JP2019114899A - Network controller and slot allocation method - Google Patents

Abstract

To provide a network controller and a slot allocation method arranged to prevent reduction of throughput and collision of data.SOLUTION: A network controller for controlling multiple pieces of radio communication equipment includes an external transceiver function part for receiving a first reception level in second radio communication equipment for the first signal transmitted from the first radio communication equipment, and a second reception level in fourth radio communication equipment for the second signal transmitted from the third radio communication equipment, respectively, from the first and third radio communication equipment, and a network control section for allocating the first communication and the second communication to the same communication slot of the same radio frame, when a determination is made that interference does not occur between the first communication of the first radio communication equipment and the second radio communication equipment, and the second communication of the third radio communication equipment and the fourth radio communication equipment, on the basis of the first and second reception levels.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a network control device and a slot allocation method.

  Currently, terminal devices (or users) can use not only a radio access scheme by Long Term Evolution (LTE), but also a radio access scheme by a wireless Local Area Network (LAN). Wireless LAN is, for example, a wireless access method whose specifications have been reviewed by the Institute of Electrical and Electronic Engineers (IEEE). Examples of the wireless LAN include IEEE 802.11ac (or VHT (Very High Throughput)) and IEEE 802.11n.

  In a wireless access method using a wireless LAN, a carrier sense multiple access / collision detection (CSMA / CA) method may be used. The CSMA / CA scheme is, for example, a communication scheme combining a carrier sense scheme and a collision avoidance algorithm. In the CSMA / CA method, for example, an AP (Access Point: Access Point) (or a master station) performs carrier sensing in a DIFS (Distributed Inter Frame Space) period, and thereafter, performs data sensing on a terminal (or Station or a slave station). It becomes possible to transmit to.

  In the carrier sense scheme such as the CSMA / CA scheme, a hidden terminal problem may occur. The hidden terminal problem is, for example, a problem that a signal collision occurs in the master station when two slave stations are out of reach of each other and both transmit signals simultaneously.

  For the hidden terminal problem, the IEEE has defined RTS (Request to Send) / CTS (Clear to Send) scheme (sometimes called "CSMA / CA with RTS / CTS"). In the RTS / CTS method, for example, an RTS frame is transmitted to the master station, a transmission priority is given to a slave station that has received a CTS frame from the master station, and a slave station that receives a CTS frame without transmitting an RTS frame Transmission priority does not occur. Therefore, even if the former slave station and the latter slave station are out of the reach of the signal, the former slave station can transmit the signal, and the latter slave station can not transmit the signal. There is no collision.

  In addition, in the CSMA / CS method, an exposed terminal problem may occur. In the exposed terminal problem, for example, when two slave stations are located within the reach of a signal, the other slave station detects the signal transmitted by one slave station to the master station, and the other slave station detects the signal. It is a problem that can not be transmitted to other master stations. Due to the exposed terminal problem, for example, the data transmission of the other slave station can not be transmitted, and the throughput may be reduced.

  Examples of such wireless communication technology include the following. That is, a cooperative BSS group is constructed by a plurality of BSSs (Basic Service Set), and based on traffic information and channel information of each terminal, a radio resource is allocated to improve the communication quality index in units of the cooperative BSS group, and allocation results There is a master base station that notifies the slave base station and the terminal station.

  According to this technology, it is possible to ensure high communication quality and to suppress a decrease in throughput.

  Further, there is a wireless communication system in which a wireless base station obtains the maximum number of sharing based on the number of wireless terminals (the number of multiplexing), and allocates a slot less than the maximum number of sharing as a speech slot.

  According to this technology, a plurality of mobile stations can share and use one communication channel up to the upper limit thereof, so that it is possible to achieve effective use of frequency.

  Furthermore, unused time zones other than downlink and uplink channel time zones in the frame are calculated, and based on the calculation results, if there is an unused time zone in the frame, for retransmission of downlink or uplink data. There is a transmitting / receiving device that assigns a data time zone to an unused time zone.

  According to this technique, it is possible to improve transmission efficiency and reduce transmission delay time.

JP, 2016-19239, A Japanese Patent Laid-Open No. 2000-106690 JP 2004-247830 A

  However, techniques for allocating radio resources such that the master base station improves the communication quality indicator in units of coordinated BSSs have not been discussed, for example, for the relationship between coordinated BSSs. Therefore, communication between a base station and a terminal belonging to a certain coordinated BSS group may interfere with communication between a base station and another terminal belonging to another coordinated BSS group. Due to the occurrence of interference, retransmission may occur in both communications, and the throughput of the entire system may be reduced.

  Furthermore, the above-mentioned technology for allocating a slot less than the maximum number of shared slots to a terminal as a talk slot is discussed at all in regard to how to cope with interference to two communications between base stations. Absent. Furthermore, the above-mentioned technique for allocating a data time zone for retransmission of downlink or uplink data to an unused time zone is likewise not discussed at all. Thus, these techniques may reduce throughput.

  Therefore, in one aspect, it is an object of the present invention to provide a network control device and a slot allocation method that are designed to prevent a decrease in throughput.

  Another aspect of the present invention is to provide a network control device and a slot allocation method that prevent data collisions.

  In one aspect, in a network control device for controlling a plurality of wireless communication devices, a first reception level in a second wireless communication device for a first signal transmitted from the first wireless communication device; An external transmission / reception function of receiving, from the first wireless communication device and the third wireless communication device, the second reception level in the fourth wireless communication device with respect to the second signal transmitted from the wireless communication device A first communication between the first wireless communication device and the second wireless communication device based on the first and second reception levels, the first wireless communication device, and the third wireless communication device; And a network control unit that assigns the first and second communications to the same communication slot of the same wireless frame when it is determined that no interference occurs with the fourth communication with the second communication with the fourth wireless communication apparatus. ,Previous External transceiver function unit transmits the information about the allocated communication slot to the first and third wireless communication device.

  In one aspect, it is possible to improve throughput. In one aspect, it is possible to prevent data collisions.

FIG. 1 is a diagram illustrating an exemplary configuration of a wireless communication system. FIG. 2 is a diagram illustrating an exemplary configuration of an AP. FIG. 3 is a diagram illustrating an exemplary configuration of the AP and the STA. FIG. 4 is a diagram showing an example of the configuration of a network control apparatus. FIG. 5A shows an example of the hardware configuration of the AP, and FIG. 5B shows an example of the hardware configuration of the AP and the STA. FIG. 6 is a diagram illustrating an exemplary configuration of a frame. FIG. 7 is a diagram illustrating an exemplary configuration of a frame. FIG. 8 is a diagram illustrating a configuration example of a wireless communication system. FIG. 9 is a sequence diagram showing an operation example. FIG. 10 is a sequence diagram showing an operation example. FIG. 11A to FIG. 11F are diagrams showing examples of slot allocation. FIG. 12A to FIG. 12F are diagrams showing an example of slot assignment. FIG. 13A to FIG. 13F are diagrams showing an example of slot assignment. FIGS. 14A to 14F are diagrams showing examples of slot allocation. FIGS. 15A to 15F are diagrams showing examples of slot allocation. FIG. 16A to FIG. 16F are diagrams showing an example of slot assignment. FIGS. 17A to 17F are diagrams showing examples of slot allocation. 18 (A) to 18 (F) are diagrams showing examples of slot assignment.

  Hereinafter, the present embodiment will be described in detail with reference to the drawings. The problems and examples in the present specification are examples and do not limit the scope of the present application. And each embodiment can be combined suitably in the range which does not make processing contents contradictory. Moreover, the term and technical content which were described in the specification as a standard regarding communication, such as IEEE, may be used suitably about the term used and the technical content which were described in this specification.

First Embodiment
<Configuration Example of Wireless Communication System>
FIG. 1 is a diagram illustrating a configuration example of a wireless communication system 10 according to the first embodiment. The wireless communication system 10 includes a plurality of APs 100-1 to 100-4, a plurality of STAs (Stations) 200-1 to 200-3, a switching hub 300, and a network control apparatus 400.

  The APs 100-1 to 100-4 are, for example, wireless communication devices capable of wireless communication with other APs 100-1 to 100-4 and STAs 200-1 to 200-3. At this time, the APs 100-1 to 100-4 perform wireless communication using, for example, carrier sense. The carrier sense is, for example, a communication scheme in which the AP 100-1 to 100-4 detects the use status of the frequency and prevents a plurality of carriers (or carriers) from being transmitted on the same frequency. For example, when the reception level of signals transmitted from the other APs 100-1 to 100-4 and STAs 200-1 to 200-3 is lower than the carrier sense threshold, the APs 100-1 to 100-4 transmit Send, otherwise do not send these. An example of the carrier sense is the CSMA / CA method described above.

  The AP 100-1 is connected to the switching hub 300 by wire. For example, the AP 100-1 receives data, messages, and the like transmitted from the APs 100-2 to 100-4, and transmits the received data, messages, and the like to the switching hub 300. Also, the AP 100-1 receives, for example, data, messages, and the like transmitted from the switching hub 300, and transmits the received data and the like to the APs 100-2 to 100-4.

  Also, the APs 100-2 to 100-4 receive, for example, data, messages, and the like transmitted from the AP 100-1, and transmit the received data and the like to the STAs 200-1 to 200-3. Further, the APs 100-2 to 100-4 receive, for example, data and messages transmitted from the STAs 200-1 to 200-3, and transmit the received data and the like to the AP 100-1.

  Further, wireless communication is also possible between the AP 100-2 and the AP 100-3, and between the AP 100-3 and the AP 100-4.

  The STAs 200-1 to 200-3 are, for example, wireless communication apparatuses or terminal apparatuses capable of wireless communication with the APs 100-2 to 100-4. The STAs 200-1 to 200-3 are, for example, a smartphone, a feature phone, a tablet terminal, a personal computer capable of wireless communication, a wireless tag attached to a product, and the like. The STAs 200-1 to 200-3 also perform wireless communication using, for example, carrier sense.

