JP4488828B2 - Master station of communication system and access control method - Google Patents

Description

  The present invention relates to a master station and an access control method of a communication system, and more particularly to an access control method used for a plurality of communication systems sharing the same channel and preventing interference between the plurality of communication systems. .

  Conventionally, as a technique for reducing interference generated between a plurality of communication systems sharing the same channel, there is an access control method for reducing the influence of interference waves using transmission power control (see Patent Document 1 and Patent Document 2). reference).

  In Patent Document 1, an attenuator is provided in a base station to attenuate signal power and interference power, while transmitting a terminal station so that the power level of a radio signal input to a receiver becomes a reference level. A method of guaranteeing with the transmission power of a machine is disclosed.

Further, in Patent Document 2, the base station that detected the interference radio wave notifies the other base station that is transmitting the interference radio wave via the local area communication network, and the other base station that is notified A method of reducing transmission power based on interference information is disclosed.
JP 2002-198834 A JP 2003-37556 A

  However, when the above-described communication system is a power line communication system, a signal that causes signal attenuation in its own communication system to interfere with other communication systems as a characteristic of the power line transmission path, depending on the configuration of devices connected to the network. In some cases, the amount of attenuation may be greatly exceeded. In other words, when Patent Document 1 and Patent Document 2 are applied to a power line communication system, if interference between communication systems is performed by power control, depending on the device configuration, there is a device in which signal strength decreases and device communication cannot be performed in the system. May occur. Also, in the case of wireless communication, the same phenomenon can occur that the signal strength is suddenly reduced due to the attenuation of the signal strength by the shield, although the physical distance is close.

  With the above conventional configuration, it becomes impossible to suppress interference with other communication systems while maintaining communication quality in the own communication system by transmission power control. For this reason, the throughput of each communication system is greatly deteriorated due to interference between communication systems, and it is difficult to control the communication band.

  Therefore, an object of the present invention is to easily avoid interference between communication systems and to guarantee QoS of the communication band of each communication system without performing transmission power control in a plurality of communication systems sharing the same channel. It is to provide a master station and an access control method that make it possible.

  The present invention is directed to a master station used in each communication system in a system environment in which a plurality of communication systems including at least one slave station and a master station that manages the slave stations share the same channel. It has been. And in order to solve the said subject, the main | base station of this invention is provided with the communication part, the acquisition part, and the judgment part.

  The communication unit is a time-division multiple access where all the master stations can access the beacon area by competing and transmitting the beacon packet, and only a specific authorized station can be accessed using a communication band allocated by time division or frequency division. The communication band is divided into a (TDMA) region or a frequency division multiple access (FDMA) region and a carrier sense multi-access (CSMA) region that can be accessed by all stations competing, and communication is repeated periodically. . The acquisition unit acquires a use state of a communication band or a frequency band in another communication system. The determination unit calculates a communication band or frequency band that can be used by the communication system in the TDMA region or the FDMA region based on the use state of the communication band or frequency band acquired by the acquisition unit, and calculates the calculated communication band or frequency According to the band, permission / non-permission of communication requested from the slave station is determined.

Typically, the acquisition unit may acquire the usage status of the communication band or the frequency band in another communication system by exchanging information with another master station using the CSMA region, or may receive other information in the beacon region. The usage status of the communication band or frequency band in another communication system may be acquired from the beacon packet of the master station.
In addition, if the determination unit determines permission of communication using the same division time in response to requests from a plurality of slave stations that do not interfere with each other, the communication band can be used effectively.

In particular, when the segmented region is a TDMA region, it is preferable that the segmentation ratio between the TDMA region and the CSMA region dynamically change according to the total communication bandwidth required by a specific station.
On the other hand, when the segmented area is an FDMA area, the determination unit desirably permits communication using an unused frequency band in the FDMA area in response to a request from the slave station. Also, if the communication band is frequency-divided by a multi-carrier communication system composed of a plurality of subcarriers, the number of subcarriers used can be changed dynamically according to the total frequency band required by a specific station. It is effective.

  Each process performed by each configuration of the master station described above can be regarded as an access control method that provides a series of processing procedures. This method is provided in the form of a program for causing a computer to execute a series of processing procedures. This program may be installed in a computer in a form recorded on a computer-readable recording medium. Further, each of the above-described configurations of the master station may be realized as an LSI that is an integrated circuit.

