WO2024034050A1 - Point d'accès - Google Patents

Point d'accès Download PDF

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Publication number
WO2024034050A1
WO2024034050A1 PCT/JP2022/030555 JP2022030555W WO2024034050A1 WO 2024034050 A1 WO2024034050 A1 WO 2024034050A1 JP 2022030555 W JP2022030555 W JP 2022030555W WO 2024034050 A1 WO2024034050 A1 WO 2024034050A1
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WO
WIPO (PCT)
Prior art keywords
frame
terminal
twt
processing unit
rts
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PCT/JP2022/030555
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English (en)
Japanese (ja)
Inventor
朗 岸田
健悟 永田
裕介 淺井
泰司 鷹取
Original Assignee
日本電信電話株式会社
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Application filed by 日本電信電話株式会社 filed Critical 日本電信電話株式会社
Priority to PCT/JP2022/030555 priority Critical patent/WO2024034050A1/fr
Publication of WO2024034050A1 publication Critical patent/WO2024034050A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W74/00—Wireless channel access
    • H04W74/04—Scheduled access
    • 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

  • Embodiments relate to access points.
  • a wireless LAN Local Area Network
  • AP access point
  • terminals located within the communication range of an AP to access the network via the AP.
  • APs and terminals may provide service periods for preferentially exchanging low-latency traffic.
  • a function that provides such a service period is called a restricted TWT (r-TWT) function.
  • Some terminals do not support the r-TWT function.
  • a quiet interval is set for the terminals that do not support the r-TWT function.
  • the time length of the quiet interval set together with the service period is determined to be a predetermined time shorter than the service period.
  • the present embodiment was developed with attention to the above-mentioned circumstances, and its purpose is to exchange low-latency traffic preferentially even when there are terminals that do not support the r-TWT function.
  • the aim is to provide a wireless communication environment that allows for
  • An access point in one embodiment includes a transmitter.
  • the transmitting unit transmits an RTS signal including an RTS frame to the terminal immediately after the start of the service period or immediately after exchanging data frames performed during the service period, and immediately after receiving the CTS frame from the terminal that received the RTS frame.
  • a trigger signal containing a trigger frame is sent to the terminal that receives the RTS frame.
  • FIG. 1 is a block diagram showing an example of the configuration of a communication system according to an embodiment.
  • FIG. 2 is a block diagram illustrating an example of the hardware configuration of the AP according to the embodiment.
  • FIG. 3 is a block diagram showing an example of the hardware configuration of the terminal according to the embodiment.
  • FIG. 4 is a block diagram illustrating an example of the functional configuration of the AP according to the embodiment.
  • FIG. 5A is a diagram illustrating a first example of the format of a beacon frame according to the embodiment.
  • FIG. 5B is a diagram illustrating a second example of the format of a beacon frame according to the embodiment.
  • FIG. 6 is a diagram showing an example of the format of a trigger frame.
  • FIG. 1 is a block diagram showing an example of the configuration of a communication system according to an embodiment.
  • FIG. 2 is a block diagram illustrating an example of the hardware configuration of the AP according to the embodiment.
  • FIG. 3 is a block diagram showing an example of the hardware configuration of the
  • FIG. 7 is a block diagram illustrating an example of a functional configuration of a terminal according to an embodiment.
  • FIG. 8 is a block diagram illustrating an example of a functional configuration regarding transmission determination processing of a terminal according to the embodiment.
  • FIG. 9 is a flowchart illustrating an example of the operation of the AP according to the embodiment.
  • FIG. 10 is a flowchart showing the operation of the terminal according to the embodiment.
  • FIG. 11 is a diagram illustrating an example of the operation during the service period r-TWT-SP by the system according to the embodiment.
  • FIG. 1 is a block diagram showing an example of the configuration of a communication system according to an embodiment.
  • the communication system 1 includes an access point (AP) 10, a terminal 20, and a network 30.
  • AP access point
  • terminal 20 a terminal 20
  • network 30 a network 30.
  • the AP 10 is, for example, a wireless LAN base station.
