WO2024009452A1 - Wireless device and wireless communication method - Google Patents

Wireless device and wireless communication method Download PDF

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Publication number
WO2024009452A1
WO2024009452A1 PCT/JP2022/026956 JP2022026956W WO2024009452A1 WO 2024009452 A1 WO2024009452 A1 WO 2024009452A1 JP 2022026956 W JP2022026956 W JP 2022026956W WO 2024009452 A1 WO2024009452 A1 WO 2024009452A1
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WIPO (PCT)
Prior art keywords
period
link
frame
unit
transmission
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PCT/JP2022/026956
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French (fr)
Japanese (ja)
Inventor
朗 岸田
健悟 永田
裕介 淺井
泰司 鷹取
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日本電信電話株式会社
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Priority to PCT/JP2022/026956 priority Critical patent/WO2024009452A1/en
Publication of WO2024009452A1 publication Critical patent/WO2024009452A1/en

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W72/00—Local resource management
    • H04W72/04—Wireless resource allocation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W74/00—Wireless channel access
    • H04W74/08—Non-scheduled access, e.g. ALOHA
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W84/00—Network topologies
    • H04W84/02—Hierarchically pre-organised networks, e.g. paging networks, cellular networks, WLAN [Wireless Local Area Network] or WLL [Wireless Local Loop]
    • H04W84/10—Small scale networks; Flat hierarchical networks
    • H04W84/12—WLAN [Wireless Local Area Networks]

Definitions

  • the present invention relates to wireless communication.
  • a wireless LAN Local Area Network
  • a wireless LAN is known as a communication system that wirelessly connects an access point and a terminal device.
  • each access point and terminal performs carrier sense based on, for example, CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance), and wirelessly transmits a data frame when a transmission right is acquired.
  • CSMA/CA Carrier Sense Multiple Access with Collision Avoidance
  • r-TWT restricted Target Wake Time
  • the r-TWT operation defines a mechanism for preferentially securing transmission opportunities for traffic with delay requirements.
  • Traffic with delay requirements is also called low-latency traffic or delay-sensitive traffic, and is traffic that requires low delay and small jitter, such as traffic generated from real-time applications such as network games.
  • a terminal device exchanges frames with the access point during a service period (SP) set for itself by the access point, and other terminal devices around the access point , communication via a link with a service period set during a part of the service period is suppressed.
  • a terminal device may use the service period to wirelessly transmit data frames containing low-latency traffic to an access point.
  • the service period is a period during which a terminal device specified by the access point is given a transmission opportunity, and the terminal device specified by the access point is given priority to send and receive data frames containing low-latency traffic. enable.
  • This service period is also called r-TWT service period.
  • a terminal device that has acquired the transmission right before the start of the r-TWT service period checks whether it is possible to complete the transmission of the data frame it is about to send by the start of the r-TWT service period. If it is not possible to complete the transmission, the terminal device postpones the transmission of the data frame and starts transmitting the data frame after the end of the r-TWT service period.
  • Multiple terminal devices may postpone transmission due to the r-TWT service period.
  • these terminal devices may start transmitting all at once after the r-TWT service period ends, and a collision may occur, making normal data transmission and reception impossible.
  • Backoff control may be used to avoid collisions caused by broadcasting data frames after the end of the r-TWT service period. For example, a plurality of terminal devices that have postponed transmission perform carrier sense again after the r-TWT service period ends, and once the transmission right is acquired again, they transmit. In this case, even though the transmission right was acquired once before the r-TWT service period, back-off control for acquiring the transmission right will be performed again, resulting in a decrease in frequency usage efficiency.
  • An object of the present invention is to provide a wireless communication technology that improves throughput and delay characteristics.
  • a wireless device includes a communication section, a first calculation section, a second calculation section, and a transmission control section.
  • the communication unit wirelessly communicates with the other wireless device using a plurality of links established between the wireless device and the other wireless device.
  • the first calculation unit calculates a frame exchange period including a time period required for frame transmission to the other wireless device.
  • the second calculation unit calculates, for each of the plurality of links, a communicable period indicating a time period until the start of a service period in which a transmission opportunity is given.
  • the transmission control unit performs the frame transmission on the link in which the frame exchange period is shorter than the communicable period; If there is no link that is shorter than the communication period, the frame transmission is postponed.
  • a wireless communication technology that improves throughput and delay characteristics is provided.
  • FIG. 1 is a block diagram showing a communication system according to an embodiment.
  • FIG. 2 is a diagram showing link management information according to the embodiment.
  • FIG. 3 is a block diagram showing the hardware configuration of the access point according to the embodiment.
  • FIG. 4 is a block diagram showing the hardware configuration of the terminal according to the embodiment.
  • FIG. 5 is a block diagram showing the functional configuration of an access point and a terminal according to the embodiment.
  • FIG. 6 is a diagram showing the channel access function of the terminal according to the embodiment.
  • FIG. 7 is a diagram illustrating transmission processing in the terminal according to the embodiment.
  • FIG. 8 is a diagram showing a situation in which the frame exchange period is shorter than the communicable period according to the embodiment.
  • FIG. 9 is a diagram illustrating a situation in which the frame exchange period is longer than the communicable period according to the embodiment.
  • FIG. 10 is a flowchart illustrating a wireless communication method according to the embodiment.
  • Multi-link operation is being considered in IEEE802.11be, which is being developed as a successor standard to IEEE802.11ax.
  • Multilink operation defines a mechanism for logically establishing multiple links using different frequency channels between an access point and a terminal device.
  • access points and terminal devices wirelessly communicate with each other using established links.
  • a terminal device performs carrier sensing based on CSMA/CA for each link, and wirelessly transmits a data frame to an access point using a link for which transmission rights have been acquired.
  • An access point is also called a base station.
  • a terminal device will be simply referred to as a terminal, and a frequency channel will be simply referred to as a channel.
  • the access point and terminal support multi-link operation and establish multiple links between the access point and the terminal. Multiple links established between an access point and a terminal are called multilinks (ML). Access points and terminals further support r-TWT operation.
  • the access point schedules r-TWT service periods for each terminal during which it is given or assigned an opportunity to transmit. During the r-TWT service period, each terminal can preferentially transmit data frames on the link for which the r-TWT service period is set. Each terminal may use the r-TWT service period to transmit data frames containing traffic with delay requirements.
  • the terminal wirelessly transmits a data frame to the access point using the following procedure, for example.
  • the terminal performs carrier sense on the multiple links included in the multilink in order to check the status of the multiple channels corresponding to each of these links.
  • the terminal determines that the channel is idle when the channel has not been used for a certain period of time, and determines that the channel is busy when it detects that the channel is in use. In response to confirming that the channel is idle, the terminal recognizes that it has acquired the right to transmit on the link corresponding to the channel.
  • the terminal checks whether data frame transmission can be completed by the start of the r-TWT service period for each of the links for which transmission rights have been acquired. If there is a link on which data frame transmission can be completed by the start of the r-TWT service period, the terminal transmits the data frame on that link. If there are no links on which data frame transmission can be completed by the start of the r-TWT service period, the terminal postpones transmission. For example, after the r-TWT service period for any link ends, the terminal may transmit data frames on that link.
  • FIG. 1 schematically shows an example of the configuration of a communication system 50 including a wireless network 45 according to an embodiment.
  • System and “network” described herein may be used interchangeably.
  • the communication system 50 includes an access point 10, a terminal 20, and a server 30. Access point 10 and terminal 20 are included in wireless network 45 .
  • the access point 10 is a wireless LAN access point.
  • the access point 10 can be wirelessly connected to one or more terminals.
  • the number of terminals wirelessly connected to the access point 10 changes dynamically.
  • the access point 10 is wirelessly connected to the terminal 20.
  • Access point 10 establishes one or more links with terminal 20 and uses the established links to wirelessly communicate with terminal 20.
  • Access point 10 is wired connected to a communications network 40, which may include the Internet.
  • the terminal 20 is a wireless terminal equipped with a wireless communication function, and operates as a wireless LAN client.
  • wireless terminals include smart phones, mobile phones, personal computers, desktop PCs, laptop PCs, and Internet of things (IoT) sensors/devices.
  • Terminal 20 accesses communication network 40 via access point 10 .
  • terminal 20 exchanges data with server 30 on communication network 40 via access point 10 .
  • the server 30 is connected to a communication network 40.
  • the server 30 may be a service provider that provides services such as network games, and exchanges data related to the service with the terminal 20 via the communication network 40.
  • Wireless communication between the access point 10 and the terminal 20 is based on the IEEE802.11 standard. Note that although wireless communication based on the IEEE802.11 standard is described as an example in this specification, a wireless communication standard different from the IEEE802.11 standard may be used.
  • the access point 10 and terminal 20 support multilink operation and r-TWT operation.
  • An access point 10 that supports multilink operation is also called an access point multilink device (AP MLD), and a terminal 20 that supports multilink operation is also called a non-access point multilink device (non-AP MLD).
  • AP MLD access point multilink device
  • non-AP MLD non-access point multilink device
  • the IEEE 802.11 standard defines the first layer and the second layer MAC (media access control) sublayer of the OSI (Open Systems Interconnection) model.
  • OSI Open Systems Interconnection
  • communication functions are divided into seven layers (1st layer: physical layer, 2nd layer: data link layer, 3rd layer: network layer, 4th layer: transport layer, 5th layer: session layer, 6th layer) : Presentation layer, 7th layer: Application layer).
  • the data link layer includes, for example, an LLC (logical link control) layer and a MAC layer.
  • the LLC layer forms an LLC packet by adding, for example, a DSAP (destination service access point) header and an SSAP (source service access point) header to data input from an upper layer.
  • DSAP destination service access point
  • SSAP source service access point
  • the MAC layer generates a MAC frame by adding a MAC header to an LLC packet, for example.
  • the physical layer generates a radio frame by adding, for example, a preamble and a PHY (physical layer) header to the MAC frame.
  • processing for the first and second MAC sublayers defined by the IEEE802.11 standard will be mainly described, and descriptions of processing for other layers will be omitted.
  • FIG. 2 schematically shows an example of link management information held by the terminal 20.
  • the link management information shown in FIG. 2 indicates the state of the link between the access point 10 and the terminal 20.
  • the link management information includes link ID, frequency band information, channel ID, link information, multilink information, and traffic information.
  • the link ID is an identifier (for example, an identification number) assigned to the link.
  • Frequency band information is information indicating a frequency band used for a link.
  • Channel ID is the identifier of the channel used for the link.
  • the terminal 20 can use three links.
  • a link whose link ID is 1 is a link that uses a channel in the 6 GHz band, and is currently using channel CH1 included in the 6 GHz band.
  • the link whose link ID is 2 is a link that uses a channel in the 5 GHz band, and is currently using channel CH2 included in the 5 GHz band.
  • the link whose link ID is 3 is a link that uses a channel in the 2.4 GHz band, and is currently using channel CH3 included in the 2.4 GHz band.
  • different frequency bands may be allocated to the plurality of links of the multilink ML, or different channels of the same frequency band may be allocated to each other.
  • the link information indicates whether a link is established between the access point 10 and the terminal 20.
  • the multilink information indicates whether a multilink ML consisting of a plurality of links is established between the access point 10 and the terminal 20. If a multilink ML is established, the multilink information indicates which links constitute the multilink ML. In the example shown in FIG. 2, the multilink ML is configured from three links with link IDs 1 to 3.
  • the traffic information indicates a TID (Traffic Indicator) assigned to each link.
  • the TID is an identifier that indicates each piece of traffic, and each piece of traffic may be associated with an access category. Access categories include, for example, VO (Voice), VI (Video), BE (Best Effort), and BK (Background).
  • VO Vehicle
  • VI Video
  • BE Best Effort
  • BK Background
  • Each of TID#1, TID#2, TID#3, and TID#4 shown in FIG. 2 corresponds to one of VO, VI, BE, and BK.
  • TID #1 is assigned to three links with link IDs 1 to 3.
  • TID #2 is assigned to the link whose link ID is 1
  • TID #3 is assigned to the link whose link ID is 2
  • TID #4 is assigned to the link whose link ID is 3. In this way, in multi-link ML, one or more links can be assigned to one TID.
  • the access point 10 holds link management information similar to the link management information illustrated in FIG. 2 for each terminal wirelessly connected to the access point 10. That is, the link management information held by the access point 10 indicates the state of the link between the access point 10 and each terminal wirelessly connected to the access point 10.
  • FIG. 3 schematically shows an example of the hardware configuration of the access point 10.
  • the access point 10 includes, for example, a CPU (Central Processing Unit) 11, a program memory 12, a RAM (Random Access Memory) 13, a wireless communication module 14, and a wired communication module 15.
  • the CPU 11 is an integrated circuit that can execute various programs, and controls the overall operation of the access point 10.
  • the program memory 12 is a nonvolatile semiconductor memory such as a ROM (read only memory) or a flash memory, and stores programs and control data for controlling the access point 10 .
  • the RAM 13 is, for example, a volatile semiconductor memory, and is used as a work area for the CPU 11.
  • the wireless communication module 14 is a circuit used for transmitting and receiving data using wireless signals.
  • the wireless communication module 14 includes a plurality of communication modules each corresponding to a plurality of links, and each communication module is connected to an antenna corresponding to the communication module among the plurality of antennas. Wireless communication module 14 can transmit and receive frames on multiple links simultaneously.
  • the wired communication module 15 is a circuit used for transmitting and receiving data using wired signals, and is connected to the communication network 40.
  • FIG. 4 schematically shows an example of the hardware configuration of the terminal 20.
  • the terminal 20 includes, for example, a CPU 21, a program memory 22, a RAM 23, a wireless communication module 24, a display 25, and a storage 26.
  • the CPU 21 is an integrated circuit that can execute various programs, and controls the overall operation of the terminal 20.
  • the program memory 22 is a nonvolatile semiconductor memory such as a ROM, and stores programs and control data for controlling the terminal 20. Storage 26 may be used as program memory 22.
  • the RAM 23 is, for example, a volatile semiconductor memory, and is used as a work area for the CPU 21.
  • the wireless communication module 24 is a circuit used for transmitting and receiving data using wireless signals.
  • the wireless communication module 24 includes a plurality of communication modules each corresponding to a plurality of links, and each communication module is connected to an antenna corresponding to the communication module among the plurality of antennas. Wireless communication module 24 can transmit and receive frames on multiple links simultaneously.
  • the display 25 displays information such as a GUI (Graphical User Interface) provided by application software, for example.
  • the display 25 may have a function as an input interface for the terminal 20.
  • a touch panel may be provided on the display 25.
  • the storage 26 is a nonvolatile storage device, and stores data including, for example, system software of the terminal 20.
  • the hardware configuration shown in FIG. 4 is an example, and the terminal 20 may have a different hardware configuration from that shown in FIG. 4.
  • the terminal 20 is an IoT device or the like, the display 25 may be deleted from the terminal 20.
  • FIG. 5 schematically shows an example of the functional configuration of the access point 10 and the terminal 20.
  • processing related to uplink transmission will be mainly explained, and specific explanation of processing related to downlink transmission will be omitted.
  • Downlink transmissions may be performed in a similar manner to the processes described for uplink transmissions.
  • the access point 10 can perform a modulation process similar to the modulation process described below in relation to the terminal 20, and the terminal 20 can perform a demodulation process similar to the demodulation process described below in relation to the access point 10. be able to.
  • Uplink transmission refers to transmission from terminal 20 to access point 10
  • downlink transmission refers to transmission from access point 10 to terminal 20.
  • the access point 10 includes an LLC processing section 110, a link management section 120, and a communication section 130.
  • the LLC processing unit 110 can be realized by a combination of the CPU 11 and the wired communication module 15.
  • the link management section 120 and the communication section 130 can be realized by the wireless communication module 14 or a combination of the CPU 11 and the wireless communication module 14.
  • the LLC processing unit 110 performs LLC layer processing and upper layer processing (third to seventh layer) on the input signal. For example, the LLC processing unit 110 receives an LLC packet from the link management unit 120 and extracts data from the LLC packet.
  • the link management unit 120 performs MAC layer processing on the input signal. Further, the link management unit 120 manages links with each terminal.
  • the link management section 120 includes a data processing section 121, a MAC frame processing section 122, and a management section 123.
  • the data processing unit 121 receives the MAC frame from the MAC frame processing unit 122, extracts the LLC packet from the MAC frame, and sends the LLC packet to the LLC processing unit 110.
  • the MAC frame processing unit 122 Upon receiving the MAC frame from the communication unit 130, the MAC frame processing unit 122 sends the MAC frame to the data processing unit 121 or the management unit 123 depending on the type of the MAC frame. Specifically, the MAC frame processing unit 122 sends the MAC frame to the data processing unit 121 when the MAC frame is a data frame, and sends the MAC frame to the data processing unit 121 when the MAC frame is a management frame or a control frame. is sent to the management section 123.
  • the management unit 123 manages links with each terminal based on information included in the management frame transmitted by each terminal. For example, the management unit 123 sets up a multilink with a terminal via the communication unit 130. Specifically, in response to receiving a connection request from the terminal 20, the management unit 123 performs association processing and subsequent authentication processing in order to establish multiple links between the access point 10 and the terminal 20. Execute. Data exchange between the access point 10 and the terminal 20 is performed using one or more links included in the multilink.
  • the management unit 123 holds link management information as illustrated in FIG. 2.
  • the access point 10 may negotiate with the terminal 20 an MCS (Modulation and Coding Scheme) used for communication between the access point 10 and the terminal 20.
  • MCS Modulation and Coding Scheme
  • the management unit 123 performs r-TWT setup for each terminal that supports r-TWT operation. For example, the management unit 123 sets the r-TWT service period and the links to be used during the r-TWT service period. The management unit 123 may set the r-TWT service period according to the cycle in which low-latency traffic occurs at the terminal. Specifically, the management unit 123 determines the time at which the r-TWT service period starts based on the generation cycle of low-latency traffic so that the r-TWT service period occurs in synchronization with the generation of low-latency traffic. , the period of the r-TWT service period, and the duration of the r-TWT service period.
  • the management unit 123 may obtain the generation cycle of low-latency traffic using any method.
  • the management unit 123 may obtain a data generation cycle set for an application that generates low-latency traffic.
  • the management unit 123 may dynamically determine, for each r-TWT service period, the links to be used during the r-TWT service period.
  • the management unit 123 generates a beacon frame including service period information that specifies the r-TWT service period set for each terminal, and transmits it via the MAC frame processing unit 122 and the communication unit 130.
  • a beacon frame is a type of management frame.
  • the service period information includes information indicating the time when the r-TWT service period starts, information indicating the duration of the r-TWT service period, information indicating the cycle of the r-TWT service period, and information used in the r-TWT service period. It may include information indicating the link to be used.
  • the service period information may further include information indicating a communication suspension period (quiet period) during which terminals other than those for which the r-TWT service period is set are suppressed from communicating.
  • the start of the communication outage period coincides with the start of the r-TWT service period.
  • the communication outage period may be shorter than the r-TWT service period.
  • the communication unit 130 wirelessly communicates with each terminal.
  • the communication unit 130 includes a wireless signal processing unit 131 configured to transmit and receive wireless signals using a 6 GHz band channel, and a wireless signal processing unit 131 configured to transmit and receive wireless signals using a 5 GHz band channel. 132, and a wireless signal processing unit 133 configured to transmit and receive wireless signals using a 2.4 GHz band channel.
  • the wireless signal processing unit 131 transmits and receives frames between the access point 10 and the terminal through wireless communication. Specifically, the wireless signal processing unit 131 performs physical layer processing on input data or wireless signals. For example, the radio signal processing unit 131 receives a radio signal from a terminal via an antenna, and performs predetermined demodulation processing on the received radio signal to obtain a radio frame.
  • the predetermined demodulation processing includes, for example, frequency conversion, OFDM demodulation, Fast Fourier Transform (FFT), subcarrier demodulation, deinterleaving, and Viterbi decoding.
  • the radio signal processing unit 131 then extracts the MAC frame from the radio frame and sends the MAC frame to the MAC frame processing unit 122.
  • the radio signal processing units 132 and 133 perform the same processing as the radio signal processing unit 131.
  • the terminal 20 includes an application execution section 210, an LLC processing section 220, a link management section 230, and a communication section 240.
  • the application execution unit 210 and the LLC processing unit 220 may be implemented by the CPU 21.
  • the link management section 230 and the communication section 240 can be realized by the wireless communication module 24 or a combination of the wireless communication module 24 and the CPU 21.
  • the application execution unit 210 executes an application such as an application that exchanges data with the server 30 shown in FIG. 1.
  • the LLC processing unit 220 performs LLC layer and upper layer processing on input data. For example, the LLC processing unit 220 receives data from the application execution unit 210, adds a DSAP header, an SSAP header, etc. to the data, generates an LLC packet, and sends the LLC packet to the link management unit 230.