  As described above, according to the present invention, the communication band is divided into the beacon area, the band-guaranteed TDMA area or FDMA area, and the CSMA area, and the allocation in the TDMA area or FDMA area is assigned to each communication system. It is determined based on the information of the used communication band. As a result, even when a plurality of communication systems share the same channel, interference between communication systems can be easily avoided and QoS in the communication band of each communication system can be guaranteed without performing transmission power control. Can do.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram showing an example of a communication system environment to which the present invention is applied. FIG. 1 illustrates an environment in which three communication systems 11 to 13 exist by interfering with each other. The communication system 11 includes a master station 111 and a slave station 112. The communication system 12 includes a master station 121, a slave station 122, and a slave station 123. The communication system 13 includes a master station 131, a slave station 132, and a slave station. The station 133 is configured.

  As shown in FIG. 2, each master station and slave station include a bandwidth management unit 21, a control unit 22, a data buffer unit 23, a data transmission / reception unit 24, a time timer unit 25, and a higher-level interface unit 26. The bandwidth management unit 21 manages various information related to the communication bandwidth. The control unit 22 controls the entire station. The data buffer unit 23 temporarily stores various packets. The data transmission / reception unit 24 transmits the packet stored in the data buffer unit 23 or stores the received packet in the data buffer unit 23. The time timer unit 25 manages the time related to data transmission / reception of the station. The upper interface unit 26 is, for example, an interface with an upper host or an interface with another medium (communication system or the like) such as a bridge form. The bandwidth management unit 21, the control unit 22, and the time timer unit 25 constitute a determination unit. The data buffer unit 23 and the data transmission / reception unit 24 constitute an acquisition unit. Further, the control unit 22 and the data transmission / reception unit 24 constitute a communication unit.

  In the present invention, the communication band used by the communication systems 11 to 13 is divided in advance into three areas: a beacon area, a band guarantee area, and a CSMA area. The beacon area is a section in which all the master stations compete and transmit beacon packets. The bandwidth guarantee area is a section in which only a specific authorized station can access using a pre-assigned bandwidth. In the present invention, time division multiple access (TDMA) and frequency division multiple access (FDMA) are described. The CSMA region is a section that can be accessed by all stations competing using carrier sense. These three regions are repeated periodically (see FIG. 3).

The master station 111, the master station 121, and the master station 131 manage the beacon area, the bandwidth guarantee area, and the CSMA area by the time timer unit 25. Typically, the system information that gives the allocation time of these three areas is stored in a beacon packet and transmitted.
An access control method using the master station and the slave station having the above configuration will be described below.

(First embodiment)
FIG. 4 is a timing chart for explaining the access control method according to the first embodiment of the present invention. In the access control method according to the first embodiment, the communication band is divided into three areas: a beacon area, a TDMA area (hereinafter referred to as a Dynamic-TDMA area) to which a communication band to be used by time division is allocated, and a CSMA area. It is divided. The partition ratio between the Dynamic-TDMA area and the CSMA area may not be constant, and the partition ratio may be changed according to the total communication bandwidth required by a specific station permitted to communicate in the Dynamic-TDMA area. Can be changed.

  First, the master stations 111, 121, and 131 transmit their beacon packets in transmission slots assigned in advance when the beacon area start time comes. In the example of FIG. 4, the master stations 111, 121, and 131 of the communication systems 11, 12, and 13 transmit beacon packets 401, 406, and 410 in order. This beacon packet includes the transmission time of the beacon packet based on the time timer, the start time of the beacon area, the start time of the Dynamic-TDMA area, the start time of the CSMA area, and the like as system information.

  The simplest method for determining the beacon packet transmission timing of each master station is to fix the transmission slots in the order of activation of the communication system. This recognition of the activation order can be realized by a method of connecting the master station with a wired backbone, a method of notifying that another communication system has been activated in the CSMA area, or the like. Further, in the beacon area, it is possible to transmit by competing between communication systems using a random access method such as a Slotted ALOHA method or a CSMA method. However, when the random access method is used, there is a case where a beacon cannot be transmitted. Therefore, both the master station and the slave station need to have a system synchronization protection function.

