JP5033853B2 - Meter reading data collection system - Google Patents

Description

  In the present invention, a large number of measuring instrument terminals installed in each consumer such as an integrating watt hour meter constitute a network, and the meter reading data is set at predetermined time intervals (on-time meter reading) or predetermined events (power failure, etc.). The present invention relates to a system that realizes automatic meter reading by transmitting to a server device by multi-hop wireless communication at the time of occurrence or the like and collecting it.

  Japanese Patent Application Laid-Open No. 2004-151867 discloses a typical conventional technique in which electricity, gas, water meter reading data, and the like are periodically taken up from the measuring instrument terminal to the server device by multi-hop wireless communication.

JP 2000-187793 A

  In the above-described prior art, a transceiver mode of PHS (Personal Handyphone System) is used for the wireless system. Therefore, the data transmission capacity is small, and there are restrictions on increasing the density of meter reading, increasing the information to be transmitted (diag information and load information), and increasing the number of accommodated terminals. In addition, since a hop route from the server device to each terminal is determined, there is a problem that it is vulnerable to a failure of the terminal along the route.

  On the other hand, with recent advances in wireless communication technology, it is very promising to use a wireless LAN for the wireless system. According to this, a general-purpose chip can be used to configure a system at a very low cost, and the data transmission capacity is large, and a number of features such as automatically searching for a detour route in the event of a failure are provided. be able to.

  By the way, normally, although the wireless LAN depends on the standard, in the case of a system that performs communication at a relatively long distance, such as between a base station (access point) installed outdoors and a terminal installed in a home, The base station (access point) is installed in a utility pole, a tall building, or the like, and communicates with the terminals of each house at the long distance. Therefore, there are elements that greatly impair communication quality such as building shadows and noise. On the other hand, in the automatic meter reading system using a wireless LAN as described above, if the excess transmission capacity is opened to a general wireless LAN service using the large transmission capacity, it is installed in each house. It is expected that the measured measuring instrument terminal is close to the wireless LAN terminal and becomes a large number of base stations (access points) and can provide extremely high quality services.

  However, if each measuring instrument terminal is adapted to the Internet TCP / IP protocol and the meter reading server device receives the meter reading data via the Internet, there is a possibility that the data cannot be received due to a general Internet line failure or the like. is there. In addition, when a general Internet line is used, the chance of unauthorized access from the outside increases, and the reliability of the meter reading data collection system decreases. The electricity, gas, water supply, etc. are important lifelines, and if their management may be weak, the side that owns the meter reading data collection system expects to provide the above-mentioned extremely high quality services. Even if possible, it is difficult to provide a general-purpose wireless LAN service. As a result, there is a problem that the meter reading data collection system becomes expensive.

  An object of the present invention is to provide a meter reading data collection system capable of suppressing costs by developing a wireless LAN service while ensuring independence in the meter reading data collecting system.

  The meter reading data collection system of the present invention includes a measuring instrument terminal installed in each consumer, a gateway connected to the measuring instrument terminal via a wireless communication network, and meter reading data transmitted from each measuring instrument terminal in a multi-hop manner. And first and second server devices connected to the gateway via a wired network, and other-use terminals connected to the measuring instrument terminal via a wireless communication network, each measuring instrument terminal comprising: A wireless communication unit that performs communication in accordance with the wireless LAN standard, and is capable of supporting an ad hoc mode and an infrastructure mode in units of frames, and an identification code corresponding to the ad hoc mode is assigned to the meter reading data generated by the own device. The data received from the other-use terminal received in the infrastructure mode in the communication unit is not included in the infrastructure. A communication control unit that adds an identification code corresponding to each mode and transmits the data from the wireless communication unit in the ad hoc mode, and transmits the data with the identification code received in the wireless communication unit in the ad hoc mode as it is. The gateway reads the identification code, and transfers the meter reading data to the first server device and the data from the other-use terminal to the second server device.

