JP6102037B2 - Communication device used in wireless network - Google Patents

Description

  The present invention relates to a communication device used in a wireless network that communicates with a master station and a device using different wireless networks.

  Conventionally, in a wireless network in which a master station and a plurality of slave stations perform wireless communication using the same channel, the interference of the channel used between the master terminal and the slave terminal is monitored, and no interference occurs. Various techniques for selecting a channel have been proposed. Patent Document 1 describes a technique for performing multi-hop communication using the same channel in a communication cell constructed by a parent terminal (parent station) and a plurality of child terminals (child stations). Also, when the child terminal receives a hello packet from a different communication cell, it evaluates the interference with other communication cells, and if the degree of interference is large, selects a new channel from the selected range and selects a channel. The technology to change is described.

JP 2012-70370 A

  When interference is occurring, selecting an available channel from the selection range is effective to avoid interference. However, if channels are freely allocated in individual communication cells, an average time until a channel to be used is determined becomes relatively long in order to search for a brute force channel without any influence of interference. In addition, since the types of channels (resources) that can be selected are limited, if channels are set without considering interference between multiple communication cells, channel resources are consumed immediately and there are not enough free channels. there's a possibility that.

  The present invention constructs a wireless network between a master station and a device, can determine a channel to be changed in a relatively short time when interference occurs, and increases the types of channels used while avoiding interference It is an object of the present invention to provide a communication device used in a wireless network that can suppress the problem.

A communication device used in a wireless network according to the present invention includes a first wireless communication unit that communicates with a master station through a first wireless network that is an ad hoc network, and a second wireless that communicates with a device through a second wireless network. A communication unit, a channel selection unit for determining a channel to be used in the second wireless communication unit, and a channel used by another communication device for communication with the device are acquired through the first wireless communication unit. A channel management unit, wherein the first wireless communication unit transmits a packet including channel information determined by the channel selection unit, and the channel management unit receives a packet received by the first wireless communication unit. The channel used by the other communication device for communication with the device is extracted and stored, and the channel selection unit stores the channel selection unit. Using the information Yaneru defines the priority order of channel selection is available by selecting a channel in order of preference to determine the channel to be used by the second radio communication unit, further, the first The wireless communication unit has a function of transmitting a packet including an interference degree, which is a rate at which traffic is interfered during communication with the device, and the channel management unit includes In addition to the channel used by the other communication device for communication with the device, the interference degree is extracted and stored from the packet received from the other communication device, and the channel selection unit is configured to store the first wireless communication unit. Adds the degree of interference extracted from the packets received from other communication devices for each channel, and the channel management unit stores the channel, and the smaller the result of the sum of the interference degrees, the higher the priority of the channel. With the condition that a higher, characterized in that to determine the priority of selection of the available channels.

In the communication device used in the wireless network, it is preferable that the first wireless communication unit transmits the interference degree included in the packet only when the interference degree exceeds a predetermined reference value.

  A communication device used for another wireless network according to the present invention includes a first wireless communication unit that communicates with a master station through a first wireless network that is an ad hoc network, and a second wireless device that communicates with a device through a second wireless network. A channel selection unit for determining a channel to be used in the second wireless communication unit, and a channel used by another communication device for communication with the device through the first wireless communication unit. A channel management unit to acquire, wherein the first wireless communication unit transmits a packet including information on the channel determined by the channel selection unit, and the channel management unit is received by the first wireless communication unit. The channel used by another communication device for communication with the device is extracted from the packet and stored, and the channel selection unit is stored by the channel management unit. Channel information is used to determine the priority order of selection of channels that can be used, and by selecting the channels in order of priority, a channel to be used in the second wireless communication unit is determined, and the channel management The first wireless communication unit is associated with the channel used by the other communication device that has received the packet by the first wireless communication unit for communication with the device, and the first wireless communication unit is connected to the other communication device. The received signal strength when a packet is received is stored, and the channel selection unit uses the same channel as the other communication device among the channels stored in the channel management unit in the second wireless communication unit When the channel information stored in the channel management unit is used, it is used on the condition that the lower the received signal strength is, the higher the channel priority is. Characterized in that determining the order of priority selected for the channel is ability.

A communication device used for still another wireless network according to the present invention includes a first wireless communication unit that communicates with a master station through a first wireless network that is an ad hoc network, and a first wireless communication unit that communicates with a device through a second wireless network. 2 wireless communication units, a channel selection unit for determining a channel to be used in the second wireless communication unit, and a channel used by another communication device for communication with the device as the first wireless communication unit The first wireless communication unit transmits a packet including channel information determined by the channel selection unit, and the first wireless communication unit transmits the packet including the channel information determined by the channel selection unit. A channel used by another communication device for communication with the device is extracted from the received packet and stored, and the channel selection unit is recorded by the channel management unit. Using the information on the channels being used, determining the priority order of selection of available channels, selecting the channels in order of priority, determining a channel to be used in the second wireless communication unit, and For each available channel, the channel selection unit obtains the number of other communication devices using the channel in the second wireless communication unit, and increases the priority of the channel as the number decreases. It is characterized in that the priority order of selection of channels that can be used is determined using conditions .

A communication device used in another wireless network according to the present invention includes a first wireless communication unit that communicates with a master station through a first wireless network that is an ad hoc network, and a second wireless device that communicates with a device through a second wireless network. A channel selection unit for determining a channel to be used in the second wireless communication unit, and a channel used by another communication device for communication with the device through the first wireless communication unit. A channel management unit to acquire, wherein the first wireless communication unit transmits a packet including information on the channel determined by the channel selection unit, and the channel management unit is received by the first wireless communication unit. The channel used by another communication device for communication with the device is extracted from the packet and stored, and the channel selection unit is stored by the channel management unit. That by using the channel information, determines the priority order of channel selection is available by selecting a channel in order of preference to determine the channel to be used by the second radio communication unit, further, the first The wireless communication unit has a function of including the interference degree, which is a ratio of the traffic having undergone interference during communication with the device, and transmitting the packet only when the interference degree exceeds a predetermined reference value. The channel management unit extracts and stores the interference degree in addition to the channel used by the other communication device for communication with the device from the packet received by the first wireless communication unit from the other communication device. and, wherein the channel selection unit, when determining the same channel with other communication devices of the channels that the channel management part is stored as a channel to be used in the second wireless communication section, the switch Among the information of the channel channel management unit is storing, using the condition that a higher priority of the higher degree of interference is smaller channel, and wherein the determining the priority of selection of the available channel .