  • the link management unit 230 performs MAC layer processing on the input signal. Furthermore, the link management unit 230 manages links with the access point 10.
  • the link management section 230 includes a data processing section 231, a MAC frame processing section 232, a management section 233, and a communication control section 234.
  • the data processing unit 231 receives the LLC packet from the LLC processing unit 220, adds a MAC header to the LLC packet to generate a MAC frame, and sends the MAC frame to the MAC frame processing unit 232.
  • This MAC frame is a data frame.
  • the MAC frame processing unit 232 receives the MAC frame from the data processing unit 231 and sends it to the communication unit 240. Further, upon receiving a MAC frame from the communication unit 240, the MAC frame processing unit 232 sends the MAC frame to the data processing unit 231 or the management unit 233 depending on the type of the MAC frame. Specifically, the MAC frame processing unit 232 sends the MAC frame to the data processing unit 231 when the MAC frame is a data frame, and sends the MAC frame to the data processing unit 231 when the MAC frame is a management frame or a control frame. is sent to the management section 233.
  • the management unit 233 manages the link with the access point 10 based on information included in the management frame transmitted by the access point 10. For example, the management unit 233 sets up a multilink with the access point 10 via the communication unit 240. Specifically, the management unit 233 executes a protocol related to association, including sending a connection request to the access point 10, and executes a protocol related to authentication subsequent to the association.
  • the management unit 233 holds link management information as illustrated in FIG. 2.
  • the link management information is referred to by the communication control unit 234.
  • the management unit 233 extracts service period information that specifies the r-TWT service period set for each terminal from the beacon frame transmitted by the access point 10, and sends the extracted service period information to the communication control unit 234. .
  • the communication control unit 234 controls the operation of the communication unit 240. For example, the communication control unit 234 adaptively selects a link to be used for communication with the access point 10. Further, the communication control unit 234 adjusts the timing of transmitting the data frame to the access point 10. The communication control unit 234 will be explained in detail later.
  • the communication unit 240 wirelessly communicates with the access point 10 under the control of the communication control unit 234.
  • the communication unit 240 includes a wireless signal processing unit 241 configured to transmit and receive wireless signals using a 6 GHz band channel, and a wireless signal processing unit 241 configured to transmit and receive wireless signals using a 5 GHz band channel. 242, and a wireless signal processing unit 243 configured to transmit and receive wireless signals using a 2.4 GHz band channel.
  • the wireless signal processing unit 241 transmits and receives frames between the access point 10 and the terminal 20 by wireless communication. Specifically, the wireless signal processing unit 241 performs physical layer processing on input data or wireless signals.
  • the radio signal processing unit 241 receives a MAC frame from the MAC frame processing unit 232, generates a radio frame by adding a preamble, a PHY (physical layer) header, etc. to the MAC frame, and performs predetermined modulation processing. Converts the radio frame into a radio signal and radiates the radio signal via an antenna. Modulation processing includes, for example, convolutional coding, interleaving, subcarrier modulation, inverse fast Fourier transform (IFFT), OFDM (orthogonal frequency division multiplexing) modulation, and frequency conversion.
  • the radio signal processing units 242 and 243 perform the same processing as the radio signal processing unit 241.
  • the application execution unit 210 sends the data to the LLC processing unit 220.
  • the LLC processing unit 220 receives data from the application execution unit 210, generates an LLC packet containing the data, and sends the LLC packet to the data processing unit 231.
  • the data processing unit 231 receives the LLC packet from the LLC processing unit 220, generates a MAC frame from the LLC packet, and sends the MAC frame to the MAC frame processing unit 232.
  • the MAC frame processing unit 232 receives the MAC frame from the data processing unit 231 and sends the MAC frame to the communication unit 240.
  • the MAC frame processing section 232 sends the MAC frame to a plurality of wireless signal processing sections corresponding to a plurality of links included in the multilink.
  • the MAC frame processing unit 232 refers to link management information held by the management unit 233 in order to identify the link established with the access point 10. When the link management information is the link management information shown in FIG. 2, three links are established between the access point 10 and the terminal 20.
  • the communication unit 240 receives the MAC frame from the MAC frame processing unit 232 and temporarily stores the MAC frame.
  • the communication unit 240 wirelessly transmits the MAC frame according to instructions from the communication control unit 234.
  • the wireless signal processing units 241, 242, and 243 receive the same MAC frame from the MAC frame processing unit 232, one of them wirelessly transmits the MAC frame, and the remaining wireless signal processing units transmit the MAC frame. Discard the frame.
  • the communication control unit 234 determines to use a link whose link ID is 1, the wireless signal processing unit 241 generates a wireless frame from the MAC frame, and performs modulation processing to convert the wireless frame into a wireless signal. and radiate a radio signal through an antenna.
  • the communication unit 130 receives a wireless signal from the terminal 20.
  • One of the wireless signal processing units 131, 132, and 133 receives a wireless signal from the terminal 20.
  • the wireless signal processing unit 131 receives a wireless signal from the terminal 20.
  • the radio signal processing unit 131 performs demodulation processing on the radio signal to obtain a radio frame.
  • the radio signal processing unit 131 extracts a MAC frame from the radio frame and sends the MAC frame to the MAC frame processing unit 122.
  • the MAC frame processing unit 122 receives a MAC frame from the communication unit 130. Since this MAC frame is a data frame, the MAC frame processing unit 122 sends the MAC frame to the data processing unit 121.
  • the data processing unit 121 receives the MAC frame from the MAC frame processing unit 122, extracts the LLC packet from the MAC frame, and sends the LLC packet to the LLC processing unit 110.
  • the LLC processing unit 110 receives the LLC packet from the data processing unit 121, extracts data from the LLC packet, and transmits the data to the server 30 on the communication network 40.
  • FIG. 6 schematically shows an example of the functional configuration of the channel access function of the radio signal processing unit 241.
  • the radio signal processing section 241 includes a classification section 2411, queues 2412A, 2412B, 2412C, 2412D, carrier sense execution sections 2413A, 2413B, 2413C, 2413D, an internal collision management section 2414, and a modulation section 2415. include.
  • the classification unit 2411 classifies the data frame into a plurality of access categories based on the TID included in the MAC header in the data frame. In the example shown in FIG. 6, the classification unit 2411 classifies data frames into four access categories VO, VI, BE, and BK.
  • the classification unit 2411 inputs the data frame into the queue 2412A when the data frame is classified into the access category VO, inputs the data frame into the queue 2412B when the data frame is classified into the access category VI, and inputs the data frame into the queue 2412B when the data frame is classified into the access category VI.
  • the data frame is classified as BE, the data frame is input into the queue 2412C, and when the data frame is classified into the access category BK, the data frame is input into the queue 2412D.
  • Each of queues 2412A, 2412B, 2412C, and 2412D buffers input data frames.
  • Carrier sense execution units 2413A, 2413B, 2413C, and 2413D are provided corresponding to queues 2412A, 2412B, 2412C, and 2412D, respectively.
  • Carrier sense execution units 2413A, 2413B, 2413C, and 2413D perform similar processing except that different access parameter sets are used.
  • the access parameter set includes, for example, four access parameters: CWmin, CWmax, AIFS (Arbitration Inter Frame Space), and TXOP (Transmission Opportunity) Limit.
  • CWmin and CWmax indicate the minimum and maximum values of the contention window, respectively.
  • the contention window is a parameter used to determine transmission waiting time for collision avoidance.
  • AIFS indicates transmission latency.
  • TXOPLimit indicates the upper limit value of the channel occupation period TXOP.
  • the access category for which the shorter CWmin, CWmax, and AIFS are set the easier it is to acquire the transmission right. Furthermore, the larger the TXOPLimit is set in the access category, the larger the amount of data that can be transmitted with one transmission right.
  • the carrier sense execution unit 2413A will be explained as a representative.
  • the carrier sense execution unit 2413A executes carrier sense based on CSMA/CA for the link whose link ID is 1, according to a preset access parameter set.
  • carrier sense execution unit 2413A starts carrier sense, carrier sense execution unit 2413A notifies communication control unit 234 of the carrier sense status. For example, when the channel remains unused, the carrier sense execution unit 2413A notifies the communication control unit 234 of the scheduled time when the transmission right will be acquired and the channel occupation time.
  • the carrier sense execution unit 2413A detects that the channel is busy, it notifies the communication control unit 234 that carrier sense is to be interrupted.
  • the carrier sense execution unit 2413A Upon acquiring the transmission right, the carrier sense execution unit 2413A notifies the communication control unit 234 that the transmission right has been acquired. In response to the notification from the carrier sense execution unit 2413A, the communication control unit 234 generates a transmission start signal instructing to start transmission, a transmission postponement signal instructing transmission postponement, or another link (wireless signal processing unit 242 or 243). A transmission stop signal indicating that data frame transmission will be performed is sent to the carrier sense execution unit 2413A. In response to receiving the transmission instruction signal from the communication control unit 234, the carrier sense execution unit 2413A takes out the data frame from the queue 2412A and sends the data frame to the modulation unit 2415 via the internal collision management unit 2414.
  • the carrier sense execution unit 2413A postpones transmission in response to receiving the transmission postponement signal from the communication control unit 234. For example, the carrier sense execution unit 2413A waits until it receives a signal from the communication control unit 234 instructing restart of carrier sense. In response to receiving the transmission stop signal from the communication control unit 234, the carrier sense execution unit 2413A discards the data frame stored at the head of the queue 2412A.
  • the internal collision management unit 2414 prevents transmission collisions when two or more carrier sense execution units acquire transmission rights at the same time. Specifically, when receiving data frames from two or more carrier sense execution units at the same time, the internal collision management unit 2414 selects an access category with a higher priority in order to transmit a data frame of an access category with a higher priority. The category data frame is sent to modulation section 2415.
  • the modulation unit 2415 receives the data frame from the internal collision management unit 2414, generates a radio frame from the data frame, converts the radio frame into a radio signal by performing modulation processing, and radiates the radio signal via the antenna.
  • Each of the radio signal processing units 242 and 243 has a channel access function similar to that shown in FIG.
  • data frame transmission in the terminal 20 will be explained in detail.
  • transmission of data frames classified into access category VO will be explained.
  • Data frames classified into other access categories may be transmitted in a manner similar to that described below.
  • FIG. 7 schematically shows an example of the functional configuration of the communication control unit 234 and the wireless signal processing units 241, 242, and 243.
  • a part of the functional configuration of each of the radio signal processing sections 241, 242, and 243 is shown.
  • the radio signal processing unit 241 the classification unit 2411, queues 2412B, 2412C, 2412D, carrier sense execution units 2413B, 2413C, 2413D, internal collision management unit 2414, and modulation unit 2415 shown in FIG. 6 are omitted. There is.
  • the radio signal processing section 242 includes a queue 2422A and a carrier sense execution section 2423A.
  • Queue 2422A buffers data frames classified into access category VO.
  • the carrier sense execution unit 2423A executes carrier sense based on CSMA/CA for the link whose link ID is 2, according to the same access parameter set as that of the carrier sense execution unit 2413A.
  • the radio signal processing section 243 includes a queue 2432A and a carrier sense execution section 2433A. Queue 2432A buffers data frames classified into access category VO.
  • the carrier sense execution unit 2433A executes carrier sense based on CSMA/CA for the link whose link ID is 3, according to the same access parameter set as that of the carrier sense execution unit 2413A. Since the MAC frame processing section 232 sends each data frame to the radio signal processing sections 241, 242, and 243, the same data frames are stored in the queues 2412A, 2422A, and 2432A.
  • the carrier sense execution units 2413A, 2423A, and 2433A can simultaneously execute carrier sense. Therefore, transmission rights may be acquired for multiple links at the same time. Upon acquiring the transmission right, each of the carrier sense execution units 2413A, 2423A, and 2433A notifies the communication control unit 234 that the transmission right has been acquired.
  • the carrier sense execution units 2413A, 2423A, and 2433A are collectively referred to as a carrier sense execution unit 245.
  • the communication control unit 234 includes an instruction unit 2341 , a link selection unit 2342 , a frame exchange period calculation unit 2343 , a communicable period calculation unit 2344 , and a determination unit 2345 .
  • the instruction unit 2341 exchanges information with the carrier sense execution unit 245. For example, the instruction unit 2341 issues instructions to the carrier sense execution units 2413A, 2423A, and 2433A. Further, the instruction unit 2341 receives notifications indicating that the transmission right has been acquired from the carrier sense execution units 2413A, 2423A, and 2433A, and sends the received notifications to the communicable period calculation unit 2344.
  • the frame exchange period calculation unit 2343 calculates a frame exchange period including the time period required for transmitting a data frame to the access point 10.
  • the frame exchange period indicates the time period required for frame exchange between the access point 10 and the terminal 20.
  • the frame exchange period may indicate the period from the time when the transmission right is acquired to the time when processing related to data frame transmission to the access point 10 ends, indicated by ⁇ in FIG. 8 .
  • a process related to transmitting a data frame to the access point 10 may refer to a process of transmitting the data frame to the access point 10, transmitting the data frame to the access point 10, and receiving a response from the access point 10 to the data frame (e.g. It may also show a series of processes for receiving an acknowledgment (ACK).
  • the frame exchange period may indicate the time period required to transmit a data frame to the access point 10, and to receive a response to the data frame from the access point 10. It may also indicate the time period required.
  • the frame exchange period calculation unit 2343 receives information indicating the size of the data frame to be transmitted (the data frame held at the head of the queue 2412A) from the carrier sense execution unit 2413A via the instruction unit 2341, Information indicating the MCS applied to data frame transmission to the access point 10 is received from the management unit 233 .
  • the frame exchange period calculation unit 2343 calculates the transmission waiting time based on the size of the data frame to be transmitted, the MCS applied to the data frame transmission, and the average backoff value determined by the contention window. , the time period required to transmit the data frame to the access point 10 is calculated.
  • the transmission waiting time calculated by the average backoff value determined by the contention window corresponds to the overhead related to acquiring the transmission right.
  • the communicable period calculation unit 2344 receives a notification indicating one or more links for which transmission rights have been acquired from the carrier sense execution unit 245 via the instruction unit 2341.
  • the communicable period calculation unit 2344 calculates a communicable period indicating the time period until the start of the r-TWT service period for each link for which the transmission right has been acquired.
  • the communicable period may indicate the period from the time when the transmission right is acquired to the time when the r-TWT service period starts, which is indicated by ⁇ in FIG.
  • the communication available period calculation unit 2344 checks whether an r-TWT service period is scheduled for the link.
  • the r-TWT service period may be set for the terminal 20 or may be set for another terminal. If the r-TWT service period is set for another terminal, the start of the r-TWT service period refers to the start of the communication suspension period.
  • the communicable period calculation unit 2344 calculates the communicable period for each of these links. If there is a link for which an r-TWT service period has not been scheduled, the communicable period calculation unit 2344 notifies the link selection unit 2342 of the link for which an r-TWT service period has not been scheduled. Alternatively, even if there is a link for which an r-TWT service period is not scheduled, the communicable period calculation unit 2344 may calculate the communicable period for all links for which transmission rights have been acquired. In this case, the communicable period calculation unit 2344 may set the communicable period for a link for which an r-TWT service period is not scheduled to a value indicating a sufficiently long period.
  • the determination section 2345 Based on the comparison between the frame exchange period calculated by the frame exchange period calculation section 2343 and the communication possible period calculated by the communication possible period calculation section 2344 for each link for which the transmission right has been acquired, the determination section 2345 performs the following: It is determined whether the data exchange including data frame transmission to the access point 10 is completed by the start of the r-TWT service period. If the frame exchange period ⁇ is shorter than the communication available period ⁇ as shown in FIG. If the exchange period ⁇ is longer than the communicable period ⁇ , it is determined that the data exchange will not end by the start of the r-TWT service period.
  • the determination unit 2345 notifies the instruction unit 2341 or the link selection unit 2342 of the determination result. If there is one or more links for which the frame exchange period ⁇ is shorter than the communicable period ⁇ , the determination unit 2345 sends a determination result notification to the link selection unit 2342. If there is one link whose frame exchange period ⁇ is shorter than the communicable period ⁇ , the determination result notification includes information indicating that link. If there are multiple links whose frame exchange period ⁇ is shorter than the communicable period ⁇ , the determination result notification includes information indicating the link with the largest difference between the communicable period ⁇ and the frame exchange period ⁇ .
  • the determination unit 2345 sends a determination result notification to the instruction unit 2341 indicating that there is no link for which data exchange ends before the start of the r-TWT service period. do.
  • the link selection unit 2342 receives the determination result notification from the determination unit 2345, selects a link to be used for transmitting the data frame to the access point 10 from among the multi-links based on the determination result notification, and sends the selected link to the instruction unit 2341. to notify. Specifically, the link selection unit 2342 selects the link indicated by the determination result notification. When the determination result notification indicates multiple links, the link selection unit 2342 selects any one of those links. When receiving a notification from the communication available period calculation unit 2344, the link selection unit 2342 selects a link based on the notification and notifies the instruction unit 2341 of the selected link. For example, the link selection unit 2342 selects the link indicated by the notification from the communicable period calculation unit 2344.
  • the determination result notification may include information indicating the plurality of links whose frame exchange period ⁇ is shorter than the communicable period ⁇ .
  • the link selection unit 2342 selects any one of those links.
  • the instruction unit 2341 instructs the carrier sense execution unit 245 to transmit the data frame using the link selected by the link selection unit 2342. For example, when the link selection unit 2342 selects a link whose link ID is 2, the instruction unit 2341 sends a transmission start signal to the carrier sense execution unit 2423A, and sends a transmission stop signal to the carrier sense execution units 2413A and 2433A. do.
  • the instruction unit 2341 instructs the carrier sense execution unit 245 to postpone data frame transmission. Specifically, the instruction unit 2341 sends a transmission postponement signal to the carrier sense execution units 2413A, 2423A, and 2433A.
  • the instruction section 2341, link selection section 2342, and determination section 2345 may be collectively referred to as the transmission control section 2346. If there is a link in which the frame exchange period ⁇ is shorter than the communicable period ⁇ , the transmission control unit 2346 transmits a data frame on that link via the communication unit 240, and when the frame exchange period ⁇ is shorter than the communicable period ⁇ . Configured to defer data frame transmission if there is no short link. When there are multiple links whose frame exchange period ⁇ is shorter than the communicable period ⁇ , the transmission control unit 2346 transmits the data frame using the link with the largest difference obtained by subtracting the frame exchange period ⁇ from the communicable period ⁇ . may be configured.
  • the transmission control unit 2346 may be configured to perform data frame transmission on the link in response to the fact that there is a link for which a service period is not scheduled.
  • FIG. 10 schematically shows a wireless communication method according to an embodiment. Specifically, FIG. 10 schematically shows an example of a method in which the terminal 20 wirelessly transmits a data frame to the access point 10. The process shown in FIG. 10 is executed for each access category individually. Here, processing regarding access category VO will be explained. Let M be the number of links established between the access point 10 and the terminal 20.
  • the frame exchange period calculation unit 2343 calculates a frame exchange period ⁇ that includes the time period required for transmitting a data frame to the access point 10. For example, the frame exchange period calculation unit 2343 calculates the time period required to transmit the data frame to the access point 10 based on the size of the data frame to be transmitted and the MCS applied to the data frame transmission, and calculates the time period required for transmitting the data frame to the access point 10.
  • the frame exchange period ⁇ is obtained by adding the time required to receive an ACK from the access point 10 and the overhead related to acquiring the transmission right to the period.
  • the carrier sense execution unit 245 performs carrier sense for each of the M links and acquires transmission rights for the m links.
  • m is an integer greater than or equal to 2 and less than or equal to M.
  • the m links for which transmission rights have been acquired are expressed as links 1 to m.
  • the carrier sense execution unit 2413A performs carrier sense for the link whose link ID is 1
  • the carrier sense execution unit 2423A performs carrier sense for the link whose link ID is 2.
  • the unit 2433A performs carrier sense for the link whose link ID is 3.
  • the communicable period calculation unit 2344 calculates the communicable period ⁇ for each of links 1 to m. It is assumed here that an r-TWT service period is scheduled for all links 1-m.
  • the communicable period ⁇ for link N is expressed as ⁇ N.
  • N is an integer greater than or equal to 1 and less than or equal to m.
  • the communicable period ⁇ N may indicate the time interval from the reference time to the time when the r-TWT service period set for link N starts.
  • the reference time indicates the time when data frame transmission can be started.
  • the time at which the transmission right for link N was acquired can be used as the reference time.
  • step S1004 the determining unit 2345 determines whether there is a link whose frame exchange period ⁇ is shorter than the communication available period ⁇ .