  The switching hub 300 transmits data, messages and the like transmitted from the AP 100-1 to the network control apparatus 400, and transmits data, messages and the like transmitted from the network control apparatus 400 to the AP 100-1.

  The network control apparatus 400 controls, for example, communication between the APs 100-2 to 100-4 and the STAs 200-1 to 200-3 via the AP 100-1. Specifically, for example, the network control apparatus 400 performs communication for communication between the APs 100-1 to 100-4 and communication between the APs 100-1 to 100-4 and the STAs 200-1 to 200-3. Allocate a slot. Details will be described in the operation example.

<Configuration Example of AP100-1>
FIG. 2 is a diagram illustrating a configuration example of the AP 100-1.

  The AP 100-1 includes an antenna 101-1, a radio unit 102-1, a demodulation unit 103-1, a reception queue control unit 104-1, a reception queue 105-1, a synchronization function unit 106-1, and a periphery measurement function unit 107-1. , An external transmission / reception function unit 108-1. Also, the AP 100-1 includes a timing generation unit 109-1, a channel control unit 110-1, a transmission queue control unit 111-1, a transmission queue 112-1, and a modulation unit 113-1.

  The antenna 101-1 receives the wireless signals transmitted from the APs 100-2 to 100-4, and outputs the received wireless signals to the wireless unit 102-1. Also, the antenna 101-1 outputs the wireless signal output from the wireless unit 102-1 to the APs 100-2 to 100-4.

  The radio unit 102-1 converts (down-converts) the radio signal received from the antenna 101-1 into a baseband signal of the baseband band, and outputs the converted baseband signal to the demodulation unit 103-1. Also, the wireless unit 102-1 converts (up-converts) the baseband signal received from the modulation unit 113-1 into a wireless signal in the wireless band, and outputs the converted wireless signal to the antenna 101-1.

  The wireless unit 102-1 may measure the received signal level of the received wireless signal. In this case, the radio unit 102-1 outputs the measured received signal level to the channel control unit 110-1. As the reception level, for example, there are a received power value and a received signal strength indication (RSSI).

  Demodulation section 103-1 performs demodulation processing and the like on the baseband signal received from radio section 102-1 in accordance with the radio channel indication signal from channel control section 110-1 to extract a beacon signal, message, etc. . The wireless channel instruction signal includes, for example, information on a wireless channel (or frequency) used by the AP 100-1 when performing wireless communication. The information on the radio channel may be, for example, information on the radio channel instructed by the network control apparatus 400, or information on the radio channel extracted by the channel control unit 110-1 performing carrier sense.

  Further, demodulation section 103-1 performs demodulation processing on the baseband signal according to the instruction information from periphery measurement function section 107-1, and extracts messages of radio channels other than the radio channel included in the radio channel information. Do. The instruction information includes, for example, radio channel information other than the radio channel information.

  The demodulation unit 103-1 outputs the demodulated message or the like to the reception queue control unit 104-1, and outputs the demodulated beacon signal to the synchronization function unit 106-1. Further, the demodulation unit 103-1 outputs a message transmitted by a wireless channel other than the wireless channel to the periphery measurement function unit 107-1.

  Reception queue control section 104-1 stores the message etc. received from demodulation section 103-1 in reception queue 105-1, reads the message etc stored in reception queue 105-1 and transmits external transmission / reception function section 108-. Output to 1.

  The reception queue 105-1 stores the demodulated message and the like.

  The synchronization function unit 106-1 generates a reference signal based on the beacon signal received from the demodulation unit 103-1, and outputs the generated reference signal to the timing generation unit 109-1. The reference signal may be based on, for example, the timing at which the AP 100-1 receives the beacon signal (or the timing at which the antenna 101-1 receives the beacon signal).

  The peripheral measurement function unit 107-1 outputs the instruction information to the demodulation unit 103-1, and receives a message or the like corresponding to the instruction information from the demodulation unit 103-1. The peripheral measurement function unit 107-1 outputs the received message or the like to the external transmission / reception function unit 108-1.

  The external transmission / reception function unit 108-1 converts a message or the like received from the reception queue control unit 104-1 into packet data of a format that can be transmitted to the switching hub 300, and transmits the converted packet data to the switching hub 300. .

  Further, the external transmission / reception function unit 108-1 receives packet data transmitted from the network control apparatus 400 via the switching hub 300, and extracts a message or the like from the received packet data. The external transmission / reception function unit 108-1 outputs the extracted message or the like to the transmission queue control unit 111-1. In this case, the external transmission / reception function unit 108-1 outputs, for example, messages addressed to the other APs 100-2 to 100-4 and messages addressed to the STAs 200-1 to 200-3 to the transmission queue control unit 111-1. . Also, the external transmission / reception function unit 108-1 outputs, for example, radio channel information in the message addressed to the own station to the channel control unit 110-1, and outputs transmission slot information to the timing generation unit 109-1. The transmission slot information is, for example, information on a communication slot allocated by the network control device 400 to the AP 100-1.

  The timing generation unit 109-1 outputs a timing signal corresponding to the reference signal received from the synchronization function unit 106-1 to the transmission queue control unit 111-1. The timing signal in this case is, for example, a timing synchronized with the beacon signal, and indicates timing such as the beginning of a frame.

  Further, the timing generation unit 109-1 extracts transmission slot information received from the external transmission / reception function unit 108-1, generates a transmission instruction signal based on the extracted transmission slot information, and transmits the transmission queue control unit 111-1. Output to The transmission instruction signal indicates, for example, the transmission timing of the communication slot that the network control apparatus 400 has instructed (or assigned) to the AP 100-1.

  The channel control unit 110-1 extracts radio channel information from the message received from the external transmission / reception function unit 108-1. The channel control unit 110-1 outputs a radio channel indication signal corresponding to the extracted radio channel information to the demodulation unit 103-1 and the modulation unit 113-1.

  Also, for example, the channel control unit 110-1 receives the reception level of the wireless signal from the wireless unit 102-1, and performs carrier sensing such as the CSMA / CA method based on the reception level. If there is a wireless channel that can be used by AP 100-1 as a result of carrier sensing, channel control unit 110-1 generates a wireless channel indication signal indicating the wireless channel, and demodulation unit 103-1 or modulation unit 113-1 Output to The channel control unit 110-1 controls the wireless channel when the AP 100-1 performs wireless communication, for example, by outputting a wireless channel instruction signal to the demodulation unit 103-1 and the modulation unit 113-1.

  The transmission queue control unit 111-1 starts operations of the transmission queue control unit 111-1 and the transmission queue 112-1, for example, in synchronization with the timing signal received from the timing generation unit 109-1. The transmission queue control unit 111-1 may output this timing signal as the beacon signal of the own AP 100-1 to the modulation unit 113-1. After that, the transmission queue control unit 111-1 may store the message received from the external transmission / reception function unit 108-1 in the transmission queue 112-1.

  Also, for example, the transmission queue control unit 111-1 outputs the message received from the external transmission / reception function unit 108-1 to the modulation unit 113-1 in synchronization with the transmission instruction signal received from the timing generation unit 109-1. Or reads a message from the transmission queue 112-1 and outputs the message to the modulation unit 113-1. Thus, the AP 100-1 can transmit a message or the like to the APs 100-2 and 100-3 and the APs 200-1 to 200-4 using the transmission slots allocated by the network control apparatus 400.

  The transmission queue 112-1 is, for example, a memory that stores messages and the like.

  Modulating section 113-1 performs modulation processing on a message or beacon signal received from transmission queue control section 111-1 in accordance with the radio channel indication signal from channel control section 110-1 to generate a baseband signal. . As a result, the AP 100-1 can transmit a wireless signal using the wireless channel instructed from the network control apparatus 400 or the wireless channel extracted by performing carrier sense. Modulating section 113-1 outputs the generated baseband signal to radio section 102-1.

<Configuration Example of AP 100-2, 100-3, ... and STA 200-1, 200-2, ...>
In the first embodiment, APs 100-2, 100-3,... And STAs 200-1, 200-2,. FIG. 3 representatively shows a configuration example of the AP 100-2 or the STA 200-1.

  The AP 100-2 includes an antenna 101-2, a radio unit 102-2, a demodulation unit 103-2, a reception queue control unit 104-2, a reception queue 105-2, a synchronization function unit 106-2, and a periphery measurement function unit 107-2. Equipped with The AP 100-2 further includes a timing generation unit 109-2, a channel control unit 110-2, a transmission queue control unit 111-2, a transmission queue 112-2, and a modulation unit 113-2. The AP 100-2 further includes an application processing unit 120-2.

  For example, in the example of FIG. 1, the AP 100-2 performs wireless communication with the AP 100-1, AP 100-3, STA 200-1, or STA 200-2, so the antenna 101-2 communicates with the AP or STA. Send and receive wireless signals.

  In this case, for example, the wireless unit 102-2 measures the reception level of the beacon signal transmitted from the AP 100-1 and the AP 100-3, and outputs the measured reception level to the application processing unit 120-2. The reception level includes, for example, a reception power value, an RSSI, and the like.

  The application processing unit 120-2 generates a message including the reception level, and transmits the generated message to the AP 100-1 and the AP 100-3 via the transmission queue control unit 111-2 and the like.

  Further, the application processing unit 120-2 executes application processing on the message received from the reception queue control unit 104-2 when the message is addressed to the own station AP 100-2.

  Furthermore, the application processing unit 120-2 outputs a message addressed to the own station to the channel control unit 110-2 and the timing generation unit 109-2. In this case, channel control section 110-2 extracts radio channel information from the message, and outputs a radio channel instruction signal indicating the radio channel instructed by network control apparatus 400 to demodulation section 103-2 and modulation section 113-2. Do. Also, in this case, the timing generation unit 109-2 extracts the information on the transmission slot allocated to the AP 100-2 by the network control apparatus 400 from the message addressed to the local station, and transmits the transmission instruction signal indicating the information on the transmission slot. It is output to the queue control unit 111-2. As a result, the AP 100-2 can transmit a message or the like using the transmission slot allocated by the network control device 400.

