JP4892409B2 - COMMUNICATION SYSTEM AND METHOD, AND COMMUNICATION DEVICE - Google Patents

Description

  The present invention relates to, for example, a communication system and method and communication apparatus related to power line carrier communication, and more particularly, to a communication system and method in which a plurality of communication systems having different communication methods or communication standards coexist on the same power line, and communication. Relates to the device.

  As this type of communication system, for example, a power line carrier communication system in which communication using a plurality of band-guaranteed modems and best-effort modems coexists has been proposed. In this power line carrier communication system, with the reference timing based on the commercial power supply voltage as the boundary, the front section is best-effort communication and the rear section is band-guaranteed communication. Time-division is performed, and different bandwidth-guaranteed communication is performed for each divided communication section (see Patent Document 1).

JP 2007-28492 A

  However, according to the background art described above, the main focus is on preventing interference with the band-guaranteed modem, and the best-effort modem is not fully disclosed. Then, as a best effort type modem, for example, if a CSMA (Carrier Sense Multiple Access) type distributed control type modem is used, there is a technical problem that the communication system may not operate normally.

  The present invention has been made in view of the above problems, for example, and includes a communication system and method capable of coexisting a plurality of communication systems, including a communication system including a distributed control type communication device, and It is an object to provide a communication device.

In order to solve the above problems, a communication system according to the present invention includes a plurality of communication devices that perform communication using a power line, and shares the power line with another communication system, wherein the plurality of communication At least one communication device among the devices includes a region detecting means for detecting one or a plurality of communicable regions that can be used by the communication system among a plurality of communicable regions separated by at least time, and a plurality of periods. History acquisition means for acquiring a use history of each of the plurality of communicable areas, and at least one of the detected one or a plurality of communicable areas detected based on the acquired use history the region, as a communication area where the communication system uses a selecting means for selecting, said selected at least one communication coverage area of which, the communication sheet As communicable area Temu use, the other declaring declaration means to the communication system, at least one communication area of declared by the declaration means, notification to the plurality of communication devices the communication system comprises And the acquired usage history includes: (i) use by the communication system in each of the plurality of communicable areas in one cycle of the plurality of cycles; (ii) the other The plurality of communication devices including the at least one communication device having the declaration unit and the notification unit indicate whether the communication system is used or (iii) unused . Communication is performed in each communicable area.

  According to the communication system of the present invention, the communication system performs communication using a power line (that is, performs power line carrier communication), for example, a plurality of communication devices such as a PC (Personal Computer), a television, or a modem. Is provided. The power line used by the communication system is also used by another communication system or communication system different from the communication system. In other words, there are a plurality of communication systems on the power line used by the communication system.

  At least one communication device of the plurality of communication devices includes a region detection unit, a declaration unit, and a notification unit. The area detecting unit, the declaring unit, and the notifying unit may have only some of the plurality of communication devices included in the communication system, or all the communication devices. Specifically, for example, when the communication system is a centralized control type system, typically, only the communication device that is a master unit has, and when the communication system is a distributed control type system, Typically, all communication devices have.

  The area detecting means detects a communicable area that can be used by the own communication system to which the communication device belongs, among a plurality of communicable areas divided into at least one of time and frequency band. Here, the “communicable area usable by the own communication system” means a communicable area used by the own communication system or a communication available area not used by another communication system different from the own communication system. To do.

  Note that the “communicable area” according to the present invention refers to a predetermined area when the local communication system and another communication system are multiplexed by, for example, time division multiple access (TDMA). A predetermined frequency band is divided when multiplexing is performed by a plurality of time regions (ie, time slots) obtained by dividing time intervals (ie, frames), or by frequency division multiple access (FDMA). The communication device in each communication system, such as a plurality of frequency bands, is an area where communication signals can be transmitted / received via the power line (that is, communication is possible). Here, the “communication signal” according to the present invention typically means a packet.

The area detecting means detects, for example, the use status immediately before a plurality of communicable areas or based on the use history, the communicable area used by the own communication system immediately before, or immediately before another communication system. One or a plurality of communicable areas that are not used in the communication are detected.
The history acquisition unit acquires a use history in which each of the plurality of communicable areas is used over a plurality of periods. The acquired use history is typically stored in a storage unit such as a volatile memory. The stored usage history may be erased after a certain period of time since it was stored, or stored as long as the capacity of the storage means permits. When the capacity is insufficient, the old usage history is deleted in order. You may make it do. The selection means selects at least one communicable area from among the detected one or plural communicable areas based on the acquired use history as a communicable area used by the own communication system.

