JP5423707B2 - Wireless access point, wireless communication device, and wireless communication system - Google Patents

Description

  The present invention relates to a wireless access point, a wireless communication device, and a wireless communication system, and can be applied to a wireless communication system that performs wireless communication in a narrow and complex space, such as in an ICT (Information and Communication Technology) device.

  As a conventional technique for efficiently performing communication between nodes in a wireless communication system, there is a technique described in Patent Document 1.

  Patent Document 1 describes a method for suitably allocating a free communication channel among a plurality of communication channels used in a fixed wireless terminal or a mobile terminal in the same service area.

Japanese Patent Laid-Open No. 9-271063

  However, in the technique described in Patent Document 1, when a wireless communication device is fixed and installed in a narrow and complex space such as in an ICT device, an incoming wave received by a receiving terminal is affected by multipath. Therefore, in this case, the communication characteristics may differ greatly if the frequency used for transmission is changed. That is, in a wireless communication system to which the technology described in Patent Document 1 is applied, communication quality may change significantly when the communication channel is changed in communication between arbitrary wireless communication apparatuses.

  On the other hand, if communication channels with good communication quality are matched in a plurality of links, there is a possibility that the communication channels may compete for the communication channels or communication may collide. Particularly in a wireless LAN (for example, IEEE 802.11 series), since the number of communication channels allocated is limited, it is important to efficiently allocate communication channels in order to increase communication efficiency of the entire system. However, even if the technique described in Patent Document 1 is applied, it has been impossible to optimize the communication between the wireless communication devices by avoiding the contention of channels as described above.

  Therefore, a wireless access point, a wireless communication device, and a wireless communication system that can efficiently allocate a communication channel in wireless communication between a plurality of nodes are desired.

According to a first aspect of the present invention, in a wireless access point device that communicates with a plurality of wireless communication devices, (1) each of the wireless communication devices is controlled to communicate using a plurality of wireless channels, and each of the wireless communication devices Communication quality value acquisition means for obtaining a communication quality value related to communication quality for each radio channel with the device, and (2) based on the communication quality value obtained by the communication quality value acquisition means for each of the wireless communication devices. A communication channel assignment determining means for determining a combination of communication channels to be allocated, which determines a combination in which communication between a larger number of the wireless communication devices and the wireless access point device is good, and (3) the communication In accordance with the content determined by the channel allocation determining means, each of the wireless communication devices uses a communication channel used with the wireless access point device Communication channel notifying means for notifying, (4) each wireless communication device, and data transmitting / receiving means for transmitting and receiving data using a communication channel according to the contents determined by the communication channel allocation determining means, (5) The communication channel assignment determining unit calculates a communication quality value for each combination of the wireless communication apparatuses and the communication channels, and for each of the calculated communication quality values, An evaluation value that considers the relationship with the communication quality value of the other communication channel of the wireless communication device related to the communication quality value is calculated, and the wireless communication device related to the communication quality value with a higher calculated evaluation value is more preferential. There line assignment of communication channels to, the determination of the (6) the communication channel allocation determining means, evaluation values based on different reference value for each of the wireless communication device And butterflies.

2nd this invention is a radio | wireless communication apparatus which carries out radio | wireless communication with the radio | wireless access point apparatus of 1st this invention, Comprising: Among the some radio | wireless channels, using the radio | wireless channel notified from the said radio | wireless access point apparatus, Data transmission / reception means for transmitting / receiving data to / from the wireless access point device is provided.

  A third aspect of the present invention is a wireless communication system comprising a plurality of wireless communication devices and one or more wireless access point devices that wirelessly communicate with the wireless communication device. The wireless access point device of the present invention is applied, and (2) the wireless communication device of the second invention is applied as each of the wireless communication devices.

  According to the present invention, communication channels can be efficiently allocated in wireless communication between a plurality of nodes.

It is the sequence diagram shown about operation | movement of the radio | wireless communications system which concerns on embodiment. It is the block diagram shown about the whole structure of the radio | wireless communications system which concerns on embodiment. It is explanatory drawing shown about the communication system employ | adopted with the radio | wireless communications system which concerns on embodiment. It is the block diagram shown about the functional structure which concerns on AP (access point node) which concerns on embodiment. It is the block diagram shown about the functional structure which concerns on ST (station node) which concerns on embodiment. It is explanatory drawing shown about the structure of the communication channel instruction | indication packet which AP (access point node) which concerns on embodiment transmits. It is explanatory drawing shown about the structure of the communication channel instruction | indication ACK packet which ST (station node) which concerns on embodiment transmits. It is explanatory drawing shown about the structure of ST data packet which ST (station node) which concerns on embodiment transmits. It is the flowchart shown about the communication channel allocation process which the channel control part of AP (access point node) which concerns on embodiment performs. It is explanatory drawing shown about the example of the content of the communication quality management table which concerns on embodiment. It is explanatory drawing shown about the example of the content of the evaluation value management table which concerns on embodiment. It is explanatory drawing shown about the example of the content of the allocation order evaluation table which concerns on embodiment. It is explanatory drawing shown about the example of the content of ST management table which concerns on embodiment.