  According to the above configuration, the measuring instrument terminals installed in each consumer constitute a multi-hop wireless communication network, and the meter reading data is transmitted to the server device at predetermined time intervals or at predetermined event occurrence points. In a system that realizes automatic meter reading, etc. by collecting, each of the measuring instrument terminals performs communication according to the wireless LAN standard, and uses a large transmission capacity of the wireless LAN. Thus, the excess transmission capacity is released to the wireless LAN service. Specifically, the wireless communication unit that performs wireless communication in the wireless LAN can be switched to an ad hoc mode mainly for communication between terminals and an infrastructure mode for communication between base stations and terminals, Instead of fixing the communication mode to any of these, the communication control unit can handle data in any mode on a frame basis. The communication control unit receives an identification code corresponding to the ad hoc mode in the meter-reading data generated by the own device, and receives the identification code corresponding to the ad hoc mode in the infrastructure mode in the wireless communication unit (the wireless LAN service The data from the terminal is appended with an identification code of the infrastructure mode and transmitted in the ad hoc mode from the wireless communication unit, and the data with the identification code received in the wireless communication unit is directly used in the ad hoc mode. Let me transfer.

  On the other hand, at the end of the wireless communication network, a gateway having a dedicated wired network is provided to each of the first server device for collecting the meter reading data and the second server device for the wireless LAN service. The gateway reads the identification code (logically divided by VLAN or the like), sorts the meter-reading data and other-use (wireless LAN service) data in units of frames, and transfers them to each server device.

  Therefore, even if a wireless LAN is used for a system that collects meter-reading data of each measuring instrument terminal by multi-hop wireless communication, and the surplus transmission capacity is released to the wireless LAN service as described above, The LAN service system can function as a separate network, and security and operability can be improved. In addition, since the measuring terminal installed at each consumer is used as a wireless LAN base station (access point), it is not necessary to provide a dedicated base station for starting the wireless LAN service, and the cost is greatly reduced. In particular, in urban areas, there are many base stations (access points) that can be seen (communicated) from each wireless LAN terminal (for example, not only a home meter terminal but also a neighbor meter terminal is a window). High communication quality can be obtained. Thus, the constructed meter reading system can be provided with a high quality wireless LAN service, and as a result, the cost of the meter reading system can be greatly reduced.

  Moreover, in the meter-reading data collection system of this invention, the said communication control part embeds the said identification code in the type field of the MAC frame in wireless LAN specification and Ethernet specification.

  According to the above configuration, in the MAC frame in the wireless LAN standard (IEEE802.11) and the Ethernet (registered trademark) standard (IEEE802.3), the identification code is embedded in a type field that is not normally used. There is no need to define a new field to add a code.

  Furthermore, in the meter-reading data collection system of the present invention, the communication control unit includes a part of the identification code in the type field of the LLC header of the WDS frame in the wireless LAN standard and the MAC frame in the Ethernet standard, in each data header. The remaining part of the identification code is embedded in the provided line number.

  According to the above configuration, as described above, the wireless communication unit mainly includes an ad hoc mode for communication between terminals and an infrastructure mode for communication between base stations and terminals in the wireless LAN standard (IEEE802.11). However, the data frame used in the wireless LAN standard is mainly a WDS (wireless distribution system) frame for base station-base station communication. Specifically, an identification code indicating whether the ad hoc mode or the infrastructure mode, which is a part of the identification code, is included in the LLC header of the WDS frame, and the remainder of the identification code is included in the line number provided in the data header. Detailed information on what kind of service is the part of is embedded. Correspondingly, on the Ethernet standard side, a part of the identification code is embedded in the type field of the MAC frame, and the remaining part of the identification code is embedded in the line number provided in the data header.

  Therefore, the base station that is not often used in the wireless LAN, that is, the WDS frame mainly used for communication between the access points is used so that other base stations other than the meter reading data collection system of the present invention, that is, the access point do not react. Can be. In addition, although the WDS frame is used for the data frame structure in the wireless LAN, each measuring instrument terminal transfers data in the ad hoc mode as described above. Such a setting can be realized by defining an ad hoc layer.

  As described above, the meter reading data collection system of the present invention is a system in which the meter terminal installed in each consumer transmits the meter reading data to the server device by multi-hop wireless communication and collects the meter. The wireless communication unit of the terminal performs communication according to the wireless LAN standard, and the communication mode is mainly set to either an ad hoc mode for communication between terminals or an infrastructure mode for communication between base stations and terminals. Instead of fixing, it is possible to support data in any mode in units of frames, and by adding different identification codes to meter reading data and data for other purposes (of the wireless LAN service), Are distributed at each gateway and transferred to each server device.