In the communication device used in the wireless network, the first wireless communication unit can communicate with the channel determined by the channel selection unit in one hop stored in the channel management unit. The channel used by the communication device for communication with the device is included in a packet and transmitted, and the channel management unit is configured to select the channel management unit from among a plurality of channels that can be used in the second wireless network. Is stored in a channel used by another communication device that can communicate with the device, and another communication device that can communicate with two hops is used for communication with the device. The channel selection unit is used by another communication device that communicates in two hops among the channel information stored in the channel management unit. It is preferable that the priority order of selection of available channels be determined on the condition that a certain channel is used in a higher priority order than a channel used in another communication device that communicates in one hop. .

Further, in the communication device used in this wireless network, the channel selection unit determines that the channel determined to be unusable is higher than the priority order of selection of available channels until a predetermined time has elapsed from the determination time point. It is preferable to lower the priority of selection.

A communication apparatus used in another wireless network according to the present invention includes a first wireless communication unit that communicates with a master station through a first wireless network that is an ad hoc network, and a first wireless communication unit that communicates with a device through a second wireless network. 2 wireless communication units, a channel selection unit for determining a channel to be used in the second wireless communication unit, and a channel used by another communication device for communication with the device as the first wireless communication unit The first wireless communication unit transmits a packet including channel information determined by the channel selection unit, and the first wireless communication unit transmits the packet including the channel information determined by the channel selection unit. The channel used by another communication device for communication with the device is extracted from the received packet and stored, and the channel selection unit stores the channel selection unit. By using the information of the channel which defines the priority order of channel selection is available by selecting a channel in order of preference to determine the channel to be used by the second radio communication unit, further, the channel When the second wireless communication unit receives a packet transmitted from another device to the device, the management unit includes identification information included in the packet and a channel that transmits the packet. A blacklist to be registered, another communication device that communicates through the first wireless communication unit, identification information that is not included in the blacklist among the devices with which the communication device is communicating, and the communication device A white list for registering channels used for communication with the device, and the channel selection unit is configured to register the channels registered in the white list. The panel with the prescribed conditions to higher priority, and determines a channel to be used by the second radio communication unit.

  In the communication device used in this wireless network, the channel selection unit is a channel registered in the white list, and when there is a channel used by another communication device, the channel is given high priority. More preferably, the channel used in the second wireless communication unit is determined using conditions determined to be in order.

  In the communication device used in the wireless network, the first wireless communication unit has a function of transmitting meter reading data from a meter installed in a consumer to the parent station and a function of receiving an instruction from the parent station. Preferably, the second wireless communication unit communicates with a device used by a consumer.

  According to the configuration of the present invention, communication is performed with a master station using a first wireless network, which is an ad hoc network, and communication with a device is performed using a second wireless network, where interference occurs. When this occurs, the channel to be changed is determined in a relatively short time, and an increase in the types of channels to be used can be suppressed while avoiding interference.

It is a block diagram common to embodiment. It is a schematic block diagram of the wireless network using the same as the above. FIG. 6 is a diagram illustrating an operation example of the first embodiment. It is a figure which shows the other operation example same as the above. It is a figure which shows the other example of an operation same as the above. It is a figure which shows another operation example same as the above. It is a figure which shows another operation example same as the above. 10 is a diagram illustrating an operation example of Embodiment 3. FIG.

(overall structure)
In the following embodiments, the operation of an electric load is performed by communicating between a slave station attached to a power meter that is a meter installed in a power consumer and an electrical load that is a device used by the consumer. A communication system provided with a wireless terminal that manages the communication will be described as an example. Wireless terminals can communicate with gas meters, water meters, and various sensors in addition to power meters installed at consumers, and manage the usage of resources such as gas and water in addition to electricity. Is also possible. In other words, the wireless terminal is intended for energy saving or resource saving in consumers, peak suppression of energy or resource demand, and reduction of the upper limit of energy or resource usage due to requests from businesses that supply resources. Used.

  The slave station receives meter reading data from a power meter or the like and notifies the master station of the meter reading data. The master station is shared by a plurality of slave stations, and has a function of reporting meter reading data collected from the plurality of slave stations to the host device in a batch. That is, the host device can remotely collect meter-reading data measured from a plurality of consumers by using the master station and the slave station.

  The host device is operated by a resource supplier such as an electric power company, or a service provider that performs remote meter reading, and is configured by a computer server. However, the host device may be composed of a plurality of computers connected to a communicable network. The host device communicates with a plurality of master stations. In the following, only the electric power among the resources used by consumers will be described, but the same applies to gas and water. In the case of gas, the meter is a gas meter and the device is a gas consuming device. In the case of water supply, the meter is a flow meter, and the equipment is a faucet, a water heater, or the like.

  If the customer is a dwelling unit of an apartment house or a tenant of a tenant building, etc., a master station will be provided for each apartment house or tenant building, and if the customer is a detached house, the master station will be in multiple detached houses. Shared. It is assumed that the master station is placed on a utility pole or placed on a specific consumer, but the installation location is not particularly limited as long as wireless communication with the slave station is possible. The master station communicates with the host device through a dedicated communication path. The communication path may be a wired communication path or a wireless communication path, but a wired communication path using an optical fiber as a transmission medium is desirable.

  The slave station is desirably housed in the casing of the power meter. The power meter includes a measurement unit that measures the amount of power used by a consumer every predetermined time, and the slave station acquires the power amount measured by the measurement unit every predetermined time as meter-reading data. The slave station communicates with the master station using an ad hoc network. In other words, the slave station communicates with the master station using a wireless communication path, and performs multi-hop communication that is permitted to use another slave station for relay in the communication route with the master station. Configured. Therefore, which parent station the slave station communicates with may change depending on the state of the communication path between the master station and the slave station.