(A) Main Embodiment Hereinafter, an embodiment of a wireless access point, a wireless communication apparatus, and a wireless communication system according to the present invention will be described in detail with reference to the drawings. The wireless access point device of this embodiment is an access point (hereinafter referred to as “AP”). The wireless communication apparatus of this embodiment is a station terminal (hereinafter referred to as “ST”).

(A-1) Configuration of Embodiment FIG. 2 is a block diagram showing the overall configuration of the wireless communication system 1 of this embodiment.

  In the wireless communication system 1, an AP 10 and four ST20 (20-1 to 20-4) are arranged.

  The AP 10 functions as a wireless access point device capable of wireless communication with each ST 20. Each ST 20 is a wireless communication device capable of wireless communication with the AP 10 based on control from the AP 10. In FIG. 2, only one AP 10 and four STs 20 are arranged for ease of explanation, but the number of APs 10 and ST 20 arranged is not limited. For example, the ST 20 may communicate with a plurality of APs 10. For example, it is good also as a structure which performs radio | wireless communication between ST20. The wireless communication system 1 can be applied to wireless communication in a narrow and complex space such as the inside of an ICT device (for example, a server device or a network device).

  For convenience of description, one AP 10 and four STs 20 are arranged in FIG. 2, but the number of APs 10 and ST 20 arranged is not limited. Further, ST 20 may communicate with a plurality of APs 10. Furthermore, you may communicate between ST20.

  Next, an outline of a wireless communication method employed in the wireless communication system 1 will be described. In the wireless communication system 1, a method called FTDMA (Frequency and Time Division Multiple Access) is adopted for communication between the AP 10 and each ST20. FTDMA is a multiple access method realized by dividing a frequency band and a time domain and assigning them to each user.

  FIG. 3 is an explanatory diagram showing an example of a wireless communication system (FTDM system) between the AP 10 and each ST 20.

  In the wireless communication system 1, as shown in FIG. 3, the frequency and time of a radio wave that is a communication medium are divided into areas called “slots”, and each slot is assigned to one of ST20. Each ST 20 communicates with the AP 10 using the assigned slot.

  FIG. 3 shows a state in which four slots SL1 to SL4 using four communication channels CH1 to CH4 are set within the time of one cycle. As shown in FIG. 3, here, it is assumed that communication channels CH1 to CH4 are assigned to the slots SL1 to SL4, respectively. 3 shows an example in which four communication channels are divided in the frequency domain and one cycle time domain is divided into eight sections in order to simplify the description. The number to be divided is not limited. In general, in a wireless communication system adopting the conventional FTDMA, a plurality of slots are arranged in each communication channel. Here, for simplicity of explanation, the number of slots arranged in each communication channel is one. Suppose that It is assumed that only one ST20 can be accommodated in one slot. Then, any communication channel (slot) is allocated from the AP 10 to each ST 20, and thereafter, communication is performed between the AP 10 and each ST 20 using a slot corresponding to the communication channel most recently allocated from the AP 10. Shall.

  Next, the internal configuration of the AP 10 and ST 20 will be described.

  FIG. 4 is a block diagram showing a functional configuration of the AP 10.

  The AP 10 includes a transmission unit 11, a reception unit 12, a transmission / reception control unit 13, a channel control unit 14, and a data storage unit 15.

  Here, the AP 10 performs wireless access point communication according to the embodiment to a device having an interface for performing wireless communication with other communication devices and an execution configuration of programs such as a CPU, ROM, RAM, EEPROM, and hard disk, for example. You may make it build by installing a program etc. Even in that case, the functional configuration of the AP 10 can be expressed as shown in FIG.

  The transmission unit 11, the reception unit 12, and the transmission / reception control unit 13 have a function of a wireless communication interface in the AP 10. For example, the transmission unit 11, the reception unit 12, and the transmission / reception control unit 13 are similar to a wireless communication apparatus that can transmit and receive an 802.11 frame format frame using the existing FTDMA method. Can be applied.

  The transmission unit 11 receives data or an instruction from the transmission / reception control unit 13, generates a corresponding packet, and further emits radio waves of a signal modulated by a predetermined method in the air.

  The receiving unit 12 receives radio waves from the air, restores a packet from a signal demodulated by a predetermined method, and passes the data to the transmission / reception control unit 13.