The declaring means declares the selected communicable area as a communicable area used by the own communication system to other communication systems. Here, “declare” means a signal indicating “a communicable area used by its own communication system” that can be recognized by other communication systems, that is, not dependent on a communication method or communication standard (hereinafter referred to as “area declaration signal as appropriate”). Is transmitted or transmitted via a power line.

  The region declaration signal transmitted or transmitted by the declaring unit may be recognized by all communication devices in other communication systems, or may be recognized by some communication devices.

  The selection means typically selects a communicable area used by the communication system from the detected communicable areas based on the acquired use history. Specifically, for example, a communicable area with the lowest use frequency is selected from the detected communicable areas. Alternatively, a communicable area with the highest use frequency of the own communication system is selected. Or even if it is a communicable area | region where use frequency is low, if another communication system was using within the predetermined period, another communicable area will be selected without selecting the communicable area. The declaring means declares the communicable area selected by the selecting means to the other communication system as a “communicable area used by the own communication system”.

  The notification means notifies the declared communication possible area to a plurality of communication devices provided in the own communication system. Here, “notify” typically means that an area declaration signal indicating “communication available area used by the local communication system” conforming to the communication method or communication standard in the local communication system is transmitted or transmitted. means.

  The plurality of communication devices included in the communication system perform communication in accordance with the communication method or communication standard in the communication system in the notified communicable area. Specifically, for example, when a plurality of communication devices are multiplexed by the time division multiple access method, each communication device is in the time domain where the notified communicable region is further time divided by the CSMA method. Each gets a communication opportunity and communicates.

  The declaring means declares a communicable area used by the own communication system to other communication systems at predetermined intervals. Accordingly, the area detecting unit, the selecting unit, and the notifying unit also detect a communicable area that can be used by the local communication system at predetermined intervals, and the communication that the local communication system uses from the detected communicable area. A possible area is selected, and the declared communicable area is notified to a plurality of communication devices provided in the own communication system. In other words, within a predetermined period, each of a plurality of communication devices included in the communication system performs communication in the same communicable region.

  In the case of multiplexing by time division multiple access, typically, within a predetermined period, a communication-enabled area that can be used by the communication system is set to exist periodically. A communicable area is assigned to the communication system. Specifically, for example, when a predetermined period is divided into 12, if the declaring means declares the communicable area at the beginning of the period (that is, the first communicable area) as the communicable area used by the own communication system. The first, fourth, seventh and tenth communicable areas can be automatically used. Then, with the first, fourth, seventh, and tenth communicable areas as the same communicable area, a plurality of communication devices included in the communication system perform communication in the communicable area.

  Here, for example, if the communication system is a distributed control system, the communication device that makes a declaration to another communication system is a communication device that performs communication first within a predetermined period. Therefore, the communication devices that make declarations are not always the same communication device. If the communication system is a centralized control system, typically, the communication device that serves as the parent device makes a declaration each time.

  According to the inventor's research, in general, power line carrier communication includes, for example, a plurality of HD-PLC (High Definition-Power Line Communications) standards, HOMEPLUG (registered trademark) standards, UPA (Universal Powerline Association) standards, and the like. There is a communication standard (or method). If multiple communication systems with different communication standards (or systems) exist on the same power line, communication signals of other communication systems are recognized as noise, causing interference or interference with each other, making communication impossible. There is a possibility.

  On the other hand, a technique has been proposed in which multiplexing is performed by time division multiple access, and communication using a bandwidth guarantee type modem and a best effort type modem coexist. However, if a CSMA distributed control type modem is used as the best effort type modem, it is difficult to recognize which communication system uses each time-division time domain (ie, time slot). Therefore, it is difficult to obtain a communication opportunity, and the communication system may not operate normally.

  In addition, when there are multiple communication systems, it is impossible to uniquely assign a specific time domain to a specific communication system because the possibility of new communication standards appearing in the future cannot be denied. It turns out that there is.

  However, in the present invention, since the communicable area used by the own communication system is declared to other communication systems by the declaring means, a plurality of communication systems recognize which communicable areas are used by each other. be able to. Accordingly, interference or interference due to communication signals of other communication systems can be avoided, and a plurality of communication systems having different communication standards or communication methods can coexist.

  Furthermore, since the notification means notifies each of a plurality of communication devices included in the own communication system of the declared communicable area, each of the plurality of communication apparatuses recognizes the communicable area used by the own communication system. be able to. Since the same communicable area is used within a predetermined period, each of a plurality of communication devices can use the same communicable area, and in the notified communicable area, for example, CSMA It becomes possible to acquire a communication opportunity by the method and perform communication.

  Note that the selection means does not select a communicable area used by another communication system within a predetermined period even if it is a communicable area that is used infrequently based on the history stored in the storage means. When configured, it is possible to reduce the possibility of collision between the communication signal of the own communication system and the communication signal of another communication system.