  • the fact that the frame exchange period ⁇ is shorter than the communication availability period ⁇ N indicates that the frame exchange is completed before the start of the r-TWT service period scheduled for link N.
  • step S1007 the transmission control unit 2346 postpones data frame transmission.
  • the determining unit 2345 notifies the instructing unit 2341 that there is no link for which frame exchange can be completed before the start of the r-TWT service period, and in response to the notification from the determining unit 2345, the instructing unit 2341 transmits the A postponement signal is sent to the carrier sense execution unit 245.
  • step S1005 the link selection unit 2342 selects the link with the largest difference obtained by subtracting the frame exchange period ⁇ from the communicable period ⁇ . In other words, the link selection unit 2342 selects the link with the longest communicable period ⁇ . For example, when the communication available periods ⁇ 1 and ⁇ 2 for links 1 and 2 are both shorter than the frame exchange period ⁇ ( ⁇ 1 , ⁇ 2 ), the frame exchange period ⁇ is changed from the communication available period ⁇ 1 .
  • step S1006 the transmission control unit 2346 transmits a data frame via the communication unit 240 on the link selected in step S1005.
  • the instruction unit 2341 instructs the carrier sense execution unit 245 to perform data frame transmission on the selected link.
  • the instruction unit 2341 sends a transmission start signal to the carrier sense execution unit 2413A, and sends a transmission stop signal to the carrier sense execution units 2423A and 2433A.
  • the carrier sense execution unit 2413A takes out the data frame from the queue 2412A and sends the data frame to the modulation unit 2415 via the internal collision management unit 2414.
  • the modulator 2415 performs modulation processing on the data frame to generate a wireless signal, and transmits the wireless signal via the antenna.
  • the carrier sense execution units 2423A and 2433A discard the data frame stored at the head of the queues 2422A and 2432A.
  • step S1003 if the r-TWT service period is not scheduled for one or more of links 1 to m, the communication available period calculation unit 2344 determines that the r-TWT service period is not scheduled.
  • the communicable period ⁇ may be set to a predetermined value indicating a sufficiently long period for each link that is not available. In this case, data frame transmission will occur on a link for which no r-TWT service period is scheduled.
  • the process may skip steps S1003 to S1005 and proceed to step S1006. good. In this case as well, data frame transmission will occur on links for which no r-TWT service period is scheduled.
  • step S1005 if the link has a frame exchange period ⁇ shorter than the communication period ⁇ , the link selection unit 2342 selects a link other than the link with the largest difference obtained by subtracting the frame exchange period ⁇ from the communication period ⁇ . You can. Specifically, when there are multiple links whose frame exchange period ⁇ is shorter than the communicable period ⁇ , the link selection unit 2342 may select any one of the links.
  • the determining unit 2345 may determine that the frame exchange can be completed before the start of the r-TWT service period scheduled for link N. In this case, in step S1004, the determining unit 2345 determines whether there is a link whose frame exchange period ⁇ is less than or equal to the communication possible period ⁇ .
  • the terminal 20 establishes multiple links with the access point 10 and selectively uses the multiple links to transmit data frames to the access point 10.
  • Terminal 20 calculates a frame exchange period that includes the time period required to transmit data frames to access point 10.
  • Terminal 20 calculates a communicable period for each of multiple links when transmission rights for multiple links are acquired and r-TWT service periods are scheduled for all of these links. If there is a link whose frame exchange period is shorter than the communicable period, the terminal 20 transmits the data frame on that link, and if there is no link whose frame exchange period is shorter than the communicable period, the terminal 20 postpones the data frame transmission. do.
  • the terminal 20 may transmit data frames using the link with the longest communicable period. This configuration increases the certainty that data frame transmission will be completed by the start of the r-TWT service period.
  • the terminal 20 may transmit a data frame on a link for which an r-TWT service period is not scheduled. According to this configuration, it is possible to omit the process of calculating the communicable period.
  • the terminal 20 may calculate the communicable period for each of the multiple links for which transmission rights have been acquired through carrier sense. According to this configuration, the calculation cost of the communicable period is reduced.
  • the frame exchange period ⁇ is calculated every time a data frame is transmitted.
  • a statistical average or median value of frame exchange periods calculated over a certain period of time may be used as the frame exchange period ⁇ .
  • the communicable period ⁇ N for link N is calculated every time the transmission right is acquired. In some cases where the transmission right is acquired, the statistical average or median value of the communicable period for link N calculated over a certain period may be used as the communicable period ⁇ N for link N. .
  • a TID may be associated with a link. Each link is used to transmit and receive traffic for the TID associated with that link.
  • traffic with TID #1 is transmitted using any of the three links with link IDs 1 to 3
  • traffic with TID #2 is transmitted using any of the three links with link ID 1.
  • traffic that is sent using a link with a TID of #3 is sent using a link with a link ID of 2
  • traffic with a TID of #4 is sent using a link with a link ID of 3. Sent using.
  • the association between TID and link may be performed when a multilink is established between the access point 10 and the terminal 20.
  • the TID of the traffic included in the data frame may be taken into consideration.
  • the carrier sense execution unit 245 may perform carrier sense on one or more links associated with the TID of traffic included in the data frame to be transmitted. Referring to the above example, if the TID of the traffic included in the data frame to be transmitted is #1, the carrier sense execution unit 245 performs carrier sense for three links with link IDs 1 to 3. conduct. When the TID of traffic included in the data frame to be transmitted is #2, the carrier sense execution unit 245 performs carrier sense for one link whose link ID is 2.
  • the terminal 20 is a transmitting station and the access point 10 is a receiving station.
  • access point 10 may perform data frame transmission in a manner similar to that described above with respect to terminal 20. That is, the access point 10 may include components equivalent to the communication control unit 234 of the terminal 20.
  • the wireless communication function provided by the wireless station may be implemented by individual components such as chips.
  • the chip may be incorporated into the substrate of the wireless station during manufacture of the wireless station.
  • the wireless device referred to herein may refer to a wireless station, or may refer to an individual component that implements the wireless communication functionality of a wireless station.
  • each embodiment may be implemented in combination as appropriate, and in that case, the combined effect can be obtained.
  • the embodiments described above include various inventions, and various inventions can be extracted by combinations selected from the plurality of disclosed components. For example, if a problem can be solved and an effect can be obtained even if some components are deleted from all the components shown in the embodiment, the configuration from which these components are deleted can be extracted as an invention.
  • Radio signal processing unit 245 ... Carrier sense execution unit 2341... Instruction unit 2342... Link selection unit 2343... Frame exchange period calculation unit 2344... Communication available period calculation unit 2345... Judgment unit 2346... Transmission Control unit 2411... Classification unit 2412A, 2412B, 2412C, 2412D, 2422A, 2432A... Queue 2413A, 2413B, 2413C, 2413D, 2423A, 2433A... Carrier sense execution unit 2414... Internal collision management unit 2415... Modulation unit

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Abstract

A wireless device according to an aspect of the present invention is provided with a communication unit, a first calculation unit, a second calculation unit, and a transmission control unit. The communication unit performs wireless communication with another wireless device by using a plurality of links established between the wireless device and the other wireless device. The first calculation unit calculates a frame exchange period including a time period required for frame transmission to the other wireless device. The second calculation unit calculates, for each of the plurality of links, a communicable period indicating a time period until a service period in which a transmission opportunity is given starts. The transmission control unit performs frame transmission by using a link having a frame exchange period shorter than a communicable period when there is the link having a frame exchange period shorter than a communicable period, and postpones the frame transmission when there is no link having a frame exchange period shorter than a communicable period.

Description

無線装置及び無線通信方法Wireless device and wireless communication method
　本発明は、無線通信に関する。 The present invention relates to wireless communication.
　アクセスポイントと端末装置との間を無線で接続する通信システムとして、無線ＬＡＮ（Local Area Network）が知られている。無線ＬＡＮでは、アクセスポイント及び端末の各々は、例えばＣＳＭＡ／ＣＡ（Carrier Sense Multiple Access with Collision Avoidance）に基づくキャリアセンスを行い、送信権を獲得したときにデータフレームを無線送信する。 A wireless LAN (Local Area Network) is known as a communication system that wirelessly connects an access point and a terminal device. In a wireless LAN, each access point and terminal performs carrier sense based on, for example, CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance), and wirelessly transmits a data frame when a transmission right is acquired.
　ＩＥＥＥ８０２．１１ａｘの後継規格として策定中であるＩＥＥＥ８０２．１１ｂｅにおいて、ｒ－ＴＷＴ（restricted Target Wake Time）動作が検討されている。ｒ－ＴＷＴ動作は、遅延要求条件があるトラヒックの送信機会を優先的に確保する仕組みを規定する。遅延要求条件があるトラヒックは、低遅延トラヒックや遅延センシティブトラヒックとも呼ばれ、ネットワークゲームなどのリアルタイムアプリケーションから生じるトラヒックのような、低遅延や小さいジッタなどを要求するトラヒックである。 In IEEE 802.11be, which is being developed as a successor standard to IEEE 802.11ax, r-TWT (restricted Target Wake Time) operation is being considered. The r-TWT operation defines a mechanism for preferentially securing transmission opportunities for traffic with delay requirements. Traffic with delay requirements is also called low-latency traffic or delay-sensitive traffic, and is traffic that requires low delay and small jitter, such as traffic generated from real-time applications such as network games.
　ｒ－ＴＷＴ動作においては、端末装置は、アクセスポイントにより自身に対して設定されたサービス期間（ＳＰ；Service Period）中にアクセスポイントとフレームを交換し、アクセスポイントの周囲にいる他の端末装置は、サービス期間の一部期間中にサービス期間が設定されているリンクで通信することを抑制される。端末装置は、低遅延トラヒックを含むデータフレームをアクセスポイントに無線送信するためにサービス期間を使用することができる。このように、サービス期間は、アクセスポイントにより指定された端末装置に送信機会が与えられる期間であり、アクセスポイントにより指定された端末装置が低遅延トラヒックを含むデータフレームを優先的に送受信することを可能にする。このサービス期間はｒ－ＴＷＴサービス期間とも呼ばれる。 In r-TWT operation, a terminal device exchanges frames with the access point during a service period (SP) set for itself by the access point, and other terminal devices around the access point , communication via a link with a service period set during a part of the service period is suppressed. A terminal device may use the service period to wirelessly transmit data frames containing low-latency traffic to an access point. In this way, the service period is a period during which a terminal device specified by the access point is given a transmission opportunity, and the terminal device specified by the access point is given priority to send and receive data frames containing low-latency traffic. enable. This service period is also called r-TWT service period.
　ｒ－ＴＷＴサービス期間の開始前に送信権を獲得した端末装置は、ｒ－ＴＷＴサービス期間の開始までに、送信しようとしているデータフレームの送信が完了可能であるかを確認する。送信の完了が不可能である場合、端末装置は、データフレームの送信を延期し、ｒ－ＴＷＴサービス期間の終了後にデータフレームの送信を開始する。 A terminal device that has acquired the transmission right before the start of the r-TWT service period checks whether it is possible to complete the transmission of the data frame it is about to send by the start of the r-TWT service period. If it is not possible to complete the transmission, the terminal device postpones the transmission of the data frame and starts transmitting the data frame after the end of the r-TWT service period.
　複数の端末装置がｒ－ＴＷＴサービス期間のために送信を延期することがある。この場合、これらの端末装置は、ｒ－ＴＷＴサービス期間の終了後に一斉に送信を開始する可能性があり、衝突が発生して正常なデータ送受信が不可能となる可能性がある。 Multiple terminal devices may postpone transmission due to the r-TWT service period. In this case, these terminal devices may start transmitting all at once after the r-TWT service period ends, and a collision may occur, making normal data transmission and reception impossible.
　ｒ－ＴＷＴサービス期間の終了後のデータフレームの一斉送信による衝突の発生を回避するために、バックオフ制御が使用され得る。例えば、送信を延期した複数の端末装置は、ｒ－ＴＷＴサービス期間の終了後にキャリアセンスを再度行い、送信権を再度獲得したら送信を行う。この場合、ｒ－ＴＷＴサービス期間前に一度送信権を獲得したにも関わらず、送信権獲得のためのバックオフ制御を再度行うこととなり、周波数利用効率が低下する。 Backoff control may be used to avoid collisions caused by broadcasting data frames after the end of the r-TWT service period. For example, a plurality of terminal devices that have postponed transmission perform carrier sense again after the r-TWT service period ends, and once the transmission right is acquired again, they transmit. In this case, even though the transmission right was acquired once before the r-TWT service period, back-off control for acquiring the transmission right will be performed again, resulting in a decrease in frequency usage efficiency.
　上述したような衝突の発生及び周波数利用効率の低下は、スループット及び遅延特性の低下をもたらす。 The occurrence of collisions and the decrease in frequency usage efficiency as described above result in a decrease in throughput and delay characteristics.
　本発明は、スループット及び遅延特性を向上する無線通信技術を提供することを目的とする。 An object of the present invention is to provide a wireless communication technology that improves throughput and delay characteristics.
　本発明の一態様に係る無線装置は、通信部、第１の算出部、第２の算出部、及び送信制御部を備える。通信部は、前記無線装置と他の無線装置との間に確立される複数のリンクを使用して前記他の無線装置と無線通信する。第１の算出部は、前記他の無線装置へのフレーム送信に要する時間期間を含むフレーム交換期間を算出する。第２の算出部は、前記複数のリンクの各々について、送信機会が与えられるサービス期間の開始までの時間期間を示す通信可能期間を算出する。送信制御部は、前記フレーム交換期間が前記通信可能期間よりも短いリンクがある場合に、前記フレーム交換期間が前記通信可能期間よりも短い前記リンクで前記フレーム送信を行い、前記フレーム交換期間が前記通信可能期間よりも短いリンクがない場合に、前記フレーム送信を延期する。 A wireless device according to one aspect of the present invention includes a communication section, a first calculation section, a second calculation section, and a transmission control section. The communication unit wirelessly communicates with the other wireless device using a plurality of links established between the wireless device and the other wireless device. The first calculation unit calculates a frame exchange period including a time period required for frame transmission to the other wireless device. The second calculation unit calculates, for each of the plurality of links, a communicable period indicating a time period until the start of a service period in which a transmission opportunity is given. If there is a link in which the frame exchange period is shorter than the communicable period, the transmission control unit performs the frame transmission on the link in which the frame exchange period is shorter than the communicable period; If there is no link that is shorter than the communication period, the frame transmission is postponed.
　本発明によれば、スループット及び遅延特性を向上する無線通信技術が提供される。 According to the present invention, a wireless communication technology that improves throughput and delay characteristics is provided.
図１は、実施形態に係る通信システムを示すブロック図である。FIG. 1 is a block diagram showing a communication system according to an embodiment. 図２は、実施形態に係るリンク管理情報を示す図である。FIG. 2 is a diagram showing link management information according to the embodiment. 図３は、実施形態に係るアクセスポイントのハードウェア構成を示すブロック図である。FIG. 3 is a block diagram showing the hardware configuration of the access point according to the embodiment. 図４は、実施形態に係る端末のハードウェア構成を示すブロック図である。FIG. 4 is a block diagram showing the hardware configuration of the terminal according to the embodiment. 図５は、実施形態に係るアクセスポイント及び端末の機能構成を示すブロック図である。FIG. 5 is a block diagram showing the functional configuration of an access point and a terminal according to the embodiment. 図６は、実施形態に係る端末のチャネルアクセス機能を示す図である。FIG. 6 is a diagram showing the channel access function of the terminal according to the embodiment. 図７は、実施形態に係る端末における送信処理を説明する図である。FIG. 7 is a diagram illustrating transmission processing in the terminal according to the embodiment. 図８は、実施形態に係る、フレーム交換期間が通信可能期間よりも短い状況を示す図である。FIG. 8 is a diagram showing a situation in which the frame exchange period is shorter than the communicable period according to the embodiment. 図９は、実施形態に係る、フレーム交換期間が通信可能期間よりも長い状況を示す図である。FIG. 9 is a diagram illustrating a situation in which the frame exchange period is longer than the communicable period according to the embodiment. 図１０は、実施形態に係る無線通信方法を示すフローチャートである。FIG. 10 is a flowchart illustrating a wireless communication method according to the embodiment.
　以下、図面を参照して本発明の実施形態を説明する。 Hereinafter, embodiments of the present invention will be described with reference to the drawings.
　ＩＥＥＥ８０２．１１ａｘの後継規格として策定中であるＩＥＥＥ８０２．１１ｂｅにおいて、マルチリンク動作が検討されている。マルチリンク動作は、異なる周波数チャネルを使用する複数のリンクをアクセスポイントと端末装置との間に論理的に確立する仕組みを規定する。マルチリンク動作では、アクセスポイント及び端末装置は、確立されたリンクを使用して互いに無線通信する。例えば、端末装置は、ＣＳＭＡ／ＣＡに基づくキャリアセンスをリンクごとに行い、送信権が獲得されたリンクでデータフレームをアクセスポイントに無線送信する。アクセスポイントは基地局とも呼ばれる。以降では、端末装置を単に端末と呼び、周波数チャネルを単にチャネルと呼ぶ。 Multi-link operation is being considered in IEEE802.11be, which is being developed as a successor standard to IEEE802.11ax. Multilink operation defines a mechanism for logically establishing multiple links using different frequency channels between an access point and a terminal device. In multilink operation, access points and terminal devices wirelessly communicate with each other using established links. For example, a terminal device performs carrier sensing based on CSMA/CA for each link, and wirelessly transmits a data frame to an access point using a link for which transmission rights have been acquired. An access point is also called a base station. Hereinafter, a terminal device will be simply referred to as a terminal, and a frequency channel will be simply referred to as a channel.
　以下に説明する実施形態に係るアクセスポイント及び端末は、マルチリンク動作をサポートし、アクセスポイントと端末との間に複数のリンクを確立する。アクセスポイントと端末との間に確立される複数のリンクをマルチリンク（ＭＬ）と呼ぶ。アクセスポイント及び端末は、ｒ－ＴＷＴ動作をさらにサポートする。アクセスポイントは、各端末に対して、送信機会が与えられる又は割り当てられるｒ－ＴＷＴサービス期間をスケジュールする。各端末は、ｒ－ＴＷＴサービス期間中に、ｒ－ＴＷＴサービス期間が設定されるリンクで、データフレーム送信を優先的に行うことができる。各端末は、遅延要求条件があるトラヒックを含むデータフレームを送信するために、ｒ－ＴＷＴサービス期間を使用することができる。 The access point and terminal according to the embodiments described below support multi-link operation and establish multiple links between the access point and the terminal. Multiple links established between an access point and a terminal are called multilinks (ML). Access points and terminals further support r-TWT operation. The access point schedules r-TWT service periods for each terminal during which it is given or assigned an opportunity to transmit. During the r-TWT service period, each terminal can preferentially transmit data frames on the link for which the r-TWT service period is set. Each terminal may use the r-TWT service period to transmit data frames containing traffic with delay requirements.
　一実施形態に係る端末は、ｒ－ＴＷＴサービス期間がマルチリンクに含まれるリンクのすべてに対してスケジュールされている場合において、例えば以下の手順で、データフレームをアクセスポイントに無線送信する。端末は、マルチリンクに含まれる複数のリンクのそれぞれに対応する複数のチャネルの状況を確認するために、これらのリンクについてキャリアセンスを行う。端末は、チャネルが特定の時間期間にわたって使用されていないときに、チャネルがアイドルであると判定し、チャネルが使用されていることを検出すると、チャネルがビジーであると判定する。端末は、チャネルがアイドルであることを確認したことに応答して、当該チャネルに対応するリンクについての送信権を獲得したと認識する。端末は、複数のリンクについての送信権を獲得すると、端末は、送信権が獲得されたリンクの各々について、データフレーム送信がｒ－ＴＷＴサービス期間の開始までに完了可能かを確認する。データフレーム送信がｒ－ＴＷＴサービス期間の開始までに完了可能であるリンクがある場合、端末は、そのリンクでデータフレームを送信する。データフレーム送信がｒ－ＴＷＴサービス期間の開始までに完了可能であるリンクがない場合、端末は、送信を延期する。例えば、いずれかのリンクのｒ－ＴＷＴサービス期間が終了した後に、端末は、そのリンクでデータフレームを送信してよい。 In a case where the r-TWT service period is scheduled for all links included in the multilink, the terminal according to one embodiment wirelessly transmits a data frame to the access point using the following procedure, for example. The terminal performs carrier sense on the multiple links included in the multilink in order to check the status of the multiple channels corresponding to each of these links. The terminal determines that the channel is idle when the channel has not been used for a certain period of time, and determines that the channel is busy when it detects that the channel is in use. In response to confirming that the channel is idle, the terminal recognizes that it has acquired the right to transmit on the link corresponding to the channel. When the terminal acquires transmission rights for multiple links, the terminal checks whether data frame transmission can be completed by the start of the r-TWT service period for each of the links for which transmission rights have been acquired. If there is a link on which data frame transmission can be completed by the start of the r-TWT service period, the terminal transmits the data frame on that link. If there are no links on which data frame transmission can be completed by the start of the r-TWT service period, the terminal postpones transmission. For example, after the r-TWT service period for any link ends, the terminal may transmit data frames on that link.