  The wireless terminal communicates with the slave station using a fixed network. That is, the communication path between the slave station and the wireless terminal communicates without changing the communication route regardless of whether the communication path is a wireless communication path or a wired communication path. However, the channel used for the communication path between the slave station and the wireless terminal can be changed. The wireless terminal has a function of a management device that forms the core of a system called HEMS (Home Energy Management System) that manages energy used in a house. This wireless terminal has a function of notifying the slave station of the amount of power used by the consumer, a function of receiving a request for the amount of power notified from the host device from the slave station, and the power used by the electrical load and the operation of the electrical load It has a function for acquiring the state and a function for instructing the electric load to operate as necessary. Note that the wireless terminal may be an electrical load having a communication function. In the embodiment described below, an example in which communication is performed using a wireless communication path between a slave station and a wireless terminal will be described. However, communication is performed using a power line communication (PLC) technology. Is also possible.

  The channel is assumed to be distinguished by the frequency of the carrier wave. However, when a plurality of time slots for transmitting data are provided in a packet used for communication, the channels may be distinguished by the position of the time slot. Further, the channel may be distinguished using both the frequency and the position of the time slot. The number of available channels is limited to a few tens at the maximum.

  A meter to which a communication function is added by attaching a slave station to the meter as described above functions as a smart meter. This smart meter is used for remote meter reading by communicating with a master station, and contributes to the management of energy or resource consumption at a consumer by communicating with a wireless terminal.

  In the following, a wireless network composed of a master station, a slave station, a wireless terminal, and a device will be described without detailing the relationship between the host device and the master station. Moreover, although the example mentioned above has divided | segmented into a slave station and a radio | wireless terminal exemplifying the case where HEMS is constructed | assembled, since the information transmission between a slave station and a radio | wireless terminal may not be radio | wireless communication, It is not essential to separate the station and the wireless terminal. Therefore, when it is not necessary to separate the slave station and the wireless terminal, the slave station and the wireless terminal are collectively referred to as a communication device.

  A communication network formed between the slave station and the parent station is referred to as a first wireless network, and a communication network formed between the wireless terminal and the device is referred to as a second wireless network. As described above, the first wireless network is an ad hoc network, and multihop communication is possible. The second wireless network is not particularly limited, and either an ad hoc network or a fixed network is adopted. A channel used in the first wireless network is assigned to each master station, and a plurality of communication devices (slave stations) communicating with one master station are 1 when communicating using the first wireless network. Share different types of channels. On the other hand, the channel used in the second communication path is different from the channel used in the first wireless network, and the second wireless network formed between the other communication device (wireless terminal) and the device is It is chosen not to interfere.

  Assume that the number of channels that can be used in both the first wireless network and the second wireless network is 10 or less. In the operation example described below, the case where the number of available channels is four, six, or ten is an example. However, the number of channels can be selected as appropriate.

(Embodiment 1)
In general, as shown in FIG. 1, the communication device 10 communicates with the first wireless communication unit 11 that communicates with the master station 20 through the first wireless network NT1, and with the device 40 through the second wireless network NT2. A second wireless communication unit 12. In the HEMS configured as described above, the first wireless communication unit 11 is provided in the slave station 31, and the second wireless communication unit 12 is provided in the wireless terminal 32.

  The communication device 10 is arranged such that the spatial distance to the device 40 is smaller than the spatial distance to the other communication device 10 or the master station 20, and the first wireless communication unit 11 and the second wireless communication unit 12 The transmission output is set to match these spatial distances. Under these conditions, if the spatial distance between the two communication devices 10 is a distance that requires two hops, even if both communication devices 10 communicate with the device 40 using the same channel, one communication device 10 There is almost no interference between the communicating device 40 and the other communication device 10.

  In this embodiment, the range of channels allocated to the second wireless communication unit 12 is limited by using this principle. In other words, in the communication between the communication device 10 and the device 40, an increase in the types of channels used is suppressed while preventing interference between the other communication device 10 and the other device 40. .

  A common channel is used in the first wireless communication units 11 of the plurality of communication apparatuses 10 that communicate with one master station 20. The channel used in the first wireless communication unit 11 can be changed, but here, for convenience, it is assumed that the channel used in the first wireless communication unit 11 is not changed. The maximum number of channels that can be used by the communication apparatus 10 is six. In other words, six channels including the first wireless communication unit 11 and the second wireless communication unit 12 can be used, and one of the channels is assigned to the first wireless communication unit 11. Yes. Therefore, the number of channels that can be used by the second wireless communication unit 12 is five.

  The channel used by the first wireless communication unit 11 and the second wireless communication unit 12 is determined by the channel selection unit 13 provided in the communication device 10. That is, the channel selection unit 13 selects a channel used by the second wireless communication unit 12 from five channels excluding the channels used by the first wireless communication unit 11. Further, the channel selection unit 13 selects a channel that does not cause interference with communication performed by the other communication device 10 with the device 40. As described above, basically, if the spatial distance between the two communication devices 10 is a distance that requires two hops, the possibility of causing interference is small even if the channels are the same. Therefore, the channel selection unit 13 disables a channel selected by another communication device 10 that can communicate in one hop, and uses a channel selected by another communication device 10 that requires two or more hops for communication. Make it possible. Hereinafter, another communication device 10 that can communicate in one hop is referred to as an “adjacent communication device”.

  Information on the channel used by the second wireless communication unit 12 for communication with the device 40 in the adjacent communication device 10 is notified by a packet received from the adjacent communication device 10. The packet may be a packet used between the communication apparatuses 10 (that is, the slave stations 31), and the type of the packet is not limited, but a hello packet (Hello packet) is preferably used. The hello packet is transmitted from each slave station 31 at a predetermined transmission interval in order to determine whether communication is possible. Although it is desirable that the transmission interval of the hello packet is regular at a constant time in a steady state, this is not essential, and the hello packet may be transmitted irregularly.

  The communication device 10 includes a channel management unit 14 that acquires information on a channel used by the adjacent communication device 10 for communication with the device 40 using a hello packet received from the adjacent communication device 10. That is, the channel management unit 14 has a function of extracting channel information from the hello packet and storing the extracted channel information. The channel selection unit 13 determines a channel to be used in the second wireless communication unit 12 by excluding the channel stored in the channel management unit 14 from the five available channels.

  The communication apparatus 10 is configured by using a device in which main parts of hardware elements excluding the first wireless communication unit 11 and the second wireless communication unit 12 operate according to a program. This type of device is selected from a combination of a microprocessor and a memory, which are independent devices, a microcomputer, a DSP (Digital Signal Processor), an FPGA (Field-Programmable Gate Array), and the like. The microcomputer means a device in which a microprocessor and a memory are configured on a single chip.