  • AP 10 is configured to communicate with a server (not shown) on network 30 via wire or wireless.
  • AP 10 is configured to communicate with terminal 20 via wireless. Communication between the AP 10 and the terminal 20 is based on, for example, the IEEE802.11 standard.
  • the terminal 20 is, for example, a wireless terminal such as a smartphone or a PC (Personal Computer). Terminal 20 is configured to communicate with a server on network 30 via AP 10. In FIG. 1, two terminals 20 are shown. The number of terminals 20 included in the communication system 1 may be one, or three or more.
  • the AP 10 and the terminal 20 have, for example, a wireless communication function based on the OSI (Open Systems Interconnection) reference model.
  • OSI Open Systems Interconnection
  • wireless 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, It is divided into 6 layers: presentation layer and 7th layer: application layer).
  • the data link layer includes an LLC (Logical Link Control) sublayer and a MAC (Media Access Control) sublayer.
  • the AP 10 has an r-TWT function to ensure an opportunity to exchange traffic that requires low latency.
  • the AP 10 can set a service period in which the exchange of traffic that requires low latency can be prioritized over the exchange of traffic that does not require low latency.
  • a service period is also called r-TWT-SP (Service Period).
  • the terminal 20 may or may not support the r-TWT function. For example, if two or more terminals 20 exist, only some of the terminals 20 may support the r-TWT function.
  • the terminal 20 that does not support the r-TWT function is a terminal of an old standard that cannot understand messages related to r-TWT, so in addition to the terminal that does not support the r-TWT function, This includes terminals that comply with the standard and can understand messages, but do not support the r-TWT function.
  • FIG. 2 is a block diagram showing an example of the hardware configuration of the AP according to the embodiment.
  • the AP 10 includes, for example, a CPU (Central Processing Unit) 11, a ROM (Read Only Memory) 12, a RAM (Random Access Memory) 13, a wireless communication module 14, and a wired communication module 15.
  • a CPU Central Processing Unit
  • ROM Read Only Memory
  • RAM Random Access Memory
  • the CPU 11 is a processing circuit that controls the overall operation of the AP 10.
  • the ROM 12 is, for example, a nonvolatile semiconductor memory.
  • the ROM 12 stores programs and data for controlling the AP 10.
  • the RAM 13 is, for example, a volatile semiconductor memory.
  • the RAM 13 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.
  • Wireless communication module 14 is connected to an antenna.
  • the wired communication module 15 is a circuit used for transmitting and receiving data using wired signals. Wired communication module 15 is connected to network 30.
  • FIG. 3 is a block diagram showing an example of the hardware configuration of the terminal according to the embodiment.
  • the terminal 20 includes, for example, a CPU 21, a ROM 22, a RAM 23, a wireless communication module 24, a display 25, and a storage 26.
  • the CPU 21 is a processing circuit that controls the overall operation of the terminal 20.
  • the ROM 22 is, for example, a nonvolatile semiconductor memory.
  • the ROM 22 stores programs and data for controlling the terminal 20.
  • the RAM 23 is, for example, a volatile semiconductor memory. RAM23 is used as a work area for CPU21.
  • the wireless communication module 24 is a circuit used for transmitting and receiving data using wireless signals. Wireless communication module 24 is connected to the antenna.
  • the display 25 is, for example, an LCD (Liquid Crystal Display) or an EL (Electro-Luminescence) display.
  • the display 25 displays a GUI (Graphical User Interface) and the like corresponding to application software.
  • the storage 26 is a nonvolatile storage device.
  • the storage 26 stores system software of the terminal 20 and the like.
  • FIG. 4 is a block diagram showing an example of the functional configuration of the AP according to the embodiment.
  • the AP 10 functions as a computer including an LLC processing section 110, a data processing section 120, a management section 130, a MAC frame processing section 140, and a wireless signal processing section 150.
  • the LLC processing unit 110 is a functional block that executes processing corresponding to the LLC sublayer of the second layer and the third to seventh layers.
  • the data processing unit 120, the management unit 130, and the MAC frame processing unit 140 are functional blocks that execute processing corresponding to the MAC sublayer of the second layer.