  When transmission data to be transmitted from the AP 10 to another node is generated, the transmission / reception control unit 13 holds the data and passes it to the transmission unit 11. The trigger and contents of data to be transmitted from the AP 10 to other nodes are not limited. For example, the data may be generated by an upper layer processing configuration (for example, an application) (not shown) in the AP 10. It is done. Then, when data to be transmitted to another node is generated in the AP 10, the transmission / reception control unit 13 may, for example, use a predetermined interface (software interface or physical interface) from an application or the like in which the data is generated. The transmission data may be held via the communication method.

  In addition, when the packet received by the receiving unit 12 is a packet in which data transmitted from another node to the AP 10 is inserted, the transmission / reception control unit 13 holds the data inserted in the packet. For example, contrary to the case of the transmission data described above, it may be delivered to a higher-layer processing configuration (not shown) via a predetermined interface. Whether or not the packet held by the transmission / reception control unit 13 is data transmitted from another node to the AP 10 may be identified by, for example, the packet type of the packet.

  Further, when receiving an instruction to transmit a communication channel control packet from the channel control unit 14, the transmission / reception control unit 13 transmits a packet based on the instruction via the transmission unit 11. Further, when receiving a communication channel control packet, the receiving unit 12 delivers the contents of the packet to the channel control unit 14. Whether or not the packet held by the transmission / reception control unit 13 is a communication channel control packet transmitted from another node to the AP 10 may be identified by, for example, the packet type of the packet.

  The data storage unit 15 is a storage unit that stores information used in processing of the channel control unit 14 to be described later, and includes a communication quality management table 151, an evaluation value management table 152, an allocation order evaluation table 153, and an ST management table. 154. Details of each table of the data storage unit 15 will be described in the section of the operation description to be described later.

  The channel control unit 14 communicates with each ST20 (ST20-1 to 20-4) using each communication channel (CH1 to CH4) via a wireless communication interface (transmission / reception control unit 13 or the like). Then, the channel control unit 14 measures a value related to communication quality (hereinafter referred to as “communication quality value”) when communicating with each ST 20 and records the measurement result in the communication quality management table 151. And the channel control part 14 determines the communication channel allocated to each ST20 using the content of the communication quality management table 151. FIG. Then, the channel control unit 14 notifies each ST 20 of information on the communication channel (slot) determined to be assigned, and thereafter communicates with each ST 20 using the assigned communication channel. The channel control unit 14 generates the evaluation value management table 152, the allocation order evaluation table 153, and the ST management table 154 based on the communication quality management table 151 in the process of determining the communication channel to be assigned to each ST 20. The details of this process will be described in the section of the operation description to be described later.

  FIG. 5 is a block diagram showing a functional configuration of ST20.

  The ST 20 includes a transmission unit 21, a reception unit 22, a transmission / reception control unit 23, and a channel management unit 24.

  Here, ST20 is a wireless communication program according to the embodiment, etc., in an apparatus having an interface for performing wireless communication with other communication devices and an execution configuration of programs such as CPU, ROM, RAM, EEPROM, and hard disk, for example. You may make it build by installing. Even in that case, the functional configuration of ST20 can be expressed as shown in FIG.

  The transmission unit 21, the reception unit 22, and the transmission / reception control unit 23 are responsible for the function of the wireless communication interface in ST20. Can be applied.

  The transmission unit 21 receives data or an instruction from the transmission / reception control unit 23, generates a corresponding packet, and further emits radio waves of a signal modulated by a predetermined method in the air.

  The receiving unit 22 receives radio waves from the air, restores a packet from a signal demodulated by a predetermined method, and passes the data to the transmission / reception control unit 23.

  When transmission data to be transmitted from the ST 20 to another node is generated, the transmission / reception control unit 23 holds the data and passes it to the transmission unit 21. The trigger and contents of data to be transmitted from the ST 20 to another node are not limited. For example, the data may be generated in a processing configuration (for example, an application) (not shown) in the ST 20. It is done. Then, when data to be transmitted to another node is generated in ST20, the transmission / reception control unit 23 may use a predetermined interface (a software interface or a physical interface) from, for example, an application in which the data is generated. The transmission data may be held via the communication method.

  In addition, when the packet received by the receiving unit 22 is a packet in which data transmitted from another node to the ST 20 is inserted, the transmission / reception control unit 23 holds the data inserted in the packet. For example, contrary to the case of the transmission data described above, it may be delivered to a higher-layer processing configuration (not shown) via a predetermined interface. Whether the packet held by the transmission / reception control unit 23 is data transmitted from another node to the ST 20 may be identified by, for example, the packet type of the packet.