  As a result, according to the communication system of the present invention, a plurality of communication systems including a communication system including a distributed control type communication apparatus can coexist.

  A communication system including a distributed control type communication device is generally used for burst data transmission such as device control data, Web data, and e-mail data. According to the communication system of the present invention, a communication system that assumes such bursty data transmission can use power lines as communication media efficiently and without colliding with each other.

  In addition, each of the plurality of distributed control communication devices provided in the communication system of the present invention uses the same communicable area within a predetermined period. This is in good agreement with the characteristics of burst data in which a certain communicable area starts to be used for a while. Accordingly, each communication device can efficiently secure a communicable area. In particular, if the selecting means is configured to select a communicable area where the frequency of use of the own communication system is the highest, this effect appears more remarkably.

  In one aspect of the communication system of the present invention, the communication system is multiplexed with the other communication system by a time division multiple access method, and the plurality of communicable regions are a plurality of time regions obtained by dividing a predetermined time interval. is there.

  According to this aspect, the communication system coexists with another communication system in a time division multiple access scheme. In this case, the plurality of communicable areas are a plurality of time areas (that is, time slots) obtained by dividing a predetermined time interval (that is, a frame). The time width of each of the plurality of time regions is typically uniform, but may be arbitrary.

  The declaring means periodically declares a communicable area used by the own communication system to other communication systems at the beginning of each predetermined time interval. The declaring unit or the communication device including the declaring unit may detect a reference signal such as a frame synchronization pulse and detect the start of a predetermined time interval. Alternatively, when the predetermined time interval starts from the zero cross point of the commercial power supply voltage, the zero cross point may be detected to detect the start of the predetermined time interval.

According to another aspect of the communication system of the present invention, the selecting means, based on the obtained usage history, the lower communicable region frequently used among the detected one or more communicable regions the It is selected as a communicable area used by the communication system .

  If comprised in this way, possibility that the communication signal of a self-communication system and the communication signal of another communication system will collide can be reduced, and it is very advantageous practically.

According to another aspect of the communication system of the present invention, the selecting means performs communication with a high use frequency of the communication system among the detected one or a plurality of communicable areas based on the acquired use history. The possible area is selected as the communicable area used by the communication system .

  If comprised in this way, the state close | similar to the state where the specific communicable area | region is allocated with respect to the own communication system can be implement | achieved, and each of the some communication apparatuses in the own communication system is based on CSMA system, for example. Stable communication can be performed.

  In addition, when another communication system temporarily uses a communicable area where the use frequency of the own communication system is high, the selection unit does not select another communication available area (that is, communication within the own communication system). May be temporarily interrupted), and a communicable area where the use frequency of the own communication system is high may be selected again after a predetermined time.

According to another aspect of the communication system of the present invention, the selecting means includes the other one within a first predetermined period of the detected one or more communicable areas based on the acquired use history. At least one of the communicable areas excluding the communicable area used in the communication system is selected as a communicable area used by the communication system .

  If comprised in this way, since other communicable area | regions except the communicable area | region which may be used again by another communication system are selected by a selection means, the communication signal and other communication of an own communication system are selected. The possibility of collision with the communication signal of the system can be further reduced, which is very advantageous in practice.

  Here, the “first predetermined period” according to the present invention is a period in which another communication system is determined to be used again, or a period in which the probability that the other communication system is used again is a predetermined threshold or more. Specifically, it is set in advance as a fixed value. Such a first predetermined period is, for example, the number of cycles in which the declaring means makes a declaration. For example, by using a simulation using a predetermined probability density function, a usage history in which each of a plurality of communicable areas is used is obtained. It may be determined and set based on the obtained usage history.

In another aspect of the communication system of the present invention, the declaring unit periodically declares the communicable area selected by the selecting unit as the communicable area used by the communication system to the other communication system. To do.

  According to this aspect, the declaring means periodically declares a communicable area used by the own communication system to other communication systems. In other words, each communication device included in the communication system performs communication using the same communicable area from the declaration means to the next declaration.

  Assuming that the declaring means is configured to declare a communicable area used by the communication system whenever any one of the plurality of communication apparatuses included in the communication system performs communication. For example, in the case of a communication apparatus that performs communication using the CSMA method, there is a possibility that communication cannot be performed normally in the communication system.

  However, in the present invention, since the same communicable area is always used from the declaration means to the next declaration, even if it is a communication apparatus that performs communication by the CSMA method, communication can be performed normally. It can be carried out.