Next, a method of dynamically allocating a communication band (communication time) that can be used by each communication system in the Dynamic-TDMA area will be described with reference to FIG.
When each master station 111, 121, and 131 receives a beacon packet from another master station via the data transmitting / receiving unit 24 (step S501), the beacon packet is temporarily stored in the data buffer unit 23. Then, the control unit 22 of each master station 111, 121, and 131, from the beacon packet stored in the data buffer unit 23, the beacon region, the Dynamic-TDMA region assigned to its own communication system, the start time of the CSMA region, The bandwidth information such as the allocation time of each area is extracted and stored in the bandwidth management unit 21 (step S502). From this band information, each master station 111, 121, and 131 can recognize at which timing each station that received the request can communicate in the Dynamic-TDMA area.

  Next, each of the parent stations 111, 121, and 131 determines whether or not a new request is generated in its own communication system (step S503). When a new request is generated, each of the master stations 111, 121, and 131 newly calculates a communication band that can be used in its own communication system based on the stored band information. A comparison is made with the total value of the communication bandwidth being used and the communication bandwidth of the new request (step S504). Then, if the total value is smaller as a result of the comparison, the parent station 111 and the parent station 131 permit a new request (step S505). On the other hand, if the total value is larger, the master station 111 and the master station 131 confirm whether or not there is a band that does not interfere with the communication according to the new request in the communication to which the band has already been allocated (step S507). .

  This is an effective use of the fact that even if a plurality of communication systems interfere with each other, there is an area that is not affected by interference if it is partially understood. In the example of FIG. 1, when the new request is communication between the slave station 132 and the slave station 133, no interference is given to the communication between the slave station 122 and the slave station 123. Therefore, this new request can be permitted in the same band as the band already allocated to the communication between the slave station 122 and the slave station 123. Typically, each master station collects which other station has received a packet transmitted from each slave station belonging to its own communication system. The station from which the packet is transmitted may be determined by an address or the like.

  As described above, when there is a band that does not interfere with communication by the new request, the master station 111 and the master station 131 permit the new request (step S505). On the other hand, if there is no band that does not interfere with the communication by the new request, the master station 111 and the master station 131 reject this new request (step S506).

  Here, the method of calculating the communication band that can be used in its own communication system based on the communication band used by another communication system performed in step S504 will be described with a specific example. For example, in the case where the maximum bandwidth in the Dynamic-TDMA area is 30 Mbps and the total communication bandwidth used by other communication systems is 6 Mbps, the MAC (Medium Access Control) efficiency is 0.65, retransmission, etc. Assume that 20% of the redundant bandwidth (margin) is secured. Therefore, in this case, the total communication band that can be used in all the communication systems is 15.6 Mbps (= 30 × 0.65 × 0.8). Therefore, the communication band that can be used in the own communication system is calculated as 9.6 Mbps (= 15.6-6.0). Therefore, in this example, if the communication bandwidth of the new request is 9.6 Mbps or less, the request is permitted.

  In addition to the above-described method of using the beacon region, a method of using the following CSMA region is conceivable as a method of acquiring communication band information used by another communication system. This method will be described with reference to FIGS.

  For example, when the slave station 122 needs to ensure QoS, the slave station 122 transmits a QoS request packet 611 to the master station 121 of the same communication system (step S701). The master station 121 that has received the packet 611 via the data transmitter / receiver 24 temporarily stores the information in the packet 611 (parameters such as the requested address of the slave station 122 and the requested bandwidth) in the data buffer unit 23. . Then, the control unit 22 of the parent station 121 sends status request packets 612 and 614 to the parent station 111 and the parent station 131 that have already been recognized as being in the vicinity by the beacon packet stored in the data buffer unit 23. Each is transmitted (step S702). Specifically, the control unit 22 of the parent station 121 generates the packets 612 and 614 in the data buffer unit 23 and transmits the packets 612 and 614 to the parent station 111 and the parent station 131 via the data transmission / reception unit 24.