　上記の構成によれば、あるリンクでそのリンクに対して設定されたｒ－ＴＷＴサービス期間の開始までにデータフレーム送信が完了できない場合にも、他のリンクでデータフレーム送信を行うことが可能となる。よって、ｒ－ＴＷＴサービス期間のために送信を延期する事態の発生頻度が減り、衝突の発生又は周波数利用効率の低下を効果的に回避することができる。その結果、スループット及び遅延特性が向上する。 According to the above configuration, even if data frame transmission cannot be completed on a certain link by the start of the r-TWT service period set for that link, it is possible to perform data frame transmission on another link. Become. Therefore, the frequency of occurrence of situations in which transmission is postponed due to the r-TWT service period is reduced, and it is possible to effectively avoid occurrence of collisions or decrease in frequency usage efficiency. As a result, throughput and delay characteristics are improved.
　図１は、一実施形態に係る無線ネットワーク４５を含む通信システム５０の構成の一例を概略的に示している。本明細書に記載される「システム」及び「ネットワーク」は相互交換可能に使用され得る。図１に示すように、通信システム５０は、アクセスポイント１０、端末２０、及びサーバ３０を備える。アクセスポイント１０及び端末２０が無線ネットワーク４５に含まれる。 FIG. 1 schematically shows an example of the configuration of a communication system 50 including a wireless network 45 according to an embodiment. "System" and "network" described herein may be used interchangeably. As shown in FIG. 1, the communication system 50 includes an access point 10, a terminal 20, and a server 30. Access point 10 and terminal 20 are included in wireless network 45 .
　アクセスポイント１０は、無線ＬＡＮのアクセスポイントである。アクセスポイント１０は、１つ又は複数の端末と無線接続することが可能である。アクセスポイント１０に無線接続される端末の数は動的に変化する。図１に示す例では、アクセスポイント１０は端末２０と無線接続されている。アクセスポイント１０は、端末２０との間に１つ又は複数のリンクを確立し、確立したリンクを使用して端末２０と無線通信する。アクセスポイント１０は、インターネットを含み得る通信ネットワーク４０に有線で接続される。 The access point 10 is a wireless LAN access point. The access point 10 can be wirelessly connected to one or more terminals. The number of terminals wirelessly connected to the access point 10 changes dynamically. In the example shown in FIG. 1, the access point 10 is wirelessly connected to the terminal 20. Access point 10 establishes one or more links with terminal 20 and uses the established links to wirelessly communicate with terminal 20. Access point 10 is wired connected to a communications network 40, which may include the Internet.
　端末２０は、無線通信機能を備える無線端末であり、無線ＬＡＮのクライアントとして動作する。無線端末の例は、スマートフォン、携帯電話、タブレットＰＣ（personal computer）、デスクトップＰＣ、ラップトップＰＣ、ＩｏＴ（Internet of things）センサ／デバイスを含む。端末２０は、アクセスポイント１０を介して通信ネットワーク４０にアクセスする。例えば、端末２０は、アクセスポイント１０を介して、通信ネットワーク４０上のサーバ３０とデータを交換する。 The terminal 20 is a wireless terminal equipped with a wireless communication function, and operates as a wireless LAN client. Examples of wireless terminals include smart phones, mobile phones, personal computers, desktop PCs, laptop PCs, and Internet of things (IoT) sensors/devices. Terminal 20 accesses communication network 40 via access point 10 . For example, terminal 20 exchanges data with server 30 on communication network 40 via access point 10 .
　サーバ３０は、通信ネットワーク４０に接続される。例えば、サーバ３０は、ネットワークゲームなどのサービスを提供するサービスプロバイダであってよく、通信ネットワーク４０を介して端末２０とサービスに関連するデータを交換する。 The server 30 is connected to a communication network 40. For example, the server 30 may be a service provider that provides services such as network games, and exchanges data related to the service with the terminal 20 via the communication network 40.
　アクセスポイント１０と端末２０との間の無線通信はＩＥＥＥ８０２．１１規格に基づいている。なお、本明細書ではＩＥＥＥ８０２．１１規格に基づいた無線通信を例として記載するが、ＩＥＥＥ８０２．１１規格とは異なる無線通信規格を使用するようにしてもよい。 Wireless communication between the access point 10 and the terminal 20 is based on the IEEE802.11 standard. Note that although wireless communication based on the IEEE802.11 standard is described as an example in this specification, a wireless communication standard different from the IEEE802.11 standard may be used.
　アクセスポイント１０及び端末２０は、マルチリンク動作及びｒ－ＴＷＴ動作をサポートする。マルチリンク動作をサポートするアクセスポイント１０はアクセスポイントマルチリンクデバイス（ＡＰ　ＭＬＤ）とも呼ばれ、マルチリンク動作をサポートする端末２０は非アクセスポイントマルチリンクデバイス（ｎｏｎ－ＡＰ　ＭＬＤ）とも呼ばれる。 The access point 10 and terminal 20 support multilink operation and r-TWT operation. An access point 10 that supports multilink operation is also called an access point multilink device (AP MLD), and a terminal 20 that supports multilink operation is also called a non-access point multilink device (non-AP MLD).
　ＩＥＥＥ８０２．１１規格は、ＯＳＩ（Open Systems Interconnection）モデルの第１層と第２層のＭＡＣ（media access control）副層とを規定する。ＯＳＩモデルでは、通信機能が７階層（第１層：物理層、第２層：データリンク層、第３層：ネットワーク層、第４層：トランスポート層、第５層：セッション層、第６層：プレゼンテーション層、第７層：アプリケーション層）に分割される。データリンク層は、例えばＬＬＣ（logical link control）層及びＭＡＣ層を含む。ＬＬＣ層は、例えば、上位層から入力されたデータにＤＳＡＰ（destination service access point）ヘッダ及びＳＳＡＰ（source service access point）ヘッダなどを付加してＬＬＣパケットを形成する。ＭＡＣ層は、例えば、ＬＬＣパケットにＭＡＣヘッダを付加してＭＡＣフレームを生成する。物理層は、例えば、ＭＡＣフレームにプリアンブル及びＰＨＹ（物理層）ヘッダなどを付加して無線フレームを生成する。ここでは、ＩＥＥＥ８０２．１１規格が規定する第１層と第２層のＭＡＣ副層とについての処理を中心に説明し、他の層についての処理の説明は省略する。 The IEEE 802.11 standard defines the first layer and the second layer MAC (media access control) sublayer of the OSI (Open Systems Interconnection) model. In the OSI model, communication functions are divided into seven layers (1st layer: physical layer, 2nd layer: data link layer, 3rd layer: network layer, 4th layer: transport layer, 5th layer: session layer, 6th layer) : Presentation layer, 7th layer: Application layer). The data link layer includes, for example, an LLC (logical link control) layer and a MAC layer. The LLC layer forms an LLC packet by adding, for example, a DSAP (destination service access point) header and an SSAP (source service access point) header to data input from an upper layer. The MAC layer generates a MAC frame by adding a MAC header to an LLC packet, for example. The physical layer generates a radio frame by adding, for example, a preamble and a PHY (physical layer) header to the MAC frame. Here, processing for the first and second MAC sublayers defined by the IEEE802.11 standard will be mainly described, and descriptions of processing for other layers will be omitted.
　図２は、端末２０が保持するリンク管理情報の一例を概略的に示している。図２に示すリンク管理情報は、アクセスポイント１０と端末２０との間のリンクの状態を示す。リンク管理情報は、リンクＩＤ、周波数帯情報、チャネルＩＤ、リンク情報、マルチリンク情報、及びトラヒック情報を含む。 FIG. 2 schematically shows an example of link management information held by the terminal 20. The link management information shown in FIG. 2 indicates the state of the link between the access point 10 and the terminal 20. The link management information includes link ID, frequency band information, channel ID, link information, multilink information, and traffic information.
　リンクＩＤは、リンクに割り当てられる識別子（例えば識別番号）である。周波数帯情報は、リンクに使用される周波数帯を示す情報である。チャネルＩＤは、リンクに使用されるチャネルの識別子である。図２に示す例では、端末２０は、３つのリンクを使用可能である。リンクＩＤが１であるリンクは、６ＧＨｚ帯のチャネルを使用するリンクであり、６ＧＨｚ帯に含まれるチャネルＣＨ１を使用中である。リンクＩＤが２であるリンクは、５ＧＨｚ帯のチャネルを使用するリンクであり、５ＧＨｚ帯に含まれるチャネルＣＨ２を使用中である。リンクＩＤが３であるリンクは、２．４ＧＨｚ帯のチャネルを使用するリンクであり、２．４ＧＨｚ帯に含まれるチャネルＣＨ３を使用中である。なお、マルチリンクＭＬの複数のリンクでは、互いに対して異なる周波数帯が割り当てられてもよく、互いに対して同一の周波数帯の異なるチャネルが割り当てられてもよい。 The link ID is an identifier (for example, an identification number) assigned to the link. Frequency band information is information indicating a frequency band used for a link. Channel ID is the identifier of the channel used for the link. In the example shown in FIG. 2, the terminal 20 can use three links. A link whose link ID is 1 is a link that uses a channel in the 6 GHz band, and is currently using channel CH1 included in the 6 GHz band. The link whose link ID is 2 is a link that uses a channel in the 5 GHz band, and is currently using channel CH2 included in the 5 GHz band. The link whose link ID is 3 is a link that uses a channel in the 2.4 GHz band, and is currently using channel CH3 included in the 2.4 GHz band. Note that different frequency bands may be allocated to the plurality of links of the multilink ML, or different channels of the same frequency band may be allocated to each other.
　リンク情報は、アクセスポイント１０と端末２０との間にリンクが確立されているか否かを示す。マルチリンク情報は、アクセスポイント１０と端末２０との間に複数のリンクから構成されるマルチリンクＭＬが確立されているか否かを示す。マルチリンクＭＬが確立されている場合、マルチリンク情報は、マルチリンクＭＬがいずれのリンクによって構成されるかを示す。図２に示す例では、リンクＩＤが１～３である３つのリンクからマルチリンクＭＬが構成される。 The link information indicates whether a link is established between the access point 10 and the terminal 20. The multilink information indicates whether a multilink ML consisting of a plurality of links is established between the access point 10 and the terminal 20. If a multilink ML is established, the multilink information indicates which links constitute the multilink ML. In the example shown in FIG. 2, the multilink ML is configured from three links with link IDs 1 to 3.
　トラヒック情報は、リンクのそれぞれに割り当てられるＴＩＤ（Traffic Indicator）を示す。ＴＩＤは、トラヒックのそれぞれを示す識別子であり、トラヒックのそれぞれは、アクセスカテゴリと対応付けられてもよい。アクセスカテゴリは、例えば、ＶＯ（Voice）、ＶＩ（Video）、ＢＥ（Best Effort）、及びＢＫ（Background）を含む。図２に示すＴＩＤ＃１、ＴＩＤ＃２、ＴＩＤ＃３、ＴＩＤ＃４の各々は、ＶＯ、ＶＩ、ＢＥ、及びＢＫのいずれかに対応する。図２に示す例では、ＴＩＤ＃１は、リンクＩＤが１～３である３つのリンクに割り当てられている。ＴＩＤ＃２はリンクＩＤが１であるリンクに割り当てられ、ＴＩＤ＃３はリンクＩＤが２であるリンクに割り当てられ、ＴＩＤ＃４はリンクＩＤが３であるリンクに割り当てられている。このように、マルチリンクＭＬでは、１個のＴＩＤに対して１つ又は複数のリンクが割り当てられ得る。 The traffic information indicates a TID (Traffic Indicator) assigned to each link. The TID is an identifier that indicates each piece of traffic, and each piece of traffic may be associated with an access category. Access categories include, for example, VO (Voice), VI (Video), BE (Best Effort), and BK (Background). Each of TID#1, TID#2, TID#3, and TID#4 shown in FIG. 2 corresponds to one of VO, VI, BE, and BK. In the example shown in FIG. 2, TID #1 is assigned to three links with link IDs 1 to 3. TID #2 is assigned to the link whose link ID is 1, TID #3 is assigned to the link whose link ID is 2, and TID #4 is assigned to the link whose link ID is 3. In this way, in multi-link ML, one or more links can be assigned to one TID.
　アクセスポイント１０は、図２に例示するリンク管理情報と同様のリンク管理情報を、アクセスポイント１０に無線接続されている端末ごとに保持する。すなわち、アクセスポイント１０が保持するリンク管理情報は、アクセスポイント１０とアクセスポイント１０に無線接続されている各端末との間のリンクの状態を示す。 The access point 10 holds link management information similar to the link management information illustrated in FIG. 2 for each terminal wirelessly connected to the access point 10. That is, the link management information held by the access point 10 indicates the state of the link between the access point 10 and each terminal wirelessly connected to the access point 10.
　図３は、アクセスポイント１０のハードウェア構成の一例を概略的に示している。図３に示すように、アクセスポイント１０は、例えば、ＣＰＵ（Central Processing Unit）１１、プログラムメモリ１２、ＲＡＭ（Random Access Memory）１３、無線通信モジュール１４、及び有線通信モジュール１５を備える。 FIG. 3 schematically shows an example of the hardware configuration of the access point 10. As shown in FIG. 3, the access point 10 includes, for example, a CPU (Central Processing Unit) 11, a program memory 12, a RAM (Random Access Memory) 13, a wireless communication module 14, and a wired communication module 15.
　ＣＰＵ１１は、様々なプログラムを実行することが可能な集積回路であり、アクセスポイント１０の全体の動作を制御する。プログラムメモリ１２は、ＲＯＭ（read only memory）又はフラッシュメモリなどの不揮発性の半導体メモリであり、アクセスポイント１０を制御するためのプログラムや制御データなどを記憶する。ＲＡＭ１３は、例えば揮発性の半導体メモリであり、ＣＰＵ１１の作業領域として使用される。無線通信モジュール１４は、無線信号によるデータの送受信に使用される回路である。無線通信モジュール１４は、複数のリンクにそれぞれ対応する複数の通信モジュールを含み、各通信モジュールは、複数のアンテナのうちの当該通信モジュールに対応するアンテナに接続される。無線通信モジュール１４は、同時に複数のリンクでフレームを送受信することができる。有線通信モジュール１５は、有線信号によるデータの送受信に使用される回路であり、通信ネットワーク４０に接続される。 The CPU 11 is an integrated circuit that can execute various programs, and controls the overall operation of the access point 10. The program memory 12 is a nonvolatile semiconductor memory such as a ROM (read only memory) or a flash memory, and stores programs and control data for controlling the access point 10 . The RAM 13 is, for example, a volatile semiconductor memory, and is used as a work area for the CPU 11. The wireless communication module 14 is a circuit used for transmitting and receiving data using wireless signals. The wireless communication module 14 includes a plurality of communication modules each corresponding to a plurality of links, and each communication module is connected to an antenna corresponding to the communication module among the plurality of antennas. Wireless communication module 14 can transmit and receive frames on multiple links simultaneously. The wired communication module 15 is a circuit used for transmitting and receiving data using wired signals, and is connected to the communication network 40.
　図４は、端末２０のハードウェア構成の一例を概略的に示している。図４に示すように、端末２０は、例えば、ＣＰＵ２１、プログラムメモリ２２、ＲＡＭ２３、無線通信モジュール２４、ディスプレイ２５、及びストレージ２６を備える。 FIG. 4 schematically shows an example of the hardware configuration of the terminal 20. As shown in FIG. 4, the terminal 20 includes, for example, a CPU 21, a program memory 22, a RAM 23, a wireless communication module 24, a display 25, and a storage 26.
　ＣＰＵ２１は、様々なプログラムを実行することが可能な集積回路であり、端末２０の全体の動作を制御する。プログラムメモリ２２は、ＲＯＭなどの不揮発性の半導体メモリであり、端末２０を制御するためのプログラムや制御データなどを記憶する。ストレージ２６がプログラムメモリ２２として使用されてもよい。ＲＡＭ２３は、例えば揮発性の半導体メモリであり、ＣＰＵ２１の作業領域として使用される。無線通信モジュール２４は、無線信号によるデータの送受信に使用される回路である。無線通信モジュール２４は、複数のリンクにそれぞれ対応する複数の通信モジュールを含み、各通信モジュールは、複数のアンテナのうちの当該通信モジュールに対応するアンテナに接続される。無線通信モジュール２４は、同時に複数のリンクでフレームを送受信することができる。ディスプレイ２５は、例えばアプリケーションソフトにより提供されるＧＵＩ（Graphical User Interface）などの情報を表示する。ディスプレイ２５は、端末２０の入力インタフェースとしての機能を有していてもよい。例えば、タッチパネルがディスプレイ２５に設けられていてもよい。ストレージ２６は、不揮発性の記憶装置であり、例えば端末２０のシステムソフトウェアなどを含むデータを格納する。 The CPU 21 is an integrated circuit that can execute various programs, and controls the overall operation of the terminal 20. The program memory 22 is a nonvolatile semiconductor memory such as a ROM, and stores programs and control data for controlling the terminal 20. Storage 26 may be used as program memory 22. The RAM 23 is, for example, a volatile semiconductor memory, and is used as a work area for the CPU 21. The wireless communication module 24 is a circuit used for transmitting and receiving data using wireless signals. The wireless communication module 24 includes a plurality of communication modules each corresponding to a plurality of links, and each communication module is connected to an antenna corresponding to the communication module among the plurality of antennas. Wireless communication module 24 can transmit and receive frames on multiple links simultaneously. The display 25 displays information such as a GUI (Graphical User Interface) provided by application software, for example. The display 25 may have a function as an input interface for the terminal 20. For example, a touch panel may be provided on the display 25. The storage 26 is a nonvolatile storage device, and stores data including, for example, system software of the terminal 20.
　図４に示すハードウェア構成は一例であり、端末２０は図４に示すものとは異なるハードウェア構成を有してよい。例えば、端末２０がＩｏＴデバイスなどである場合に、ディスプレイ２５が端末２０から削除されてもよい。 The hardware configuration shown in FIG. 4 is an example, and the terminal 20 may have a different hardware configuration from that shown in FIG. 4. For example, if the terminal 20 is an IoT device or the like, the display 25 may be deleted from the terminal 20.
　図５は、アクセスポイント１０及び端末２０の機能構成の例を概略的に示している。ここでは、アップリンク伝送に関する処理について主に説明し、ダウンリンク伝送に関する処理についての具体的な説明は省略する。ダウンリンク伝送は、アップリンク伝送に関して説明する処理と同様にして行われることができる。例えば、アクセスポイント１０は、端末２０に関連して後述する変調処理と同様の変調処理を行うことができ、端末２０は、アクセスポイント１０に関連して後述する復調処理と同様の復調処理を行うことができる。アップリンク伝送は端末２０からアクセスポイント１０への伝送を指し、ダウンリンク伝送はアクセスポイント１０から端末２０への伝送を指す。 FIG. 5 schematically shows an example of the functional configuration of the access point 10 and the terminal 20. Here, processing related to uplink transmission will be mainly explained, and specific explanation of processing related to downlink transmission will be omitted. Downlink transmissions may be performed in a similar manner to the processes described for uplink transmissions. For example, the access point 10 can perform a modulation process similar to the modulation process described below in relation to the terminal 20, and the terminal 20 can perform a demodulation process similar to the demodulation process described below in relation to the access point 10. be able to. Uplink transmission refers to transmission from terminal 20 to access point 10, and downlink transmission refers to transmission from access point 10 to terminal 20.
　図５に示すように、アクセスポイント１０は、ＬＬＣ処理部１１０、リンクマネジメント部１２０、及び通信部１３０を備える。ＬＬＣ処理部１１０は、ＣＰＵ１１と有線通信モジュール１５の組み合わせによって実現され得る。リンクマネジメント部１２０及び通信部１３０は、無線通信モジュール１４又はＣＰＵ１１と無線通信モジュール１４の組み合わせによって実現され得る。 As shown in FIG. 5, the access point 10 includes an LLC processing section 110, a link management section 120, and a communication section 130. The LLC processing unit 110 can be realized by a combination of the CPU 11 and the wired communication module 15. The link management section 120 and the communication section 130 can be realized by the wireless communication module 14 or a combination of the CPU 11 and the wireless communication module 14.