  In another aspect of the communication system of the present invention, the one communication device further includes a collision detection unit that detects a collision of communication signals on the power line, and when the collision is detected, the declaration unit includes: The second predetermined period is not declared.

  According to this aspect, the collision detection unit detects a collision between the communication signal of the own communication system and the communication signal of another communication system. Specifically, for example, an error signal indicating that communication has failed due to collision of communication signals is detected.

  When a collision is detected, the declaring means does not make a declaration for the second predetermined period. That is, since the communicable area used by the own communication system is not acquired during the second predetermined period, each communication device in the own communication system cannot perform communication.

  Here, the “second predetermined period” according to the present invention is a period until a retry is performed when a collision of communication signals occurs, that is, after the collision is detected by the collision detection means, and then the declaration means. Is a period until the declaration is made, for example, a period set based on a random number.

In order to solve the above-described problem, the communication device of the present invention is a communication device in a communication system that performs communication using a power line and shares the power line with other communication systems, and at least a plurality of the communication devices separated by time Area detection means for detecting one or a plurality of communicable areas that can be used by the communication system among the communicable areas, and history acquisition for acquiring a usage history in which each of the plurality of communicable areas is used over a plurality of periods And means for selecting at least one communicable area from among the detected one or more communicable areas as a communicable area used by the communication system based on the acquired use history. , the selected at least one communication coverage area of which, as a communication area where the communication system uses, Hsuan to the other communication system Declarative means for a communicable region declared by the declaration means, recognizing means for recognizing a communicable region in which the communication system uses, and transmitting and receiving means for transmitting and receiving communication signals in the recognized communicable regions The acquired usage history includes, in one cycle among the plurality of cycles, each of the plurality of communicable areas is (i) used by the communication system, (ii) used by the other communication system, and (Iii) Indicates whether the state is unused .

According to the communication apparatus of the present invention, the area detecting means detects a communicable area that can be used by the communication system among a plurality of communicable areas. The history acquisition unit acquires a use history in which each of the plurality of communicable areas is used over a plurality of periods. The selection means selects at least one of the detected communicable areas as the communicable area used by the communication system based on the acquired use history. The declaring means declares the selected at least one communicable area as a communicable area used by the own communication system to which the communication apparatus belongs to another communication system.

  As a result, the communicable area used by the local communication system is declared to other communication systems, so that it is possible to recognize which communicable areas are used by a plurality of communication systems. Alternatively, a plurality of communication systems having different communication methods can coexist.

  Typically, a plurality of communication devices belong to the own communication system, and one communication device among the plurality of communication devices declares a communicable area used by the own communication system to other communication systems. At the same time, the declared communication available area is notified to each of the plurality of communication devices belonging to the communication system, that is, a signal indicating the declared communication available area is transmitted. The recognition means in each communication device recognizes the declared communicable area as the communicable area used by the own communication system by receiving the transmitted signal. As a result, each communication device can perform communication in the recognized communicable region by acquiring a communication opportunity, for example, by the CSMA method.

  The transmission / reception means transmits / receives a communication signal in the recognized communicable area. That is, a plurality of communication devices in the own communication system including the communication device communicate with each other in the recognized communicable area.

  As a result, according to the communication apparatus of the present invention, a plurality of communication systems including a communication system including a distributed control type communication apparatus can coexist.

In order to solve the above-described problem, the communication method of the present invention is a communication method in a communication system that includes a plurality of communication devices that perform communication using a power line and shares the power line with other communication systems, at least a region detecting means for one of the communication devices has one of a plurality of communication devices, for detecting at least the time of the divided plurality of communicable regions in one such communication system is available or more communication area region A detection step, a history acquisition step of acquiring a use history in which each of the plurality of communicable regions is used over a plurality of periods , and the one or more communicable regions detected based on the acquired use history at least one coverage area of a communicable region in which the communication system uses, and a selection step of selecting, said one communication apparatus having one of Word means, said selected at least one communication coverage area of which, as a communication area where the communication system uses declares declarative step to the other communication system, the notification means the one communication apparatus has A notification step of notifying the communicable area declared in the declaration step to the plurality of communication devices included in the communication system, wherein the acquired use history is in one cycle of the plurality of cycles Each of the plurality of communicable areas indicates (i) use by the communication system, (ii) use by the other communication system, and (iii) unused. The plurality of communication devices including the one communication device having the notification unit perform communication in the notified communicable area.

  According to the communication method of the present invention, similarly to the communication system of the present invention described above, a plurality of communication systems including a communication system including a distributed control type communication device can coexist.

  In the communication method of the present invention, various aspects similar to the various aspects of the communication system of the present invention described above can be adopted.

  The operation and other advantages of the present invention will become apparent from the best mode for carrying out the invention described below.