  In the illustrated example, since the communication apparatus 10 includes the slave station 31 and the wireless terminal 32, the slave station 31 and the wireless terminal 32 each include the devices described above. The first wireless communication unit 11 is provided in the slave station 31, and the second wireless communication unit 12 is provided in the wireless terminal 32. The channel selection unit 13 and the channel management unit 14 may be provided in either the slave station 31 or the wireless terminal 32. However, when the HEMS is constructed, since the slave station 31 has limited hardware resources, the wireless terminal 32 is desirable. When a wireless communication path is used between the slave station 31 and the wireless terminal 32, a channel used by the first wireless communication unit 11 is selected for communication from the slave station 31 to the wireless terminal 32, and the wireless terminal 32 is selected. The channel used by the second wireless communication unit 12 is selected for communication from the slave station 31 to the slave station 31.

  A specific operation example will be described using the arrangement example shown in FIG. Hereinafter, the function of the communication device 10 will be described separately for the slave station 31 that communicates through the first wireless network NT1 and the wireless terminal 32 that communicates through the second wireless network NT2. Therefore, in the following description, the description of the slave station 31 or the wireless terminal 32 is used instead of the communication device 10 as necessary. Further, “adjacent slave station 31” is used instead of “adjacent communication device 10”. The channel selection unit 13 and the channel management unit 14 may be provided in the slave station 31, but a configuration provided in the wireless terminal 32 is assumed below.

  In the illustrated example, the slave station 31 of interest is “A”, the slave stations 31 adjacent to the slave station 31 of “A” are “B”, “C”, “D”, “E”, and “A”. The slave stations 31 that communicate with each other in two hops are “F”, “G”, “H”, “I”, “J”, and “K”. Each slave station 31 communicates with one wireless terminal 32. The wireless terminal 32 distinguishes the slave stations 31 by adding alphabetic lowercase letters “a” to “k” corresponding to the alphabetic capital letters “A” to “K”. That is, the slave station 31 and the wireless terminal 32 communicate with the wireless terminal 32 of “a” and the slave station 31 of “B” communicates with the wireless terminal 32 of “b”. Are associated one-on-one. An area D1 surrounded by an inner circle of the two areas D1 and D2 illustrated in FIG. 2 indicates a range in which communication can be performed in one hop from the slave station 31 of “A” of interest. A region D2 between the inner circle and the outer circle indicates a range that requires two hops for communication from the slave station 31 of “A” to which attention is paid.

  Assume that the “a” wireless terminal 32 corresponding to the “A” slave station 31 determines a channel for communicating with the device 40. Further, it is assumed that the channel management unit 14 of the wireless terminal 32 of “a” stores the information illustrated in FIG. 3A regarding the channel used by the wireless terminal 32 corresponding to the adjacent slave station 31. To do. As described above, the same channel is used by the “b” wireless terminal 32 corresponding to the “B” slave station 31 and the “e” wireless terminal 32 corresponding to the “E” slave station 31 that require two hops for communication. “2” is adopted.

  There are six available channels, one of which is used by the first wireless network NT1 including the master station 20. The channel “3” is used by the “d” wireless terminal 32 corresponding to the “D” slave station 31, and the channel “4” is “c” wireless terminal 32 corresponding to the “C” slave station 31. Is using. Therefore, the usage status of the six channels is listed as shown in FIG. The channel selection unit 13 determines a channel used by the wireless terminal 32 of “a” corresponding to the slave station 31 of “A” to communicate with the device 40 using the relationship shown in FIG. .

The conditions for determining the channel through which the channel selection unit 13 communicates with the device 40 are defined as follows. If the condition (1) is not satisfied, the condition (2) is used, and if the condition (2) is not satisfied, the condition (3) is adopted. That is, the priority of conditions for determining channels in the order of conditions (1), (2), and (3) is determined. However, when a plurality of channels satisfy the same priority condition, the channels are selected in ascending order of numerical values.
(1) Select an empty channel.
(2) The channel is selected from the channels used by the adjacent communication device 10 for communication with the device 40.
(3) Select a channel used in the first wireless network NT1.

  Since the wireless terminal 32 corresponding to the slave station 31 that requires two hops for communication can select the same channel for the second wireless communication unit 12, in many cases, the channel can be determined according to the condition (1). . That is, there is almost no possibility that the channel for the wireless terminal 32 to communicate with the device 40 is selected by the condition (2) or the condition (3). When the wireless terminal 32 corresponding to the adjacent slave station 31 uses a channel as shown in FIG. 3A, the wireless terminal 32 corresponding to the slave station 31 of “A” is “ Channels are selected in the priority order of “5” “6” “2” “3” “4” “1”. That is, the channel selection unit 13 first selects the channel “5” that is an empty channel according to the condition (1), and selects the channel “6” when the channel “5” cannot be used. Similarly, the channel selection unit 13 determines whether or not the channel selected in the above-described priority order can be used, and causes the second wireless communication unit 12 to use the channel determined to be usable.

  By the way, when the channel “5” is selected as described above and interference occurs due to the operation of other devices or the influence of environmental noise, the channel selection unit 13 selects the channel “6” according to the priority order. To do. Here, when the channel “6” cannot be used due to interference, the channel “5” having a higher priority than the channel “6” is selected again. In this case, the channel selection unit 13 cannot select a channel having a lower priority than the channel “6”.

  In order to avoid this problem, it is desirable that the channel selection unit 13 has a function of lowering the priority by penalizing a channel determined to be unusable until a predetermined time elapses from the unusable determination time. . The time is set to be longer than the time when the channel is assumed to be usable from the point of time when it is determined that the channel cannot be used, and may be a fixed time determined by a design value. It may be adjustable.

  In the above-described operation example, it is determined that channels “5” and “6” cannot be used. Therefore, the priority order of channels that can be selected immediately after it is determined that channel “6” cannot be used is temporarily “2”, “3”, “4”, “5”, “6”, and “1”. That is, the channel selection unit 13 selects the channel “2” next to the channel “6”. Although the channel “2” is used by the wireless terminals 32 of “b” and “e” corresponding to “B” and “E” which are the adjacent slave stations 31, there is a possibility that the channel “2” may receive interference. 13 evaluates the degree of interference, and selects channel “2” if it is determined that it can be used. At this point in time, the priority order of channel “1” is after channels “5” and “6”. The channel used in first radio network NT1 is not used in second radio network NT2. This is because of the principle.