  The data transmission / reception units 24 of the parent station 111 and the parent station 131 that have received the packets 612 and 614 store the packets in the data buffer unit 23. Then, the control unit 22 of the parent station 111 and the parent station 131 transmits status reply packets 613 and 615 including information on the used communication band held by the band management unit 21 to the parent station 121. Specifically, the control unit 22 of the parent station 111 and the parent station 131 generates the packets 613 and 615 in the data buffer unit 23 and transmits the packets 613 and 615 to the parent station 121 via the data transmission / reception unit 24.

  When the packets 613 and 615 are received from the master station 111 and the master station 131 (step S703), the control unit 22 of the master station 121 transmits information on the used communication band included in the packet, the maximum bandwidth of the above-described Dynamic-TDMA region, and Based on the margin, it is determined whether or not the request from the slave station 122 can be permitted (step S704). In addition, the control unit 22 of the master station 121 checks whether there is a band that does not interfere with the communication according to the new request among the communication to which the band has already been allocated (step S707). Then, the control unit 22 of the master station 121 generates a QoS reply packet 616 including request permission or request non-permission based on the above determination and confirmation results in the data buffer unit 23, Transmit to the station 122 (steps S705 and S706). At the same time, the control unit 22 of the master station 121 updates the band information managed by the band management unit 21.

  If the request is permitted, the master station 121 transmits to the slave station 122 band information indicating the timing at which transmission is permitted in the Dynamic-TDMA area in a beacon packet. The slave station 122 detects the update of the band information of the received beacon packet by the control unit 22 and transmits data at the designated transmission timing. Thereby, data can be transmitted without competing with other stations.

  Further, the result of request permission or request disapproval for the slave station 122 is notified to the other master stations 111 and 131 by transmitting QoS change notification packets 617 and 618, respectively. The other master stations 111 and 131 are managed by the bandwidth management unit 21 when it is necessary to change the start time of the Dynamic-TDMA area used by the communication system by receiving the packets 617 and 618. Update the bandwidth information.

  Then, the control unit 22 of the slave station 122 that has received the request permission packet 616 transmits a data packet using a predetermined communication band in the Dynamic-TDMA area, and the receiving side that has received the data packet receives a response packet. Will be returned.

  In the first embodiment, each communication system performs packet transmission (packet 402, packet 403, etc.) by further time-dividing the bandwidth allocated in the Dynamic-TDMA area for each station. However, instead of this time division, other multiple access methods such as frequency division and code division may be applied. In the first embodiment, a case has been described in which the Dynamic-TDMA area is time-divided in units of communication systems. However, time-division may be performed in units of stations that have transmitted bandwidth requests. Furthermore, although the case where the desired rate is notified as the band information has been described in the first embodiment, the desired transmission time required to satisfy the desired rate may be notified in consideration of the media state.

(Second Embodiment)
FIG. 8 is a timing chart for explaining the access control method according to the second embodiment of the present invention. In the access control method according to the second embodiment, the communication band is divided into three areas: a beacon area, an FDMA area (hereinafter referred to as a Dynamic-FDMA area) to which a communication band to be used by frequency division is allocated, and a CSMA area. It is divided.

  First, the master stations 111, 121, and 131 transmit their beacon packets in transmission slots assigned in advance when the beacon area start time comes. In the example of FIG. 8, the master stations 111, 121, and 131 of the communication systems 11, 12, and 13 transmit beacon packets 801, 806, and 810 in order. This beacon packet includes, as system information, the transmission time of the beacon packet based on the time timer, the start time of the beacon area, the start time of the Dynamic-FDMA area, the start time of the CSMA area, and the like. Note that the method for determining the beacon packet transmission timing of each master station is as described in the first embodiment.

  Next, a method of dynamically allocating a communication band (frequency bandwidth) that can be used by each communication system in the Dynamic-FDMA area will be described. In the following description, it is assumed that a multi-carrier communication scheme in which communication is performed using a plurality of narrow-band subcarriers is employed in the frequency bandwidth usable in each communication system. In addition, as an example, an OFDM scheme using 400 subcarriers to which subcarrier numbers 1 to 400 are added is adopted.