  Hereinafter, an embodiment according to a communication system of the present invention will be described with reference to FIGS. 1 to 5.

  First, the configuration of the communication system according to the present embodiment will be described with reference to FIG. FIG. 1 is a schematic diagram illustrating a configuration of a communication system according to the present embodiment.

  In FIG. 1, a communication system 1 includes a plurality of distributed control type best effort modems 11 to 15 as an example of “communication devices” according to the present invention. The plurality of modems 11 to 15 are connected to each other through the power line 4.

  The communication system 1 is connected to other communication systems 2 and 3 through a power line 4 and multiplexed by time division multiple access. Therefore, in this embodiment, each of the modems 11 to 15, 21, and 31 included in each of the communication systems 1, 2, and 3 performs communication in the time slot as an example of the “communication available area” according to the present invention.

  The plurality of modems 21 included in the communication system 2 and the plurality of modems 31 included in the communication system 3 may be distributed control type best effort type modems or centralized control type best effort types. It may be a modem. Alternatively, a band-guaranteed modem may be used. The communication system or communication standard of the communication systems 2 and 3 is typically different from the communication system or communication standard of the communication system 1.

  Here, with reference to FIG. 2, the time slot according to the present embodiment will be described. FIG. 2 is a conceptual diagram showing the concept of a time slot according to the present embodiment.

  In FIG. 2, the plurality of time slots 210 divide the frame with, for example, one cycle (from time T1 at the zero cross point Z1 to time T2 at the zero cross point Z2) based on the zero cross point of the commercial power supply voltage a as one frame. (For example, 12 divisions) are set. For example, identifiers (here, A, B, and C) are assigned to each of the plurality of time slots 210, and there are time slots to which the same identifier is periodically added in one frame. . In FIG. 2, the identifier is shown for only one frame, but the identifier is also assigned to the other time slots 210 in the same manner.

  In the same frame, each of the communication systems 1 to 3 performs communication using a time slot to which the same identifier is assigned. Therefore, for example, in a certain frame, when the communication system 1 uses a time slot to which the identifier A is assigned, there is a time slot in which communication is not actually performed in the time slot, that is, there is an unused time slot. Even so, the other communication systems 2 and 3 cannot use the unused time slots.

  Next, the modem 11 will be described with reference to FIG. FIG. 3 is a block diagram showing a configuration of the modem 11 according to the present embodiment. Note that the configuration of each of the modems 12 to 15 in the communication system 1 is the same as the configuration of the modem 11, and thus the description thereof is omitted.

  3, the modem 11 includes an area detection unit 101, a history acquisition unit 102, a selection unit 103, a declaration unit 104, a notification unit 105, a recognition unit 106, a memory 107, a collision detection unit 108, a control unit 109, a transmission / reception unit 110, and An input / output unit 111 is provided. Here, “area detection unit 101”, “history acquisition unit 102”, “selection unit 103”, “declaration unit 104”, “notification unit 105”, “recognition unit 106”, “collision detection unit” according to the present embodiment 108 ”and“ transmission / reception unit 110 ”are respectively“ area detection means ”,“ history acquisition means ”,“ selection means ”,“ declaration means ”,“ notification means ”,“ recognition means ”,“ collision ”according to the present invention. It is an example of "detection means" and "transmission / reception means".

  During the operation, the history acquisition unit 102 first acquires the use history of the time slot 210 and stores the acquired use history in the memory 107. Here, the usage history of the time slot 210 typically means a usage history for each identifier assigned to the time slot 210. In other words, it means the usage history of the time slot group to which the same identifier is assigned.

  When the modem 11 is activated or connected to the power line 4, the history acquisition unit 102 typically uses the time slot 210 for a predetermined number of times or a predetermined period (for example, 10 times). To get. At this time, the control unit 109 controls the transmission / reception unit 110 and the like so as not to perform communication.

  Next, the area detection unit 101 detects a time slot that can be used by the communication system 1 to which the modem 11 belongs, based on the previous use history stored in the memory 107. Specifically, the area detection unit 101 detects an identifier assigned to a time slot used by the communication system 1 or an identifier assigned to a time slot not used by the other communication systems 2 and 3. .

  The selection unit 103 selects a time slot used by the communication system 1 from the time slots detected by the area detection unit 101 based on the usage history stored in the memory 107.

  Here, with reference to FIG. 4, a method for detecting and selecting a time slot will be described. FIG. 4 is a conceptual diagram illustrating an example of a usage history according to the present embodiment. In FIG. 4, “1” indicates that the communication system 1 to which the modem 11 belongs is used, and “2” indicates that another communication system 2 or 3 different from the communication system 1 is used. “0” indicates that no communication system is used. In addition, A, B, and C shown at the top of the use history represent identifiers assigned to the time slots 210, respectively.