  In the STA 200-1, for example, in the example of FIG. 1, since the wireless communication is performed with the AP 100-2 and the AP 100-3, the antenna 101-2 transmits and receives a wireless signal to and from the AP 100-2 and the AP 100-3. The application processing unit 120-2 also performs processing related to the application to a message addressed to the STA 200-1 or the like, or outputs a message addressed to the own station to the channel control unit 110-2 or the timing generation unit 109-1. Do. The timing generation unit 109-1 extracts information on the transmission slot allocated to the STA 200-1 by the network control apparatus 400 from the message addressed to the own station, and outputs a transmission instruction signal to the transmission queue control unit 111-2. As a result, the STA 200-1 can transmit a message or the like using the transmission slot allocated by the network control apparatus 400.

  In the following, unless otherwise noted, the APs 100-1 to 100-4 may be referred to as the AP 100, and the STAs 200-1 to 200-3 may be referred to as the STA 200.

<Network control device 400>
FIG. 4 is a diagram illustrating a configuration example of the network control device 400.

  The network control device 400 includes an external transmission / reception function unit 410, a network control unit 420, and a memory 430.

  The external transmission / reception function unit 410 exchanges packet data with the AP 100-1 via the switching hub 300. For example, upon receiving packet data transmitted from the AP 100-1 via the switching hub 300, the external transmission / reception function unit 410 extracts a message etc. from the received packet data, and outputs the extracted message etc. to the network control unit 420. Do. Further, for example, the external transmission / reception function unit 410 generates packet data including a message for the message received from the network control unit 420, and transmits the generated packet data to the AP 100-1 via the switching hub 300. .

  The network control unit 420 assigns slots to the communication in the AP 100 and the STA 200. For example, when the network control unit 420 receives a slot allocation request message of the AP 100 or the STA 200 from the external transmission / reception function unit 410, the network control unit 420 allocates a slot to the AP 100 or the STA 200. Then, the network control unit 420 generates a message including information on the assigned slot, and outputs the generated message to the external transmission / reception function unit 410. Details will be described in the operation example.

  The memory 430 appropriately stores, for example, information and data when the network control unit 420 performs processing.

<Example of hardware configuration of AP100-1>
FIG. 5A is a diagram illustrating an example of a hardware configuration of the AP 100-1.

  The AP 100-1 further includes a central processing unit (CPU) 130-1, a read only memory (ROM) 131-1, a random access memory (RAM) 132-1, a digital signal processor (DSP) 133-1, an IF Face) 134-1.

  The CPU 130-1 reads the program stored in the ROM 131-1, loads the program into the RAM 132-1, and executes the loaded program, whereby the reception queue control unit 104-1, synchronization function unit 106-1, peripheral measurement The function of the function unit 107-1 is realized. In addition, the CPU 130-1 realizes the functions of the timing generation unit 109-1, the channel control unit 110-1, and the transmission queue control unit 111-1 by executing such a program. Therefore, for example, the CPU 130-1 is, for example, the reception queue control unit 104-1, the synchronization function unit 106-1, the periphery measurement function unit 107-1, the timing generation unit 109-1, the channel control unit 110-1, the transmission queue control unit It corresponds to 111-1.

  Also, the DSP 133-1 corresponds to, for example, the demodulation unit 103-1 and the modulation unit 113-1. Furthermore, the IF 134-1 corresponds to, for example, the external transmission / reception function unit 108-1.

  FIG. 5B is a diagram illustrating an example of a hardware configuration of the AP 100-2,... Or the STAs 200-1, 200-1,. FIG. 5B representatively shows a hardware configuration example of the AP 100-2 or the STA 200-1.

  The AP 100-1 or STA 200-1 further includes a CPU 130-2, a ROM 131-2, a RAM 132-2, and a DSP 133-2.

  The CPU 130-2 reads the program stored in the ROM 131-2, loads the program into the RAM 132-2, and executes the loaded program to receive the reception queue control unit 104-2, the synchronization function unit 106-2, and the peripheral measurement function. The function of the unit 107-2 is realized. In addition, the CPU 130-2 implements the functions of the timing generation unit 109-2, the channel control unit 110-2, the transmission queue control unit 111-2, and the application processing unit 120-2 by executing such a program. Do. For example, the CPU 130-2 is, for example, a reception queue control unit 104-2, a synchronization function unit 106-2, a periphery measurement function unit 107-2, a timing generation unit 109-1, a channel control unit 110-2, a transmission queue control unit 111-. 2 and the application processing unit 120-2.

  Also, the DSP 133-2 corresponds to, for example, the demodulation unit 103-2 and the modulation unit 113-2.

  Note that, instead of the CPUs 130-1 and 130-2, a processor or a controller such as a micro processing unit (MPU), a DSP, or a field programmable gate array (FPGA) may be used.

<Configuration Example of Wireless Frame>
6 and 7 are diagrams showing an example of the configuration of a radio frame (hereinafter sometimes referred to as "frame") in the first embodiment. FIG. 6 shows an example of the configuration of a frame, and FIG. 7 shows another example of the configuration of the frame.

  As shown in FIG. 6, a frame used in the first embodiment is called a super frame. The super frame includes two frames (frame #n and frame # (n + 1)). The two frames are frames in the uplink direction (direction from STA 200 to AP 100) and in the downlink direction (direction from AP 100 to STA 200). For example, the nth frame (frame #n) is a downlink direction, and the (n + 1) th frame (frame # (n + 1)) is an uplink frame.

  The n-th frame (frame #n) includes two types of slots: a time division multiple access (DA) slot and a carrier sense multiple access (CS) slot.

  The DA slot is, for example, a slot assigned by the network control apparatus 400. Therefore, the AP 100 and the STA 200 perform wireless communication with the other AP 100 and the other STA 200 using the slot assigned to the own station. Therefore, the RTS / CTS method is not used in the DA slot, and after performing carrier sensing in a short inter frame space (SIFS) period from the slot start timing, the transmitting side transmits transmission data, and the SIFS period has elapsed. After that, the receiving side transmits an ACK (Acknowledge) signal. The DA slot is, for example, a slot that can be assigned by the network control apparatus 400, and is also a slot that can be used by the AP 100 and the STA 200 in time division.

  For example, the CS slot is a slot that can be used in common by the AP 100 and the STA 200 without being allocated by the network control device 400. The AP 100 and the STA 200 wirelessly communicate with other APs 100 and other STAs 200 using available slots according to the RTS / CTS method. Therefore, in the CS slot, after an SIFS period has elapsed from the slot start timing, the transmitting side transmits an RTS signal, and after the SIFS period has elapsed, the receiving side transmits a CTS signal, and then the transmitting side transmits data. Is sent.

  In the (n + 1) th frame, the order of the DA slot and the CS slot is reversed with respect to the nth frame. This is because, for example, in order to perform the procedure of SIFS → RTS → SIFS → CTS → SIFS → transmission data → SIFS → ACK, it takes time to access as compared with the DA slot, so these are grouped into one and accessed. To ensure time for

  Also, the number of slots included in the DA slot and the CS slot is, for example, the same in the entire wireless communication system 10, but the DA slot is variable depending on the number of STAs 200 (or the number of users) accommodated in the entire wireless communication system 10. It is also possible. The number of DA slots and the number of CS slots, for example, are set by the network control device 400, for example, and transmitted to the AP 100 using a beacon signal.

  Furthermore, in the DA slot and the CS slot, retransmission is performed using the retransmission slot.

  Furthermore, in the DA slot, transmission of transmission data and transmission of retransmission data are performed for each slot. On the other hand, in the CS slot, a procedure according to the RTS / CTS method is included, and access takes time, so one CS group is formed by a plurality of slots for the purpose of distributing APs 100 and STAs 200 to access. The network control apparatus 400 assigns the CS group to the AP 100 and the STA 200, and transmission data, retransmission data, and the like are transmitted.

  FIG. 7 shows an example in which all frames in a superframe are CS slots. As shown in FIG. 7, transmission and retransmission are performed in CS group units, and in each CS group, the procedure of SIFS → RTS → SIFS → ... → ACK is performed as in the case of the CS group in FIG. .

  Since the DA slot has an upper limit on the transmission rate, it is suitable for networks that transmit packets with a constant packet length, but when the packet length transmitted by the AP 100 or STA 200 is variable, the CS slot is assigned rather than allocating the DA slot. It may be more efficient to distribute the packet transmission by Whether to allocate a DA slot or to allocate to a CS slot is set by the user for the network control apparatus 400, and determines whether to allocate traffic to the CS slot or to allocate to a DA slot. Furthermore, the assignment of the CS frame and DA slot of the superframe is determined according to the traffic type.

  As described above, assignment of the DA slot is performed by the network control apparatus 400. Hereinafter, an example of assignment of DA slots in the network control apparatus 400 will be described.

<Operation example>
FIG. 8 is a sequence diagram showing a configuration example of the wireless communication system 10. This operation example is operated by the wireless communication system 10 shown in FIG.

  In FIG. 8, the switching hub 300 in the wireless communication system 10 shown in FIG. 1 is omitted. Further, the AP 100-1 is connected to the network control device 400 by wire as in the case of FIG. 1, and can wirelessly communicate with the APs 100-2 and 100-3. Further, the STA 200-1 can wirelessly communicate with the APs 100-2 and 100-3, and the STA 200-2 can wirelessly communicate with the APs 100-1 and 100-3. Furthermore, the STA 200-3 can wirelessly communicate with the APs 100-1 and 100-2.

  In FIG. 8, (1) to (8) show the order of slot assignment. Hereinafter, a slot used for transmission of transmission data may be referred to as a “communication slot” (or “transmission slot”), and a slot used for transmission of retransmission data may be referred to as a “retransmission slot”. Also, in the following, when the communication slot and the retransmission slot are not distinguished, they may be simply referred to as "slots".

  9 and 10 are sequence diagrams showing an operation example. Also in FIGS. 9 to 10, numbers (1) to (9) are assigned to indicate the assignment order corresponding to FIG.