  Therefore, the meter reading system and the wireless LAN service system can function as separate networks, respectively, and a large capacity transmission capacity of the wireless LAN can be used to convert the surplus transmission capacity to the wireless LAN service. Even if it is opened, security and operability can be improved. In addition, since the measuring instrument terminal installed at each consumer is used as a base station for the wireless LAN, it is not necessary to provide a dedicated base station for starting the wireless LAN service, and the cost can be greatly reduced. Especially in urban areas, there are many base stations that can be seen from each wireless LAN terminal, and high communication quality can be obtained. Thus, the constructed meter reading system can be provided with a high quality wireless LAN service, and as a result, the cost of the meter reading system can be greatly reduced.

It is a block diagram which shows schematic structure of the meter-reading data collection system which concerns on one Embodiment of this invention. It is a figure for demonstrating the logic structure of the said meter-reading data collection system. It is a block diagram which shows the structure of each meter terminal in the said meter-reading data collection system. It is a figure for demonstrating the MAC frame structure of wireless LAN and Ethernet. It is a figure for demonstrating in detail the aspect of communication in the meter-reading data collection system of one Embodiment of this invention. 6 is a table specifically showing changes in address data and identification codes in the MAC frame shown in FIG. 4 corresponding to FIG. It is a figure for demonstrating the frame structure of wireless LAN and Ethernet of other Embodiment of this invention. 8 is a table specifically showing changes in address data and identification codes in the frame shown in FIG. 7 corresponding to FIG.

[Embodiment 1]
FIG. 1 is a block diagram showing a schematic configuration of a meter reading data collection system according to an embodiment of the present invention. This meter-reading data collection system is connected to each of the consumers H1, H2,... (When collectively referred to as the reference symbol H hereinafter), respectively. , Which is indicated by the reference symbol U), dynamically, that is, constantly looking around the surroundings, autonomously switching to the most preferred route to form a multi-hop wireless communication network, This is a system that realizes automatic meter reading by transmitting to the server device 1 and collecting it at the time of occurrence of a predetermined event.

  The meter terminal U is realized as an integrated watt-hour meter in the present embodiment, and it should be noted that in the present embodiment, each meter terminal U performs communication according to the wireless LAN standard, and its wireless Using a large transmission capacity of the LAN, the excess transmission capacity is released to the wireless LAN service. As the terminal 2 used in the wireless LAN service, a personal computer, a portable terminal, or the like is used to browse a home page, download music, or the like via the wireless LAN service.

  Therefore, each measuring instrument terminal U functions as a wireless LAN base station (access point) and performs wireless communication as indicated by reference numeral I1 in the infrastructure mode for wireless LAN base station-terminal communication. The measuring terminals U are wirelessly indicated by reference numerals A1, A2, A3, A4, and A5 (hereinafter collectively referred to as reference numeral A) according to the ad-hoc mode for inter-terminal communication of the wireless LAN. Communicate. When the wireless LAN terminal 2 is activated (powered on), it monitors the surrounding radio wave conditions, determines the base station with the best communication quality (hanging destination: measuring terminal U1 in the example of FIG. 1), and connects to it. And start communication in the infrastructure mode. When each measuring instrument terminal U is also activated (powered on), it monitors the surrounding radio wave conditions, and the measuring terminal having the best communication quality (hanging destination: U4 with respect to the measuring instrument terminal U3 in the example of FIG. 1). ) To connect, that is, join the network, autonomously select a route to the gateway 3 that is the end of the wireless communication network, and start communication in the ad hoc mode.

  The gateway 3 connects a wireless communication network and a wired network 4 dedicated to a network operating company such as an electric power company. The server device 1 is connected to the wired network 4. This gateway 3 is provided in, for example, a main utility pole, and the number of accommodation terminals is several hundred. Further, the number of hops of each measuring instrument terminal U is several tens at the maximum, preferably 10 hops or less.

  On the other hand, a handy terminal HT can also be used for maintenance. When the handy terminal HT is activated (powered on), it is connected to a measuring instrument terminal (hanging destination: measuring instrument terminal U3 in the example of FIG. 1). Wireless communication is performed as indicated by reference numeral I2 in the infrastructure mode, and direct reading of meter-reading data, start / stop of energization, various settings, and the like are possible.