  • the wireless signal processing unit 150 is a functional block that executes processing corresponding to the MAC sublayer of the second layer and the first layer.
  • the LLC processing unit 110 generates an LLC packet by adding, for example, a DSAP (Destination Service Access Point) header, an SSAP (Source Service Access Point) header, etc. to the data received from the network 30.
  • the LLC processing unit 110 then inputs the generated LLC packet to the data processing unit 120. Further, the LLC processing unit 110 extracts data from the LLC packet input from the data processing unit 120. The LLC processing unit 110 then transmits the extracted data to the network 30.
  • the data processing unit 120 adds a MAC header to the LLC packet input from the LLC processing unit 110 to generate a MAC frame.
  • the data processing unit 120 then inputs the generated MAC frame to the MAC frame processing unit 140.
  • the data processing unit 120 extracts LLC packets from the MAC frame input from the MAC frame processing unit 140.
  • the data processing unit 120 then inputs the extracted LLC packet to the LLC processing unit 110.
  • a MAC frame containing data is also referred to as a "data frame”.
  • the management unit 130 manages communication between the AP 10 and the terminal 20. For example, the management unit 130 sets up r-TWT when low-latency traffic is scheduled to be exchanged. In r-TWT setup, the management unit 130 sets a service period r-TWT-SP for the terminal 20 that supports the r-TWT function. Furthermore, the management unit 130 determines that traffic exchange by the terminal 20 scheduled to exchange low-latency traffic during the service period r-TWT is higher than traffic exchange by the terminal 20 not scheduled to exchange low-latency traffic. Ensure that implementation is prioritized. Various MAC frames are input and output between the management unit 130 and the MAC frame processing unit 140.
  • the management section 130 includes a beacon management section 131, a trigger management section 132, and a transmission timing processing section 133.
  • the beacon management unit 131 manages information transmitted by the AP 10 as a beacon signal. Specifically, the beacon management unit 131 generates a beacon frame including r-TWT management information regarding the r-TWT function. The beacon management unit 131 then inputs the generated beacon frame to the MAC frame processing unit 140.
  • FIG. 5A is a diagram illustrating a first example of the format of a beacon frame according to the embodiment.
  • the beacon frame of the first example includes, for example, r-TWT-SP start time and r-TWT-SP duration as r-TWT management information used in the r-TWT function. include.
  • the r-TWT-SP start time is information indicating the time when the service period r-TWT-SP starts.
  • the r-TWT-SP duration is information indicating the length of the service period r-TWT-SP. That is, the service period r-TWT-SP is set as the period from the r-TWT-SP start time to the time when the r-TWT-SP duration period has elapsed.
  • the terminal 20 supporting the r-TWT function can recognize the service period r-TWT-SP by the r-TWT-SP start time and r-TWT-SP duration included in the beacon frame.
  • the terminal 20 that does not support the r-TWT function may not be able to recognize the service period r-TWT-SP depending on the r-TWT-SP start time and r-TWT-SP duration included in the beacon frame. Or even if they recognize it, they ignore it.
  • FIG. 5B is a diagram showing a second example of the format of the beacon frame according to the embodiment.
  • the second example beacon frame includes, for example, r-TWT-SP start time and r-TWT-SP duration, as r-TWT management information used in the r-TWT function.
  • it includes a transmission suppression period.
  • the transmission suppression period is a period in which transmission of data frames is suppressed.
  • the transmission suppression period can be set using, for example, a quiet interval defined in the IEEE802.11 standard.
  • the time length of the quiet interval as the transmission suppression period is, for example, 1 TU (time unit).
  • the transmission suppression period is set to overlap with the service period.
  • the start time of the transmission suppression period is set to be the same as the r-TWT-SP start time. Multiple transmission suppression periods may be set during the r-TWT-SP. Even terminals 20 that do not support the r-TWT function can recognize the transmission suppression period. On the other hand, even if the terminal 20 that supports the r-TWT function receives a notification of a transmission suppression period that overlaps with the service period, it behaves as if it were not there.