  As shown in FIG. 9, the AP 100-1 transmits a beacon signal (S10). The APs 100-2 and 100-3 and the STAs 200-1 and 200-2 receive the beacon signal transmitted by the AP 100-1.

  The AP 100-2 also transmits a beacon signal (S20), and the STAs 200-1 and 200-3 receive the beacon signal. Furthermore, the AP 100-3 also transmits a beacon signal (S20), and the STA 200-2 receives this beacon signal.

  The APs 100-1 to 100-3 can transmit beacon signals periodically at predetermined timings. It is assumed that APs 100-1 to 100-3 and STAs 200-1 to 200-3 know the timing.

  Below, the example of allocation of a communication slot is demonstrated in order of (1) to (8). Transmission of each message shown in FIG. 9 and FIG. 10 is performed using a CS slot.

<1. Slot assignment for communication between AP 100-1 and AP 100-2>
First, an example of slot assignment ((1)) for communication between the AP 100-1 and the AP 100-2 will be described.

  As shown in FIG. 9, the AP 100-2 executes a procedure for joining a network via the AP 100-1 (S40).

  Specifically, the AP 100-2 generates an association request, and transmits the generated association request to the AP 100-1 (S41). The association request is, for example, a message indicating a request for joining (or connection) to the network. For example, the application processing unit 120-2 of the AP 100-2 generates an association request, and transmits the association request to the AP 100-1 via the transmission queue control unit 111-2 and the like.

  Next, the AP 100-1 transmits the received association request to the network control apparatus 400 (S42). For example, the external transmission / reception function unit 108-1 of the AP 100-1 performs the following processing. That is, the external transmission and reception function unit 108-1 receives the association request via the reception queue control unit 104-1 and the like. Then, the external transmission / reception function unit 108-1 generates packet data including an association request, and transmits the generated packet data to the network control apparatus 400.

  When receiving the association request, the network control device 400 transmits an association response to the AP 100-1 (S43). The association response is, for example, a message representing a response to the participation request. For example, when the network control unit 420 receives an association request via the external transmission / reception function unit 410, it determines that the AP 100-2 participates in the network, generates an association response including that effect, and transmits the association response to the AP 100-1. Do. In the first embodiment, the network control unit 420 determines that participation is permitted.

  Upon receiving the association response, the AP 100-1 transmits the received association response to the AP 100-2 (S44). For example, the external transmission / reception function unit 108-1 of the AP 100-1 extracts an association response from packet data received from the network control apparatus 400, and transmits the extracted association response to the AP 100-2. Then, the AP 100-2 receives the association response. For example, the application processing unit 120-2 receives the association response transmitted from the AP 100-1. Thus, the procedure for joining (or connecting) the AP 100-2 to the wireless communication system 10 is completed.

  Next, the AP 100-2 transmits a route request to the AP 100-1 (S45). The route request is, for example, a message for requesting the route through which the AP 100-2 should transmit and receive data, and is also a message indicating a request for allocation of communication slots. The AP 100-2 measures RSSI # 1 based on the beacon signal (S10), and transmits a route request including the measured RSSI # 1. For example, the AP 100-2 performs the following processing.

  That is, the wireless unit 102-2 measures the RSSI based on the beacon signal transmitted from the AP 100-1, and outputs the measured RSSI to the application processing unit 120-2. The application processing unit 120-2 generates a route request including the RSSI and transmits the route request to the AP 100-1.

  In the following, the RSSI measured by the AP 100 or the STA 200 may be referred to as “RSSI # 1” based on the signal received from the AP 100-1. Moreover, based on the signal received from AP100-2, the RSSI which AP100 or STA200 measured may be called "RSSI # 2." Furthermore, based on the signal received from the AP 100-3, the RSSI measured by the AP 100 or the STA 200 may be referred to as "RSSI # 3".

  Upon receiving the route request, the AP 100-1 transmits the received route request to the network control device 400 (S45). For example, the external transmission / reception function unit 108-1 of the AP 100-1 transmits the route request received via the reception queue control unit 104-1 or the like to the network control apparatus 400 as packet data including the route request.

  When the network control device 400 receives the route request, it assigns a slot (slot assignment) to the communication between the AP 100-1 and the AP 100-2 (S46). For example, the external transmission / reception function unit 410 of the network control apparatus 400 extracts a route request from the packet data, and outputs the extracted route request to the network control unit 420. The network control unit 420, for example, assigns slots to communication between the AP 100-1 and the AP 100-2.

  FIG. 11A to FIG. 11F are diagrams showing examples of communication slot allocation. FIGS. 11A and 11B show an example of allocation of communication slots to the AP 100-1. 11C and 11D show examples of allocation of communication slots to the AP 100-2, and FIGS. 11E and 11F show allocation of communication slots to the AP 100-3. 11 (A), 11 (C), and 11 (E) are in the downstream direction (frame #n), and FIGS. 11 (B), 11 (D), and 11 (F) are in the upstream direction (frame #n). The example of slot allocation of flame | frame # (n + 1) is each represented. As shown in FIG. 11A and the like, one frame includes 16 slots from slot numbers “0” to “15”. Sixteen slots represent the number of slots included in one DA slot in one frame.

  The network control device 400 performs, for example, the following processing. That is, when receiving the route request, the network control unit 420 determines the occurrence of interference based on RSSI # 1 included in the route request. When RSSI # 1 is higher than the interference threshold, network control section 420 determines that interference will occur with respect to another communication (for example, communication between AP 100-1 and AP 100-3), otherwise interference is caused. Is determined not to occur. In the present process, the network control unit 420 determines that interference occurs. The network control unit 420 also determines the route of the AP 100-2 (the AP 100-2 via the AP 100-1). Then, the network control unit 420 allocates a downlink communication slot from the AP 100-1 to the AP 100-2 on the determined route and its retransmission slot. In the example of FIG. 11A, the network control unit 420 assigns a slot number “3” as a communication slot and a slot number “8” as a retransmission slot.

  In the example of FIG. 11A, etc., the network control unit 420 assigns the first half slot in a frame as a communication slot and the second half slot in a frame as a retransmission slot, but if it is in the same frame, It may be allocated to other slots.

  When the AP 100-1 or AP 100-2 retransmits data by allocating a communication slot and a retransmission slot in the same frame, the network control unit 420 retransmits without waiting until the next transmission cycle. It becomes possible. Therefore, in the first embodiment, it is possible to improve the data throughput as compared with the case of waiting for the next transmission cycle.

  Further, as shown in FIG. 11B, the network control unit 420 assigns the uplink communication slot from the AP 100-2 to the AP 100-1 to the slot number “0” and the retransmission slot to the slot number “8”, respectively. . In the uplink slot assignment, the communication slot and the retransmission slot are assigned to the same frame.

  Further, as shown in FIG. 11C, the network control unit 420 assigns a communication slot assigned to the AP 100-1 to the AP 100-2 as a downlink communication slot from the AP 100-1 to the AP 100-2. Assign the same slot as slot number "3". The network control unit 420 assigns the same slot (slot number “8”) to the retransmission slot.

  Further, as shown in FIG. 11D, the network control unit 420 is the same slot as the slots (slot numbers “0” and “8”) allocated in the uplink direction in the AP 100-1 and the slots in the AP 100-2. Assign as

  As shown in FIGS. 11A and 11C, the network control unit 420 assigns the same communication slot and retransmission slot to the AP 100-1 and the AP 100-2 for the same communication. . Even if different slots are allocated in the same communication, the use of the slots becomes redundant, and by allocating the same slots, effective utilization of the slots can be achieved.

  In FIG. 11E and FIG. 11F, the network control unit 420 does not allocate a communication slot and a retransmission slot. This is because the AP 100-3 has not performed the network joining procedure at this stage.

  Returning to FIG. 9, the network control apparatus 400 transmits a route response to the AP 100-1 after slot assignment (S47). The route response is, for example, a message representing a result of response to a route request, and includes a result of assignment of communication slots and retransmission slots. For example, the network control unit 420 generates a route response including the assignment results shown in FIGS. 11A to 11F, and transmits the route response to the AP 100-1.

  When the AP 100-1 receives the route response, the AP 100-1 transmits the received route response to the AP 100-2 (S47). For example, in AP 100-1, the following processing is performed.

  That is, the external transmission / reception function unit 108-1 transmits the route response received from the network control apparatus 400 to the AP 100-2 via the transmission queue control unit 111-1 and the like. At this time, the external transmission / reception function unit 108-1 outputs a route response to the timing generation unit 109-1. The timing generation unit 109-1 extracts the slot allocation result included in the route response, and outputs a timing signal indicating the communication slot (or retransmission slot) allocated to the own station to the transmission queue control unit 111-1. . By this, the transmission queue control unit 111-1 can output data etc. to the modulation unit 113-1 in synchronization with the timing signal, and the AP 100-1 can output the data at the timing of the communication slot (or retransmission slot). Data and the like can be transmitted (or retransmitted) to the AP 100-2.

  Further, when the AP 100-2 receives the route response, for example, the AP 100-2 performs the following processing.

  That is, when receiving the route response via the reception queue control unit 104-2 or the like, the application processing unit 120-2 outputs the route response to the timing generation unit 109-2. The timing generation unit 109-2 extracts the slot allocation result included in the route response, and outputs a timing signal indicating the communication slot (or retransmission slot) allocated to the own station to the transmission queue control unit 111-2. . Thereby, the transmission queue control unit 111-2 can output data etc. to the modulation unit 113-2 in synchronization with the timing signal, and the AP 100-2 can output the data at the timing of the communication slot (or retransmission slot). , Data, etc. can be transmitted (or retransmitted) to the AP 100-1.

  As a result, in the DA slot period, the AP 100-1 and the AP 100-2 can perform data transmission and retransmission thereof using the allocated communication slot and retransmission slot.

  Note that the AP 100-1 performs data transmission and retransmission with the transmission power calculated by the following equation in order to minimize interference with the other APs 100-2 and 100-3 and the STA 200.