  FIG. 2 is a diagram for explaining a logical configuration of the meter reading data collection system as described above. As a terminal connected to each measuring instrument terminal U, for example, a personal computer 2a or a portable music player 2b as a wireless LAN terminal 2 can be considered as another measuring instrument terminal U, and meter reading and setting are performed locally. The handy terminal HT that can be used is considered. As described above, each weighing terminal U communicates with the personal computer 2a, the portable music player 2b, and the like in the infrastructure mode, and communicates with the other weighing terminal U in the ad hoc mode. Furthermore, since the handy terminal HT communicates only with the measuring instrument terminal U, the handy terminal HT communicates in the infrastructure mode.

  Between each measuring terminal U and to the gateway 3, the wireless LAN communication unit Ua in each measuring terminal U constitutes an ad hoc logical network. On the other hand, the gateway 3 is provided at the end of the ad hoc wireless communication network, and is always connected to the ad hoc wireless communication network such as an optical fiber network of a power company using PPPoE (Point-to-point protocol over Ethernet). This is for connecting to the wired network 4.

  For this reason, the gateway 3 is installed in a center that performs original power distribution monitoring work such as collection of meter reading data and control of power supply / power outage using a VLAN (Virtual Local Area Network (IEEE 802.5)). As described later, data is distributed (connected) to the server apparatus 1A, which is the server apparatus, and the server apparatus 1B, which is installed in the center that provides the additional wireless LAN service, and is the second server apparatus. Switch provider). By dividing the network using the VLAN and restricting access in this way, the server device 1A side and the server device 1B side can function as separate networks, and security and operability can be improved. It can be done. In the following description, the VLAN group belonging to the MAC address is identified for network separation by VLAN (MAC-based VLAN), but the VLAN group to which the terminal belongs may be identified from the IP address of the terminal ( Subnet-based VLAN).

  FIG. 3 is a block diagram showing a configuration of each measuring instrument terminal U. As shown in FIG. The measuring instrument terminal U includes a wireless communication unit 10 including a wireless device 11 and a driver 12 corresponding to a wireless LAN standard (for example, IEEE 802.11), and a meter reading network and a wireless LAN service network as described later. A distribution interface 13 for distributing data, an interface 14 for wireless communication in the ad-hoc mode, an interface 15 for wireless communication in the infrastructure mode, an IP stack 16, 17 and an application 18 in each mode , 19 and a communication control unit 20. Data exchange (transfer of wireless LAN service data to the ad hoc network side) is possible in the IP stacks 16 and 17 between the two modes.

  A signal received by the wireless device 11 shared in the infrastructure mode and the ad hoc mode is input to the distribution interface 13 via the driver 12, and the ad hoc interface 14 and the infrastructure interface are received for each frame. It is distributed to the face 15, processed by the ad hoc protocol or the IEEE 802.11 protocol, given from the IP stacks 16 and 17 to the applications 18 and 19, and predetermined processing is performed.

  On the other hand, transmission data generated by the applications 18 and 19 is given to the interface 14 or the interface 15 of the corresponding mode via the IP stacks 16 and 17 for each frame, and processed by the respective protocols. The data is not subjected to frame processing in the distribution interface 13 and is sent from the driver 12 to the shared wireless device 11 as it is.

  FIG. 4 is a diagram for explaining the function of the interface 13, 14, 15 according to the embodiment of the present invention. In the present embodiment, the ad hoc mode and the infrastructure mode are the MAC frame types that are not normally used in the MAC frame in the wireless LAN standard (IEEE802.11) and the Ethernet (registered trademark) standard (IEEE802.3). Switching is performed by embedding the identification code in the field. By embedding the identification code in the type field in this way, it is not necessary to define a new field in particular to add the identification code.

  Specifically, first, in the MAC frame of the wireless LAN standard (IEEE 802.11), the From DS or To DS flag in the frame control field specifies which of the transmitting side and the receiving side is the base station. Next, it is realized by embedding the identification code in the type field of the MAC frame of the wireless LAN standard (IEEE802.11) and the MAC frame of the Ethernet standard (IEEE802.3).