  • the transmission suppression period may be transmitted to the terminal 20 using a MAC frame such as a trigger frame that is different from the beacon frame.
  • the trigger management unit 132 manages trigger frames transmitted to the terminal 20.
  • the trigger management unit 132 before generating the trigger frame, the trigger management unit 132 generates a Request to Send (RTS) frame addressed to the terminal 20 whose service period is scheduled.
  • RTS Request to Send
  • CTS Clear to Send
  • the trigger management unit 132 Based on the Clear to Send (CTS) frame returned from the terminal 20 in response to the RTS frame, the trigger management unit 132 generates a trigger frame for causing the terminal 20 that has transmitted the CTS frame to acquire the transmission right. .
  • FIG. 6 is a diagram showing an example of the format of a trigger frame.
  • the MAC header of the trigger frame includes a Frame Control field, a Duration field, an RA (Receiving STA address) field, a TA (Transmitting STA address) field, a Common Info field, and a User Info List. field.
  • the Frame Control field is a field for storing various control information such as information indicating the frame type.
  • the Duration field is a field for storing the scheduled period for using the wireless line.
  • the RA field is a field for storing the MAC address of the receiving station.
  • the TA field is a field for storing the MAC address of the transmitting station.
  • the Common Info field is a field for storing common information in the subordinate terminals 20.
  • the User Info List field is a field for storing information regarding a specific terminal 20.
  • the User Info List field in the embodiment includes, for example, 12 AID (Association Identifier) subfields and RU (Resource Unit) Allocation subfields.
  • the AID12 subfield is a subfield for storing a terminal identifier (AID) that identifies the terminal 20 to which resources are allocated by the RU Allocation subfield.
  • the RU Allocation subfield is a subfield for storing information about resource allocation to the terminal 20 specified by the AID12 subfield.
  • the resources include things such as the frequency (channel) used by the corresponding terminal 20, transmission start timing, and transmission period. Note that subfields other than the AID12 subfield and RU Allocation that constitute the User Info List may be determined as appropriate.
  • the transmission timing processing unit 133 determines the transmission timing of the RTS frame and trigger frame from the trigger management unit 132. Specifically, the transmission timing processing unit 133 sets a priority for each terminal 20, and determines the transmission timing of the RTS frame and the trigger frame in the order of the set priority.
  • the priority of the terminals 20 may be determined, for example, according to the priority of traffic that each terminal 20 attempts to exchange. For example, a high priority is set for terminals 20 that require low-latency traffic exchange. If there are multiple terminals 20 that require low-latency traffic exchange, a higher priority is set for the terminals 20 with the shortest tolerable delay.
  • the MAC frame processing unit 140 When the MAC frame is input from the data processing unit 120 or the management unit 130, the MAC frame processing unit 140 inputs the input MAC frame to the radio signal processing unit 150. Further, when a MAC frame is input from the radio signal processing unit 150, the MAC frame processing unit 140 inputs the MAC frame to the data processing unit 120 or the management unit 130 depending on the type of the MAC frame. Specifically, the MAC frame processing unit 140 inputs the MAC frame to the data processing unit 120 when the MAC frame is a data frame. The MAC frame processing unit 140 inputs the MAC frame to the management unit 130 when the MAC frame is a management frame or a control frame.
  • the radio signal processing unit 150 adds a preamble and the like to the MAC frame input from the MAC frame processing unit 140 to generate a radio frame.
  • the wireless signal processing unit 150 converts the generated wireless frame into a wireless signal. Then, the wireless signal processing unit 150 radiates (transmits) the converted wireless signal via the antenna.
  • the conversion process from a radio frame to a radio signal includes, for example, convolutional encoding processing, interleaving processing, subcarrier modulation processing, inverse fast Fourier transform processing, OFDM (Orthogonal Frequency Division Multiplexing) modulation processing, and frequency conversion processing.
  • the radio signal processing unit 150 converts a radio signal received from the terminal 20 via the antenna into a radio frame.