  Transmit power of AP 100 = (transmit power of other AP + RSSI for other AP) + noise level of AP 100 + D / U (Desired Signal / Undesired Signal) ratio (1)

  Formula (1) represents, for example, the lowest level of transmission power of AP 100-1 and represents the level of transmission power at which no interference occurs in all communications if all APs transmit with this transmission power. . However, in the case of (transmission power of AP 100> maximum transmission power of AP 100), transmission power of AP 100 = maximum transmission power of AP 100. Further, in the case of (transmission power of AP 100 <minimum transmission power of AP 100), transmission power of AP 100 = minimum transmission power of AP 100.

  For example, the wireless unit 102-1 stores the equation (1) in an internal memory or the like, reads the above equation from the internal memory at the time of transmission, and calculates transmission power. The D / U ratio and the transmission power of the AP 100-2 are broadcasted by, for example, a beacon signal.

<2. Slot assignment for communication between AP 100-1 and AP 100-3>
Next, a slot allocation example ((2)) for communication between the AP 100-1 and the AP 100-3 will be described.

  As shown in FIG. 9, the AP 100-3 performs a network joining procedure with the network control apparatus 400 via the AP 100-1 (S50).

  When the AP 100-3 is permitted to join the network in the network joining procedure, the AP 100-3 transmits a route request to the network control apparatus 400 via the AP 100-1 (S51). In this case, the AP 100-3 transmits a read request including RSSI # 1 measured based on the beacon signal transmitted from the AP 100-1.

  When the network control device 400 receives the route request, it assigns a slot to the communication between the AP 100-1 and the AP 100-3 (S52).

  12 (A) to 12 (F) are diagrams showing examples of communication slot allocation. The network control apparatus 400 allocates slots, for example, as follows.

  That is, as shown in FIG. 12A, the network control unit 420 assigns, to the AP 100-1, the downlink communication slot from the AP 100-1 to the AP 100-3 to the slot number “4”. Also, the network control unit 420 assigns the retransmission slot to the slot number “9”.

  Further, as illustrated in FIG. 12B, the network control unit 420 assigns, to the AP 100-1, the communication slot in the uplink direction from the AP 100-3 to the AP 100-1 to the slot number “1”. Also, the network control unit 420 assigns the retransmission slot to the slot number “9”. As in the case of (1), the allocation of the communication slot and the retransmission slot is an example, and it may be another slot that is in the same frame and is free.

  Furthermore, as shown in FIG. 12C and FIG. 12D, the network control unit 420 has the same slot as that assigned to the AP 100-1 with respect to the AP 100-2 (see FIG. Communication slots and retransmission slots are allocated to FIG.

  In this case, as shown in FIG. 12E and FIG. 12F, the network control unit 420 also assigns the same slot as the slot assigned to the AP 100-1 or AP 100-2 to the AP 100-3. .

  That is, the network control unit 420 assigns slot numbers “3” and “8” assigned to the AP 100-1 and the AP 100-2 also in the AP 100-3 in the downlink direction. Then, the network control unit 420 assigns a communication slot to the slot number “4” and a retransmission slot to the slot number “9” for communication with the AP 100-1 and the AP 100-3 in the downlink direction.

  In the case of (2), unlike in the case of (1), the AP 100-3 is permitted to join the network. Further, as shown in FIG. 8, the communicable range of the AP 100-1 includes the AP 100-3, and the communication from the AP 100-1 to the AP 100-2 may cause interference to the AP 100-3.

  For communications that may cause interference, including (1) described above, a communication slot and a retransmission slot are allocated to AP 100 for communication with another AP 100 even if it is not related to the communication of the own station. There is a case. For example, as shown in FIG. 12E, the slot number “3” is a communication slot for communication from the AP 100-1 to the AP 100-2, but the communication allocated for the AP 100-3 to perform direct communication. It is not a slot. Allocation of the same slot restricts the use of the other AP 100, AP 100-3 in FIG. 12 (E), and communication between AP 100-1 and AP 100-2 and communication between AP 100-1 and AP 100-3. Interference with can be avoided. This can prevent, for example, a decrease in throughput.

  The determination of interference is performed based on the RSSI included in the route request, for example, when the network control unit 420 receives the route request (S51). For example, the network control unit 420 determines that interference occurs when the RSSI # 1 received in S51 is higher than the interference threshold, and determines that interference does not occur otherwise. In this process, the network control unit 420 assigns the same communication slot and retransmission slot to the AP 100-1 to AP 100-3 on the assumption that interference occurs.

  Returning to FIG. 9, the network control apparatus 400 transmits a route response including the slot allocation result to the AP 100-3 via the AP 100-1 (S53).

  During the DA slot period, the AP 100-1 and the AP 100-3 can perform data transmission and retransmission using the allocated communication slot and retransmission slot. In this case, the AP 100-1 and the AP 100-3 may perform data transmission or retransmission with the transmission power calculated using Equation (1).

<3. Slot Allocation for Communication Between AP 100-1 and STA 200-1>
Next, an example of slot assignment ((3)) for communication between the AP 100-1 and the STA 200-1 will be described.

  As shown in FIG. 8, the STA 200-1 has two routes, a route to the AP 100-1 via the AP 100-2 and a route directly to the AP 100-1. Here, an example will be described in which slot allocation is performed on a route directly to the AP 100-1.

  As shown in FIG. 9, the STA 200-1 executes a network joining procedure with the network control apparatus 400 via the AP 100-1 (S60). At this time, the network control apparatus 400 issues, for example, a BSSID (Basic Service Set Identification) to the STA 200-1. Thereafter, the STA 200-1 can communicate with the AP 100-1 using the BSSID. In the first embodiment, the STA 200-1 can communicate with other APs 100-2 and 100-3 using this BSSID. Therefore, the STA 200-1 may switch the connection to the other APs 100-2 and 100-3, or may not perform the network joining procedure. This makes it possible to prevent a decrease in throughput.

  Next, the STA 200-1 transmits a route request to the network control apparatus 400 via the AP 100-1 (S61). The STA 200-1 transmits the RSSI # 1 for the AP 100-1 and the two RSSI (RSSI # 2> RSSI # 1) for the RSSI # 2 for the AP 100-2 in the route request.

  Next, the network control device 400 allocates slots (S62). In this case, since the network control apparatus 400 includes two RSSIs in the route request, the two routes (from the STA 200-1 to the AP 100-2 via the AP 100-2) are transmitted to the STA 200-1. , Direct route from STA 200-1 to AP 100-1 can be confirmed. When there are a plurality of routes, the network control apparatus 400 calculates an evaluation value for each route using the following formula, and selects one of the routes based on the evaluation value.

In Equation 1, for example, SNR (Signal to Noise Ratio) _i represents the SNR of the path i, Delay _i represents the delay time of the path _i , and TxPow _i represents the transmission power of the path i. Further, in the equation 1, α, β and γ represent, for example, coefficients, and can be set preferentially by the user.

  For example, in FIG. 8, the evaluation values for the route from the STA 200-1 to the AP 100-1 via the AP 100-2 are as follows. That is, the evaluation value is a value obtained by adding the SNR, Delay, and TxPow of the route between the STA 200-1 and the AP 100-2 and the SNR, Delay, and TxPow of the route between the AP 100-2 and the AP 100-1. Here, the SNR of each route may be, for example, the SNR measured by the STA 200 based on the beacon signal (S20). Also, the Delay of each route represents, for example, the time taken for the message transmission between the STA 200 and the AP 100, and may be a predetermined time determined in advance. Furthermore, TxPow of each route may be, for example, the transmission power of the STA 200-1 or the transmission power of the AP 100-2.

  In the stage of (3), for example, although the network control unit 420 can grasp that there are a plurality of routes for the STA 200-1, since the route request is directly transmitted from the STA 200-1 to the AP 100-1, 1 Only the SNR of one route can be obtained. Therefore, the network control unit 420 may select a route directly to the AP 100-1 for the route of the STA 200-1, without calculating the evaluation value.

  Alternatively, the network control unit 420 reads, for example, SNR, Delay, and TxPow of each route acquired from the memory in the past communication, and two routes (a route directly from the STA 200-1 to the AP 100-2 and the STA 200-1 The evaluation value (equation 1) of the route from AP100-1 to AP100-2 may be calculated, and the higher evaluation value may be selected.

  Also, the higher the SNR (eg, dB), the higher the evaluation value, and the shorter the delay, the higher the evaluation value. Also, the smaller the value of TxPow, the higher the evaluation value. Therefore, since the RSSI included in the route request (S61) is RSSI # 2> RSSI # 1, the network control unit 420 is a route from the STA 200-1 to the AP 100-1 via the AP 100-2. May be selected.

  In the following, since the evaluation value is higher for the route from the STA 200-1 directly to the AP 100-2, the network control unit 420 is described as selecting this route.

  The network control unit 420 may calculate the evaluation value of Equation 1 using the RSSI calculated by the AP 100 or the STA 200 based on the beacon signal, instead of the SNR.

  Then, the network control unit 420 allocates a slot to the communication between the AP 100-1 and the STA 200-1 on the selected route.

  FIG. 13A to FIG. 13F are diagrams showing an example of allocation of communication slots. The network control apparatus 400 allocates slots, for example, as follows.

  That is, as shown in FIG. 13A, the network control unit 420 assigns, to the AP 100-1, the downlink communication slot from the AP 100-1 to the STA 200-1 to the slot number "5". Also, the network control unit 420 assigns the retransmission slot to the slot number “10”.

  Further, as shown in FIG. 13B, the network control unit 420 assigns, to the AP 100-1, the communication slot in the uplink direction from the STA 200-1 to the AP 100-1 to the slot number “2”. Also, the network control unit 420 assigns the retransmission slot to the slot number “10”. As in the case of (1), the assignment of the communication slot and the retransmission slot is an example, and it may be in the same frame.

  Further, as shown in FIG. 13C and FIG. 12D, the network control unit 420 has the same slot as that assigned to the AP 100-1 for the AP 100-2 (see FIG. Communication slots and retransmission slots are assigned to A) and FIG. 13 (B).

  Further, as shown in FIG. 13E and FIG. 13F, the network control unit 420 sets a communication slot and a retransmission slot in the same slot as the slot allocated to the AP 100-1 with respect to the AP 100-3. And assign.