  FIG. 5 is a diagram for explaining in detail the mode of communication in the meter-reading data collection system of the present embodiment. Corresponding to FIG. 5, FIG. 6 is a table specifically showing changes in the address data and the identification code in the MAC frame shown in FIG. First, when the meter reading data shown in FIG. 5 (a) is transmitted, the meter reading data D1 generated by the application 18, the meter reading data in the MAC frame type field in the Ethernet standard (IEEE802.3), as indicated by reference numeral F1. In the case of FIG. 5A, the own measuring device is added to the transmission address field of the address 2 of the MAC frame of the wireless LAN standard (IEEE802.11). The IP stack 16 adds the address of the terminal U 3, the base station address field of the address 1 adds the address of the higher-level measuring instrument terminal U 4, and the address of the last destination address of the address 3 adds the address of the server device 1 A From the ad hoc interface 14 to the distribution interface 13 Spent, it is transmitted in the ad hoc mode from the driver 12 by the wireless LAN device 11. When transmitting the meter-reading data, the From DS and To DS flags in the frame control field are set to the base station side on the receiving side.

  Similarly, as indicated by the reference symbol F1 ′, the identification code L1 is also added to the data D1 such as ACK of the meter reading data from the server device 1A, and the server device 1A is included in the source address field of the address 2 , The address of the upper measuring instrument terminal U4 is described in the base station address field of address 1, and the address of the own measuring instrument terminal U3 is described in the final destination address field of address 3, respectively. The IP stack 16 reads it from the distribution interface 13 through the ad hoc interface 14 and provides it to the application 18.

  On the other hand, at the time of transmission of control data such as a request for retransmission of the meter reading data shown in FIG. 5B and ON / OFF of power feeding, the control data D2 from the server apparatus 1A is controlled in advance as indicated by reference numeral F2. An identification code L2 representing data is added, the address of the server device 1A is added to the source address field of address 2, the address of the higher-level measuring instrument terminal U4 is added to the base station address field of address 1, The address of the own measuring device terminal U3 is described in the final destination address field of the address 3, and when it is received by the wireless LAN device 11, it is given from the driver 12 to the distribution interface 13 and is added to the ad hoc interface. It is given from the face 14 to the application 18 through the IP stack 16.

  In response to this, the application 18 adds the identification code L2 to the reply signal D2 as indicated by the reference symbol F2 ′, and the address of the own measuring device terminal U3 is stored in the source address field of the address 2, In the base station address field of address 1, the address of the upper measuring instrument terminal U 4 is added by the IP stack 16 in the field of the final destination address of address 3, and the address of the server device 1 A is added from the ad hoc interface 14. Then, it passes through the distribution interface 13 and is transmitted from the driver 12 by the wireless LAN device 11 in the ad hoc mode. Even when this control data is transmitted, the From DS and To DS flags in the frame control field are set to the base station side on the receiving side.

  At the time of transmitting these meter reading data and control data, the measuring terminal (U2, U4 in the example of FIG. 1) at the relay station has a wireless LAN device 11, a driver 12, a distribution interface 13, an ad hoc interface 14 and an IP stack. 16 is used, only the configuration on the ad hoc mode side using 16 is used, the BSSID of the hopping destination of the own device is sequentially rewritten, and the remaining data is left as it is, so that sequential transfer is performed in the ad hoc mode.

  On the other hand, when transmitting the data of the wireless LAN service shown in FIG. 5 (c), the transmission data D3 from the terminal 2 is normally the type field of the MAC frame in the Ethernet standard as indicated by the reference symbol F5. The address of the own terminal 2 is in the source address field of the address 2, the address of the higher-level measuring instrument terminal U 1 is in the base station address field of the address 1, and the final destination address field of the address 3 The address of the server device 1B is described and transmitted. However, among the plurality of SSIDs possessed by each measuring instrument terminal U in the wireless LAN infrastructure mode, an identification code S1 predetermined for the wireless LAN service is set in the SSID field. In the infrastructure mode, the SSID assigned to the access point and the network key are mutually authenticated, and communication is possible when they match.

  The measuring instrument terminal U1 that has received this data via the wireless LAN device 11, the driver 12, the distribution interface 13 and the infrastructure interface 15 delivers the data from the IP stack 17 to the IP stack 16 side. The transfer in the ad hoc mode is performed through the face 14, the distribution interface 13, the driver 12, and the wireless LAN device 11, as indicated by reference numeral F3. At this time, in the base station address field of address 1, in the case of FIG. 1, the address of the upper measuring terminal U2 is set. Also, the identification code S1 in the SSID field of the wireless LAN standard is canceled, and instead, an identification code L3 indicating wireless LAN data is added to the type field of the Ethernet standard.