  When each parent station 111, 121, and 131 receives a beacon packet from another parent station via the data transmission / reception unit 24, the beacon packet is temporarily stored in the data buffer unit 23. Then, the control unit 22 of each master station 111, 121, and 131, from the beacon packet stored in the data buffer unit 23, the beacon region, the Dynamic-FDMA region allocated to its own communication system, the start time of the CSMA region, The bandwidth information such as the allocation time of each area is extracted and stored in the bandwidth management unit 21. From this band information, each of the master stations 111, 121, and 131 can recognize which frequency band can be used by each station that has accepted the request in the Dynamic-FDMA area.

  Next, each of the master stations 111, 121, and 131 determines whether or not a new request is generated in its own communication system. When a new request is generated, each master station 111, 121, and 131 confirms a frequency bandwidth that can be used in its communication system, that is, a subcarrier, based on the stored bandwidth information, and then creates a new request. It is determined whether or not there is a subcarrier that can be used. Then, the master station 111 and the master station 131 permit a new request if there is a subcarrier as a result of the determination. On the other hand, if there is no subcarrier, the master station 111 and the master station 131 confirm whether there is a subcarrier that does not interfere with communication by the new request among the already assigned subcarriers. The determination of the influence due to the interference is as described above.

  Here, a method for calculating a communication band that can be used in its own communication system based on a communication band used by another communication system will be described with a specific example. For example, it is assumed that the maximum bandwidth in the Dynamic-FDMA region is 40 Mbps, the total communication bandwidth used by other communication systems is 6 Mbps, and subcarriers numbered 300 to 400 are in use. Further, it is assumed that a margin for absorbing the difference in efficiency depending on retransmission and frequency characteristics for each subcarrier is secured by 40%. Therefore, in this case, the total communication band that can be used in all communication systems is 24 Mbps (= 40 × 0.6). Therefore, the communication band that can be used in the own communication system is calculated as 18 Mbps (= 24-6.0) and subcarriers of numbers 1 to 299. Therefore, in this example, if the communication bandwidth of the new request is 18 Mbps or less, the request is permitted.

  In addition to the above-described method of using the beacon region, the method for acquiring the communication band information used by other communication systems includes the following method of using the CSMA region as in the first embodiment. Conceivable. The processing procedure is based on FIG.

  For example, when the slave station 122 needs to secure QoS, the slave station 122 transmits a QoS request packet to the master station 121 of the same communication system. The master station 121 that has received this packet via the data transmitter / receiver 24 temporarily stores the information (parameters such as the requested address of the slave station 122 and the requested bandwidth) in the data buffer 23. Then, the control unit 22 of the parent station 121 transmits a status request packet to each of the parent station 111 and the parent station 131 that have already recognized that they are in the vicinity by the beacon packet stored in the data buffer unit 23. .

  The data transmission / reception units 24 of the parent station 111 and the parent station 131 that have received the packet store the packet in the data buffer unit 23. Then, the control unit 22 of the parent station 111 and the parent station 131 transmits a status reply packet including information on the used communication band held by the band management unit 21 to the parent station 121. The status reply packet includes necessary minimum bandwidth information, a used subcarrier number, and the like required in the communication system of the master station 111 and the master station 131.

  When receiving the packet from the master station 111 and the master station 131, the control unit 22 of the master station 121 determines the child communication bandwidth based on the information on the used communication band included in the packet and the above-described maximum bandwidth and margin of the Dynamic-FDMA area. It is determined whether the request from the station 122 can be permitted. In addition, the control unit 22 of the master station 121 checks whether there is a band that does not interfere with communication due to a new request among the communication that has already been allocated a band. Then, the control unit 22 of the master station 121 generates a QoS reply packet including request permission or request non-permission based on the determination and confirmation results in the data buffer unit 23, and the slave station via the data transmission / reception unit 24. 122. At the same time, the control unit 22 of the master station 121 updates the band information managed by the band management unit 21.

  When the request is permitted, the master station 121 transmits to the slave station 122 the band information indicating which subcarrier number and timing in the Dynamic-FDMA area permit transmission at the beacon packet. The slave station 122 detects the update of the band information of the received beacon packet by the control unit 22 and transmits data at the designated subcarrier and transmission timing. Thereby, data can be transmitted without competing with other stations.