  In addition, when receiving an instruction to transmit a communication channel control packet from the channel management unit 24, the transmission / reception control unit 23 transmits a packet based on the instruction via the transmission unit 21. In addition, when receiving the control packet, the receiving unit 22 delivers the content of the communication channel control packet to the channel management unit 24. Whether or not the packet held by the transmission / reception control unit 23 is a communication channel control packet transmitted from another node to the ST 20 may be identified by, for example, the packet type of the packet.

  Next, the format of various packets flowing between the AP 10 and the ST 20 will be described. Here, the IEEE 802.11 frame format is applied as the format of the packet flowing between the AP 10 and the ST 20 as described above, but the format of the packet is not limited. Here, the type of packet flowing between the AP 10 and the ST 20 is identified using the packet type value of the 802.11 header, but other fields are used (for example, in the data field). (Predetermined information may be added).

  The channel management unit 24 exchanges communication channel control packets with the channel control unit 14 on the AP 10 side, holds information on the communication channel assigned to the ST 20, and performs wireless communication using the assigned communication channel. As is performed, processing for controlling a wireless communication interface (such as the transmission / reception control unit 23) is performed.

  Next, an example of the format of various packets flowing between the AP 10 and the ST 20 will be described. Here, as described above, the IEEE 802.11 frame format is applied as the format of the packet flowing between the AP 10 and the ST 20, but the format of these packets is not limited.

  FIG. 6 is a communication channel control packet (hereinafter referred to as “communication channel instruction packet”) transmitted when the AP 10 instructs each ST 20 on the assigned communication channel.

  The communication channel instruction packet is a packet used to instruct the assigned communication channel from the AP 10 to each ST 20.

  The communication channel instruction packet has a control field, a packet type, an AP address, an ST address, and a communication channel number field.

  As the “control field”, a control field such as a preamble used in the 802.11 header can be applied.

  The “packet type” is a number for identifying the type of the communication channel instruction packet, and “1” is set here.

  “AP address” indicates address information (for example, MAC address) of the AP 10 that is the transmission source of the communication channel instruction packet.

  “ST address” indicates address information (for example, a MAC address) of the transmission destination ST 20 of the communication channel instruction packet.

  “Communication channel number” indicates the identification number of the communication channel instructed to the destination ST 20 by the communication channel instruction packet. Here, it is assumed that the radio channel numbers of the radio channels CH1 to CH4 are 1 to 4, respectively. Therefore, for example, when instructing the destination ST20 of the communication channel instruction packet to use the radio channel CH1, “1” is entered.

  FIG. 7 is an explanatory diagram showing the format of a communication channel control packet (hereinafter referred to as “communication channel instruction ACK packet”) for ST 20 that has received the communication channel instruction packet to acknowledge (ACK) the AP 10. is there.

  The communication channel instruction ACK packet has a control field, a packet type, an ST address, and an AP10 address field.

  As the “control field”, a control field such as a preamble used in the 802.11 header can be applied.

  “Packet type” is a number for identifying the type of the packet, and “2” is set here.

  “ST address” indicates the address information (for example, MAC address) of ST 20 that is the transmission source of the communication channel instruction ACK packet.

  “AP address” indicates address information (for example, MAC address) of the AP 10 that is the transmission destination of the communication channel instruction ACK packet.

  FIG. 8 is an explanatory diagram showing a format of a packet (hereinafter referred to as “ST data packet”) used when data is transmitted from the ST 20 to the AP 10 using the communication channel instructed by the communication channel instruction packet.

  The ST data packet has a control field, a packet type, an ST address, an AP address, and a data field.

  As the “control field”, a control field such as a preamble used in the 802.11 header can be applied.

  “Packet type” is a number for identifying the type of the packet, and “3” is set here.

  “ST address” indicates address information (for example, MAC address) of ST 20 that is the transmission source of the ST data packet.

  “AP address” indicates address information (for example, MAC address) of the AP 10 that is the transmission destination of the ST data packet.

  “Data” is a field of data to be transmitted to the AP 10 (for example, data supplied from an upper layer application or the like).

(A-2) Operation | movement of embodiment Next, operation | movement of the radio | wireless communications system 1 of this embodiment which has the above structures is demonstrated.

  FIG. 1 is a sequence diagram showing the operation of the wireless communication system 1 (communication control between the AP 10 and the ST 20).

  First, a communication channel instruction packet is transmitted from the AP 10 to each ST 20. The combination of communication channel numbers that the AP 10 instructs to each ST 20 in the communication channel instruction packet will be described later. Then, ST 20 receives the communication channel instruction packet from AP 10 and sets to use the instructed communication channel. Here, each ST 20 returns a communication channel instruction ACK packet as a confirmation response to the AP 10 when the communication channel instruction packet normally arrives (S101).