  Further, as indicated by the reference symbol F3 ′, the identification code L3 is also added to the wireless LAN data D3 from the server device 1B, and the address of the server device 1B is stored in the address 2 transmission source address field. In the base station address field of 1, the address of the higher-level measuring instrument terminal U2 is described, and in the final destination address field of address 3, the address of the terminal 2 is described. The measuring instrument terminal U1 that has received this data via the wireless LAN device 11, the driver 12, the distribution interface 13 and the ad hoc interface 14 delivers the data from the IP stack 16 to the IP stack 17 side. Transfer in the infrastructure mode is performed through the face 15, the distribution interface 13, the driver 12, and the wireless LAN device 11, as indicated by reference numeral F4. At this time, the identification code L3 is canceled from the type field of the Ethernet standard, and the identification code S1 set for the wireless LAN service is set in the SSID field of the wireless LAN standard. At the time of transmitting the wireless LAN data, the From DS and To DS flags in the frame control field are set on the base station side on the server device 1B side.

  Furthermore, when the handy terminal HT shown in FIG. 5 (d) is connected, the connected measuring instrument terminal U3 is a wireless LAN device 11, a driver 12, a distribution interface 13, an infrastructure interface 15, an IP stack 17, and an application. Only the configuration on the 19th infrastructure mode side is used, and communication is performed in the infrastructure mode as indicated by reference numerals F6 and F7. In this case, regarding the data from the measuring instrument terminal U3 indicated by the reference symbol F6, the destination address field of the address 1 and the upper station address field of the address 2 become the same address, and the data from the handy terminal HT indicated by the reference symbol F7. Are the same address in the upper station address field of address 1 and the destination address field of address 3. In addition, the From DS and To DS flags in the frame control field are set on the base station side on the measuring instrument terminal U3 side. Furthermore, an identification code S2 preset for the handy terminal HT is set in the SSID field.

  As described above, in the meter-reading data collection system of the present embodiment, the meter terminal U installed in each customer H constitutes a multi-hop wireless communication network, and the meter-reading data is determined every predetermined time or in advance. In a system that realizes automatic meter reading by transmitting to the server device 1 and collecting it at the time of occurrence of an event, etc., the wireless communication unit 10 of each measuring instrument terminal U communicates in accordance with the wireless LAN standard. In addition, the communication mode of the wireless communication unit 10 is not fixed to either the ad hoc mode for mainly communication between terminals or the infrastructure mode for communication between base stations and terminals, but communication control is performed. The unit 20 adds an identification code corresponding to each mode so as to be able to handle data in any mode in units of frames. Is provided with a gateway 3 having a dedicated wired network 4 for each of the server device 1A for collecting the meter reading data and the server device 1B for the wireless LAN service, and the gateway 3 reads the identification code. The data is distributed in units of frames and transferred to the respective server apparatuses 1A and 1B.

  Therefore, even if the surplus transmission capacity is released to the wireless LAN service in the meter reading mode using the large capacity transmission capacity of the wireless LAN, the meter reading system and the wireless LAN service system function as separate networks. Security and operability can be improved. In addition, since the measuring terminal U installed at each consumer is used as a wireless LAN base station (access point), it is not necessary to provide a dedicated base station for starting the wireless LAN service, and the cost is greatly reduced. In particular, in urban areas, there are many base stations (access points) visible (communicable) from each wireless LAN terminal 2 (for example, not only a home meter terminal but also a home meter terminal) Can be seen through the window), and high communication quality can be obtained. Thus, the constructed meter reading system can be provided with a high quality wireless LAN service, and as a result, the cost of the meter reading system can be greatly reduced.

[Embodiment 2]
FIG. 7 is a diagram for explaining functions of another embodiment of the present invention in the interfaces 13, 14 and 15. It should be noted that in this embodiment, the switching between the ad hoc mode and the infrastructure mode is performed by using the LLC header of the WDS frame in the wireless LAN standard (IEEE 802.11) and the Ethernet (registered trademark) standard (IEEE 802.3). This is realized by using the type field of the MAC frame and each data header.