  In addition, the result of request permission or request disapproval for the slave station 122 is notified to the other master stations 111 and 131 by transmitting a QoS change notification packet. The other master stations 111 and 131 are managed by the bandwidth management unit 21 when it is necessary to change the used subcarrier number information of the Dynamic-FDMA area used by the own communication system by receiving a packet. Update the bandwidth information.

  Then, the control unit 22 of the slave station 122 that has received the request permission packet 616 transmits a data packet using a predetermined communication band in the Dynamic-FDMA area, and the receiving side that has received the data packet receives a response packet. Will be returned.

  In the second embodiment, each communication system performs packet transmission (packet 802, packet 803, etc.) by further time-dividing the subcarriers allocated in the Dynamic-FDMA area for each station. . However, instead of this time division, other multiple access methods such as frequency division and code division may be applied. In particular, when the frequency division method is used, the information necessary for allocating the communication band in units of stations is only the used subcarrier number, and the overhead of the control packet can be reduced. In a communication system in which no bandwidth is allocated in the Dynamic-FDMA area, it is also possible to perform communication using a random access method using subcarriers that are not used.

  As described above, according to the access control method of the present invention, the communication band is divided into the beacon area, the band guaranteed area, and the CSMA area, and the allocation in the band guaranteed area is used as information on the used communication band of each communication system. Determine based on. As a result, even when a plurality of communication systems share the same channel, interference between communication systems can be easily avoided and QoS in the communication band of each communication system can be guaranteed without performing transmission power control. Can do.

  The technique using the Dynamic-TDMA area described in the first embodiment and the technique using the Dynamic-FDMA area described in the second embodiment may be used in combination. By performing band allocation in both the time and frequency directions, it is possible to construct a system that is flexible in terms of time characteristics and frequency characteristics in each communication system.

  Each of the above-described embodiments is realized by the CPU interpreting and executing predetermined program data stored in a storage device (ROM, RAM, hard disk, etc.) that can execute the above-described processing procedure. In this case, the program data may be introduced into the storage device via the recording medium, or may be directly executed from the recording medium. The recording medium refers to a semiconductor memory such as a ROM, a RAM, or a flash memory, a magnetic disk memory such as a flexible disk or a hard disk, an optical disk memory such as a CD-ROM, DVD, or BD, and a memory card. The recording medium is a concept including a communication medium such as a telephone line or a conveyance path.

Further, all or some of the functional blocks constituting the master station of the present invention are typically integrated circuits such as LSI (depending on the degree of integration, referred to as IC, system LSI, super LSI, ultra LSI, etc. Realized). These may be individually made into one chip, or may be made into one chip so as to include a part or all of them.
Further, the method of circuit integration is not limited to LSI's, and implementation using dedicated circuitry or general purpose processors is also possible. Also, an FPGA (Field Programmable Gate Array) that can be programmed after manufacturing the LSI, or a reconfigurable processor that can reconfigure the connection and setting of circuit cells inside the LSI may be used.
Furthermore, if integrated circuit technology comes out to replace LSI's as a result of the advancement of semiconductor technology or a derivative other technology, it is naturally also possible to carry out function block integration using this technology. There is a possibility of adaptation of biotechnology.

  In addition, an example in which the invention described in each of the above embodiments is applied to an actual network system is shown below. FIG. 9 is a diagram showing an example of a network system in which the present invention is applied to high-speed power line transmission. In FIG. 9, the power line is connected to the IEEE 1394 interface, the USB interface, and the like included in multimedia devices such as a personal computer, a DVD recorder, a digital TV, and a home server system via a module having the function of the present invention. . Thereby, it is possible to construct a network system capable of transmitting digital data such as multimedia data using a power line as a medium at high speed. In this system, a power line already installed in a home or office can be used as a network line as it is without installing a new network cable as in a conventional wired LAN. Convenience is great.