  Next, each ST 20 that has received the communication channel instruction packet from the AP 10 uses the channel indicated by the communication channel instruction packet to use ST data packets (hereinafter referred to as “inspection data packets”) used for inspection of communication quality. ) Shall be transmitted continuously. Then, the AP 10 receives the inspection data packet transmitted from each ST 20, obtains the communication quality value according to the reception status, and stores the information in the communication quality management table 151 (S102). .

  The data to be inserted into the test data packet transmitted by ST 20 after receiving the communication channel instruction packet is not limited. For example, predetermined dummy data or the like may be inserted so that it can be identified on the AP 10 side. good.

  In addition, the number and transmission interval of test data packets transmitted by the ST 20 to the AP 10 are not limited, but the number set in advance in each ST 20 may be applied, or the communication channel instruction packet may be used. You may make it notify to each ST20.

  And AP10 transmits the communication channel instruction | indication packet for instruct | indicating the radio channel of the combination different from the above-mentioned step S101 with respect to each ST20. Then, ST 20 receives the communication channel instruction packet from AP 10 and sets to use the instructed communication channel. Each ST 20 that has received the communication channel instruction packet returns a communication channel instruction ACK packet to the AP 10 (S103).

  Next, each ST 20 that has received the communication channel instruction packet from the AP 10 continuously transmits a plurality of test data packets using the channel indicated by the communication channel instruction packet, as in step S102 described above. Then, in the same manner as in step S102 described above, the AP 10 receives the inspection data packet from each ST 20, obtains the communication quality value based on the communication quality at the time of packet reception, and stores the result in the communication quality management table 151. Information is stored (S104).

  Although not shown in FIG. 1, in the wireless communication system 1, thereafter, each ST 20 transmits inspection data packets to the AP 10 using all the communication channels CH1 to CH4, and the communication quality on the AP 10 side. The same processing is repeated until the contents of the management table 151 are completed. Details of the communication quality management table 151 will be described later.

  Further, the combination of the radio channels instructed by each AP 20 in the communication channel instruction packet by the AP 10 and the order thereof are not limited. In this embodiment, since four channels CH1 to CH4 are set for the four STs 20-1 to 20-4, if the AP 10 transmits communication channel instruction packets in four different combinations, the communication quality The management table 151 is completed. When the number of channels is smaller than the number of STs 20, it is desirable that the AP 10 side limit the number of STs 20 that simultaneously transmit inspection data packets to be equal to or less than the number of channels. As a method of restricting ST20 that simultaneously transmits inspection data packets on the AP 10 side, for example, a control packet instructing prohibition of transmission of ST data packets is transmitted to 20 that wants to stop transmission of inspection data packets. You may make it do.

  When the content of the communication quality management table 151 is completed, the AP 10 (channel control unit 14) performs processing for determining a communication channel to be assigned to each ST 20 based on the content of the communication quality management table 151 (S105). The details of the process of assigning communication channels to each ST 20 performed by the channel control unit 14 will be described later.

  Next, a communication channel instruction packet for notifying the communication channel assigned in step S105 described above is transmitted from the AP 10 to each ST20. Each ST 20 receives the communication channel instruction packet from the AP 10 and sets to use the instructed communication channel. Each ST 20 returns a communication channel instruction ACK packet to the AP 10 as a confirmation response to the communication channel instruction packet (S106).

  Thereafter, wireless communication is performed between the AP 10 and each ST 20 through the communication channel indicated by the communication channel indication packet. Further, the AP 10 repeats the processing of the above-described steps S101 to S106, for example, at any timing (for example, a timing according to a periodic timing or a user operation), and reassigns communication channels. Also good. Further, for some ST20, communication channels may be reassigned when communication quality deteriorates (for example, when an error rate increases or a packet is not transmitted for a certain period of time). .

  Next, details of the communication quality management table 151 created by the AP 10 (channel control unit 14) will be described.

  FIG. 10 is an explanatory diagram showing an example of the contents of the communication quality management table 151.

  The communication quality management table 151 includes information on ST name and communication quality items.

  The item “ST name” indicates information for identifying each ST. The content of the ST name is not limited, but here, the ST names of ST20-1 to 20-4 are assumed to be ST1 to ST4, respectively. In the communication quality management table 151, a communication quality value corresponding to each ST name (ST20) is registered.

  The item “communication quality value” indicates a communication quality value for each communication channel (CH1 to CH4) according to ST20.

  As described above, the AP 10 (channel control unit 14) obtains the communication quality value according to the reception status of the inspection data packet transmitted from each ST 20, but the way of obtaining the communication quality value is not limited. Here, each communication quality value is represented by any value between 0 and 100, and the larger the value, the better the communication quality. Then, the AP 10 may obtain the communication quality value in consideration of, for example, the reception success rate of the inspection data packet, the reception intensity when the inspection data packet is received, and the like.