　ＬＬＣ処理部１１０は、入力された信号に対してＬＬＣ層の処理と上位層（第３層から第７層）の処理とを実行する。例えば、ＬＬＣ処理部１１０は、リンクマネジメント部１２０からＬＬＣパケットを受け取り、ＬＬＣパケットからデータを抽出する。 The LLC processing unit 110 performs LLC layer processing and upper layer processing (third to seventh layer) on the input signal. For example, the LLC processing unit 110 receives an LLC packet from the link management unit 120 and extracts data from the LLC packet.
　リンクマネジメント部１２０は、入力された信号に対してＭＡＣ層の処理を実行する。さらに、リンクマネジメント部１２０は、各端末との間のリンクを管理する。リンクマネジメント部１２０は、データ処理部１２１、ＭＡＣフレーム処理部１２２、及びマネジメント部１２３を備える。 The link management unit 120 performs MAC layer processing on the input signal. Further, the link management unit 120 manages links with each terminal. The link management section 120 includes a data processing section 121, a MAC frame processing section 122, and a management section 123.
　データ処理部１２１は、ＭＡＣフレーム処理部１２２からＭＡＣフレームを受け取り、ＭＡＣフレームからＬＬＣパケットを抽出し、ＬＬＣパケットをＬＬＣ処理部１１０に送出する。 The data processing unit 121 receives the MAC frame from the MAC frame processing unit 122, extracts the LLC packet from the MAC frame, and sends the LLC packet to the LLC processing unit 110.
　ＭＡＣフレーム処理部１２２は、通信部１３０からＭＡＣフレームを受け取ると、ＭＡＣフレームの種別に応じてＭＡＣフレームをデータ処理部１２１又はマネジメント部１２３に送出する。具体的には、ＭＡＣフレーム処理部１２２は、ＭＡＣフレームがデータフレームである場合には、ＭＡＣフレームをデータ処理部１２１に送出し、ＭＡＣフレームがマネジメントフレーム又は制御フレームである場合には、ＭＡＣフレームをマネジメント部１２３に送出する。 Upon receiving the MAC frame from the communication unit 130, the MAC frame processing unit 122 sends the MAC frame to the data processing unit 121 or the management unit 123 depending on the type of the MAC frame. Specifically, the MAC frame processing unit 122 sends the MAC frame to the data processing unit 121 when the MAC frame is a data frame, and sends the MAC frame to the data processing unit 121 when the MAC frame is a management frame or a control frame. is sent to the management section 123.
　マネジメント部１２３は、各端末により送信されたマネジメントフレームに含まれる情報に基づいて、各端末とのリンクを管理する。例えば、マネジメント部１２３は、通信部１３０を介して端末とマルチリンクのセットアップを行う。具体的には、マネジメント部１２３は、端末２０から接続要求を受信したことに応答して、アクセスポイント１０と端末２０との間の複数のリンクを確立するために、アソシエーション処理及び後続する認証処理を実行する。アクセスポイント１０と端末２０との間でのデータのやりとりは、マルチリンクに含まれる１つ又は複数のリンクを使用して行われる。マネジメント部１２３は、図２に例示されるようなリンク管理情報を保持する。アクセスポイント１０は、アクセスポイント１０と端末２０との間の通信に使用するＭＣＳ（Modulation and Coding Scheme）を端末２０とネゴシエートしてよい。 The management unit 123 manages links with each terminal based on information included in the management frame transmitted by each terminal. For example, the management unit 123 sets up a multilink with a terminal via the communication unit 130. Specifically, in response to receiving a connection request from the terminal 20, the management unit 123 performs association processing and subsequent authentication processing in order to establish multiple links between the access point 10 and the terminal 20. Execute. Data exchange between the access point 10 and the terminal 20 is performed using one or more links included in the multilink. The management unit 123 holds link management information as illustrated in FIG. 2. The access point 10 may negotiate with the terminal 20 an MCS (Modulation and Coding Scheme) used for communication between the access point 10 and the terminal 20.
　マネジメント部１２３は、ｒ－ＴＷＴ動作をサポートする各端末に対してｒ－ＴＷＴのセットアップを行う。例えば、マネジメント部１２３は、ｒ－ＴＷＴサービス期間、及びｒ－ＴＷＴサービス期間において使用すべきリンクを設定する。マネジメント部１２３は、端末において低遅延トラヒックが発生する周期に応じてｒ－ＴＷＴサービス期間を設定してよい。具体的には、マネジメント部１２３は、低遅延トラヒックの発生と同期してｒ－ＴＷＴサービス期間が発生するように、低遅延トラヒックの発生周期に基づいて、ｒ－ＴＷＴサービス期間が開始される時刻、ｒ－ＴＷＴサービス期間の周期、及びｒ－ＴＷＴサービス期間の継続時間を決定する。マネジメント部１２３は、低遅延トラヒックの発生周期をいかなる手法で取得してもよい。一例では、マネジメント部１２３は、低遅延トラヒックを発生するアプリケーションに設定されたデータ発生周期を取得してよい。マネジメント部１２３は、ｒ－ＴＷＴサービス期間ごとに、ｒ－ＴＷＴサービス期間において使用すべきリンクを動的に決定してよい。 The management unit 123 performs r-TWT setup for each terminal that supports r-TWT operation. For example, the management unit 123 sets the r-TWT service period and the links to be used during the r-TWT service period. The management unit 123 may set the r-TWT service period according to the cycle in which low-latency traffic occurs at the terminal. Specifically, the management unit 123 determines the time at which the r-TWT service period starts based on the generation cycle of low-latency traffic so that the r-TWT service period occurs in synchronization with the generation of low-latency traffic. , the period of the r-TWT service period, and the duration of the r-TWT service period. The management unit 123 may obtain the generation cycle of low-latency traffic using any method. In one example, the management unit 123 may obtain a data generation cycle set for an application that generates low-latency traffic. The management unit 123 may dynamically determine, for each r-TWT service period, the links to be used during the r-TWT service period.
　マネジメント部１２３は、端末ごとに設定されたｒ－ＴＷＴサービス期間を特定するサービス期間情報を含むビーコンフレームを生成し、ＭＡＣフレーム処理部１２２及び通信部１３０を介して送信する。ビーコンフレームはマネジメントフレームの一種である。サービス期間情報は、ｒ－ＴＷＴサービス期間が開始される時刻を示す情報、ｒ－ＴＷＴサービス期間の継続時間を示す情報、ｒ－ＴＷＴサービス期間の周期を示す情報、及びｒ－ＴＷＴサービス期間において使用すべきリンクを示す情報を含んでよい。サービス期間情報は、ｒ－ＴＷＴサービス期間が設定された端末以外の端末が通信を抑制される通信停止期間（ｑｕｉｅｔ期間）を示す情報をさらに含んでよい。通信停止期間の開始はｒ－ＴＷＴサービス期間の開始と一致する。通信停止期間はｒ－ＴＷＴサービス期間より短くてよい。 The management unit 123 generates a beacon frame including service period information that specifies the r-TWT service period set for each terminal, and transmits it via the MAC frame processing unit 122 and the communication unit 130. A beacon frame is a type of management frame. The service period information includes information indicating the time when the r-TWT service period starts, information indicating the duration of the r-TWT service period, information indicating the cycle of the r-TWT service period, and information used in the r-TWT service period. It may include information indicating the link to be used. The service period information may further include information indicating a communication suspension period (quiet period) during which terminals other than those for which the r-TWT service period is set are suppressed from communicating. The start of the communication outage period coincides with the start of the r-TWT service period. The communication outage period may be shorter than the r-TWT service period.
　通信部１３０は、各端末と無線通信する。通信部１３０は、６ＧＨｚ帯のチャネルを使用して無線信号を送受信するように構成された無線信号処理部１３１、５ＧＨｚ帯のチャネルを使用して無線信号を送受信するように構成された無線信号処理部１３２、及び２．４ＧＨｚ帯のチャネルを使用して無線信号を送受信するように構成された無線信号処理部１３３を備える。無線信号処理部１３１は、無線通信により、アクセスポイント１０と端末との間でフレームを送受信する。具体的には、無線信号処理部１３１は、入力されたデータ又は無線信号に対して物理層の処理を実行する。例えば、無線信号処理部１３１は、アンテナを介して端末からの無線信号を受信し、受信した無線信号に対して所定の復調処理を行って無線フレームを得る。所定の復調処理は、例えば、周波数変換、ＯＦＤＭ復調、高速フーリエ変換（ＦＦＴ；Fast Fourier Transform）、サブキャリア復調、デインタリーブ、及びビタビ復号を含む。そして、無線信号処理部１３１は、無線フレームからＭＡＣフレームを抽出し、ＭＡＣフレームをＭＡＣフレーム処理部１２２に送出する。無線信号処理部１３２、１３３は、無線信号処理部１３１と同様の処理を行う。 The communication unit 130 wirelessly communicates with each terminal. The communication unit 130 includes a wireless signal processing unit 131 configured to transmit and receive wireless signals using a 6 GHz band channel, and a wireless signal processing unit 131 configured to transmit and receive wireless signals using a 5 GHz band channel. 132, and a wireless signal processing unit 133 configured to transmit and receive wireless signals using a 2.4 GHz band channel. The wireless signal processing unit 131 transmits and receives frames between the access point 10 and the terminal through wireless communication. Specifically, the wireless signal processing unit 131 performs physical layer processing on input data or wireless signals. For example, the radio signal processing unit 131 receives a radio signal from a terminal via an antenna, and performs predetermined demodulation processing on the received radio signal to obtain a radio frame. The predetermined demodulation processing includes, for example, frequency conversion, OFDM demodulation, Fast Fourier Transform (FFT), subcarrier demodulation, deinterleaving, and Viterbi decoding. The radio signal processing unit 131 then extracts the MAC frame from the radio frame and sends the MAC frame to the MAC frame processing unit 122. The radio signal processing units 132 and 133 perform the same processing as the radio signal processing unit 131.
　端末２０は、アプリケーション実行部２１０、ＬＬＣ処理部２２０、リンクマネジメント部２３０、及び通信部２４０を備える。アプリケーション実行部２１０及びＬＬＣ処理部２２０は、ＣＰＵ２１によって実現され得る。リンクマネジメント部２３０及び通信部２４０は、無線通信モジュール２４又は無線通信モジュール２４とＣＰＵ２１の組み合わせによって実現され得る。 The terminal 20 includes an application execution section 210, an LLC processing section 220, a link management section 230, and a communication section 240. The application execution unit 210 and the LLC processing unit 220 may be implemented by the CPU 21. The link management section 230 and the communication section 240 can be realized by the wireless communication module 24 or a combination of the wireless communication module 24 and the CPU 21.
　アプリケーション実行部２１０は、図１に示すサーバ３０とデータをやり取りするアプリケーションなどのアプリケーションを実行する。ＬＬＣ処理部２２０は、入力されたデータに対してＬＬＣ層及び上位層の処理を実行する。例えば、ＬＬＣ処理部２２０は、アプリケーション実行部２１０からデータを受け取り、データにＤＳＡＰヘッダ及びＳＳＡＰヘッダなどを付加してＬＬＣパケットを生成し、ＬＬＣパケットをリンクマネジメント部２３０に送出する。 The application execution unit 210 executes an application such as an application that exchanges data with the server 30 shown in FIG. 1. The LLC processing unit 220 performs LLC layer and upper layer processing on input data. For example, the LLC processing unit 220 receives data from the application execution unit 210, adds a DSAP header, an SSAP header, etc. to the data, generates an LLC packet, and sends the LLC packet to the link management unit 230.
　リンクマネジメント部２３０は、入力された信号に対してＭＡＣ層の処理を実行する。さらに、リンクマネジメント部２３０は、アクセスポイント１０との間のリンクを管理する。リンクマネジメント部２３０は、データ処理部２３１、ＭＡＣフレーム処理部２３２、マネジメント部２３３、及び通信制御部２３４を備える。 The link management unit 230 performs MAC layer processing on the input signal. Furthermore, the link management unit 230 manages links with the access point 10. The link management section 230 includes a data processing section 231, a MAC frame processing section 232, a management section 233, and a communication control section 234.
　データ処理部２３１は、ＬＬＣ処理部２２０からＬＬＣパケットを受け取り、ＬＬＣパケットにＭＡＣヘッダを付加してＭＡＣフレームを生成し、ＭＡＣフレームをＭＡＣフレーム処理部２３２に送出する。このＭＡＣフレームはデータフレームである。 The data processing unit 231 receives the LLC packet from the LLC processing unit 220, adds a MAC header to the LLC packet to generate a MAC frame, and sends the MAC frame to the MAC frame processing unit 232. This MAC frame is a data frame.
　ＭＡＣフレーム処理部２３２は、データ処理部２３１からＭＡＣフレームを受け取り、通信部２４０に送出する。また、ＭＡＣフレーム処理部２３２は、通信部２４０からＭＡＣフレームを受け取ると、ＭＡＣフレームの種別に応じてＭＡＣフレームをデータ処理部２３１又はマネジメント部２３３に送出する。具体的には、ＭＡＣフレーム処理部２３２は、ＭＡＣフレームがデータフレームである場合には、ＭＡＣフレームをデータ処理部２３１に送出し、ＭＡＣフレームがマネジメントフレーム又は制御フレームである場合には、ＭＡＣフレームをマネジメント部２３３に送出する。 The MAC frame processing unit 232 receives the MAC frame from the data processing unit 231 and sends it to the communication unit 240. Further, upon receiving a MAC frame from the communication unit 240, the MAC frame processing unit 232 sends the MAC frame to the data processing unit 231 or the management unit 233 depending on the type of the MAC frame. Specifically, the MAC frame processing unit 232 sends the MAC frame to the data processing unit 231 when the MAC frame is a data frame, and sends the MAC frame to the data processing unit 231 when the MAC frame is a management frame or a control frame. is sent to the management section 233.
　マネジメント部２３３は、アクセスポイント１０により送信されたマネジメントフレームに含まれる情報に基づいて、アクセスポイント１０とのリンクを管理する。例えば、マネジメント部２３３は、通信部２４０を介してアクセスポイント１０とマルチリンクのセットアップを行う。具体的には、マネジメント部２３３は、アクセスポイント１０への接続要求の送信を含むアソシエーションに関するプロトコルを実行し、アソシエーションに後続する認証に関するプロトコルを実行する。マネジメント部２３３は、図２に例示されるようなリンク管理情報を保持する。リンク管理情報は、通信制御部２３４によって参照される。 The management unit 233 manages the link with the access point 10 based on information included in the management frame transmitted by the access point 10. For example, the management unit 233 sets up a multilink with the access point 10 via the communication unit 240. Specifically, the management unit 233 executes a protocol related to association, including sending a connection request to the access point 10, and executes a protocol related to authentication subsequent to the association. The management unit 233 holds link management information as illustrated in FIG. 2. The link management information is referred to by the communication control unit 234.
　マネジメント部２３３は、アクセスポイント１０により送信されたビーコンフレームから、端末ごとに設定されたｒ－ＴＷＴサービス期間を特定するサービス期間情報を抽出し、抽出したサービス期間情報を通信制御部２３４に送出する。 The management unit 233 extracts service period information that specifies the r-TWT service period set for each terminal from the beacon frame transmitted by the access point 10, and sends the extracted service period information to the communication control unit 234. .
　通信制御部２３４は、通信部２４０の動作を制御する。例えば、通信制御部２３４は、アクセスポイント１０との通信に使用するリンクを適応的に選択する。さらに、通信制御部２３４は、アクセスポイント１０へデータフレームを送信するタイミングを調整する。通信制御部２３４については後に詳細に説明する。 The communication control unit 234 controls the operation of the communication unit 240. For example, the communication control unit 234 adaptively selects a link to be used for communication with the access point 10. Further, the communication control unit 234 adjusts the timing of transmitting the data frame to the access point 10. The communication control unit 234 will be explained in detail later.
　通信部２４０は、通信制御部２３４による制御に従って、アクセスポイント１０と無線通信する。通信部２４０は、６ＧＨｚ帯のチャネルを使用して無線信号を送受信するように構成された無線信号処理部２４１、５ＧＨｚ帯のチャネルを使用して無線信号を送受信するように構成された無線信号処理部２４２、及び２．４ＧＨｚ帯のチャネルを使用して無線信号を送受信するように構成された無線信号処理部２４３を備える。無線信号処理部２４１は、無線通信により、アクセスポイント１０と端末２０との間でフレームを送受信する。具体的には、無線信号処理部２４１は、入力されたデータ又は無線信号に対して物理層の処理を実行する。例えば、無線信号処理部２４１は、ＭＡＣフレーム処理部２３２からＭＡＣフレームを受け取り、ＭＡＣフレームにプリアンブル及びＰＨＹ（物理層）ヘッダなどを付加して無線フレームを生成し、所定の変調処理を行うことにより無線フレームを無線信号に変換し、アンテナを介して無線信号を放射する。変調処理は、例えば、畳み込み符号化、インタリーブ、サブキャリア変調、逆高速フーリエ変換（ＩＦＦＴ；Inverse Fast Fourier Transform）、ＯＦＤＭ（Orthogonal Frequency Division Multiplexing）変調、及び周波数変換を含む。無線信号処理部２４２、２４３は、無線信号処理部２４１と同様の処理を行う。 The communication unit 240 wirelessly communicates with the access point 10 under the control of the communication control unit 234. The communication unit 240 includes a wireless signal processing unit 241 configured to transmit and receive wireless signals using a 6 GHz band channel, and a wireless signal processing unit 241 configured to transmit and receive wireless signals using a 5 GHz band channel. 242, and a wireless signal processing unit 243 configured to transmit and receive wireless signals using a 2.4 GHz band channel. The wireless signal processing unit 241 transmits and receives frames between the access point 10 and the terminal 20 by wireless communication. Specifically, the wireless signal processing unit 241 performs physical layer processing on input data or wireless signals. For example, the radio signal processing unit 241 receives a MAC frame from the MAC frame processing unit 232, generates a radio frame by adding a preamble, a PHY (physical layer) header, etc. to the MAC frame, and performs predetermined modulation processing. Converts the radio frame into a radio signal and radiates the radio signal via an antenna. Modulation processing includes, for example, convolutional coding, interleaving, subcarrier modulation, inverse fast Fourier transform (IFFT), OFDM (orthogonal frequency division multiplexing) modulation, and frequency conversion. The radio signal processing units 242 and 243 perform the same processing as the radio signal processing unit 241.
　アップリンクでのデータフレーム送信に関する処理について簡単に説明する。 Processing related to data frame transmission on the uplink will be briefly explained.
　アプリケーションがサーバ３０（図１に示される）へ送信すべきデータを発生すると、アプリケーション実行部２１０は、そのデータをＬＬＣ処理部２２０に送出する。ＬＬＣ処理部２２０は、アプリケーション実行部２１０からデータを受け取り、データを含むＬＬＣパケットを生成し、ＬＬＣパケットをデータ処理部２３１に送出する。 When the application generates data to be sent to the server 30 (shown in FIG. 1), the application execution unit 210 sends the data to the LLC processing unit 220. The LLC processing unit 220 receives data from the application execution unit 210, generates an LLC packet containing the data, and sends the LLC packet to the data processing unit 231.
　データ処理部２３１は、ＬＬＣ処理部２２０からＬＬＣパケットを受け取り、ＬＬＣパケットからＭＡＣフレームを生成し、ＭＡＣフレームをＭＡＣフレーム処理部２３２に送出する。ＭＡＣフレーム処理部２３２は、データ処理部２３１からＭＡＣフレームを受け取り、ＭＡＣフレームを通信部２４０に送出する。ＭＡＣフレーム処理部２３２は、マルチリンクに含まれる複数のリンクに対応する複数の無線信号処理部にＭＡＣフレームを送出する。ＭＡＣフレーム処理部２３２は、アクセスポイント１０との間に確立されているリンクを特定するために、マネジメント部２３３が保持しているリンク管理情報を参照する。リンク管理情報が図２に示すリンク管理情報である場合、３つのリンクがアクセスポイント１０と端末２０との間に確立されている。 The data processing unit 231 receives the LLC packet from the LLC processing unit 220, generates a MAC frame from the LLC packet, and sends the MAC frame to the MAC frame processing unit 232. The MAC frame processing unit 232 receives the MAC frame from the data processing unit 231 and sends the MAC frame to the communication unit 240. The MAC frame processing section 232 sends the MAC frame to a plurality of wireless signal processing sections corresponding to a plurality of links included in the multilink. The MAC frame processing unit 232 refers to link management information held by the management unit 233 in order to identify the link established with the access point 10. When the link management information is the link management information shown in FIG. 2, three links are established between the access point 10 and the terminal 20.