  When the usage history 301 as shown in FIG. 4A is stored in the memory 107, the area detection unit 101 uses “the communication system 1 uses all the time slots based on the previous usage history 301 a. It is detected as “possible time slot”.

  The selection unit 103 is given the time slot with the highest use frequency of the communication system 1 to which the modem 11 belongs, that is, the identifier A, based on the use history 301b related to the detected time slot (all in this case). Select a time slot. If there is a time slot used immediately before by the communication system 1 (in this case, a time slot to which the identifier A is assigned), the time slot may be selected only for that reason.

  Alternatively, when the usage history 302 as shown in FIG. 4B is stored in the memory 107, the area detection unit 101 determines whether the identifier B or C is given based on the immediately preceding usage history 302a. The slot is detected as “a time slot in which the communication system 1 can be used”.

  The selection unit 103 simply selects the time slot with the lowest usage frequency, that is, the time slot to which the identifier C is assigned, based on the usage history 302b related to the detected time slot.

  Here, if the first predetermined period is set to, for example, five periods (that is, the immediately preceding five times), the time slot to which the identifier C is assigned is used by another communication system 2 or 3 in the previous time. Therefore, the selection unit 103 determines that the time slot to which the identifier C is assigned may be used again by another communication system 2 or 3, and the time to which the identifier B is assigned. A slot may be selected.

  Alternatively, when the usage history 303 as shown in FIG. 4C is stored in the memory 107, the area detection unit 101 sets all the time slots to “communication system 1” based on the previous usage history 303a. Is detected as a usable time slot.

  Here, referring to the usage history 303b related to the detected time slot, the time slot to which the identifier A is assigned has the highest usage frequency of the communication system 1, but is used by another communication system 2 or 3 before the previous time. Has been.

  In this case, the selection unit 103 uses the communication system 1 after a predetermined time without selecting any time slot (that is, temporarily interrupting communication) based on the use history 303b related to the detected time slot. You may make it select the time slot which the identifier A was provided on condition that it is possible. Note that the selection unit 103 may select a time slot to which the identifier C is assigned that is least frequently used.

  Returning to FIG. 3 again, the declaring unit 104 declares the time slot selected by the selecting unit 103 to the other communication systems 2 and 3 as the time slot used by the communication system 1. Note that the declaration unit 104 typically makes a declaration periodically at the beginning of each frame, such as times T1, T2, and T3 in FIG.

  The notification unit 105 notifies the time slots declared by the declaration unit 104 to the modems 11 to 15 included in the communication system 1. The recognizing unit 106 recognizes the notified time slot as a time slot used by the communication system 1.

  The control unit 109 controls the transmission / reception unit 110 to perform communication according to the communication method or communication standard in the communication system 1 in the recognized time slot. Specifically, for example, when the modems 11 to 15 in the communication system 1 are multiplexed by the time division multiple access method in the communication system 1, each of the modems 11 to 15 is notified by the CSMA method in the notified time slot. Get communication opportunities and communicate.

  Thus, since the time slot used by the communication system 1 is declared to the communication systems 2 and 3 by the declaring unit 104, a plurality of communication systems can recognize which time slot each other uses. Can do. Therefore, it is possible to avoid interference or interference due to communication signals of each of the plurality of communication systems, and a plurality of communication systems having different communication standards or communication methods can coexist.

  In addition, since the notification unit 105 notifies each of the modems 11 to 15 constituting the communication system 1 of the declared time slot, each of the modems 11 to 15 determines the time slot used by the communication system 1. Can be recognized. Since the time slots to which the same identifier is assigned are used within the same period, each of the modems 11 to 15 can acquire a communication opportunity and perform communication in the notified time slot.

  By the way, when the declaring unit 104 declares the time slot used by the communication system 1 or within the time considered to be simultaneous, one of the plurality of modems 21 included in the communication system 2 or the communication system 3 If one modem among the plurality of modems 31 provided declares that it uses the same time slot as the time slot declared by the declaring unit 104, at least two communication systems compete. Then, communication signals of each communication system collide, that is, communication fails.

  The collision detection unit 108 in the modem 11 detects an error signal indicating that the communication has failed, and detects that the communication signal of the communication system 1 and the communication signal of the communication system 2 or 3 have collided. When a collision is detected, the control unit 109 is a period set based on, for example, one cycle or a random number, and the collision avoidance period as an example of the “second predetermined period” according to the present invention is declared. The declaration unit 104 is controlled so as not to be performed. Thereby, possibility that a collision will generate | occur | produce again can be reduced.