  Specifically, among the transmission data in the wireless LAN standard (IEEE802.11) shown in FIG. 7 (a), the 802.11 header shown in FIG. 7 (b) is composed of a WDS frame, and the lower order of the LLC header. A part of an identification code for switching between the ad hoc mode and the infrastructure mode is embedded in 2 bytes. On the other hand, in the type field of the MAC frame of the 802.3 header in the transmission data of the Ethernet (registered trademark) standard (IEEE802.3) shown in FIG. A part of the identification code for switching to the mode is embedded.

  Furthermore, in the data header that can be uniquely defined, as shown in FIG. 7E, a line number is newly defined in general matters such as an address, the number of transmissions, the number of retries, and the ad hoc mode and the infrastructure mode. The remainder of the identification code for switching to is embedded. For example, in the LLC header and the MAC frame type field of the WDS frame, an identification code that simply switches between the ad hoc mode and the infrastructure mode is embedded, for example, what wireless LAN service the user receives, etc. The line type is embedded in the line number.

  FIG. 8 is a table specifically showing changes in the address data and the identification code in the frame shown in FIG. 7, and is similar to FIG. The difference from FIG. 6 is that the WDS frame for inter-base station communication is used as described above. Therefore, in the ad hoc mode, both the From DS and To DS flags are set in the base station. At the same time, the destination address field of address 1 is the same as the address of the adjacent terminal as the destination address field of address 3. Further, the source address field of address 4 is the same as the address of the own device as the source address field of address 2.

  Furthermore, in the communication in the ad hoc mode, the MAC frame type field of the 802.3 header is a common identification code only indicating that the communication is performed in the ad hoc mode, although a unique identification code is attached. Specific service contents are identified by the line number.

  With this configuration, communication is performed using an ad-hoc mode for terminal-to-terminal communication and an infrastructure mode for base-station-to-terminal communication, but a base station that is not frequently used in a wireless LAN, that is, an access point By using the WDS frame mainly used for communication between each other, it is possible to prevent other base stations other than the meter reading data collection system of the present invention, that is, access points from reacting. In addition, although the WDS frame is used for the data frame structure in the wireless LAN, each measuring instrument terminal U transfers the data in the ad hoc mode as described above. Such a setting can be realized by defining an ad hoc layer.

DESCRIPTION OF SYMBOLS 1; 1A, 1B Server apparatus 2 Terminal 2a Personal computer 2b Portable music player 3 Gateway 4 Wired network 10 Wireless communication part 11 Wireless device 12 Driver 13 Distribution interface 14 Ad hoc mode interface 15 Infrastructure mode interface 16, 17 IP stack 18, 19 Application 20 Communication control unit H1, H2, ... Consumer HT Handy terminal U1, U2, ... Meter terminal

Claims (3)

A measuring instrument terminal installed in each consumer, a gateway connected to the measuring instrument terminal via a wireless communication network, and meter reading data is transmitted from each measuring instrument terminal in a multi-hop manner, and the gateway and a wired network First and second server devices connected to each other and a terminal for other purposes connected to the measuring instrument terminal via a wireless communication network,
Each weighing terminal is
A wireless communication unit for performing communication according to the wireless LAN standard;
The ad hoc mode and the infrastructure mode can be supported on a frame-by-frame basis, and the meter reading data generated by the own device has an identification code corresponding to the ad hoc mode received in the infrastructure mode in the wireless communication unit for the other uses. An identification code corresponding to the infrastructure mode is added to the data from the terminal, respectively, and the wireless communication unit transmits the data in the ad hoc mode. The data with the identification code received by the wireless communication unit is directly used as the ad hoc data. A communication control unit for transferring in mode,
The gateway reads the identification code, and transfers the meter reading data to the first server device and the data from the terminal for other use to the second server device.   The meter-reading data collection system according to claim 1, wherein the communication control unit embeds the identification code in a type field of a MAC frame in a wireless LAN standard and an Ethernet standard. The communication control unit includes a part of the identification code in an LLC header of a WDS frame in a wireless LAN standard and a MAC frame type field in the Ethernet standard, and a remaining part of the identification code in a line number provided in each data header. The meter-reading data collection system according to claim 1, wherein:

Images