  Specifically, for example, the AP 10 causes the ST 20 to transmit 10 test data packets, and when 100% is normally received (that is, when 10 are normally received), the AP 10 sets the communication quality value. When 100% and 80% are normally received (that is, when 8 are normally received), the communication quality value is set to 80, and the communication quality value corresponding to the reception success rate of the test data packet is obtained. Anyway. Further, for example, the AP 10 may obtain a higher communication quality value as the reception intensity of the radio wave when the test data packet is received is higher. Further, the AP 10 may inspect a plurality of inspection items and obtain a communication quality value in consideration of all the inspection items (for example, set and add a weighting factor for each inspection item).

  In the processing of steps S101 to S105 described above, the AP 10 communicates with each ST 20 using each communication channel (CH1 to CH4), obtains a communication quality value based on the communication, and registers it in the communication quality management table 151. For example, in FIG. 10, the communication quality value of ST20-1 (ST name: ST1) is 90 for communication channel CH1, 70 for communication channel CH2, 100 for communication channel CH3, and 70 for communication channel CH4. ing.

  Next, the details of the process of assigning communication channels to each ST 20 by the AP 10 (channel control unit 14) (the process in step S105 described above) will be described.

  FIG. 9 is a flowchart showing details of a process for assigning a communication channel to each ST 20 by the AP 10 (channel control unit 14).

  First, the AP 10 (channel control unit 14) generates the evaluation value management table 152 based on the communication quality management table 151 (S201).

  Here, a basic policy of a method in which the AP 10 allocates a communication channel to each ST 20 will be described. The AP 10 assigns a communication channel to each ST 20 in consideration of the contents of the evaluation value management table 152. At this time, if there is an ST 20 whose communication quality value is high only in a certain communication channel, the AP 10 preferentially allocates the communication channel from such ST 20. For example, in the example illustrated in FIG. 10, when the communication quality values of the communication channels (CH1 to CH4) according to ST20-4 are compared, only the communication channel CH3 has a relatively high communication quality value, and the remaining communication channels have the communication quality. The value tends to be relatively low. In such a case, it is desirable that the AP 10 preferentially assigns the communication channel CH3 to the ST 20-4, because communication is improved for more STs 20.

  Then, the AP 10 obtains a value (hereinafter referred to as “evaluation value”) for evaluating the order for assigning communication channels based on the communication quality management table 151, and creates the evaluation value management table 152 (S202).

  FIG. 11 is an explanatory diagram showing an example of the contents of the evaluation value management table 152.

  The evaluation value management table 152 has information on ST name and evaluation value items.

  The item “ST name” indicates information for identifying each ST, and is the same as the communication quality management table 151. In the evaluation value management table 152, evaluation value information corresponding to each ST name (ST20) is registered.

  The item “evaluation value” indicates an evaluation value for each communication channel (CH1 to CH4) according to ST20.

  Here, it is assumed that the evaluation value is obtained by the AP 10 using the “calculation formula that increases the evaluation value when the communication quality is high only in the target communication channel”. Specifically, the AP 10 may obtain an evaluation value using, for example, the following expression (1). In the equation (1), the evaluation value E indicates an evaluation value for any communication channel according to any ST20. In the following equation (1), the communication quality value Vo indicates the communication quality value of an arbitrary communication channel according to ST20. Moreover, the average communication quality value Vm has shown the average value of the communication quality value of all the communication channels with respect to the said ST20.

Evaluation value E = communication quality value Vo / average communication quality value Vm (1)
As an example, a case will be described in which an evaluation value related to each communication channel of ST20-4 (ST name: ST4) is calculated using the above equation (1). Here, it is assumed that the content of the communication quality management table 151 is the content of FIG. 10 described above. In this case, the average communication quality value Vm of ST20-4 is 27.5 as shown in the following equation (2). Then, the evaluation value E of the communication channel CH1 in ST20-4 is about 0.36 as shown in the following equation (3). Similarly, when the evaluation value E is calculated for the communication channels CH2 to CH4 of ST20-4, the result is as shown in FIG. As shown in FIG. 11, evaluation values E relating to communication channels CH2 to CH4 in ST20-4 are 0.36, 2.91, and 0.36, respectively. Similarly for other ST20, when the evaluation value E is calculated based on the communication quality management table 151 shown in FIG. 10, the content shown in FIG. 11 is obtained.