  For example, as shown in FIG. 13A, FIG. 13C, and FIG. 13E, for the AP 100-1 to AP 100-3, the slot number “5” is assigned from the AP 100-1 to the STA 200-1. Communication slots are commonly assigned. This is because APs 100-2 and 100-3 are installed within the communicable range of AP 100-1, and the communication from AP 100-1 to STA 200-1 interferes with the communication at APs 100-2 and 100-3. Because it may give

  For example, the network control unit 420 determines that interference occurs when the RSSI # 1 acquired in the route request (S61) is higher than the interference threshold, and determines that interference does not occur otherwise. In this process, the network control unit 420 assigns the same communication slot and retransmission slot to the AP 100-1 to AP 100-3 on the assumption that interference occurs.

  Returning to FIG. 9, the network control apparatus 400 transmits a route response including the slot allocation result to the STA 200-1 via the AP 100-1 (S63).

  During the DA slot period, the AP 100-1 and the STA 200-1 can perform data transmission and retransmission using the allocated communication slot and retransmission slot. In this case, the AP 100-1 and the STA 200-1 may perform data transmission and retransmission with the transmission power calculated using Equation (1).

<4. Slot assignment for communication between AP 100-2 and STA 200-1>
Next, an example of slot assignment ((4)) for communication between the AP 100-2 and the STA 200-1 will be described.

  Above <3. By slot assignment to STA 200-1, the network control apparatus 400 assigns a communication slot etc. to STA 200-1 on the direct route to AP 100-1 selected based on the evaluation value (Equation 1) (S60 To S63). Next, the network control apparatus 400 selects a route that has not been selected based on the evaluation value, and allocates a communication slot to the STA 200-1 in this route.

  As shown in FIG. 9, the STA 200-1 executes a network joining procedure on the AP 100-2 (S70). For example, since the STA 200-1 has not received a route response via the AP 100-2 from the network control apparatus 400, the STA 200-1 is to perform network participation on this route.

  In this case, the AP 100-2 does not execute the network joining procedure for the STA 200-1 with respect to the network control apparatus 400. For example, the network control apparatus 400 is aware of the route from the STA 200-1 to the AP 100-2 via the received power report in the route request (S61). For example, the STA 200-1 causes the AP 100-2 not to transmit the association request to the network control apparatus 400 by transmitting the association request of the network participation procedure including the purport that there is the route response (S63). It is possible.

  Next, the network control apparatus 400 assigns a slot to the communication between the AP 100-2 and the STA 200-1 (S71).

  FIGS. 14A to 14F are diagrams showing examples of slot allocation. The network control apparatus 400 allocates slots, for example, as follows.

  That is, as shown in FIG. 14A, the network control unit 420 assigns the downlink communication slot from the AP 100-2 to the STA 200-1 to the slot number “6”, and retransmits the slot to the slot number “11”. Assign to

  Also, as shown in FIG. 14B, the network control unit 420 assigns an uplink communication slot from the STA 200-1 to the AP 100-2 to the slot number “3”, and retransmits that slot to the slot number “11”. Assign to

  Similarly, as shown in FIG. 14 (C) and FIG. 14 (D), the network control unit 420 sets the communication slot in the same slot as the slot assigned to the AP 100-1 also to the AP 100-2. And retransmit slots are allocated.

  However, as shown in FIG. 14E, the network control unit 420 assigns the downlink communication slot from the AP 100-2 to the STA 200-1 to the same slot number "6" as the AP 100-1 and the AP 100-2. I do not do it. The network control unit 420 also does not assign the retransmission slot to the same slot number “11” as the AP 100-1 and the AP 100-2. As shown in FIG. 14F, the network control unit 420 similarly does not assign a communication slot and a retransmission slot to the same slot number as that of the AP 100-1 and the AP 100-2 in the uplink direction.

  For example, as shown in FIG. 8, the wireless signal transmitted from AP 100-2 to STA 200-1 does not reach AP 100-3, and the wireless signal transmitted from STA 200-1 to AP 100-2 is also AP 100-3. Because it does not arrive at That is, the communication between the AP 100-2 and the STA 200-1 does not cause interference to the AP 100-3. The network control unit 420 does not assign a communication slot and a retransmission slot to the same slot as the AP 100-1 and the AP 100-2 for communication that does not cause interference. As a result, for example, the network control unit 420 can allocate the slot numbers “6” and “11” of the AP 100-3 for other communications, and can make effective use of the slots.

  The network control unit 420 may determine that communication between the AP 100-2 and the STA 200-1 does not cause interference to the AP 100-3 based on, for example, RSSI # 2 included in the route request (S61). . For example, the network control unit 420 may determine that interference does not occur when RSSI # 2 is smaller than the interference threshold, and may determine that interference occurs when RSSI # 2 is equal to or greater than the interference threshold. In this process, for example, the network control unit 420 determines that the RSSI # 2 is smaller than the interference threshold, and determines that no interference occurs with the AP 100-3.

  Returning to FIG. 9, the network control apparatus 400 transmits a route indication to the STA 200-1 via the AP 100-2 (S72). The route display is, for example, a message for the network control device 400 to transmit information on the route to the AP 100 or the STA 200 without receiving the route request. The route display includes, for example, slot allocation results shown in FIG. 14 (A) to FIG. 14 (F).

  During the DA slot period, the AP 100-2 and the STA 200-1 can perform data transmission and retransmission using the allocated communication slot and retransmission slot. In this case, the AP 100-2 and the STA 200-1 may perform data transmission or retransmission with the transmission power calculated using Equation (1).

  Although FIG. 9 shows an example in which the network control apparatus 400 performs S62 and S71 separately, for example, in the process of S62, the slot assignment between the AP 100-2 and the STA 200-1 You may In this case, S71 may be included in S62 and S71 may be omitted.

  Also, although the STA 200-1 initially performs the network participation procedure via the AP 100-1 (S60), it may first perform the network participation procedure via the AP 100-2 (S70). Therefore, in FIG. 9, the order of the process of (3) and the process of (4) may be reversed.

<5. Allocation of slots for communication between AP 100-1 and STA 200-2>
Next, a slot allocation example ((5)) for communication between the AP 100-1 and the STA 200-2 will be described.

  As shown in FIG. 8, the STA 200-2 has two routes, a route to the AP 100-1 via the AP 100-3 and a route directly to the AP 100-1. Here, an example will be described in which slot allocation is performed on a route directly to the AP 100-1.

  As shown in FIG. 10, the STA 200-1 executes a network joining procedure with the network control apparatus 400 via the AP 100-1 (S80). Also in this case, the network control apparatus 400 issues a BSSID to the STA 200-2. The STA 200-2 can use this BSSID not only for the AP 100-1 but also when switching the connection and communicating with the APs 100-2 and 100-3.

  Next, the STA 200-2 transmits a route request to the network control apparatus 400 via the AP 100-1 (S61). The STA 200-1 transmits a route request including RSSI # 3 and RSSI # 1 (RSSI # 3> RSSI # 1).

  Next, the network control device 400 allocates slots (S82). In this case, since the network control device 400 includes two RSSIs in the route request, the two routes (from the STA 200-2 to the AP 100-1 via the AP 100-3) are transmitted to the STA 200-2. , And the direct route from STA 200-2 to AP 100-1 can be confirmed. In this case, the network control apparatus 400 may calculate evaluation values for two routes using Equation 1 and select a direct route from the STA 200-2 to the AP 100-1. Alternatively, the network control apparatus 400 may select this route without calculating the evaluation value because the acquired numerical value is only a direct route to the AP 100-1.

  Then, the network control device 400 assigns slots to the selected route.

  FIGS. 15A to 15F are diagrams showing examples of allocation of communication slots. The network control apparatus 400 allocates slots, for example, as follows.

  That is, as shown in FIG. 15A, the network control unit 420 assigns, to the AP 100-1, the downlink communication slot from the AP 100-1 to the STA 200-2 to the slot number “7”. Also, the network control unit 420 assigns the retransmission slot to the slot number “12”.

  Further, as illustrated in FIG. 15B, the network control unit 420 assigns, to the AP 100-1, the communication slot in the uplink direction from the STA 200-2 to the AP 100-1 to the slot number “4”. . Also, the network control unit 420 assigns the retransmission slot to the slot number “12”.

  As shown in FIG. 15C to FIG. 15F, the network control unit 420 assigns each slot in the uplink direction and the downlink direction of the AP 100-2 and AP 100-3 to the AP 100-1. Assign the same slot number as. This is because APs 100-2 and 100-3 are installed within the communicable range of AP 100-1, and the communication from AP 100-1 to STA 200-2 interferes with the communication at APs 100-2 and 100-3. Because it may give

  For example, the network control unit 420 determines that interference occurs when RSSI # 1 included in the route request is higher than the interference threshold, and determines that interference does not occur otherwise. In this process, the network control unit 420 determines that interference occurs, and assigns the same communication slot and retransmission slot to the AP 100-1 to AP 100-3.

  Returning to FIG. 10, the network control apparatus 400 transmits a route response including the slot allocation result to the STA 200-1 via the AP 100-1 (S83).

  During the DA slot period, the AP 100-1 and the STA 200-2 can perform data transmission and retransmission using the allocated communication slot and retransmission slot. Note that the AP 100-1 and the STA 200-2 may perform data transmission and retransmission with the transmission power calculated using Equation (1).

<6. Allocation of slots for communication between AP 100-3 and STA 200-2>
Next, a slot allocation example ((6)) for communication between the AP 100-3 and the STA 200-2 will be described.

  Above <5. Allocation of Slots for Communication Between AP 100-1 and STA 200-2 In the network control apparatus 400, communication slots and the like are allocated to the AP 100-1 and STA 200-2 (S 80 to S 83). Next, the network control apparatus 400 selects a route that has not been selected based on the evaluation value, and allocates a slot for communication between the AP 100-3 and the STA 200-2 on this route. Do.