　通信部２４０は、ＭＡＣフレーム処理部２３２からＭＡＣフレームを受け取り、ＭＡＣフレームを一時的に格納する。通信部２４０は、通信制御部２３４からの指示に従ってＭＡＣフレームを無線送信する。通信部２４０では、無線信号処理部２４１、２４２、２４３がＭＡＣフレーム処理部２３２から同じＭＡＣフレームを受け取り、それらのいずれか１つがそのＭＡＣフレームを無線送信し、残りの無線信号処理部はそのＭＡＣフレームを破棄する。例えば、通信制御部２３４がリンクＩＤが１であるリンクを使用することを決定した場合、無線信号処理部２４１は、ＭＡＣフレームから無線フレームを生成し、変調処理を行うことにより無線フレームを無線信号に変換し、アンテナを介して無線信号を放射する。 The communication unit 240 receives the MAC frame from the MAC frame processing unit 232 and temporarily stores the MAC frame. The communication unit 240 wirelessly transmits the MAC frame according to instructions from the communication control unit 234. In the communication unit 240, the wireless signal processing units 241, 242, and 243 receive the same MAC frame from the MAC frame processing unit 232, one of them wirelessly transmits the MAC frame, and the remaining wireless signal processing units transmit the MAC frame. Discard the frame. For example, when the communication control unit 234 determines to use a link whose link ID is 1, the wireless signal processing unit 241 generates a wireless frame from the MAC frame, and performs modulation processing to convert the wireless frame into a wireless signal. and radiate a radio signal through an antenna.
　アクセスポイント１０において、通信部１３０は、端末２０から無線信号を受信する。無線信号処理部１３１、１３２、１３３のいずれかが端末２０から無線信号を受信する。例えば、端末２０がリンクＩＤが１であるリンクを使用した場合、無線信号処理部１３１が端末２０から無線信号を受信する。無線信号処理部１３１は、無線信号に対して復調処理を行って無線フレームを得る。無線信号処理部１３１は、無線フレームからＭＡＣフレームを抽出し、ＭＡＣフレームをＭＡＣフレーム処理部１２２に送出する。 In the access point 10, the communication unit 130 receives a wireless signal from the terminal 20. One of the wireless signal processing units 131, 132, and 133 receives a wireless signal from the terminal 20. For example, when the terminal 20 uses a link whose link ID is 1, the wireless signal processing unit 131 receives a wireless signal from the terminal 20. The radio signal processing unit 131 performs demodulation processing on the radio signal to obtain a radio frame. The radio signal processing unit 131 extracts a MAC frame from the radio frame and sends the MAC frame to the MAC frame processing unit 122.
　ＭＡＣフレーム処理部１２２は、通信部１３０からＭＡＣフレームを受け取る。このＭＡＣフレームはデータフレームであるので、ＭＡＣフレーム処理部１２２は、ＭＡＣフレームをデータ処理部１２１に送出する。 The MAC frame processing unit 122 receives a MAC frame from the communication unit 130. Since this MAC frame is a data frame, the MAC frame processing unit 122 sends the MAC frame to the data processing unit 121.
　データ処理部１２１は、ＭＡＣフレーム処理部１２２からＭＡＣフレームを受け取り、ＭＡＣフレームからＬＬＣパケットを抽出し、ＬＬＣパケットをＬＬＣ処理部１１０に送出する。ＬＬＣ処理部１１０は、データ処理部１２１からＬＬＣパケットを受け取り、ＬＬＣパケットからデータを抽出し、データを通信ネットワーク４０上のサーバ３０に送信する。 The data processing unit 121 receives the MAC frame from the MAC frame processing unit 122, extracts the LLC packet from the MAC frame, and sends the LLC packet to the LLC processing unit 110. The LLC processing unit 110 receives the LLC packet from the data processing unit 121, extracts data from the LLC packet, and transmits the data to the server 30 on the communication network 40.
　図６は、無線信号処理部２４１のチャネルアクセス機能の機能構成の一例を概略的に示している。図６に示すように、無線信号処理部２４１は、分類部２４１１、キュー２４１２Ａ、２４１２Ｂ、２４１２Ｃ、２４１２Ｄ、キャリアセンス実行部２４１３Ａ、２４１３Ｂ、２４１３Ｃ、２４１３Ｄ、内部衝突管理部２４１４、及び変調部２４１５を含む。 FIG. 6 schematically shows an example of the functional configuration of the channel access function of the radio signal processing unit 241. As shown in FIG. 6, the radio signal processing section 241 includes a classification section 2411, queues 2412A, 2412B, 2412C, 2412D, carrier sense execution sections 2413A, 2413B, 2413C, 2413D, an internal collision management section 2414, and a modulation section 2415. include.
　データフレームが無線信号処理部２４１に入力されると、分類部２４１１は、データフレーム中のＭＡＣヘッダに含まれるＴＩＤに基づいて、データフレームを複数のアクセスカテゴリに分類する。図６に示す例では、分類部２４１１は、データフレームを４つのアクセスカテゴリＶＯ、ＶＩ、ＢＥ、ＢＫに分類する。 When a data frame is input to the wireless signal processing unit 241, the classification unit 2411 classifies the data frame into a plurality of access categories based on the TID included in the MAC header in the data frame. In the example shown in FIG. 6, the classification unit 2411 classifies data frames into four access categories VO, VI, BE, and BK.
　分類部２４１１は、データフレームをアクセスカテゴリＶＯに分類した場合にデータフレームをキュー２４１２Ａに入力し、データフレームをアクセスカテゴリＶＩに分類した場合にデータフレームをキュー２４１２Ｂに入力し、データフレームをアクセスカテゴリＢＥに分類した場合にデータフレームをキュー２４１２Ｃに入力し、データフレームをアクセスカテゴリＢＫに分類した場合にデータフレームをキュー２４１２Ｄに入力する。キュー２４１２Ａ、２４１２Ｂ、２４１２Ｃ、２４１２Ｄの各々は、入力されたデータフレームをバッファする。 The classification unit 2411 inputs the data frame into the queue 2412A when the data frame is classified into the access category VO, inputs the data frame into the queue 2412B when the data frame is classified into the access category VI, and inputs the data frame into the queue 2412B when the data frame is classified into the access category VI. When the data frame is classified as BE, the data frame is input into the queue 2412C, and when the data frame is classified into the access category BK, the data frame is input into the queue 2412D. Each of queues 2412A, 2412B, 2412C, and 2412D buffers input data frames.
　キャリアセンス実行部２４１３Ａ、２４１３Ｂ、２４１３Ｃ、２４１３Ｄはそれぞれ、キュー２４１２Ａ、２４１２Ｂ、２４１２Ｃ、２４１２Ｄに対応して設けられている。キャリアセンス実行部２４１３Ａ、２４１３Ｂ、２４１３Ｃ、２４１３Ｄは、異なるアクセスパラメータセットを使用することを除いて同様の処理を行う。アクセスパラメータセットは、例えば、ＣＷｍｉｎ、ＣＷｍａｘ、ＡＩＦＳ（Arbitration Inter Frame Space）、及びＴＸＯＰ（Transmission Opportunity）Ｌｉｍｉｔという４つのアクセスパラメータを含む。ＣＷｍｉｎ及びＣＷｍａｘはそれぞれ、コンテンションウインドウの最小値及び最大値を示す。コンテンションウインドウは、衝突回避のための送信待ち時間を決定するために用いるパラメータである。ＡＩＦＳは、送信待ち時間を示す。ＴＸＯＰＬｉｍｉｔは、チャネルの占有期間ＴＸＯＰの上限値を示す。すなわち、短いＣＷｍｉｎ及びＣＷｍａｘ、並びにＡＩＦＳが設定されるアクセスカテゴリほど、送信権を取得しやすい。また、大きなＴＸＯＰＬｉｍｉｔが設定されるアクセスカテゴリほど、一度の送信権で送信できるデータ量が多い。 Carrier sense execution units 2413A, 2413B, 2413C, and 2413D are provided corresponding to queues 2412A, 2412B, 2412C, and 2412D, respectively. Carrier sense execution units 2413A, 2413B, 2413C, and 2413D perform similar processing except that different access parameter sets are used. The access parameter set includes, for example, four access parameters: CWmin, CWmax, AIFS (Arbitration Inter Frame Space), and TXOP (Transmission Opportunity) Limit. CWmin and CWmax indicate the minimum and maximum values of the contention window, respectively. The contention window is a parameter used to determine transmission waiting time for collision avoidance. AIFS indicates transmission latency. TXOPLimit indicates the upper limit value of the channel occupation period TXOP. That is, the access category for which the shorter CWmin, CWmax, and AIFS are set, the easier it is to acquire the transmission right. Furthermore, the larger the TXOPLimit is set in the access category, the larger the amount of data that can be transmitted with one transmission right.
　キャリアセンス実行部２４１３Ａを代表として説明する。キャリアセンス実行部２４１３Ａは、リンクＩＤが１であるリンクについて、あらかじめ設定されたアクセスパラメータセットに従って、ＣＳＭＡ／ＣＡに基づくキャリアセンスを実行する。キャリアセンス実行部２４１３Ａは、キャリアセンスを開始すると、キャリアセンスのステータスを通信制御部２３４に通知する。例えば、チャネルが使用されていない状態が続いたときに、キャリアセンス実行部２４１３Ａは、送信権が獲得される予定時刻及びチャネル占有時間を通信制御部２３４に通知する。キャリアセンス実行部２４１３Ａは、チャネルがビジーであることを検出した場合に、キャリアセンスを中断することを通信制御部２３４に通知する。 The carrier sense execution unit 2413A will be explained as a representative. The carrier sense execution unit 2413A executes carrier sense based on CSMA/CA for the link whose link ID is 1, according to a preset access parameter set. When carrier sense execution unit 2413A starts carrier sense, carrier sense execution unit 2413A notifies communication control unit 234 of the carrier sense status. For example, when the channel remains unused, the carrier sense execution unit 2413A notifies the communication control unit 234 of the scheduled time when the transmission right will be acquired and the channel occupation time. When the carrier sense execution unit 2413A detects that the channel is busy, it notifies the communication control unit 234 that carrier sense is to be interrupted.
　キャリアセンス実行部２４１３Ａは、送信権を獲得すると、送信権が獲得されたことを通信制御部２３４に通知する。通信制御部２３４は、キャリアセンス実行部２４１３Ａからの通知に応答して、送信開始を指示する送信開始信号、送信延期を指示する送信延期信号、又は他のリンク（無線信号処理部２４２又は２４３）でデータフレーム送信を行うことを示す送信中止信号をキャリアセンス実行部２４１３Ａに送出する。キャリアセンス実行部２４１３Ａは、通信制御部２３４から送信指示信号を受け取ったことに応答して、キュー２４１２Ａからデータフレームを取り出し、内部衝突管理部２４１４を介して変調部２４１５にデータフレームを送出する。キャリアセンス実行部２４１３Ａは、通信制御部２３４から送信延期信号を受け取ったことに応答して、送信を延期する。例えば、キャリアセンス実行部２４１３Ａは、通信制御部２３４からキャリアセンスの再開を指示する信号を受け取るまで、待機する。キャリアセンス実行部２４１３Ａは、通信制御部２３４から送信中止信号を受け取ったことに応答して、キュー２４１２Ａの先頭に格納されているデータフレームを破棄する。 Upon acquiring the transmission right, the carrier sense execution unit 2413A notifies the communication control unit 234 that the transmission right has been acquired. In response to the notification from the carrier sense execution unit 2413A, the communication control unit 234 generates a transmission start signal instructing to start transmission, a transmission postponement signal instructing transmission postponement, or another link (wireless signal processing unit 242 or 243). A transmission stop signal indicating that data frame transmission will be performed is sent to the carrier sense execution unit 2413A. In response to receiving the transmission instruction signal from the communication control unit 234, the carrier sense execution unit 2413A takes out the data frame from the queue 2412A and sends the data frame to the modulation unit 2415 via the internal collision management unit 2414. The carrier sense execution unit 2413A postpones transmission in response to receiving the transmission postponement signal from the communication control unit 234. For example, the carrier sense execution unit 2413A waits until it receives a signal from the communication control unit 234 instructing restart of carrier sense. In response to receiving the transmission stop signal from the communication control unit 234, the carrier sense execution unit 2413A discards the data frame stored at the head of the queue 2412A.
　内部衝突管理部２４１４は、２つ以上のキャリアセンス実行部が同時に送信権を取得した場合に、送信の衝突を防止する。具体的には、内部衝突管理部２４１４は、２つ以上のキャリアセンス実行部からデータフレームを同時に受け取ると、優先度のより高いアクセスカテゴリのデータフレームを送信するために、優先度のより高いアクセスカテゴリのデータフレームを変調部２４１５に送出する。 The internal collision management unit 2414 prevents transmission collisions when two or more carrier sense execution units acquire transmission rights at the same time. Specifically, when receiving data frames from two or more carrier sense execution units at the same time, the internal collision management unit 2414 selects an access category with a higher priority in order to transmit a data frame of an access category with a higher priority. The category data frame is sent to modulation section 2415.
　変調部２４１５は、内部衝突管理部２４１４からデータフレームを受け取り、データフレームから無線フレームを生成し、変調処理を行うことにより無線フレームを無線信号に変換し、アンテナを介して無線信号を放射する。 The modulation unit 2415 receives the data frame from the internal collision management unit 2414, generates a radio frame from the data frame, converts the radio frame into a radio signal by performing modulation processing, and radiates the radio signal via the antenna.
　無線信号処理部２４２、２４３の各々は、図６に示すものと同様のチャネルアクセス機能を備える。 Each of the radio signal processing units 242 and 243 has a channel access function similar to that shown in FIG.
　図７を参照して、端末２０におけるデータフレーム送信について詳細に説明する。ここでは、アクセスカテゴリＶＯに分類されるデータフレームの送信について説明する。他のアクセスカテゴリに分類されるデータフレームは、以下に説明するものと同様にして送信されることができる。 With reference to FIG. 7, data frame transmission in the terminal 20 will be explained in detail. Here, transmission of data frames classified into access category VO will be explained. Data frames classified into other access categories may be transmitted in a manner similar to that described below.
　図７は、通信制御部２３４及び無線信号処理部２４１、２４２、２４３の機能構成の例を概略的に示している。図７において、無線信号処理部２４１、２４２、２４３の各々に関して、機能構成の一部が示されている。例えば、無線信号処理部２４１に関しては、図６に示した分類部２４１１、キュー２４１２Ｂ、２４１２Ｃ、２４１２Ｄ、キャリアセンス実行部２４１３Ｂ、２４１３Ｃ、２４１３Ｄ、内部衝突管理部２４１４、及び変調部２４１５が省略されている。 FIG. 7 schematically shows an example of the functional configuration of the communication control unit 234 and the wireless signal processing units 241, 242, and 243. In FIG. 7, a part of the functional configuration of each of the radio signal processing sections 241, 242, and 243 is shown. For example, regarding the radio signal processing unit 241, the classification unit 2411, queues 2412B, 2412C, 2412D, carrier sense execution units 2413B, 2413C, 2413D, internal collision management unit 2414, and modulation unit 2415 shown in FIG. 6 are omitted. There is.
　図７に示すように、無線信号処理部２４２は、キュー２４２２Ａ及びキャリアセンス実行部２４２３Ａを備える。キュー２４２２Ａは、アクセスカテゴリＶＯに分類されるデータフレームをバッファする。キャリアセンス実行部２４２３Ａは、リンクＩＤが２であるリンクについて、キャリアセンス実行部２４１３Ａのものと同じアクセスパラメータセットに従って、ＣＳＭＡ／ＣＡに基づくキャリアセンスを実行する。無線信号処理部２４３は、キュー２４３２Ａ及びキャリアセンス実行部２４３３Ａを備える。キュー２４３２Ａは、アクセスカテゴリＶＯに分類されるデータフレームをバッファする。キャリアセンス実行部２４３３Ａは、リンクＩＤが３であるリンクについて、キャリアセンス実行部２４１３Ａのものと同じアクセスパラメータセットに従って、ＣＳＭＡ／ＣＡに基づくキャリアセンスを実行する。ＭＡＣフレーム処理部２３２は各データフレームを無線信号処理部２４１、２４２、２４３に送出するため、キュー２４１２Ａ、２４２２Ａ、２４３２Ａには同じデータフレームが格納されている。 As shown in FIG. 7, the radio signal processing section 242 includes a queue 2422A and a carrier sense execution section 2423A. Queue 2422A buffers data frames classified into access category VO. The carrier sense execution unit 2423A executes carrier sense based on CSMA/CA for the link whose link ID is 2, according to the same access parameter set as that of the carrier sense execution unit 2413A. The radio signal processing section 243 includes a queue 2432A and a carrier sense execution section 2433A. Queue 2432A buffers data frames classified into access category VO. The carrier sense execution unit 2433A executes carrier sense based on CSMA/CA for the link whose link ID is 3, according to the same access parameter set as that of the carrier sense execution unit 2413A. Since the MAC frame processing section 232 sends each data frame to the radio signal processing sections 241, 242, and 243, the same data frames are stored in the queues 2412A, 2422A, and 2432A.
　キャリアセンス実行部２４１３Ａ、２４２３Ａ、２４３３Ａは、同時にキャリアセンスを実行し得る。このため、複数のリンクについて送信権が同時に獲得されることがある。キャリアセンス実行部２４１３Ａ、２４２３Ａ、２４３３Ａの各々は、送信権を獲得すると、送信権を獲得したことを通信制御部２３４に通知する。キャリアセンス実行部２４１３Ａ、２４２３Ａ、２４３３Ａをキャリアセンス実行部２４５と総称する。 The carrier sense execution units 2413A, 2423A, and 2433A can simultaneously execute carrier sense. Therefore, transmission rights may be acquired for multiple links at the same time. Upon acquiring the transmission right, each of the carrier sense execution units 2413A, 2423A, and 2433A notifies the communication control unit 234 that the transmission right has been acquired. The carrier sense execution units 2413A, 2423A, and 2433A are collectively referred to as a carrier sense execution unit 245.
　通信制御部２３４は、指示部２３４１、リンク選択部２３４２、フレーム交換期間算出部２３４３、通信可能期間算出部２３４４、及び判定部２３４５を備える。 The communication control unit 234 includes an instruction unit 2341 , a link selection unit 2342 , a frame exchange period calculation unit 2343 , a communicable period calculation unit 2344 , and a determination unit 2345 .
　指示部２３４１は、キャリアセンス実行部２４５と情報をやり取りする。例えば、指示部２３４１は、キャリアセンス実行部２４１３Ａ、２４２３Ａ、２４３３Ａに対し指示を出す。また、指示部２３４１は、キャリアセンス実行部２４１３Ａ、２４２３Ａ、２４３３Ａから、送信権が獲得されたことを示す通知を受け取り、受け取った通知を通信可能期間算出部２３４４に送出する。 The instruction unit 2341 exchanges information with the carrier sense execution unit 245. For example, the instruction unit 2341 issues instructions to the carrier sense execution units 2413A, 2423A, and 2433A. Further, the instruction unit 2341 receives notifications indicating that the transmission right has been acquired from the carrier sense execution units 2413A, 2423A, and 2433A, and sends the received notifications to the communicable period calculation unit 2344.
　フレーム交換期間算出部２３４３は、アクセスポイント１０へのデータフレーム送信に要する時間期間を含むフレーム交換期間を算出する。フレーム交換期間は、アクセスポイント１０と端末２０との間でのフレーム交換に要する時間期間を示す。フレーム交換期間は、図８においてαで示される、送信権が獲得された時刻からアクセスポイント１０へのデータフレーム送信に関連する処理が終了する時刻までの期間を示し得る。アクセスポイント１０へのデータフレーム送信に関連する処理は、データフレームをアクセスポイント１０へ送信する処理を示してもよく、データフレームをアクセスポイント１０へ送信し、アクセスポイント１０からデータフレームに対する応答（例えば確認応答であるＡＣＫ）を受信する一連の処理を示してもよい。言い換えると、フレーム交換期間は、アクセスポイント１０へデータフレームを送信するのに要する時間期間を示してもよく、アクセスポイント１０へデータフレームを送信し、アクセスポイント１０からデータフレームに対する応答を受信するのに要する時間期間を示してもよい。 The frame exchange period calculation unit 2343 calculates a frame exchange period including the time period required for transmitting a data frame to the access point 10. The frame exchange period indicates the time period required for frame exchange between the access point 10 and the terminal 20. The frame exchange period may indicate the period from the time when the transmission right is acquired to the time when processing related to data frame transmission to the access point 10 ends, indicated by α in FIG. 8 . A process related to transmitting a data frame to the access point 10 may refer to a process of transmitting the data frame to the access point 10, transmitting the data frame to the access point 10, and receiving a response from the access point 10 to the data frame (e.g. It may also show a series of processes for receiving an acknowledgment (ACK). In other words, the frame exchange period may indicate the time period required to transmit a data frame to the access point 10, and to receive a response to the data frame from the access point 10. It may also indicate the time period required.