Average communication quality value Vm
= (Communication quality value of radio channels CH1 to CH4) / number of channels = (10 + 10 + 80 + 10) /4=110/4=27.5 (2)
Evaluation value E of communication channel CH4
= Communication quality value of radio channel CH4 / average communication quality value Vm
= 10 / 27.5 ≒ 0.36
In the communication quality management table 151 (see FIG. 10), the communication quality values related to the communication channels CH1 to CH4 of ST20-4 are 10, 10, 80, and 10, respectively, and the communication channels CH1, CH2, and CH4 Although the communication quality value is low, only the communication channel CH3 has a high communication quality value. In the evaluation value management table 152 (see FIG. 11), the evaluation values related to the communication channels CH1 to CH4 in ST20-4 are 0.36, 0.36, 2.91, and 0.36, respectively. .

  On the other hand, the communication quality values related to the communication channels CH1 to CH4 of ST20-1 are 90, 70, 100, and 70, respectively, and the communication quality values are good at 70 or more in all the communication channels. Accordingly, in ST20-1, the communication quality value of the communication channel CH3 is 100, which is the channel with the best communication quality, but other communication channels also have high communication quality values, so the evaluation value tends to be low. .

  Therefore, it can be seen from the above equation (1) that the above-described calculation formula “the evaluation value is high when the communication quality is high only in the target communication channel” can be realized. In other words, in the AP 10, the communication quality value for each combination of ST20 and the communication channel, and the communication quality value of other communication channels of ST20 related to the communication quality value, according to the above equation (1), It can be said that the evaluation value is calculated in consideration of the result of comparing.

  Then, when generating the evaluation value management table 152, the AP 10 (channel control unit 14) generates an allocation order evaluation table 153 sorted in descending order of evaluation values for each combination of ST name and communication channel (S203). ).

  FIG. 12 is an explanatory diagram showing an example of the contents of the allocation order evaluation table 153.

  In the allocation order evaluation table 153, as shown in FIG. 12, information on evaluation values and communication quality is registered for each combination of ST name and communication channel, and further sorted in descending order using the evaluation values as keys. .

  The allocation rank evaluation table 153 includes information on items of rank, evaluation value, ST name, communication channel, and communication quality value.

  The items “ST name” and “communication channel” indicate combinations of ST names and communication channels.

  The “evaluation value” item indicates an evaluation value related to the combination (value of the evaluation value management table 152).

  The item “communication quality value” indicates a communication quality value (value of the communication quality management table 151) related to the combination.

  The item “rank” indicates the rank based on the evaluation value related to the combination. Here, since there are four ST20 and four communication channels, the number of combinations of ST names and communication channels is 16. Therefore, as shown in FIG. 12, any one of the ranks 1 to 16 is registered in the rank item.

  Then, the AP 10 (channel control unit 14) determines the communication channel used by each ST 20 in accordance with the order of the allocation order evaluation table 153, and registers the determined content in the ST management table 154 (S204).

  Specifically, the AP 10 assigns communication channels related to the combination in order from the ST 20 related to the combination having the highest order in the assignment order evaluation table 153. In other words, the AP 10 preferentially assigns a communication channel with a better communication quality as the ST 10 in which a communication quality value having a higher evaluation value is measured.

  Next, a specific example in which the AP 10 (channel control unit 14) allocates a communication channel to each ST 20 will be described with reference to FIG. In the allocation rank evaluation table 153, the rank “1” is a combination of ST20-4 and communication channel CH3. Therefore, AP 10 first decides to allocate communication channel CH3 to ST20-4. In the allocation rank evaluation table 153, the rank “2” is a combination of ST20-3 and communication channel CH4. Therefore, AP10 next determines to allocate communication channel CH4 to ST20-3. In the allocation rank evaluation table 153, the rank “3” is a combination of ST20-2 and communication channel CH3. However, since communication channel CH3 is already occupied by ST20-4, AP 10 skips the process of this combination. In the allocation rank evaluation table 153, the rank “4” is a combination of ST20-3 and communication channel CH2. However, since the use of the communication channel CH4 is already determined in ST20-3, the AP 10 skips this combination process. In the allocation rank evaluation table 153, the rank “5” is a combination of ST20-2 and communication channel CH2. Here, AP10 determines to allocate communication channel CH2 to ST20-2. In the allocation rank evaluation table 153, the rank “6” is a combination of ST20-1 and communication channel CH3. Here, AP10 determines to allocate communication channel CH1 to ST20-1.

  As described above, the AP 10 (channel control unit 14) performs a process of assigning a communication channel to each ST 20, and determines a combination of communication channel assignments in which the communication quality of more STs 10 is good. Then, the AP 10 (channel control unit 14) performs processing for registering the allocation result in the ST management table 154.

  FIG. 13 is an explanatory diagram showing an example of the contents of the ST management table 154.

  In the ST management table 154, communication channels and communication quality values assigned for each ST name are registered.

  As shown in FIG. 13, the allocation order evaluation table 153 includes information on items of ST name, communication channel, and communication quality value.

  The item “ST name” indicates the identification name of ST20.