  In the present embodiment, the declaration unit 104 in the modem 11 declares the time slot used by the communication system 1 and the notification unit 105 notifies the declared time slot. The modem may be any of the modems 11 to 15 included in the communication system 1. Typically, the modem that performs communication first in a certain frame declares and notifies.

  When the time slot used by the communication system 1 is declared and notified by one of the modems 12 to 15 different from the modem 11, the recognition unit 106 in the modem 11 is notified by the notification unit in the one modem. The notified time slot is recognized as a time slot used by the communication system 1.

  As a result, according to the communication system according to the present embodiment, a plurality of communication systems including a communication system including a distributed control type modem can coexist.

  Next, the operation of the modem 11 in the communication system 1 configured as described above will be described with reference to the flowchart of FIG. Note that the operation of each of the modems 12 to 15 is the same as that of the modem 11, and thus the description thereof is omitted.

  5, first, the history acquisition unit 102 acquires the usage history of the time slot 210 and stores it in the memory 107 (step S101). Subsequently, the control unit 109 determines whether or not the usage history has been acquired a predetermined number of times (for example, 10 times) (step S102). If it is determined that the usage history has not been acquired (step S102: No), the control unit 109 109 controls the history acquisition unit 102 to acquire the use history until the predetermined number of times is reached. The case where it is determined that the usage history is not acquired is typically a case where the use history is acquired for the first time after the modem 11 is activated or connected to the power line 4.

  If it is determined that the usage history has been acquired a predetermined number of times (step S102: Yes), then, whether or not the collision avoidance period is set by the control unit 109 or whether or not the collision avoidance period is not zero. Is determined (step S103). When it is determined that the collision avoidance period is set or not zero (step S103: Yes), the control unit 109 decreases the collision avoidance period by a predetermined amount (for example, a time corresponding to one cycle) (step S117). ), And the process is temporarily terminated.

  When it is determined that the collision avoidance period is not set or is zero (step S103: No), the area detection unit 101 detects a time slot that can be used by the communication system 1 (step S104). Subsequently, it is determined whether or not a usable time slot has been detected (step S105). If not detected (step S105: No), the process is temporarily terminated.

  If a time slot that can be used by the communication system 1 is detected (step S105: Yes), then, does the detected time slot include the time slot that was used immediately before by the communication system 1? It is determined whether or not (step S106). When it is determined that it is included (step S106: Yes), the selection unit 103 selects the time slot used immediately before by the communication system 1 as the time slot used by the communication system 1 (step S110). ).

  When it is determined that it is not included (step S106: No), it is subsequently determined whether or not there is a usage history used by the communication system 1 in the usage history stored in the memory 107 (step S107). ). When it is determined that there is a usage history used by the communication system 1 (step S107: Yes), the selection unit 103 selects the time slot with the highest usage frequency of the communication system 1 as the time slot used by the communication system 1. (Step S111).

  When it is determined that there is no usage history used by the communication system 1 (step S107: No), it is subsequently determined whether or not a plurality of time slots that can be used by the communication system 1 are detected (step S108). When it is determined that a plurality of times are detected (step S108: Yes), the selection unit 103 selects the time slot with the lowest usage frequency as the time slot used by the communication system 1 (step S112). In this case, the time slot used for the communication system 2 or 3 may not be selected within the first predetermined period.

  When it is determined that a plurality is not detected (step S108: No), the selection unit 103 selects the detected time slot as a time slot used by the communication system 1 (step S109).

  Next, the time slot selected by the declaring unit 104 is declared to the communication systems 2 and 3 as the time slot used by the communication system 1, and the declared time slot is transmitted to the communication system by the notifying unit 105. 1 is notified to each of the modems 11 to 15 belonging to 1 (step S113). Subsequently, the recognized time slot is recognized by the recognition unit 106 as a time slot used by the communication system 1, and communication is performed by the transmission / reception unit 110 in the recognized time slot (step S114).

  Next, it is determined whether or not an error signal is detected by the collision detection unit 108 (step S115). When it is determined that the error signal has not been detected (step S115: No), the process is temporarily ended. If it is determined that an error signal has been detected (step S115: Yes), a predetermined collision avoidance period is set (step S116), and the process is temporarily terminated.

  Note that the present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist or concept of the invention that can be read from the claims and the entire specification, and communication involving such changes. Systems and methods and communication devices are also within the scope of the present invention.