  As shown in FIG. 10, the STA 200-2 executes a network joining procedure on the AP 100-3 (S90). For example, the STA 200-2 is to perform network participation on a route via the AP 100-3.

  Also in this case, the AP 100-3 does not execute the network joining procedure for the STA 200-2 with respect to the network control apparatus 400. For example, the STA 200-1 can prevent the AP 100-3 from transmitting the association request to the network control apparatus 400 by transmitting the association request including the fact that there is the route response (S83). is there.

  Next, the network control apparatus 400 allocates a slot to the communication between the AP 100-3 and the STA 200-2 (S91).

  FIG. 16A to FIG. 16F are diagrams showing an example of slot assignment. The network control apparatus 400 allocates slots, for example, as follows.

  That is, as shown in FIG. 16E, the network control unit 420 assigns the downlink communication slot from the AP 100-3 to the STA 200-2 to the slot number “6”, and sets the retransmission slot to the slot number “ Assign to 11 ".

  In this case, focusing on FIG. 16 (A) and FIG. 16 (C), the slot number “6” is assigned to the communication slot in the downlink direction from AP 100-2 to STA 200-1 (the communication slot of (4)). It is done. As shown in FIG. 8, the communication between the AP 100-3 and the STA 200-2 does not interfere with the communication between the AP 100-2 and the STA 200-1. For example, when it is determined that interference does not occur, the network control unit 420 determines that communication between the AP 100-3 and the STA 200-2 and communication between the AP 100-2 and the STA 200-1 are the same in the same frame (frame #n). Is assigned to the communication slot (slot number "6") of Similarly, in the uplink direction, the network control unit 420 assigns a communication slot to the same communication slot (slot number “3”) of the same frame (frame # (n + 1)) for two communications. The same applies to retransmission slots.

  Even if the network control apparatus 400 assigns the same communication slot, no interference occurs, so there is no retransmission, and it is possible to prevent a decrease in data throughput. Further, since there is no interference, the AP 100-3 does not receive the signal of the STA 200-1, so that collision of data from the STA 200-2 and data from the STA 200-1 can be prevented.

  The determination of interference may be performed, for example, as follows. That is, the network control unit 420 determines that interference occurs when both RSSI # 3 (S81) included in the route request (S81) are higher than the interference threshold, and otherwise determines that interference does not occur. In this process, the network control unit 420 determines that the RSSI # 3 is less than or equal to the interference threshold, and that the communication between the AP 100-3 and the STA 200-2 does not interfere with the communication at the AP 100-1 and the AP 100-2. It is judged. On the other hand, when the network control unit 420 determines that interference occurs, the communication slot allocated for communication from the AP 100-3 to the STA 200-2 and the communication slot allocated for communication in the AP 100-1 or AP 100-2 are: , Assign to different slots. For example, in FIG. 16E, a slot “6” allocated for communication from the AP 100-3 to the STA 200-2 and a slot “5” allocated for communication from the AP 100-1 to the STA 200-1 are: It is a different slot.

  Returning to FIG. 10, the network control apparatus 400 transmits a route indication to the STA 200-1 via the AP 100-2 (S92). The route display includes, for example, the slot allocation results shown in FIG. 16 (A) to FIG. 16 (F).

  During the DA slot period, the AP 100-3 and the STA 200-2 can perform data transmission and retransmission using the allocated communication slot and retransmission slot. The AP 100-3 and the STA 200-2 may perform data transmission and retransmission with the transmission power calculated using Equation (1).

  In FIG. 10, S91 may be included in S82 and S91 may be omitted. Also, although the STA 200-1 initially performs the network participation procedure via the AP 100-1 (S80), it may first perform the network participation procedure via the AP 100-3 (S90). In this case, in FIG. 10, the order of the process of (5) and the process of (6) may be reversed.

<7. Allocation of Slots for Communication Between AP 100-1 and STA 200-3>
Next, a slot allocation example ((7)) for communication between the AP 100-1 and the STA 200-3 will be described.

  As shown in FIG. 8, the STA 200-3 has two routes, a route to the AP 100-1 via the AP 100-2 and a route directly to the AP 100-1. Here, an example will be described in which slot allocation is performed on a route directly to the AP 100-1.

  As shown in FIG. 10, the STA 200-3 executes a network joining procedure with the network control apparatus 400 via the AP 100-1 (S100). Also in this case, the network control apparatus 400 issues a BSSID to the STA 200-3. The STA 200-3 can use this BSSID not only for the AP 100-1 but also when switching the connection and communicating with the APs 100-2 and 100-3.

  Next, the STA 200-3 transmits a route request to the network control apparatus 400 via the AP 100-1 (S101). The STA 200-3 transmits a route request including RSSI # 1 and RSSI # 2.

  Next, the network control device 400 allocates slots (S102). In this case, since the route request includes two RSSIs, the network control apparatus 400 uses Equation 1 to calculate evaluation values for the two routes, and the STA 200-3 to the AP 100-1. You may choose the direct route of Alternatively, the network control apparatus 400 may select this route without calculating the evaluation value because the acquired numerical value is only a direct route to the AP 100-1. Then, the network control device 400 assigns slots to the selected route.

  FIGS. 17A to 17F are diagrams showing examples of slot assignment. The network control apparatus 400 allocates slots, for example, as follows.

  That is, as shown in FIG. 17A, the network control unit 420 assigns, to the AP 100-1, the downlink communication slot from the AP 100-1 to the STA 200-3 to the slot number "10". Also, the network control unit 420 assigns the retransmission slot to the slot number “12”.

  The slot number “10” is a slot assigned as a retransmission slot from the AP 100-1 to the STA 200-1. The network control unit 420 allocates a communication slot, and when there is no slot, allocates a retransmission slot as a communication slot. In the example of FIG. 17A, since the slot numbers “13” to “15” are vacant, the network control unit 420 may assign any one of these slots, but the example of FIG. 17A. In the above, the retransmission slot is assigned as a communication slot.

  In this case, the network control unit 420 commonly assigns the retransmission slot (slot number "10") from the AP 100-1 to the STA 200-1 originally assigned, to the slot assigned as another retransmission slot. . For example, in the example of FIG. 17A, slot number “12” is used as a retransmission slot for the following three communications.

  1) A retransmission slot for communication from the AP 100-1 to the STA 200-2 originally assigned to the slot number "12".

  2) Since the slot number "10" is changed from the retransmission slot (communication from AP 100-1 to STA 200-1) to the communication slot (communication from AP 100-1 to STA 3), AP 100-assigned before the change Retransmission slot for communication from 1 to STA 200-1.

  3) A retransmission slot for communication from the AP 100-1 to the STA 200-3 assigned to the slot number "10".

  As shown in FIG. 17C and FIG. 17E, the network control unit 420 also has the same communication slot and retransmission slot for the AP 100-2 and AP 100-4 as the slot allocated to the AP 100-1. Assign to

  Also, as shown in FIG. 17B, FIG. 17D, and FIG. 17F, the network control unit 420 changes the slot number “5”, which is an empty slot, from the STA 200-3 to the AP 100-1. And assign the retransmission slot to the slot number "13".

  Also in these cases, for example, the network control unit 420 determines that interference will occur, assuming that the RSSI # 1 acquired in the route request (S101) is higher than the interference threshold, thereby causing the AP 100-1 to 100-3 to , And assign the same communication slot and retransmission slot.

  Returning to FIG. 10, the network control apparatus 400 transmits a route response including the assignment result to the STA 200-3 via the AP 100-1 (S103).

  In addition, since the network control apparatus 400 changes the retransmission slot, it transmits a route indication including the allocation result of the changed retransmission slot to the STA 200-3 and the STA 200-2 via the AP 100-1 (S104, S105). The network control apparatus 400 may include the result of allocation of retransmission slots (S104) in the route response (S103). In this case, the route display of S104 is not transmitted.

  During the DA slot period, the AP 100-1 and the STA 200-3 can perform data transmission and retransmission using the allocated communication slot and retransmission slot. The AP 100-1 and the STA 200-3 may perform data transmission and retransmission with the transmission power calculated using Equation (1).

<8. Slot Assignment for Communication Between AP 100-2 and STA 200-3>
Next, a slot allocation example ((8)) for communication between the AP 100-2 and the STA 200-3 will be described.

  Above <7. Allocation of Slots for Communication Between AP 100-1 and STA 200-3 In the network control apparatus 400, communication slots and the like are allocated to the AP 100-1 and STA 200-3 (S 100 to S 105). Next, the network control apparatus 400 selects a route that has not been selected based on the evaluation value, and allocates a slot for communication between the AP 100-2 and the STA 200-3 on this route.

  As shown in FIG. 10, the STA 200-3 executes a network joining procedure on the AP 100-2 (S110).

  Also in this case, the AP 100-2 does not execute the network joining procedure for the STA 200-3 with respect to the network control apparatus 400.

  Next, the network control apparatus 400 allocates a slot to the communication between the AP 100-2 and the STA 200-3 (S111).

  18 (A) to 18 (F) are diagrams showing examples of slot assignment. The network control apparatus 400 allocates slots, for example, as follows.

  That is, as shown in FIG. 18A, the network control unit 420 assigns a slot number “11” assigned as a retransmission slot for communication of the AP 100-2 to the STA 200-1 from the AP 100-2 to the STA 200-3. Allocate as a communication slot for communication. Also, the network control unit 420 allocates a slot number “14”, which is an empty slot, as the retransmission slot. At this time, the network control unit 420 also assigns the slot number “14” as a retransmission slot of the communication from the AP 100-2 to the STA 200-3 originally assigned to the slot number “11”. The slot number "14" is commonly assigned as a retransmission slot for communication from the AP 100-2 to the STA 200-1, and as a retransmission slot for communication from the AP 100-2 to the STA 200-3.

  As shown in FIG. 18C, the network control unit 420 also assigns a slot having the same number as the slot assigned to the AP 100-1 to the AP 100-2 as a communication slot and a retransmission slot.