  The item “communication channel” indicates a communication channel assigned to the ST 20.

  “Communication quality value” indicates the communication quality value (value of the communication quality management table 151) related to the communication channel assigned to the ST20.

  When the AP 10 performs processing for assigning a communication channel to each ST 20 based on the above-described assignment order evaluation table 153 shown in FIG. 12, the contents of the ST management table 154 are as shown in FIG.

(A-3) Effects of Embodiment According to this embodiment, the following effects can be achieved.

  In the wireless communication system 1, the AP 10 manages communication quality values for each combination of ST20 and communication channels. Then, when the AP 10 assigns a communication channel to each ST 20 and there is an ST 20 whose communication quality is high only in the target communication channel, the use of the target communication channel is preferentially determined from such ST 20. I take the way to go. Thereby, in the radio | wireless communications system 1, the bias of the communication quality of each ST20 can be eliminated, and a communication channel can be allocated efficiently.

(B) Other Embodiments The present invention is not limited to the above-described embodiments, and may include modified embodiments as exemplified below.

(B-1) In the wireless communication system 1 of the above-described embodiment, the FTDMA method is used in which slots in which the frequency domain and the time domain are logically divided are assigned to each ST20. It may be divided only in the frequency domain (communication channel), and each communication channel may be assigned to one or a plurality of ST20.

(B-2) In the above embodiment, the ST 20 has been described as communicating with the AP 10. However, the ST 20 itself may function as an access point and accommodate other nodes (such as ST 20).

(B-3) In the above embodiment, each ST 20 has been described as generating and transmitting a test data packet when a communication channel instruction packet is received, but explicitly generating a test data packet. It may not be performed. For example, an ST data packet for transmitting a main signal (for example, data based on a higher-order application) transmitted from each ST 20 to the AP 10 may be used as an inspection data packet.

(B-4) In the above embodiment, the measurement of communication quality is performed on the AP 10 side, but it may be performed on the ST 20 side and the result may be reported to the AP 10. Further, the AP 10 may measure the communication quality on both sides of the AP 10 and the ST 20 and obtain a communication quality value based on both results (for example, obtain an average value of two communication qualities).

  DESCRIPTION OF SYMBOLS 1 ... Wireless communication system, 10 ... AP (access point), 11 ... Transmission part, 12 ... Reception part, 13 ... Transmission / reception control part, 14 ... Channel control part, 15 ... Data storage part, 151 ... Communication quality management table, 152 ... evaluation value management table, 153 ... allocation order evaluation table, 154 ... ST management table, 20, 20-1 to 20-4 ... ST (station terminal).

Claims (4)

In a wireless access point device that communicates with a plurality of wireless communication devices,
Communication quality value acquisition means for controlling each of the wireless communication devices, communicating using a plurality of wireless channels, and obtaining a communication quality value related to communication quality for each wireless channel with each of the wireless communication devices;
Based on the communication quality value obtained by the communication quality value acquisition means, a combination of communication channels to be assigned to each of the wireless communication devices is determined, and more wireless communication devices and wireless access points Communication channel assignment determining means for determining a combination that provides good communication with the apparatus;
In accordance with the content determined by the communication channel assignment determining means, a communication channel notifying means for notifying each wireless communication device of a communication channel to be used with the wireless access point device,
Using a communication channel according to the content determined by the communication channel allocation determining means, and a data transmitting / receiving means for transmitting / receiving data to / from each of the wireless communication devices,
The communication channel allocation determining means calculates a communication quality value for each combination of each wireless communication device and each communication channel, and for each of the calculated communication quality values, the communication quality value and the communication quality An evaluation value that considers the relationship with the communication quality value of the other communication channel of the wireless communication device related to the value is calculated, and the wireless communication device related to the communication quality value having a higher calculated evaluation value is preferentially used for the communication channel. There line of allocation,
The wireless access point device, wherein the communication channel assignment determining means obtains an evaluation value based on a reference value that is different for each wireless communication device. The reference value used for calculating the evaluation value by the communication channel allocation determining means is an average value of communication quality values related to the wireless communication device that is a target of evaluation value calculation among the calculated communication quality values. The wireless access point device according to claim 1 . A wireless communication device that wirelessly communicates with the wireless access point device according to claim 1,
A wireless communication apparatus, comprising: a data transmission / reception unit configured to transmit / receive data to / from the wireless access point apparatus using a wireless channel notified from the wireless access point apparatus among a plurality of wireless channels. In a wireless communication system comprising a plurality of wireless communication devices and one or more wireless access point devices that wirelessly communicate with the wireless communication device,
Applying the wireless access point device according to claim 1 or 2 as the wireless access point device,
A wireless communication system, wherein the wireless communication device according to claim 3 is applied as each of the wireless communication devices.

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