　例えば、フレーム交換期間算出部２３４３は、指示部２３４１を介してキャリアセンス実行部２４１３Ａから、送信しようとしているデータフレーム（キュー２４１２Ａの先頭に保持されているデータフレーム）のサイズを示す情報を受け取り、マネジメント部２３３から、アクセスポイント１０へのデータフレーム送信に適用するＭＣＳを示す情報を受け取る。フレーム交換期間算出部２３４３は、送信しようとしているデータフレームのサイズと、データフレーム送信に適用するＭＣＳと、コンテンションウインドウにより決定される平均バックオフ値で算出される送信待ち時間と、に基づいて、アクセスポイント１０へのデータフレーム送信に要する時間期間を算出する。コンテンションウインドウにより決定される平均バックオフ値で算出される送信待ち時間は、送信権獲得に関わるオーバヘッドに相当する。 For example, the frame exchange period calculation unit 2343 receives information indicating the size of the data frame to be transmitted (the data frame held at the head of the queue 2412A) from the carrier sense execution unit 2413A via the instruction unit 2341, Information indicating the MCS applied to data frame transmission to the access point 10 is received from the management unit 233 . The frame exchange period calculation unit 2343 calculates the transmission waiting time based on the size of the data frame to be transmitted, the MCS applied to the data frame transmission, and the average backoff value determined by the contention window. , the time period required to transmit the data frame to the access point 10 is calculated. The transmission waiting time calculated by the average backoff value determined by the contention window corresponds to the overhead related to acquiring the transmission right.
　通信可能期間算出部２３４４は、指示部２３４１を介してキャリアセンス実行部２４５から、送信権が獲得された１つ又は複数のリンクを示す通知を受け取る。通信可能期間算出部２３４４は、送信権が獲得されたリンクの各々について、ｒ－ＴＷＴサービス期間の開始までの時間期間を示す通信可能期間を算出する。通信可能期間は、図８においてβで示される、送信権が獲得された時刻からｒ－ＴＷＴサービス期間が開始する時刻までの期間を示し得る。通信可能期間算出部２３４４は、リンクに対してｒ－ＴＷＴサービス期間がスケジュールされているかを確認する。ｒ－ＴＷＴサービス期間は、端末２０に対して設定されたものであってもよく、他の端末に対して設定されたものであってもよい。ｒ－ＴＷＴサービス期間が他の端末に対して設定されたものである場合、ｒ－ＴＷＴサービス期間の開始は通信停止期間の開始を指す。 The communicable period calculation unit 2344 receives a notification indicating one or more links for which transmission rights have been acquired from the carrier sense execution unit 245 via the instruction unit 2341. The communicable period calculation unit 2344 calculates a communicable period indicating the time period until the start of the r-TWT service period for each link for which the transmission right has been acquired. The communicable period may indicate the period from the time when the transmission right is acquired to the time when the r-TWT service period starts, which is indicated by β in FIG. The communication available period calculation unit 2344 checks whether an r-TWT service period is scheduled for the link. The r-TWT service period may be set for the terminal 20 or may be set for another terminal. If the r-TWT service period is set for another terminal, the start of the r-TWT service period refers to the start of the communication suspension period.
　ｒ－ＴＷＴサービス期間が送信権が獲得されたリンクのすべてに対してスケジュールされている場合に、通信可能期間算出部２３４４は、これらのリンクの各々について通信可能期間を算出する。ｒ－ＴＷＴサービス期間がスケジュールされていないリンクがある場合、通信可能期間算出部２３４４は、ｒ－ＴＷＴサービス期間がスケジュールされていないリンクをリンク選択部２３４２に通知する。代替として、ｒ－ＴＷＴサービス期間がスケジュールされていないリンクがある場合にも、通信可能期間算出部２３４４は、送信権が獲得されたリンクすべてについて通信可能期間を算出してもよい。この場合、通信可能期間算出部２３４４は、ｒ－ＴＷＴサービス期間がスケジュールされていないリンクについての通信可能期間を充分に長い期間を示す値に設定してよい。 If the r-TWT service period is scheduled for all links for which transmission rights have been acquired, the communicable period calculation unit 2344 calculates the communicable period for each of these links. If there is a link for which an r-TWT service period has not been scheduled, the communicable period calculation unit 2344 notifies the link selection unit 2342 of the link for which an r-TWT service period has not been scheduled. Alternatively, even if there is a link for which an r-TWT service period is not scheduled, the communicable period calculation unit 2344 may calculate the communicable period for all links for which transmission rights have been acquired. In this case, the communicable period calculation unit 2344 may set the communicable period for a link for which an r-TWT service period is not scheduled to a value indicating a sufficiently long period.
　判定部２３４５は、送信権が獲得されたリンクの各々について、フレーム交換期間算出部２３４３により算出されたフレーム交換期間と通信可能期間算出部２３４４により算出された通信可能期間との比較に基づいて、アクセスポイント１０へのデータフレーム送信を含むデータ交換がｒ－ＴＷＴサービス期間の開始までに終わるか否かを判定する。判定部２３４５は、図８に示すようにフレーム交換期間αが通信可能期間βよりも短い場合に、データ交換がｒ－ＴＷＴサービス期間の開始までに終わると判定し、図９に示すようにフレーム交換期間αが通信可能期間βよりも長い場合に、データ交換がｒ－ＴＷＴサービス期間の開始までに終わらないと判定する。 Based on the comparison between the frame exchange period calculated by the frame exchange period calculation section 2343 and the communication possible period calculated by the communication possible period calculation section 2344 for each link for which the transmission right has been acquired, the determination section 2345 performs the following: It is determined whether the data exchange including data frame transmission to the access point 10 is completed by the start of the r-TWT service period. If the frame exchange period α is shorter than the communication available period β as shown in FIG. If the exchange period α is longer than the communicable period β, it is determined that the data exchange will not end by the start of the r-TWT service period.
　判定部２３４５は、判定結果を指示部２３４１又はリンク選択部２３４２に通知する。フレーム交換期間αが通信可能期間βよりも短いリンクが１つ又は複数ある場合、判定部２３４５は判定結果通知をリンク選択部２３４２に送出する。フレーム交換期間αが通信可能期間βよりも短いリンクが１つである場合、判定結果通知は、そのリンクを示す情報を含む。フレーム交換期間αが通信可能期間βよりも短いリンクが複数ある場合、判定結果通知は、通信可能期間βからフレーム交換期間αを引いた差が最も大きいリンクを示す情報を含む。フレーム交換期間αが通信可能期間βよりも短いリンクがない場合、判定部２３４５は、データ交換がｒ－ＴＷＴサービス期間の開始までに終わるリンクがないことを示す判定結果通知を指示部２３４１に送出する。 The determination unit 2345 notifies the instruction unit 2341 or the link selection unit 2342 of the determination result. If there is one or more links for which the frame exchange period α is shorter than the communicable period β, the determination unit 2345 sends a determination result notification to the link selection unit 2342. If there is one link whose frame exchange period α is shorter than the communicable period β, the determination result notification includes information indicating that link. If there are multiple links whose frame exchange period α is shorter than the communicable period β, the determination result notification includes information indicating the link with the largest difference between the communicable period β and the frame exchange period α. If there is no link for which the frame exchange period α is shorter than the communication available period β, the determination unit 2345 sends a determination result notification to the instruction unit 2341 indicating that there is no link for which data exchange ends before the start of the r-TWT service period. do.
　リンク選択部２３４２は、判定部２３４５から判定結果通知を受け取り、判定結果通知に基づいてマルチリンクの中からアクセスポイント１０へのデータフレーム送信に使用するリンクを選択し、選択したリンクを指示部２３４１に通知する。具体的には、リンク選択部２３４２は、判定結果通知により示されるリンクを選択する。判定結果通知が複数のリンクを示す場合、リンク選択部２３４２は、それらのリンクのいずれか１つを選択する。リンク選択部２３４２は、通信可能期間算出部２３４４から通知を受け取る場合、当該通知に基づいてリンク選択を行い、選択したリンクを指示部２３４１に通知する。例えば、リンク選択部２３４２は、通信可能期間算出部２３４４からの通知により示されるリンクを選択する。 The link selection unit 2342 receives the determination result notification from the determination unit 2345, selects a link to be used for transmitting the data frame to the access point 10 from among the multi-links based on the determination result notification, and sends the selected link to the instruction unit 2341. to notify. Specifically, the link selection unit 2342 selects the link indicated by the determination result notification. When the determination result notification indicates multiple links, the link selection unit 2342 selects any one of those links. When receiving a notification from the communication available period calculation unit 2344, the link selection unit 2342 selects a link based on the notification and notifies the instruction unit 2341 of the selected link. For example, the link selection unit 2342 selects the link indicated by the notification from the communicable period calculation unit 2344.
　なお、フレーム交換期間αが通信可能期間βよりも短いリンクが複数ある場合において、判定結果通知は、フレーム交換期間αが通信可能期間βよりも短い複数のリンクを示す情報を含んでもよい。この場合、リンク選択部２３４２は、それらのリンクのいずれか１つを選択する。 Note that in the case where there are a plurality of links whose frame exchange period α is shorter than the communicable period β, the determination result notification may include information indicating the plurality of links whose frame exchange period α is shorter than the communicable period β. In this case, the link selection unit 2342 selects any one of those links.
　指示部２３４１は、リンク選択部２３４２から通知を受け取ったことに応答して、リンク選択部２３４２により選択されたリンクでデータフレーム送信を行うことをキャリアセンス実行部２４５に指示する。例えば、リンク選択部２３４２がリンクＩＤが２であるリンクを選択した場合、指示部２３４１は、送信開始信号をキャリアセンス実行部２４２３Ａに送出し、送信中止信号をキャリアセンス実行部２４１３Ａ、２４３３Ａに送出する。指示部２３４１は、判定部２３４５から判定結果通知を受け取ったことに応答して、データフレーム送信を延期することをキャリアセンス実行部２４５に指示する。具体的には、指示部２３４１は、送信延期信号をキャリアセンス実行部２４１３Ａ、２４２３Ａ、２４３３Ａに送出する。 In response to receiving the notification from the link selection unit 2342, the instruction unit 2341 instructs the carrier sense execution unit 245 to transmit the data frame using the link selected by the link selection unit 2342. For example, when the link selection unit 2342 selects a link whose link ID is 2, the instruction unit 2341 sends a transmission start signal to the carrier sense execution unit 2423A, and sends a transmission stop signal to the carrier sense execution units 2413A and 2433A. do. In response to receiving the determination result notification from the determination unit 2345, the instruction unit 2341 instructs the carrier sense execution unit 245 to postpone data frame transmission. Specifically, the instruction unit 2341 sends a transmission postponement signal to the carrier sense execution units 2413A, 2423A, and 2433A.
　指示部２３４１、リンク選択部２３４２、及び判定部２３４５を送信制御部２３４６と総称することもある。送信制御部２３４６は、フレーム交換期間αが通信可能期間βよりも短いリンクがある場合に、通信部２４０を介してそのリンクでデータフレーム送信を行い、フレーム交換期間αが通信可能期間βよりも短いリンクがない場合に、データフレーム送信を延期するように構成される。フレーム交換期間αが通信可能期間βよりも短いリンクが複数ある場合において、送信制御部２３４６は、通信可能期間βからフレーム交換期間αを引いた差が最も大きいリンクでデータフレーム送信を行うように構成されてよい。通信可能期間βからフレーム交換期間αを引いた差が最も大きいリンクは、通信可能期間βが最も長いリンクに一致する。送信制御部２３４６は、サービス期間がスケジュールされていないリンクがあることに応答して、そのリンクでデータフレーム送信を行うように構成されてもよい。 The instruction section 2341, link selection section 2342, and determination section 2345 may be collectively referred to as the transmission control section 2346. If there is a link in which the frame exchange period α is shorter than the communicable period β, the transmission control unit 2346 transmits a data frame on that link via the communication unit 240, and when the frame exchange period α is shorter than the communicable period β. Configured to defer data frame transmission if there is no short link. When there are multiple links whose frame exchange period α is shorter than the communicable period β, the transmission control unit 2346 transmits the data frame using the link with the largest difference obtained by subtracting the frame exchange period α from the communicable period β. may be configured. The link with the largest difference obtained by subtracting the frame exchange period α from the communicable period β corresponds to the link with the longest communicable period β. The transmission control unit 2346 may be configured to perform data frame transmission on the link in response to the fact that there is a link for which a service period is not scheduled.
　図１０は、一実施形態に係る無線通信方法を概略的に示している。具体的には、図１０は、端末２０がデータフレームをアクセスポイント１０へ無線送信する方法の一例を概略的に示している。図１０に示す処理は、アクセスカテゴリに対して個別に実行される。ここでは、アクセスカテゴリＶＯについての処理を説明する。アクセスポイント１０と端末２０との間に確立されているリンクの数をＭとする。 FIG. 10 schematically shows a wireless communication method according to an embodiment. Specifically, FIG. 10 schematically shows an example of a method in which the terminal 20 wirelessly transmits a data frame to the access point 10. The process shown in FIG. 10 is executed for each access category individually. Here, processing regarding access category VO will be explained. Let M be the number of links established between the access point 10 and the terminal 20.
　図１０のステップＳ１００１において、フレーム交換期間算出部２３４３は、アクセスポイント１０へのデータフレーム送信に要する時間期間を含むフレーム交換期間αを算出する。例えば、フレーム交換期間算出部２３４３は、送信しようとしているデータフレームのサイズとデータフレーム送信に適用するＭＣＳとに基づいて、アクセスポイント１０へのデータフレーム送信に要する時間期間を算出し、算出した時間期間にアクセスポイント１０からＡＣＫを受信するのに要する時間及び送信権獲得に関わるオーバヘッドを加算して、フレーム交換期間αを得る。 In step S1001 in FIG. 10, the frame exchange period calculation unit 2343 calculates a frame exchange period α that includes the time period required for transmitting a data frame to the access point 10. For example, the frame exchange period calculation unit 2343 calculates the time period required to transmit the data frame to the access point 10 based on the size of the data frame to be transmitted and the MCS applied to the data frame transmission, and calculates the time period required for transmitting the data frame to the access point 10. The frame exchange period α is obtained by adding the time required to receive an ACK from the access point 10 and the overhead related to acquiring the transmission right to the period.
　ステップＳ１００２において、キャリアセンス実行部２４５は、Ｍ個のリンクの各々についてキャリアセンスを行い、ｍ個のリンクについての送信権を獲得する。ここで、ｍは２以上Ｍ以下の整数とする。送信権が獲得されたｍ個のリンクをリンク１～ｍと表す。図７に示す例では、キャリアセンス実行部２４１３Ａは、リンクＩＤが１であるリンクについてキャリアセンスを行い、キャリアセンス実行部２４２３Ａは、リンクＩＤが２であるリンクについてキャリアセンスを行い、キャリアセンス実行部２４３３Ａは、リンクＩＤが３であるリンクについてキャリアセンスを行う。 In step S1002, the carrier sense execution unit 245 performs carrier sense for each of the M links and acquires transmission rights for the m links. Here, m is an integer greater than or equal to 2 and less than or equal to M. The m links for which transmission rights have been acquired are expressed as links 1 to m. In the example shown in FIG. 7, the carrier sense execution unit 2413A performs carrier sense for the link whose link ID is 1, and the carrier sense execution unit 2423A performs carrier sense for the link whose link ID is 2. The unit 2433A performs carrier sense for the link whose link ID is 3.
　ステップＳ１００３において、通信可能期間算出部２３４４は、リンク１～ｍの各々について通信可能期間βを算出する。ここでは、リンク１～ｍのすべてに対してｒ－ＴＷＴサービス期間がスケジュールされているとする。リンクＮについての通信可能期間βをβＮと表す。ここで、Ｎは１以上ｍ以下の整数である。通信可能期間βＮは、基準時刻からリンクＮに対して設定されているｒ－ＴＷＴサービス期間が開始される時刻までの時間間隔を示してよい。基準時刻は、データフレーム送信を開始できる時刻を示す。基準時刻として、リンクＮについての送信権が獲得された時刻を使用することができる。 In step S1003, the communicable period calculation unit 2344 calculates the communicable period β for each of links 1 to m. It is assumed here that an r-TWT service period is scheduled for all links 1-m. The communicable period β for link N is expressed as β N. Here, N is an integer greater than or equal to 1 and less than or equal to m. The communicable period β N may indicate the time interval from the reference time to the time when the r-TWT service period set for link N starts. The reference time indicates the time when data frame transmission can be started. The time at which the transmission right for link N was acquired can be used as the reference time.
　ステップＳ１００４において、判定部２３４５は、フレーム交換期間αが通信可能期間βよりも短いリンクがあるか否かを判定する。フレーム交換期間αが通信可能期間βＮよりも短いことは、フレーム交換がリンクＮに対してスケジュールされているｒ－ＴＷＴサービス期間の開始前に完了することを示す。 In step S1004, the determining unit 2345 determines whether there is a link whose frame exchange period α is shorter than the communication available period β. The fact that the frame exchange period α is shorter than the communication availability period β N indicates that the frame exchange is completed before the start of the r-TWT service period scheduled for link N.
　フレーム交換期間αが通信可能期間βよりも短いリンクがない場合（ステップＳ１００４；Ｎｏ）、処理はステップＳ１００７に進む。ステップＳ１００７において、送信制御部２３４６は、データフレーム送信を延期する。例えば、判定部２３４５は、フレーム交換がｒ－ＴＷＴサービス期間の開始前に完了できるリンクがないことを指示部２３４１に通知し、指示部２３４１は、判定部２３４５からの通知に応答して、送信延期信号をキャリアセンス実行部２４５に送出する。 If there is no link for which the frame exchange period α is shorter than the communicable period β (step S1004; No), the process proceeds to step S1007. In step S1007, the transmission control unit 2346 postpones data frame transmission. For example, the determining unit 2345 notifies the instructing unit 2341 that there is no link for which frame exchange can be completed before the start of the r-TWT service period, and in response to the notification from the determining unit 2345, the instructing unit 2341 transmits the A postponement signal is sent to the carrier sense execution unit 245.
　フレーム交換期間αが通信可能期間βよりも短いリンクがある場合（ステップＳ１００４；Ｙｅｓ）、処理はステップＳ１００５に進む。ステップＳ１００５において、リンク選択部２３４２は、通信可能期間βからフレーム交換期間αを引いた差が最も大きいリンクを選択する。言い換えると、リンク選択部２３４２は、通信可能期間βが最も長いリンクを選択する。例えば、リンク１、２についての通信可能期間β１、β２がともにフレーム交換期間αよりも短い（α＜β１、α＜β２）場合において、通信可能期間β１からフレーム交換期間αを引いた差（β１－α）が通信可能期間β２からフレーム交換期間αを引いた差（β２－α）よりも大きければ、リンク１が選択され、通信可能期間β１からフレーム交換期間αを引いた差（β１－α）が通信可能期間β２からフレーム交換期間αを引いた差（β２－α）よりも小さければ、リンク２が選択される。 If there is a link whose frame exchange period α is shorter than the communicable period β (step S1004; Yes), the process advances to step S1005. In step S1005, the link selection unit 2342 selects the link with the largest difference obtained by subtracting the frame exchange period α from the communicable period β. In other words, the link selection unit 2342 selects the link with the longest communicable period β. For example, when the communication available periods β 1 and β 2 for links 1 and 2 are both shorter than the frame exchange period α (α<β 1 , α<β 2 ), the frame exchange period α is changed from the communication available period β 1 . If the difference (β 1 - α) is greater than the difference (β 2 - α) obtained by subtracting the frame exchange period α from the communication period β 2 , link 1 is selected and the frame exchange period is changed from the communication period β 1. If the difference (β 1 - α) obtained by subtracting α is smaller than the difference (β 2 - α) obtained by subtracting the frame exchange period α from the communication available period β 2 , link 2 is selected.