  As in the above-described operation example, as in the condition (2), when the channel selection unit 13 has to select a channel used by the wireless terminal 32 corresponding to the adjacent slave station 31, it is adjacent. When there are a plurality of slave stations 31, it is desirable to select a channel by one of the following procedures. When the channel selected in the condition (2) is used, since the wireless terminal 32 corresponding to the adjacent slave station 31 uses the same channel for communication with the device 40, the probability of interference occurring in communication increases. For this reason, if the priority order is fixed so that the numerical values representing the channels are selected in ascending order, the time required for channel selection may increase.

  Therefore, the channel selection unit 13 evaluates the degree of interference for each channel with respect to the channel used by the wireless terminal 32 corresponding to the adjacent slave station 31, and determines the priority order of the channel from the lowest degree of interference. It is desirable. For the evaluation of the degree of interference for each channel, received signal strength (RSSI value: Received Signal Strength Indicator), the degree of interference, the number of communication devices 10 using the channel, and the like are used as indicators. The degree of interference is a rate at which traffic is interfered. For example, a rate at which traffic is interfered in a certain time is used.

  When the RSSI value is used as an index of interference, the channel management unit 14 not only acquires the channel used by the wireless terminal 32 corresponding to the adjacent child station 31, but also from the child station 31 where the child station 31 is adjacent. The RSSI value when the packet is received is acquired. The packet used to acquire the RSSI value is not limited to the hello packet. When the RSSI value for each slave station 31 is obtained, the correspondence between the slave station 31 (or the wireless terminal 32), the channel, and the RSSI value is stored in the channel management unit 14, as shown in FIG.

  The channel selection unit 13 organizes the information in FIG. 4A for each channel, and obtains an RSSI value for each channel as shown in FIG. 4B. Here, since the channel “2” is used by the wireless terminal 32 corresponding to the two slave stations 31 of “B” and “E”, the RSSI value is obtained for each of the two slave stations 31. Thus, when a plurality of RSSI values are obtained for the same channel, the maximum RSSI value is selected. In the illustrated example, since the RSSI values are “−70” and “−75”, and the largest is “−70”, the RSSI value of the channel “2” is “−70”.

  When the wireless terminal 32 corresponding to the adjacent slave station 31 uses the same channel, it is considered that the possibility of interference is lower when the RSSI value is smaller. Therefore, the channel selector 13 gives priority to the channel with the smaller RSSI value. Set priority to select. That is, in the example of FIG. 4B, the priority order of the channels is “4” “2” “3” “1”. Thus, even when it is necessary to select the same channel as that of the wireless terminal 32 corresponding to the adjacent slave station 31, the wireless terminal 32 communicates with the device 40 by selecting a channel with a low probability of communication interference. In addition, since the channel selection criteria are clear, the channel to be used can be determined in a relatively short time.

  When the degree of interference is used as an index of interference, the channel management unit 14 not only acquires the channel used by the wireless terminal 32 corresponding to the adjacent child station 31, but also from the adjacent child station 31 to the wireless terminal 32. The degree of interference at the time of communication with the device 40 is acquired. The degree of interference is notified by a packet received from the adjacent slave station 31. The packet for notifying the degree of interference is not limited to the hello packet, and may be any type of packet. When the interference level is notified from the adjacent slave station 31, the correspondence between the slave station 31 (or the wireless terminal 32), the channel, and the interference level is stored in the channel management unit 14 as shown in FIG. The

  The channel selection unit 13 organizes the information in FIG. 5A for each channel, and obtains the interference degree for each channel as shown in FIG. When a plurality of interference levels can be obtained for the same channel, the maximum interference level is selected. In the illustrated example, the interference degrees of the radio terminals 32 of “b” and “e” corresponding to the slave stations 31 of “B” and “E” using the channel “2” are “0.2” and “0.01”, respectively. Therefore, the larger interference degree “0.2” is assigned to the channel “2”.

  When the same channel as that of the wireless terminal 32 corresponding to the adjacent slave station 31 is used, it is considered that the possibility of interference is lower when the degree of interference is small. Therefore, the channel selection unit 13 gives priority to a channel with a small degree of interference. Set priority to select. In the example shown in FIG. 5B, the priority order of the channels is “3” “2” “4” “1”. As described above, even when the degree of interference is used as a selection criterion, the channel to be used can be determined in a relatively short time.

  In the example described above, when a plurality of interference degrees are obtained for the same channel, the maximum interference degree is selected, but the total interference degree may be used. Now, as shown in FIG. 6A, assuming that the interference degree acquired from each slave station 31 is stored in the channel management unit 14, the channel selection unit 13 organizes the information in FIG. 6A for each channel. Then, as shown in FIG. 6B, the degree of interference for each channel is obtained. In the example shown in FIG. 6B, when a plurality of interference degrees are obtained for the same channel, the maximum interference degree is not selected, but a value obtained by adding all the interference degrees of the same channel is used. . That is, for the wireless terminals 32 of “b” and “e” corresponding to the slave stations 31 of “B” and “E” using the channel “2”, the respective interference degrees are “0.2” and “0.1”. Therefore, the sum of interference of channel “2” is “0.3”.

  As in the above example, the channel selection unit 13 sets the priority so that the channel having a low interference degree is preferentially selected. Therefore, in the example shown in FIG. 6B, the priority order of the channels is “4” “3” “2” “1”.

  By the way, since the interference degree of the wireless terminal 32 corresponding to the adjacent slave station 31 is notified using a packet, when all the slave stations 31 transmit a packet including the interference degree, the traffic amount in the first wireless network NT1 May increase. Therefore, a configuration may be adopted in which the interference level is notified to the other slave stations 31 only when the interference level exceeds a predetermined reference value. Now, the reference value is set to 0.1. In the example shown in FIG. 5A, the interference degree of the radio terminal 32 of “d” corresponding to the slave station 31 of “D” is 0.02, and the radio of “e” corresponding to the slave station 31 of “E” is used. Since the interference degree of the terminal 32 is 0.01, these slave stations 31 do not notify the interference degree. Therefore, only the slave stations 31 that notify the degree of interference are “B” and “C”, and traffic in the first wireless network NT1 is reduced.