  • the conversion process from a radio signal to a radio frame includes, for example, frequency conversion process, OFDM demodulation process, fast Fourier transform process, subcarrier demodulation process, deinterleaving process, and Viterbi decoding process.
  • the radio signal processing unit 150 extracts a MAC frame from the converted radio frame. Then, the wireless signal processing unit 150 inputs the extracted MAC frame to the MAC frame processing unit 140.
  • the wireless signal processing unit 150 performs a transmission determination process to determine whether a data frame can be transmitted when transmitting a wireless frame.
  • the transmission determination process will be explained later.
  • FIG. 7 is a block diagram showing an example of the functional configuration of the terminal according to the embodiment.
  • the terminal 20 functions as a computer including an application execution section 200, an LLC processing section 210, a data processing section 220, a management section 230, a MAC frame processing section 240, and a wireless signal processing section 250.
  • the application execution unit 200 is a functional block that executes processing corresponding to the seventh layer.
  • the LLC processing unit 210 is a functional block that executes processing corresponding to the LLC sublayer of the second layer and the third to sixth layers.
  • the data processing section 220, the management section 230, and the MAC frame processing section 240 are functional blocks that execute processing corresponding to the MAC sublayer of the second layer.
  • the wireless signal processing unit 250 is a functional block that executes processing corresponding to the MAC sublayer of the second layer and the first layer.
  • the application execution unit 200 executes an application based on data input from the LLC processing unit 210. Further, the application execution unit 200 inputs data to the LLC processing unit 210. For example, the application execution unit 200 can display application information on the display 25. Further, the application execution unit 200 can operate based on the operation of the input interface.
  • the LLC processing unit 210 adds a DSAP header, an SSAP header, etc. to the data input from the application execution unit 200, and generates an LLC packet.
  • the LLC processing unit 210 then inputs the generated LLC packet to the data processing unit 220. Additionally, the LLC processing unit 210 extracts data from the LLC packet input from the data processing unit 220. The LLC processing unit 210 then inputs the extracted data to the application execution unit 200.
  • the data processing unit 220 adds a MAC header to the LLC packet input from the LLC processing unit 210 to generate a MAC frame.
  • the data processing unit 220 then inputs the generated MAC frame to the MAC frame processing unit 240.
  • the data processing unit 220 extracts LLC packets from the MAC frame input from the MAC frame processing unit 240.
  • the data processing unit 220 then inputs the extracted LLC packet to the LLC processing unit 210.
  • the management unit 230 manages communication between the AP 10 and the terminal 20. Various MAC frames are input and output between the management section 230 and the MAC frame processing section 240.
  • the management section 230 includes a beacon management section 231.
  • the beacon management unit 231 manages information included in the beacon signal received from the AP 10. Specifically, the beacon management unit 231 extracts management information regarding the r-TWT function from the beacon frame input from the MAC frame processing unit 240, and holds the extracted management information. For example, the beacon management unit 231 of the terminal 20 that supports the r-TWT function extracts the r-TWT-SP start time and r-TWT-SP duration as management information regarding the r-TWT function. Further, for example, the beacon management unit 231 of the terminal 20 that supports the r-TWT function and the terminal 20 that does not support the r-TWT function extracts the transmission suppression period as management information regarding the r-TWT function.
  • the MAC frame processing unit 240 When the MAC frame is input from the data processing unit 220 or the management unit 230, the MAC frame processing unit 240 inputs the input MAC frame to the radio signal processing unit 250. Further, when a MAC frame is input from the wireless signal processing unit 250, the MAC frame processing unit 240 inputs the MAC frame to the data processing unit 220 or the management unit 230 depending on the type of the MAC frame. Specifically, the MAC frame processing unit 240 inputs the MAC frame to the data processing unit 220 when the MAC frame is a data frame. The MAC frame processing unit 240 inputs the MAC frame to the management unit 230 when the MAC frame is a management frame or a control frame.
  • the radio signal processing unit 250 adds a preamble and the like to the MAC frame input from the MAC frame processing unit 240 to generate a radio frame.
  • the radio signal processing unit 250 converts the generated radio frame into a radio signal.