　ステップＳ１００６において、送信制御部２３４６は、通信部２４０を介して、ステップＳ１００５において選択されたリンクでデータフレーム送信を行う。具体的には、指示部２３４１は、選択されたリンクでデータフレーム送信を行うようキャリアセンス実行部２４５に指示する。例えば図７に示す例においてステップＳ１００５でリンク１が選択される場合、指示部２３４１は、送信開始信号をキャリアセンス実行部２４１３Ａに送出し、送信中止信号をキャリアセンス実行部２４２３Ａ、２４３３Ａに送出する。キャリアセンス実行部２４１３Ａは、指示部２３４１から送信開始信号を受け取ったことに応答して、キュー２４１２Ａからデータフレームを取り出し、データフレームを内部衝突管理部２４１４を介して変調部２４１５に送出する。変調部２４１５は、データフレームに対して変調処理を行って無線信号を生成し、アンテナを介して無線信号を送信する。キャリアセンス実行部２４２３Ａ、２４３３Ａは、指示部２３４１から送信中止信号を受け取ったことに応答して、キュー２４２２Ａ、２４３２Ａの先頭に格納されているデータフレームを破棄する。 In step S1006, the transmission control unit 2346 transmits a data frame via the communication unit 240 on the link selected in step S1005. Specifically, the instruction unit 2341 instructs the carrier sense execution unit 245 to perform data frame transmission on the selected link. For example, in the example shown in FIG. 7, when link 1 is selected in step S1005, the instruction unit 2341 sends a transmission start signal to the carrier sense execution unit 2413A, and sends a transmission stop signal to the carrier sense execution units 2423A and 2433A. . In response to receiving the transmission start signal from the instruction unit 2341, the carrier sense execution unit 2413A takes out the data frame from the queue 2412A and sends the data frame to the modulation unit 2415 via the internal collision management unit 2414. The modulator 2415 performs modulation processing on the data frame to generate a wireless signal, and transmits the wireless signal via the antenna. In response to receiving the transmission stop signal from the instruction unit 2341, the carrier sense execution units 2423A and 2433A discard the data frame stored at the head of the queues 2422A and 2432A.
　図１０に示す処理は一例に過ぎない。例えば、ステップＳ１００３において、リンク１～ｍのうちの１つ又は複数のリンクに対してｒ－ＴＷＴサービス期間がスケジュールされていない場合、通信可能期間算出部２３４４は、ｒ－ＴＷＴサービス期間がスケジュールされていない各リンクについて、通信可能期間βを充分に長い期間を示す所定値に設定してよい。この場合、データフレーム送信は、ｒ－ＴＷＴサービス期間がスケジュールされていないリンクで行われるようになる。 The process shown in FIG. 10 is only an example. For example, in step S1003, if the r-TWT service period is not scheduled for one or more of links 1 to m, the communication available period calculation unit 2344 determines that the r-TWT service period is not scheduled. The communicable period β may be set to a predetermined value indicating a sufficiently long period for each link that is not available. In this case, data frame transmission will occur on a link for which no r-TWT service period is scheduled.
　また、リンク１～ｍのうちの１つ又は複数のリンクに対してｒ－ＴＷＴサービス期間がスケジュールされていない場合、処理は、ステップＳ１００３からステップＳ１００５までの処理をスキップしてステップＳ１００６に進んでもよい。この場合にも、データフレーム送信は、ｒ－ＴＷＴサービス期間がスケジュールされていないリンクで行われるようになる。 Furthermore, if the r-TWT service period is not scheduled for one or more of links 1 to m, the process may skip steps S1003 to S1005 and proceed to step S1006. good. In this case as well, data frame transmission will occur on links for which no r-TWT service period is scheduled.
　ステップＳ１００５において、リンク選択部２３４２は、フレーム交換期間αが通信可能期間βよりも短いリンクであれば、通信可能期間βからフレーム交換期間αを引いた差が最も大きいリンク以外のリンクを選択してもよい。具体的には、フレーム交換期間αが通信可能期間βよりも短いリンクが複数ある場合において、リンク選択部２３４２は、それらのリンクの中のいずれのリンクを選択してもよい。 In step S1005, if the link has a frame exchange period α shorter than the communication period β, the link selection unit 2342 selects a link other than the link with the largest difference obtained by subtracting the frame exchange period α from the communication period β. You can. Specifically, when there are multiple links whose frame exchange period α is shorter than the communicable period β, the link selection unit 2342 may select any one of the links.
　フレーム交換期間αが通信可能期間βＮに等しい場合、判定部２３４５は、フレーム交換がリンクＮに対してスケジュールされているｒ－ＴＷＴサービス期間の開始前に完了できると判定してもよい。この場合、ステップＳ１００４において、判定部２３４５は、フレーム交換期間αが通信可能期間β以下であるリンクがあるか否かを判定する。 If the frame exchange period α is equal to the communication availability period β N , the determining unit 2345 may determine that the frame exchange can be completed before the start of the r-TWT service period scheduled for link N. In this case, in step S1004, the determining unit 2345 determines whether there is a link whose frame exchange period α is less than or equal to the communication possible period β.
　以上のように、端末２０は、アクセスポイント１０との間に複数のリンクを確立し、複数のリンクを選択的に使用してデータフレームをアクセスポイント１０へ送信する。端末２０は、アクセスポイント１０へのデータフレーム送信に要する時間期間を含むフレーム交換期間を算出する。端末２０は、複数のリンクについての送信権が獲得され、ｒ－ＴＷＴサービス期間がこれらのリンクのすべてに対してスケジュールされている場合に、これらのリンクの各々についての通信可能期間を算出する。端末２０は、フレーム交換期間が通信可能期間よりも短いリンクがある場合に、そのリンクでデータフレーム送信を行い、フレーム交換期間が通信可能期間よりも短いリンクがない場合に、データフレーム送信を延期する。 As described above, the terminal 20 establishes multiple links with the access point 10 and selectively uses the multiple links to transmit data frames to the access point 10. Terminal 20 calculates a frame exchange period that includes the time period required to transmit data frames to access point 10. Terminal 20 calculates a communicable period for each of multiple links when transmission rights for multiple links are acquired and r-TWT service periods are scheduled for all of these links. If there is a link whose frame exchange period is shorter than the communicable period, the terminal 20 transmits the data frame on that link, and if there is no link whose frame exchange period is shorter than the communicable period, the terminal 20 postpones the data frame transmission. do.
　上記の構成によれば、ｒ－ＴＷＴサービス期間の開始までにデータフレーム送信が完了できるリンクが発見され、データフレーム送信が行われ得る。この場合、ｒ－ＴＷＴサービス期間のためにデータフレーム送信を延期する事態が回避される。よって、ｒ－ＴＷＴサービス期間のためにデータフレーム送信を延期する事態の発生頻度が減り、衝突の発生又は周波数利用効率の低下を効果的に回避することができる。その結果、スループット及び遅延特性が向上する。 According to the above configuration, a link on which data frame transmission can be completed by the start of the r-TWT service period is discovered, and data frame transmission can be performed. In this case, the situation where data frame transmission is postponed due to the r-TWT service period is avoided. Therefore, the frequency of occurrence of situations in which data frame transmission is postponed due to the r-TWT service period is reduced, and it is possible to effectively avoid occurrence of collisions or decrease in frequency usage efficiency. As a result, throughput and delay characteristics are improved.
　端末２０は、フレーム交換期間が通信可能期間よりも短いリンクが複数ある場合に、通信可能期間が最も長いリンクでデータフレーム送信を行ってよい。当該構成によれば、データフレーム送信がｒ－ＴＷＴサービス期間の開始までに完了する確実性が増す。 If there are multiple links whose frame exchange period is shorter than the communicable period, the terminal 20 may transmit data frames using the link with the longest communicable period. This configuration increases the certainty that data frame transmission will be completed by the start of the r-TWT service period.
　端末２０は、ｒ－ＴＷＴサービス期間がスケジュールされていないリンクがあることに応答して、ｒ－ＴＷＴサービス期間がスケジュールされていないリンクでデータフレーム送信を行ってよい。当該構成によれば、通信可能期間を算出する処理を省略することが可能になる。 In response to the fact that there is a link for which an r-TWT service period is not scheduled, the terminal 20 may transmit a data frame on a link for which an r-TWT service period is not scheduled. According to this configuration, it is possible to omit the process of calculating the communicable period.
　端末２０は、キャリアセンスにより送信権が獲得された複数のリンクの各々について、通信可能期間を算出してよい。当該構成によれば、通信可能期間の計算コストが軽減される。 The terminal 20 may calculate the communicable period for each of the multiple links for which transmission rights have been acquired through carrier sense. According to this configuration, the calculation cost of the communicable period is reduced.
　（変形例）
　上述した実施形態では、データフレーム送信のたびにフレーム交換期間αを算出している。データフレーム送信のいくつかでは、一定期間に算出されたフレーム交換期間の統計的な平均値又は中央値をフレーム交換期間αとして使用してもよい。 (Modified example)
In the embodiment described above, the frame exchange period α is calculated every time a data frame is transmitted. In some data frame transmissions, a statistical average or median value of frame exchange periods calculated over a certain period of time may be used as the frame exchange period α.
　上述した実施形態では、送信権が獲得されるたびに、リンクＮについての通信可能期間βＮを算出している。送信権が獲得される場合のいくつかでは、一定期間に算出されたリンクＮについての通信可能期間の統計的な平均値又は中央値をリンクＮについての通信可能期間βＮとして使用してもよい。 In the embodiment described above, the communicable period β N for link N is calculated every time the transmission right is acquired. In some cases where the transmission right is acquired, the statistical average or median value of the communicable period for link N calculated over a certain period may be used as the communicable period β N for link N. .
　マルチリンク動作では、リンクにＴＩＤが関連付けられることがある。各リンクは、当該リンクに関連付けられたＴＩＤのトラヒックを送受信するために使用される。図２に示す例では、ＴＩＤが＃１であるトラヒックは、リンクＩＤが１～３である３つのリンクのいずれかを使用して送信され、ＴＩＤが＃２であるトラヒックは、リンクＩＤが１であるリンクを使用して送信され、ＴＩＤが＃３であるトラヒックは、リンクＩＤが２であるリンクを使用して送信され、ＴＩＤが＃４であるトラヒックは、リンクＩＤが３であるリンクを使用して送信される。ＴＩＤとリンクとの関連付け（TID-to-link mapping）は、アクセスポイント１０と端末２０との間でマルチリンクが確立される際に行われてよい。 In multi-link operation, a TID may be associated with a link. Each link is used to transmit and receive traffic for the TID associated with that link. In the example shown in FIG. 2, traffic with TID #1 is transmitted using any of the three links with link IDs 1 to 3, and traffic with TID #2 is transmitted using any of the three links with link ID 1. traffic that is sent using a link with a TID of #3 is sent using a link with a link ID of 2, and traffic with a TID of #4 is sent using a link with a link ID of 3. Sent using. The association between TID and link (TID-to-link mapping) may be performed when a multilink is established between the access point 10 and the terminal 20.
　図９に示す処理において、データフレームに含まれるトラヒックのＴＩＤを考慮してよい。具体的には、ステップＳ１００２において、キャリアセンス実行部２４５は、送信しようとしているデータフレームに含まれるトラヒックのＴＩＤに関連付けられている１つ又は複数のリンクについてキャリアセンスを行うようにしてもよい。上述した例を参照すると、送信しようとしているデータフレームに含まれるトラヒックのＴＩＤが＃１である場合には、キャリアセンス実行部２４５は、リンクＩＤが１～３である３つのリンクについてキャリアセンスを行う。送信しようとしているデータフレームに含まれるトラヒックのＴＩＤが＃２である場合には、キャリアセンス実行部２４５は、リンクＩＤが２である１つのリンクについてキャリアセンスを行う。 In the process shown in FIG. 9, the TID of the traffic included in the data frame may be taken into consideration. Specifically, in step S1002, the carrier sense execution unit 245 may perform carrier sense on one or more links associated with the TID of traffic included in the data frame to be transmitted. Referring to the above example, if the TID of the traffic included in the data frame to be transmitted is #1, the carrier sense execution unit 245 performs carrier sense for three links with link IDs 1 to 3. conduct. When the TID of traffic included in the data frame to be transmitted is #2, the carrier sense execution unit 245 performs carrier sense for one link whose link ID is 2.
　上述した実施形態では、端末２０が送信局であり、アクセスポイント１０が受信局である場面を想定している。アクセスポイント１０が送信局であり、端末２０が受信局である場面において、アクセスポイント１０は、端末２０に関して上述したものと同様にして、データフレーム送信を行ってよい。すなわち、アクセスポイント１０は、端末２０の通信制御部２３４と同等の構成要素を備えてよい。 In the embodiment described above, it is assumed that the terminal 20 is a transmitting station and the access point 10 is a receiving station. In situations where access point 10 is a transmitting station and terminal 20 is a receiving station, access point 10 may perform data frame transmission in a manner similar to that described above with respect to terminal 20. That is, the access point 10 may include components equivalent to the communication control unit 234 of the terminal 20.
　無線局（アクセスポイント１０及び端末２０）が備える無線通信機能はチップなどの個別部品により実施されてもよい。例えば、無線局の製造時に無線局の基板にチップが組み込まれてよい。ここで言及される無線装置は、無線局を指してもよく、無線局の無線通信機能を実現する個別部品を指してもよい。 The wireless communication function provided by the wireless station (access point 10 and terminal 20) may be implemented by individual components such as chips. For example, the chip may be incorporated into the substrate of the wireless station during manufacture of the wireless station. The wireless device referred to herein may refer to a wireless station, or may refer to an individual component that implements the wireless communication functionality of a wireless station.
　なお、本発明は、上記実施形態に限定されるものではなく、実施段階ではその要旨を逸脱しない範囲で種々に変形することが可能である。また、各実施形態は適宜組み合わせて実施してもよく、その場合組み合わせた効果が得られる。さらに、上記実施形態には種々の発明が含まれており、開示される複数の構成要素から選択された組み合わせにより種々の発明が抽出され得る。例えば、実施形態に示される全構成要素からいくつかの構成要素が削除されても、課題が解決でき、効果が得られる場合には、この構成要素が削除された構成が発明として抽出され得る。 Note that the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the invention at the implementation stage. Moreover, each embodiment may be implemented in combination as appropriate, and in that case, the combined effect can be obtained. Furthermore, the embodiments described above include various inventions, and various inventions can be extracted by combinations selected from the plurality of disclosed components. For example, if a problem can be solved and an effect can be obtained even if some components are deleted from all the components shown in the embodiment, the configuration from which these components are deleted can be extracted as an invention.
　１０…アクセスポイント
　１１…ＣＰＵ
　１２…プログラムメモリ
　１３…ＲＡＭ
　１４…無線通信モジュール
　１５…有線通信モジュール
　２０…端末
　２１…ＣＰＵ
　２２…プログラムメモリ
　２３…ＲＡＭ
　２４…無線通信モジュール
　２５…ディスプレイ
　２６…ストレージ
　３０…サーバ
　４０…通信ネットワーク
　４５…無線ネットワーク
　５０…通信システム
　１１０…ＬＬＣ処理部
　１２０…リンクマネジメント部
　１２１…データ処理部
　１２２…ＭＡＣフレーム処理部
　１２３…マネジメント部
　１３０…通信部
　１３１、１３２、１３３…無線信号処理部
　２１０…アプリケーション実行部
　２２０…ＬＬＣ処理部
　２３０…リンクマネジメント部
　２３１…データ処理部
　２３２…ＭＡＣフレーム処理部
　２３３…マネジメント部
　２３４…通信制御部
　２４０…通信部
　２４１、２４２、２４３…無線信号処理部
　２４５…キャリアセンス実行部
　２３４１…指示部
　２３４２…リンク選択部
　２３４３…フレーム交換期間算出部
　２３４４…通信可能期間算出部
　２３４５…判定部
　２３４６…送信制御部
　２４１１…分類部
　２４１２Ａ、２４１２Ｂ、２４１２Ｃ、２４１２Ｄ、２４２２Ａ、２４３２Ａ…キュー
　２４１３Ａ、２４１３Ｂ、２４１３Ｃ、２４１３Ｄ、２４２３Ａ、２４３３Ａ…キャリアセンス実行部
　２４１４…内部衝突管理部
　２４１５…変調部
  10...Access point 11...CPU
12...Program memory 13...RAM
14... Wireless communication module 15... Wired communication module 20... Terminal 21... CPU
22...Program memory 23...RAM
24...Wireless communication module 25...Display 26...Storage 30...Server 40...Communication network 45...Wireless network 50...Communication system 110...LLC processing section 120...Link management section 121...Data processing section 122...MAC frame processing section 123...Management Unit 130... Communication unit 131, 132, 133...Wireless signal processing unit 210...Application execution unit 220...LLC processing unit 230...Link management unit 231...Data processing unit 232...MAC frame processing unit 233...Management unit 234...Communication control unit 240... Communication unit 241, 242, 243... Radio signal processing unit 245... Carrier sense execution unit 2341... Instruction unit 2342... Link selection unit 2343... Frame exchange period calculation unit 2344... Communication available period calculation unit 2345... Judgment unit 2346... Transmission Control unit 2411... Classification unit 2412A, 2412B, 2412C, 2412D, 2422A, 2432A... Queue 2413A, 2413B, 2413C, 2413D, 2423A, 2433A... Carrier sense execution unit 2414... Internal collision management unit 2415... Modulation unit

Claims (5)

  1. 　無線装置であって、
    　前記無線装置と他の無線装置との間に確立される複数のリンクを使用して前記他の無線装置と無線通信する通信部と、
    　前記他の無線装置へのフレーム送信に要する時間期間を含むフレーム交換期間を算出する第１の算出部と、
    　前記複数のリンクの各々について、送信機会が与えられるサービス期間の開始までの時間期間を示す通信可能期間を算出する第２の算出部と、
    　前記フレーム交換期間が前記通信可能期間よりも短いリンクがある場合に、前記フレーム交換期間が前記通信可能期間よりも短い前記リンクで前記フレーム送信を行い、前記フレーム交換期間が前記通信可能期間よりも短いリンクがない場合に、前記フレーム送信を延期する送信制御部と、
    　を備える無線装置。     A wireless device,
    a communication unit that wirelessly communicates with the other wireless device using a plurality of links established between the wireless device and the other wireless device;
    a first calculation unit that calculates a frame exchange period including a time period required for frame transmission to the other wireless device;
    a second calculation unit that calculates, for each of the plurality of links, a communicable period indicating a time period until the start of a service period in which a transmission opportunity is given;
    If there is a link in which the frame exchange period is shorter than the communicable period, the frame transmission is performed on the link whose frame exchange period is shorter than the communicable period, and the frame exchange period is shorter than the communicable period. a transmission control unit that postpones the frame transmission when there is no short link;
    A wireless device comprising:
  2. 　前記送信制御部は、前記フレーム交換期間が前記通信可能期間よりも短いリンクが複数ある場合に、前記通信可能期間が最も長いリンクで前記フレーム送信を行う、
    　請求項１に記載の無線装置。     The transmission control unit transmits the frame using the link with the longest communicable period when there are a plurality of links in which the frame exchange period is shorter than the communicable period.
    The wireless device according to claim 1.
  3. 　前記第２の算出部は、前記複数のリンクの各々について、前記サービス期間がスケジュールされているか否かを確認し、
    　前記送信制御部は、前記サービス期間がスケジュールされていないリンクがあることに応答して、前記サービス期間がスケジュールされていない前記リンクで前記フレーム送信を行う、
    　請求項１に記載の無線装置。     The second calculation unit checks whether the service period is scheduled for each of the plurality of links;
    The transmission control unit performs the frame transmission on the link for which the service period is not scheduled in response to the fact that there is a link for which the service period is not scheduled.
    The wireless device according to claim 1.
  4. 　前記複数のリンクについてキャリアセンスを行うキャリアセンス実行部をさらに備え、
    　前記第２の算出部は、前記キャリアセンスにより送信権が獲得された複数のリンクの各々について、前記通信可能期間を算出する、
    　請求項１に記載の無線装置。     further comprising a carrier sense execution unit that performs carrier sense on the plurality of links,
    The second calculation unit calculates the communicable period for each of the plurality of links for which transmission rights have been acquired by the carrier sense.
    The wireless device according to claim 1.
  5. 　無線装置により実行される無線通信方法であって、
    　前記無線装置と他の無線装置との間に確立される複数のリンクを使用して前記他の無線装置と無線通信することと、
    　前記他の無線装置へのフレーム送信に要する時間期間を含むフレーム交換期間を算出することと、
    　前記複数のリンクの各々について、送信機会が与えられるサービス期間の開始までの時間期間を示す通信可能期間を算出することと、
    　前記フレーム交換期間が前記通信可能期間よりも短いリンクがある場合に、前記フレーム交換期間が前記通信可能期間よりも短い前記リンクで前記フレーム送信を行い、前記フレーム交換期間が前記通信可能期間よりも短いリンクがない場合に、前記フレーム送信を延期することと、
    　を備える無線通信方法。
          A wireless communication method performed by a wireless device, the method comprising:
    wirelessly communicating with the other wireless device using a plurality of links established between the wireless device and the other wireless device;
    calculating a frame exchange period including a time period required for frame transmission to the other wireless device;
    Calculating, for each of the plurality of links, a communicable period indicating a time period until the start of a service period in which a transmission opportunity is given;
    If there is a link in which the frame exchange period is shorter than the communicable period, the frame transmission is performed on the link whose frame exchange period is shorter than the communicable period, and the frame exchange period is shorter than the communicable period. deferring the frame transmission if there is no short link;
    A wireless communication method comprising:
PCT/JP2022/026956 2022-07-07 2022-07-07 Wireless device and wireless communication method WO2024009452A1 (en)

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