  In the above-described operation, the channel management unit 14 receives the interference degree from only a part of the adjacent slave stations 31, and therefore the channel selection unit 13 selects the channel “3” in the list shown in FIG. Assess the degree of interference to be below the lower limit. Also, regarding the channel “2”, the interference degree is notified from the slave station 31 of “B”, but the interference degree is not notified from the slave station 31 of “E”. In this example, the channel selection unit 13 A process for comparing the degree of interference is not necessary. In the state shown in FIG. 5A, when the interference level is not notified from the slave stations 31 of “D” and “E”, the channel selection unit 13 sets the channel priority order to “3”, “2”, “4”. “1”.

  When the number of communication devices 10 using the same channel is used as an index, the channel management unit 14 obtains the number of communication devices 10 using each channel for each channel. For example, when the number of communication devices 10 using each channel is obtained when the channels used by the communication device 10 for communication with the device 40 are in the state shown in FIG. It becomes like this.

  Here, it is considered that the chance of interference is reduced as the number of communication devices 10 using the same channel is smaller. Therefore, the channel selection unit 13 uses the number of communication devices 10 that are using the same channel as a selection criterion, and preferentially selects a channel with a small number. That is, in the example shown in FIG. 7, the priority order of the selected channels is “3” “4” “2” “1”.

  As in the various operation examples described above, depending on the degree of interference, it may be permitted to select the same channel as the wireless terminal 32 corresponding to the adjacent slave station 31. From this, when it is allowed to select the same channel as that of the wireless terminal 32 corresponding to the adjacent child station 31, the wireless terminal corresponding to the adjacent child station 31 satisfies the condition for the channel selection unit 13 to determine the channel. It is desirable to add a condition that the same channel as 32 is preferentially selected. If the channel selection unit 13 applies this condition in preference to the condition of selecting an empty channel, it is possible to increase the number of communication apparatuses 10 for the channel type. In other words, it is possible to quickly select a channel that does not cause interference while limiting the type of channel to be used.

  For example, as shown in FIG. 3B, when the priority of the empty channel is increased, the wireless terminal 32 of “a” corresponding to the slave station 31 of “A” uses the channel “5” for communication with the device 40. "To try to use. On the other hand, as described above, if the condition that the channel selection unit 13 selects the same channel as the wireless terminal 32 corresponding to the adjacent slave station 31 is used in preference to other conditions, the channel “5” is used. ”, And any one of the channels“ 2 ”to“ 4 ”is preferentially used. Therefore, the channel selection unit 13 secures channel “5” as an empty channel. This channel can be used for another communication device 10 and can be used as a spare when communication quality deteriorates when another channel is used.

(Embodiment 2)
As described in the first embodiment, the channel selection unit 13 can select a channel used by the wireless terminal 32 corresponding to the adjacent slave station 31 for communication with the device 40. The channel selection unit 13 of the first embodiment employs a selection criterion for evaluating the degree of interference in units of channels. That is, the channel selection unit 13 does not determine with which communication device 10 the interference occurs.

  The channel selection unit 13 according to the present embodiment determines, for each adjacent communication device 10, whether or not interference has occurred with the adjacent communication device 10, and the communication device 10 in which the interference has been detected is detected. Is set an interference flag, and a non-interference flag is set for the communication apparatus 10 in which no interference is detected. If there are a plurality of adjacent communication devices 10, a list (not shown) of the communication device 10 with the interference flag set and the communication device 10 with the non-interference flag set is generated. The former is called the black list and the latter is called the white list.

  Incidentally, the packet transmitted between the wireless terminal 32 and the device 40 communicating with each other includes the identification information of the wireless terminal 32 or the identification information of the slave station 31 to which the wireless terminal 32 belongs. If the communication protocol of the wireless terminal 32 is unified, the wireless terminal 32 can extract information from the interfering packet. Using this, the wireless terminal 32 that has detected the interference extracts the identification information of the slave station 31 or the wireless terminal 32 from the packet causing the interference and notifies the slave station 31 of the identification information.

  That is, the channel management unit 14 initially sets a non-interference flag and registers it in the white list for the adjacent communication device 10, and sets an interference flag and registers it in the black list when interference is detected. . Also, if the state where no interference with the communication device 10 registered in the black list is not detected continues for a predetermined time, the communication device 10 is re-registered in the white list. The predetermined time is about the time for penalizing the above-mentioned penalty. In this operation, each adjacent communication device 10 is registered only in one of the white list and the black list, and is always registered in either the white list or the black list.

  The channel selection unit 13 of the communication device 10 uses a selection criterion that preferentially selects the same channel as the communication device 10 registered in the white list. An operation example will be described assuming that the channel used by the wireless terminal 32 corresponding to the adjacent slave station 31 is in the state shown in FIG.

  In a state where all adjacent communication devices 10 are registered in the white list, the channel selection unit 13 selects channels in the priority order of “2”, “3”, and “4”. The channel selection unit 13 first selects the channel “2”. At this time, the channel management unit 14 detects a packet transmitted between the wireless terminal 32 of “b” corresponding to the slave station 31 of “B” and the device 40 and corresponds to the slave station 31 of “E”. Assume that no packet transmitted between the wireless terminal 32 of “e” and the device 40 is detected. In this case, among the two slave stations 31 of “B” and “E” that use the channel “2”, the slave station 31 of “B” is registered in the black list. Decrease the priority of selecting "". That is, the channel selection unit 13 updates the channel selection order to “3” “4” “2” “1”.

  Next, the channel selection unit 13 selects the channel “3”. At this time, it is assumed that the channel management unit 14 detects a packet transmitted between the “d” wireless terminal 32 corresponding to the “D” slave station 31 and the device 40. Here, the channel management unit 14 registers the slave station 31 of “D” in the black list, and the channel selection unit 13 tries to change the channel to be used. Thereafter, if the channel used between the wireless terminal 32 of “b” corresponding to the slave station 31 of “B” and the device 40 is changed from the channel “2” to the channel “3”, the channel “2” is Registered in the white list.

  Therefore, at this time, the priority order selected by the channel selection unit 13 is “2” “4” “3” “1”. That is, finally channel “2” is selected. If the channel used by the slave station 31 of “B” has not been changed, channel “4” is selected. When all available channels are registered in the black list, the channel selection unit 13 preferentially selects a channel having the smallest number of slave stations 31 registered in the black list.

