal 10 of the present embodiment, signal channels are reserved in advance corresponding to IP addresses or IP address systems such as multicast and broadcast. Therefore, it is possible to comfortably execute an application that uses multicast.

  Some application programs use a mixture of unicast communication and multicast communication or broadcast communication. Even when such an application is executed, it is possible to comfortably execute the application because a signal channel corresponding to each IP address system is reserved.

  As shown in Table 1, in this embodiment, all IP address systems of unicast, multicast, and broadcast are registered in the IP address management table 20, but this is only an example. Some of these (unicast, multicast, etc.) IP addresses may be registered. For example, a plurality of terminals that want to secure a band as unicast may be registered.

It is a functional block diagram of the superimposition communication terminal which concerns on this Embodiment. It is a figure which shows the address system of the IP address used for a multicast. It is a setting process flowchart of a signal channel when transmitting an IP packet. It is a reception setting flowchart when an IP address management table is changed. It is a reception setting flowchart when an application is started.

Explanation of symbols

5 Power line 10 Superimposed communication terminal 20 IP address management table

Claims (2)

A terminal that transmits an IP packet superimposed on a transmission medium,
A management table in which a signal channel corresponding to a combination of an IP address system to which a destination IP address belongs and a destination IP address is set;
Time of transmission of the IP packet by the communication application, when the signal channel corresponding to the IP address system and the destination IP address belongs destination IP address of the IP packet before Symbol communication application sends is registered in the management table Selecting a registered signal channel, and if a signal channel corresponding to the IP address system and the destination IP address is not registered in the management table, means for selecting a default signal channel;
Means for transmitting an IP packet superimposed on the transmission medium in a selected signal channel;
A superimposed communication terminal comprising: In the superimposed communication terminal according to claim 1,
In the management table, a plurality of address systems selected from unicast, multicast, and broadcast are registered as IP address systems .

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