It is a schematic diagram which shows the structure of the communication system which concerns on embodiment of this invention. It is a conceptual diagram which shows the concept of the time slot which concerns on embodiment of this invention. It is a block diagram which shows the structure of the modem which concerns on embodiment of this invention. It is a conceptual diagram which shows an example of the usage history which concerns on embodiment of this invention. It is a flowchart which shows operation | movement of the modem which concerns on embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1, 2, 3 ... Communication system, 4 ... Power line, 11-15, 21, 31 ... Modem, 101 ... Area | region detection part, 102 ... History acquisition part, 103 ... Selection part, 104 ... Declaration part, 105 ... Notification part, 106: Recognition unit, 107: Memory, 108: Collision detection unit, 109: Control unit, 110: Transmission / reception unit, 111: Input / output unit

Claims (9)

A communication system comprising a plurality of communication devices that communicate using a power line, and sharing the power line with other communication systems,
At least one communication device among the plurality of communication devices is:
An area detecting means for detecting one or more communicable areas that can be used by the communication system among a plurality of communicable areas divided at least by time;
History acquisition means for acquiring a usage history in which each of the plurality of communicable areas is used over a plurality of periods;
Based on the acquired use history, selection means for selecting at least one communicable area from among the one or more detected communicable areas as a communicable area used by the communication system;
Declaring means for declaring the selected at least one communicable area as the communicable area used by the communication system to the other communication system;
Notification means for notifying the plurality of communication devices provided in the communication system of at least one communicable region declared by the declaration means ;
The acquired usage history includes, in one cycle among the plurality of cycles, each of the plurality of communicable regions (i) used by the communication system, (ii) used by the other communication system, and (iii) ) Indicates whether it is unused,
The plurality of communication devices including the at least one communication device having the declaration unit and the notification unit communicate with each other in the notified communicable area. The communication system is multiplexed with the other communication system by a time division multiple access method,
The communication system according to claim 1, wherein the plurality of communicable areas are a plurality of time areas obtained by dividing a predetermined time interval. The selecting means selects, based on the acquired use history, a communicable area having a low use frequency from the one or more communicable areas detected as a communicable area used by the communication system. The communication system according to claim 1 . Based on the acquired use history, the selecting means sets a communicable area where the communication system is frequently used among the one or more detected communicable areas as a communicable area used by the communication system. The communication system according to claim 1 , wherein the communication system is selected. The selecting means is a communication that excludes a communicable area used by the other communication system within a first predetermined period from the one or more communicable areas detected based on the acquired use history. communication system according to claim 1, at least one communication area of the region, as the communication area where the communication system is used, and selects. The declaration means a communicable area selected by the selecting means, as the communication area where the communication system uses, according to claim 1, wherein the declaring to periodically the other communication system The communication system according to any one of the above. The one communication device further includes collision detection means for detecting a collision of communication signals on the power line,
The communication system according to any one of claims 1 to 6 , wherein, when the collision is detected, the declaring unit does not make a declaration for a second predetermined period. A communication device in a communication system that performs communication using a power line and shares the power line with another communication system,
An area detecting means for detecting one or a plurality of communicable areas usable by the communication system among a plurality of communicable areas divided at least by time;
History acquisition means for acquiring a usage history in which each of the plurality of communicable areas is used over a plurality of periods;
Selection means for selecting, as the communicable area used by the communication system, at least one communicable area from the one or more communicable areas detected based on the acquired use history;
Declaring means for declaring the selected at least one communicable area to the other communication system as a communicable area used by the communication system;
Recognizing means for recognizing the communicable area declared by the declaring means as a communicable area used by the communication system;
Transmitting and receiving means for transmitting and receiving communication signals in the recognized communicable area ,
The acquired usage history includes: (i) use by the communication system, (ii) use by the other communication system, and (iii) ) Indicates whether it is unused
A communication device. A communication method in a communication system including a plurality of communication devices that perform communication using a power line and sharing the power line with another communication system,
Region detecting means having at least one communication device of the plurality of communication devices, among the plurality of communication area which is divided by at least the time, the communication system detects one or more communication area available An area detection step;
A history acquisition step of acquiring a usage history in which each of the plurality of communicable areas is used over a plurality of periods;
A selection step of selecting at least one communicable area from the detected one or more communicable areas as a communicable area used by the communication system based on the acquired use history;
A declaring step in which the declaring means of the one communication device declares the selected at least one communicable area as a communicable area used by the communication system, to the other communication system;
The notification means of the one communication device comprises a notification step of notifying the plurality of communication devices included in the communication system of the communicable area declared in the declaration step ,
The acquired usage history includes, in one cycle among the plurality of cycles, each of the plurality of communicable regions (i) used by the communication system, (ii) used by the other communication system, and (iii) ) Indicates whether it is unused,
The communication method, wherein the plurality of communication devices including the one communication device having the declaration unit and the notification unit perform communication in the notified communicable area.

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