  In the uplink direction, as shown in FIGS. 18B and 18D, the network control unit 420 sets the slot number “6”, which is an empty slot, between the AP 100-2 and the STA 200-3. Allocate to a communication slot. Also, the network control unit 420 assigns the slot number "14" to the retransmission slot.

  On the other hand, the network control unit 420 does not assign a communication slot for communication from the AP 100-2 to the STA 200-1 to the slot number “11” for the AP 100-3. This is because the communication from the AP 100-2 to the STA 200-1 is determined to be interference with the communication of the AP 100-3. For example, the network control unit 420 determines that the RSSI # 2 received in the route request (S101) is equal to or less than the interference threshold, and determines that no interference occurs.

  Returning to FIG. 10, the network control apparatus 400 transmits a route indication including the assignment result to the STA 200-3 via the AP 100-2 (S112).

  During the DA slot period, the AP 100-2 and the STA 200-3 can perform data transmission and retransmission using the allocated communication slot and retransmission slot. The AP 100-2 and the STA 200-3 may perform data transmission and retransmission with the transmission power calculated using Equation (1).

  In FIG. 10, S111 may be included in S102 and S111 may be omitted. Also, although the STA 200-3 initially performs the network participation procedure via the AP 100-1 (S 100), it may first perform the network participation procedure via the AP 100-2 (S 110). In this case, in FIG. 10, the order of the process of (7) and the process of (8) may be reversed.

[Other Embodiments]
In the first embodiment, an example in which the AP 100 wired to the network control apparatus 400 is one AP 100-1 has been described. There may be a plurality of APs 100-1, 100-2,.

  Also, in the first embodiment, the RSSI has been described as an example of the reception level included in the route request (S45, S51, S61, S81, S101). For example, as the reception level included in the route request, the SNR or the received power value may be used. For example, the network control unit 420 may determine the occurrence of interference by comparing the SNR or the received power value with the interference threshold value.

  Summarizing the above, it looks like a note.

(Supplementary Note 1)
In a network control device that controls a plurality of wireless communication devices,
A first reception level in the second wireless communication device in response to the first signal transmitted from the first wireless communication device; and a fourth wireless communication device in response to the second signal transmitted from the third wireless communication device An external transmission / reception functional unit that receives the second reception level at the time from the first wireless communication apparatus and the third wireless communication apparatus, respectively;
First communication between the first wireless communication device and the second wireless communication device, the third wireless communication device, and the fourth wireless based on the first and second reception levels A network control unit that allocates the first and second communications to the same communication slot of the same radio frame when it is determined that interference does not occur between the communication apparatus and the second communication;
The network control device, wherein the external transmission / reception function unit transmits information on the allocated communication slot to the first and third wireless communication devices.

(Supplementary Note 2)
The network control unit is configured to transmit the data when the first or second wireless communication device or the third or fourth wireless communication device can not transmit data using the communication slot. The network control device according to claim 1, wherein a retransmission slot to be used for retransmission is assigned in the same wireless frame as the wireless frame to which the communication slot is assigned.

(Supplementary Note 3)
The network control device according to claim 2, wherein the network control unit allocates a retransmission slot for the first communication and a retransmission slot for the second communication to the same slot.

(Supplementary Note 4)
When the network control unit determines that interference occurs between the first communication and the second communication, the communication slot for the first communication and the communication slot for the second communication are the same. The network control device according to claim 1, wherein the network control device is assigned to different slots in a frame.

(Supplementary Note 5)
When the network control unit determines that interference occurs between the first communication and the second communication, the retransmission slot for the first communication and the retransmission slot for the second communication are the same. The network control device according to claim 1, wherein the network control device is assigned to different slots in a frame.

(Supplementary Note 6)
The network control unit is used by the first or fifth wireless communication device to retransmit data for the third communication between the first wireless communication device and the fifth wireless communication device. The network control device according to claim 1, wherein a communication slot for the first communication is assigned to a second retransmission slot.

(Appendix 7)
The network control unit may allocate the second retransmission slot to a first retransmission slot used by the first or second wireless communication apparatus to retransmit data for the first communication. The network control device according to appendix 1, characterized in that

(Supplementary Note 8)
The network control unit is configured such that the communication slot in the first wireless frame allocated to the first wireless communication device and the communication slot in the second wireless frame allocated to the third wireless communication device are the same slot. The network control device according to claim 1, wherein the first wireless frame and the second wireless frame have the same frame number.

(Appendix 9)
The network control unit
A communication slot in a first wireless frame allocated to the first wireless communication device for communication from the first wireless communication device to the second wireless communication device, and the communication slot from the third wireless communication device The communication slot in the second wireless frame allocated to the third wireless communication apparatus for communication to the fourth wireless communication apparatus is the same slot, and the first wireless communication from the second wireless communication apparatus A communication slot in a third wireless frame allocated to the first wireless communication device for communication to a communication device, and the communication slot from the fourth wireless communication device to the second wireless communication device The communication slot in the fourth wireless frame allocated to the third wireless communication apparatus is the same slot, and
The first wireless frame and the second wireless frame have the same frame number, and the third wireless frame and the fourth wireless frame have the same frame number. Network controller.

(Supplementary Note 10)
The network control unit is configured such that a retransmission slot in a first wireless frame allocated to the first wireless communication device and a retransmission slot in a second wireless frame allocated to the third wireless communication device are the same slot. The network control device according to claim 3, wherein the first wireless frame and the second wireless frame have the same frame number.

(Supplementary Note 11)
The network control unit
A retransmission slot in a first wireless frame allocated to the first wireless communication device for communication from the first wireless communication device to the second wireless communication device, and the third wireless communication device from the third wireless communication device The same slot as the retransmission slot in the second wireless frame allocated to the third wireless communication device for communication to the fourth wireless communication device, and the first wireless communication device from the second wireless communication device A retransmission slot in a third wireless frame allocated to the first wireless communication device for communication to a communication device, and the communication slot from the fourth wireless communication device to the second wireless communication device The retransmission slot in the fourth radio frame allocated to the third wireless communication apparatus is the same slot, and
5. The first wireless frame and the second wireless frame have the same frame number, and the third wireless frame and the fourth wireless frame have the same frame number. Network controller.

(Supplementary Note 12)
The wireless frame can be assigned by the network control unit, and the first slot can be used by time division in one of the first to fourth wireless communication devices, and the wireless frame is not assigned by the network control unit. And a second slot in which the first to fourth wireless communication devices can be commonly used,
The network control device according to claim 1, wherein the network control unit allocates the communication slot to a slot included in the first slot.

(Supplementary Note 13)
The first radio frame includes the first slot and the second slot in this order, and the second radio frame of the next frame number of the first radio frame is the second slot The network control device according to claim 12, wherein the first slot is included in this order.

(Supplementary Note 14)
The network control device according to claim 1, wherein the first and third wireless communication devices are access points, and the second and fourth wireless communication devices are terminal devices.

(Supplementary Note 15)
A slot assignment method in a network control device for controlling a plurality of wireless communication devices, comprising:
A first reception level in the second wireless communication device in response to the first signal transmitted from the first wireless communication device; and a fourth wireless communication device in response to the second signal transmitted from the third wireless communication device Receiving a second reception level at each of the first wireless communication device and the third wireless communication device,
First communication between the first wireless communication device and the second wireless communication device, the third wireless communication device, and the fourth wireless based on the first and second reception levels When it is determined that interference does not occur between the communication apparatus and the second communication, the first and second communication are assigned to the same communication slot of the same radio frame,
A slot allocation method comprising: transmitting information related to allocated communication slots to the first and third wireless communication devices.

10: Wireless communication system 100 (100-1 to 100-4): AP
102-1, 102-2: Radio unit 103-1, 103-2: Demodulation unit 104-1, 104-2: Reception queue control unit 106-1, 106-2: Synchronization function unit 108-1: External transmission / reception function Units 109-1 and 109-2: Timing generation units 110-1 and 110-2: Channel control units 111-1 and 111-2: Transmission queue control unit 120-2: Application processing units 130-1 and 130-2: CPU
200 (200-1 to 200-3): STA
400: Network control unit 410: External transmission / reception function unit 420: Network control unit

Claims (5)

In a network control device that controls a plurality of wireless communication devices,
A first reception level in the second wireless communication device in response to the first signal transmitted from the first wireless communication device; and a fourth wireless communication device in response to the second signal transmitted from the third wireless communication device An external transmission / reception functional unit that receives the second reception level at the time from the first wireless communication apparatus and the third wireless communication apparatus, respectively;
First communication between the first wireless communication device and the second wireless communication device, the third wireless communication device, and the fourth wireless based on the first and second reception levels A network control unit that allocates the first and second communications to the same communication slot of the same radio frame when it is determined that interference does not occur between the communication apparatus and the second communication;
The network control device, wherein the external transmission / reception function unit transmits information on the allocated communication slot to the first and third wireless communication devices.   The network control unit is configured to transmit the data when the first or second wireless communication device or the third or fourth wireless communication device can not transmit data using the communication slot. The network control device according to claim 1, wherein a retransmission slot used for retransmission is assigned in the same radio frame as the radio frame to which the communication slot is assigned.   3. The network control device according to claim 2, wherein the network control unit allocates the retransmission slot for the first communication and the retransmission slot for the second communication to the same slot.   When the network control unit determines that interference occurs between the first communication and the second communication, the communication slot for the first communication and the communication slot for the second communication are the same. The network control device according to claim 1, wherein the network control device is assigned to different slots in a frame. A slot assignment method in a network control device for controlling a plurality of wireless communication devices, comprising:
A first reception level in the second wireless communication device in response to the first signal transmitted from the first wireless communication device; and a fourth wireless communication device in response to the second signal transmitted from the third wireless communication device Receiving a second reception level at each of the first wireless communication device and the third wireless communication device,
First communication between the first wireless communication device and the second wireless communication device, the third wireless communication device, and the fourth wireless based on the first and second reception levels When it is determined that interference does not occur between the communication apparatus and the second communication, the first and second communication are assigned to the same communication slot of the same radio frame,
A slot allocation method comprising: transmitting information related to allocated communication slots to the first and third wireless communication devices.

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