  The above form is an example in which an existing device is applied to power line communication by using an adapter that converts the signal interface of the existing multimedia device into a power line communication interface. However, in the future, when the multimedia device incorporates the function of the present invention, data transmission between the devices will be possible via the power cord of the multimedia device. In this case, as shown in FIG. 9, an adapter, an IEEE 1394 cable, and a USB cable are not required, and wiring is simplified. Further, since connection to the Internet via a router or connection to a wireless / wired LAN using a hub or the like is possible, the LAN system using the high-speed power line transmission system of the present invention can be expanded. Further, in the power line transmission method, since communication data flows through the power line, there is no problem that radio waves are intercepted and data leaks unlike a wireless LAN. Therefore, the power line transmission method is also effective for data protection from the security aspect. Of course, data flowing through the power line is protected by, for example, IPsec in the IP protocol, encryption of the content itself, other DRM methods, and the like.

  As described above, the power line can be used by implementing the QoS function including the copyright protection function by content encryption and the effect of the present invention (the improvement of throughput, the bandwidth allocation flexibly corresponding to the increase in retransmission and the traffic fluctuation). High quality AV content can be transmitted.

  The control method according to the present invention can be used, for example, when a plurality of communication systems share the same channel, and can easily avoid interference between communication systems without performing transmission power control. This is useful when guaranteeing the QoS of the communication band.

The figure which showed an example of the environment of the communication system to which this invention is applied Block diagram showing a detailed configuration example of a station Diagram explaining area division of communication band Timing chart for explaining the access control method according to the first embodiment of the present invention The flowchart for demonstrating the access control method which concerns on the 1st Embodiment of this invention. Sequence for explaining a method using a CSMA region Flow chart for explaining a method of using a CSMA region Timing chart for explaining the access control method according to the second embodiment of the present invention The figure which shows the network system example which applied the access control method of this invention to the high-speed power line transmission

Explanation of symbols

11-13 Communication system 111, 121, 131 Master station 112, 122, 123, 132, 133 Slave station 21 Band management unit 22 Control unit 23 Data buffer unit 24 Data transmission / reception unit 25 Time timer unit 26 Upper interface unit

Claims (8)

Each of the master stations used in one communication system among a plurality of communication systems composed of a master station and a slave station that performs communication based on band information notified from the master station,
A transmission / reception unit for transmitting / receiving packets to / from a master station of another communication system;
A communication band is divided into a plurality of areas, and a beacon area in which each of the master stations of the plurality of communication systems transmits a beacon packet, and a master station and a slave station of the plurality of communication systems acquire access rights due to contention. A CSMA (carrier sense multi-access) area for performing communication and a bandwidth guarantee area allocated to the own communication system, and the beacon area and the CSMA area are allocated to the same area as other communication systems. Including the master station. The transmitting and receiving unit from the parent station of the other communication system in the CSMA region, receives a packet including information indicating whether the bandwidth request is granted from Oiteko station to said other communication system,
Wherein, based on the information included in the received packet, and changes the bandwidth guaranteed area allocated before Symbol own communication system, a master station according to claim 1.   2. The master station according to claim 1, wherein the bandwidth guarantee area assigned to the own communication system and the bandwidth guarantee area assigned to another communication system are assigned in a time division manner.   2. The master station according to claim 1, wherein the bandwidth guarantee area assigned to the own communication system and the bandwidth guarantee area assigned to another communication system are assigned by frequency division. An access control method executed by a master station used in one communication system among a plurality of communication systems each including a master station and a slave station that performs communication based on band information notified from the master station. There,
Send and receive packets with the master station of other communication systems,
A communication band is divided into a plurality of areas, and a beacon area in which each of the master stations of the plurality of communication systems transmits a beacon packet, and a master station and a slave station of the plurality of communication systems acquire access rights due to contention. An access control method for setting a CSMA (carrier sense multi-access) area for performing communication and a bandwidth guarantee area assigned to the own communication system, and assigning the beacon area and the CSMA area to the same area as other communication systems . From the master station of the other communication system in the CSMA period, when receiving a packet containing information indicating whether or not the bandwidth request is granted from Oiteko station to said other communication system, to the the received packet based on the information contained, before SL and changes the bandwidth guaranteed area allocated to the own communication system, the access control method according to claim 5. 6. The access control method according to claim 5 , wherein the bandwidth guarantee area assigned to the own communication system and the bandwidth guarantee area assigned to another communication system are assigned in a time division manner. 6. The access control method according to claim 5 , wherein the bandwidth guarantee area assigned to the own communication system and the bandwidth guarantee area assigned to another communication system are assigned by frequency division.

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