  In the present embodiment, by using a black list and a white list for managing the presence / absence of interference for each slave station 31 (communication device 30), the same channel as that of the adjacent communication device 10 can be used. Therefore, as described in the first embodiment, as a condition for the channel selection unit 13 to select a channel, a condition for using the same channel as that of the adjacent communication device 10 is set in preference to the condition for selecting an empty channel. It is possible. By selecting a channel under this condition, the type of channel assigned to the communication device 10 is reduced as compared with the case where only a free channel is used.

  Further, by repeating updating of the contents of the black list and the white list, a channel with less interference can be predicted by learning. Other configurations and operations are the same as those of the first embodiment.

(Embodiment 3)
In the configurations of the first and second embodiments, the channel management unit 14 manages information on the channel used by the second wireless communication unit 12 for only the adjacent communication device 10. On the other hand, this embodiment shows the example which manages the information of a channel about the communication apparatus 10 provided with the sub_station | mobile_unit 31 within 2 hops. Further, there are ten channels “1” to “10” that can be used. The channel used by the adjacent communication device 10 is the same as that in the first embodiment, and the channel management unit 14 stores the information shown in FIG. The information shown in FIG. 3A is extracted from the hello packet by the channel management unit 14.

  In the first embodiment, information on the channel used for communication with the device 40 is included in the hello packet, whereas in the present embodiment, the adjacent communication device 10 is used for communication with the device 40. The information of the existing channel is also included in the hello packet. That is, the hello packet received by the slave station 31 from the adjacent slave station 31 includes information on the channel used by the adjacent communication device 10 for communication with the device 40, and the communication device 10 separated by 2 hops from the device 40. Information on the channel used for communication.

  Therefore, the channel management unit 14 determines the channel used by the wireless terminal 32 of “b” to “k” with the device 40 for each of the slave stations 31 of “B” to “K” within two hops. Extract information from hello packets. As shown in FIG. 8A, the channel management unit 14 stores channel information extracted from the hello packet. In FIG. 8A, the number of hops is the number of hops when the slave station 31 of “A” communicates with another slave station 31.

The channel selection unit 13 is a channel that is not used for communication with the device 40 by the adjacent communication device 10 as a condition having higher priority than the condition employed in the first embodiment, and communication that requires two hops for communication. The condition that the channel used by the device 10 is selected is added. That is, the condition for determining the channel for the channel selection unit 13 to communicate with the device 40 is defined as follows.
(1) The channel which the communication apparatus 10 which the adjacent communication apparatus 10 is not using for the communication with the apparatus 40 and which requires 2 hops is used is selected.
(2) Select an empty channel.
(3) The channel is selected from the channels used by the adjacent communication device 10 for communication with the device 40.
(4) Select a channel used in the first wireless network NT1.

  Among these conditions, the conditions (2) to (4) are the same as those in the first embodiment. However, by adding the condition (1), it is possible to allocate channels while leaving an empty channel. When the channels used by the communication apparatus 10 within 2 hops for communication with the device 40 are set as shown in FIG. 8A, the channel usage status is listed as shown in FIG. 8B. become that way. The channel selection unit 13 corresponding to the slave station 31 of “A” “5” “6” “7” “8” “9” “10” “2” “3” “4” “1” ”In order of priority. Other configurations and operations are the same as those in the first and second embodiments. Therefore, this embodiment can be used in combination with the configurations of the first and second embodiments. That is, although Embodiment 1 and 2 demonstrated using the relationship with the substation 31 which communicates by 1 hop, you may perform the same process by the relationship with the substation 31 which communicates by 2 hops. In this case, the priority order of the channels used by the communication apparatus 10 including the slave station 31 communicating in two hops is set higher than the channels used by the communication apparatus 10 including the slave station 31 communicating in one hop. Therefore, the channel selection by the processing of the first embodiment may be used when the priority order is determined among the hop numbers.

  The number of channels and various numerical values in the operation example of each embodiment described above are values exemplified for explanation, and are not intended to limit the embodiment.

DESCRIPTION OF SYMBOLS 10 Communication apparatus 11 1st radio | wireless communication part 12 2nd radio | wireless communication part 13 Channel selection part 14 Channel management part 20 Master station 31 Slave station 32 Radio | wireless terminal 40 Equipment NT1 1st radio network NT2 2nd radio network

Claims (12)

A first wireless communication unit that communicates with a master station through a first wireless network that is an ad hoc network;
A second wireless communication unit that communicates with the device through a second wireless network;
A channel selection unit for determining a channel to be used in the second wireless communication unit;
A channel management unit for acquiring a channel used by another communication device for communication with the device through the first wireless communication unit;
The first wireless communication unit transmits a packet including channel information determined by the channel selection unit,
The channel management unit extracts and stores a channel used by another communication device for communication with the device from the packet received by the first wireless communication unit,
The channel selection unit uses the channel information stored in the channel management unit to determine the priority order of selection of channels that can be used, and selects the channels in order of priority, whereby the second wireless communication Determine the channel to use
Furthermore, the first wireless communication unit has a function of transmitting a packet including an interference degree, which is a rate at which traffic is interfered during communication with the device,
The channel management unit extracts and stores the interference degree in addition to the channel used by the other communication device for communication with the device from the packet received by the first wireless communication unit from the other communication device. ,
The channel selection unit adds the interference degrees extracted from the packets received by the first wireless communication unit from other communication devices for each channel, and adds the interference degrees for the channels stored in the channel management unit. A communication apparatus used for a wireless network, wherein the priority order of selection of channels that can be used is determined under the condition that the smaller the result is, the higher the priority order of the channels is . 2. The communication apparatus used for a wireless network according to claim 1, wherein the first wireless communication unit transmits the interference degree included in the packet only when the interference degree exceeds a predetermined reference value . A first wireless communication unit that communicates with a master station through a first wireless network that is an ad hoc network;
A second wireless communication unit that communicates with the device through a second wireless network;
A channel selection unit for determining a channel to be used in the second wireless communication unit;
A channel management unit for acquiring a channel used by another communication device for communication with the device through the first wireless communication unit;
The first wireless communication unit transmits a packet including channel information determined by the channel selection unit,
The channel management unit extracts and stores a channel used by another communication device for communication with the device from the packet received by the first wireless communication unit,
The channel selection unit uses the channel information stored in the channel management unit to determine the priority order of selection of channels that can be used, and selects the channels in order of priority, whereby the second wireless communication Determine the channel to use
Further, the channel management unit is associated with a channel used by another communication device that has received the packet by the first wireless communication unit for communication with the device, and the first wireless communication unit Stores the received signal strength when a packet is received from another communication device,
When the channel selection unit determines the same channel as the other communication device among the channels stored in the channel management unit as a channel to be used in the second wireless communication unit, the channel management unit stores for channel information which are using the condition that a higher priority of the higher received signal strength is small channel, it is used to radio network you characterized by determining the priority order of selection for the available channel Communication device. A first wireless communication unit that communicates with a master station through a first wireless network that is an ad hoc network;
A second wireless communication unit that communicates with the device through a second wireless network;
A channel selection unit for determining a channel to be used in the second wireless communication unit;
A channel management unit for acquiring a channel used by another communication device for communication with the device through the first wireless communication unit;
The first wireless communication unit transmits a packet including channel information determined by the channel selection unit,
The channel management unit extracts and stores a channel used by another communication device for communication with the device from the packet received by the first wireless communication unit,
The channel selection unit uses the channel information stored in the channel management unit to determine the priority order of selection of channels that can be used, and selects the channels in order of priority, whereby the second wireless communication Determine the channel to use
Further, the channel selection unit obtains the number of other communication devices that use the channel in the second wireless communication unit for each available channel, and the channel priority is increased as the number decreases. it is used on condition that the communication device used to radio network you characterized by determining the priority order of channel selection is available. The first wireless communication unit is used for communication with the device by another communication device capable of communicating with one hop stored in the channel management unit in addition to the channel determined by the channel selection unit. The current channel in a packet,
The channel management unit allows other communication devices that can communicate with one hop stored in the channel management unit to communicate with the device from among a plurality of channels that can be used in the second wireless network. Extracting and storing the channel used and the channel used by another communication device capable of communication in two hops for communication with the device;
The channel selection unit uses the channel information stored in the channel management unit in another communication device that communicates in one hop with a channel used in another communication device that communicates in two hops. The wireless communication device according to any one of claims 1 to 4, wherein a priority order of selection of channels that can be used is determined on the condition that the channels are used in a higher priority order than the existing channels. A communication device used in a network. The channel selector, for channels that are determined to be unusable, from decision point until a predetermined time has elapsed, claim 1, characterized in that lowering the priority than the priority order of selection of the available channel The communication apparatus used for the wireless network of any one of -5 . A first wireless communication unit that communicates with a master station through a first wireless network that is an ad hoc network;
A second wireless communication unit that communicates with the device through a second wireless network;
A channel selection unit for determining a channel to be used in the second wireless communication unit;
A channel management unit for acquiring a channel used by another communication device for communication with the device through the first wireless communication unit;
The first wireless communication unit transmits a packet including channel information determined by the channel selection unit,
The channel management unit extracts and stores a channel used by another communication device for communication with the device from the packet received by the first wireless communication unit,
The channel selection unit uses the channel information stored in the channel management unit to determine the priority order of selection of channels that can be used, and selects the channels in order of priority, whereby the second wireless communication Determine the channel to use
Further, the first wireless communication unit transmits the packet including the interference degree, which is a ratio of the traffic being interfered when communicating with the device, only when the interference degree exceeds a predetermined reference value. Has the function to
The channel management unit extracts and stores the interference degree in addition to the channel used by the other communication device for communication with the device from the packet received by the first wireless communication unit from the other communication device. ,
When the channel selection unit determines the same channel as the other communication device among the channels stored in the channel management unit as a channel to be used in the second wireless communication unit, the channel management unit stores of the channels of information are, with the condition that a higher priority of the higher degree of interference is smaller channel used to radio network you characterized by determining the priority order of selection of the available channel Communication device. The first wireless communication unit is used for communication with the device by another communication device capable of communicating with one hop stored in the channel management unit in addition to the channel determined by the channel selection unit. The current channel in a packet,
The channel management unit allows other communication devices that can communicate with one hop stored in the channel management unit to communicate with the device from among a plurality of channels that can be used in the second wireless network. Extracting and storing the channel used and the channel used by another communication device capable of communication in two hops for communication with the device;
The channel selection unit uses the channel information stored in the channel management unit in another communication device that communicates in one hop with a channel used in another communication device that communicates in two hops. 8. The communication apparatus for use in a wireless network according to claim 7 , wherein the priority order of selection of channels that can be used is determined on the condition that the channels are used in a higher priority order than the existing channels . The channel selector, for channels that are determined to be unusable, from decision point until a predetermined time has elapsed, claim, characterized in that than the priority order of selection of the available channel lowers the priority 7 Or the communication apparatus used for the radio | wireless network of 8 . A first wireless communication unit that communicates with a master station through a first wireless network that is an ad hoc network;
A second wireless communication unit that communicates with the device through a second wireless network;
A channel selection unit for determining a channel to be used in the second wireless communication unit;
A channel management unit for acquiring a channel used by another communication device for communication with the device through the first wireless communication unit;
The first wireless communication unit transmits a packet including channel information determined by the channel selection unit,
The channel management unit extracts and stores a channel used by another communication device for communication with the device from the packet received by the first wireless communication unit,
The channel selection unit uses the channel information stored in the channel management unit to determine the priority order of selection of channels that can be used, and selects the channels in order of priority, whereby the second wireless communication Determine the channel to use
Furthermore, the channel manager
When the second wireless communication unit receives a packet transmitted to another device by another communication device, identification information included in the packet and a black channel in which the channel that transmitted the packet is registered List and
Other communication devices that communicate through the first wireless communication unit and identification information that is not included in the blacklist among the devices with which the communication device is communicating, and communication between the communication device and the device With a whitelist that registers the channels used in
The channel selector, the using conditions defined to the high priority channel which is registered in the white list, you and determining a channel used by the second radio communication unit communication apparatus for use in non-linear network. The channel selection unit uses a condition determined so that the channel is registered in the white list, and when there is a channel used by another communication device, the channel is set to a high priority. The communication apparatus used for the wireless network according to claim 10 , wherein a channel used in the second wireless communication unit is determined .   The first wireless communication unit has a function of transmitting meter reading data by a meter installed in a consumer to the parent station, and a function of receiving an instruction from the parent station,
  The second wireless communication unit communicates with a device used by a consumer
  The communication apparatus used for the wireless network of any one of Claims 1-11 characterized by the above-mentioned.

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