  • the wireless signal processing unit 250 radiates (transmits) the converted wireless signal via the antenna.
  • the conversion process from a radio frame to a radio signal includes, for example, convolutional encoding processing, interleaving processing, subcarrier modulation processing, inverse fast Fourier transform processing, OFDM modulation processing, and frequency conversion processing.
  • the wireless signal processing unit 250 converts a wireless signal received from the AP 10 via the antenna into a wireless frame.
  • the conversion process from a radio signal to a radio frame includes, for example, frequency conversion process, OFDM demodulation process, fast Fourier transform process, subcarrier demodulation process, deinterleaving process, and Viterbi decoding process.
  • the radio signal processing unit 250 extracts the MAC frame from the converted radio frame. Then, the wireless signal processing section 250 inputs the extracted MAC frame to the MAC frame processing section 240.
  • the wireless signal processing unit 250 performs a transmission determination process to determine whether a data frame can be transmitted when transmitting a wireless frame.
  • the transmission determination process will be explained later.
  • FIG. 8 is a block diagram illustrating an example of a functional configuration related to transmission determination processing of a terminal according to the embodiment.
  • FIG. 8 shows the functional configuration of the radio signal processing unit 250 as a functional configuration related to transmission determination processing of the terminal.
  • the functional configuration related to the transmission determination process of the AP is also equivalent to the functional configuration shown in FIG. 8 .
  • the radio signal processing section 250 includes a classification section 251, a plurality of queues 252A, 252B, 252C, and 252D, a plurality of carrier sense sections 253A, 253B, 253C, and 253D, and an internal collision management section 254.
  • the classification unit 251 classifies the data frame into a plurality of access categories based on the TID (Traffic Indicator) included in the MAC header.
  • TID is an identifier indicating traffic, and can be associated with an access category. Traffic access categories include, for example, "VO (Voice),” "VI (Video),” "BE (Best Effort),” and "BK (Background).”
  • the classification unit 251 inputs the data frame into a corresponding one of the plurality of queues 252A, 252B, 252C, and 252D. In the example of FIG. 8, the classification unit 251 inputs data frames corresponding to access categories VO, VI, BE, and BK to queues 252A, 252B, 252C, and 252D, respectively.
  • Each of the plurality of queues 252A, 252B, 252C, and 252D buffers input data frames.
  • multiple queues 252A, 252B, 252C, and 252D buffer data frames corresponding to access categories VO, VI, BE, and BK, respectively.
  • the plurality of carrier sense units 253A, 253B, 253C, and 253D correspond to the plurality of queues 252A, 252B, 252C, and 252D, respectively.
  • Each of the plurality of carrier sense units 253A, 253B, 253C, and 253D executes carrier sense processing based on CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance) according to preset access parameters. If it is determined that the channel is in an idle state for a predetermined period of time, each of the plurality of carrier sense units 253A, 253B, 253C, and 253D acquires the right to transmit a data frame and ends the carrier sense process. If it is determined that the channel is in a busy state, each of the plurality of carrier sense units 253A, 253B, 253C, and 253D stops acquiring the transmission right and ends the carrier sense process.
  • CSMA/CA Carrier Sense Multiple Access with Collision Avoidance
  • CWmin and CWmax indicate the minimum and maximum values of the contention window, respectively.
  • the contention window is a parameter that indicates the time range within which random backoff for collision avoidance is determined.
  • AIFS is a fixed transmission waiting time set for each access category.
  • 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. Further, the access category for which a larger TXOPLimit is set, the larger the amount of data that can be transmitted with one transmission right can be set.
  • the internal collision management unit 254 prevents transmission collisions when two or more carrier sense units acquire transmission rights at the same time. Specifically, for example, when a plurality of data frames are input at the same time, the internal collision management unit 254 preferentially transmits a data frame of an access category with a high priority.
  • FIG. 9 is a flowchart illustrating an example of the AP operation according to the embodiment.
  • FIG. 9 basically shows the operation during the service period r-TWT-SP.
  • An r-TWT setup operation is performed before the start of the service period r-TWT-SP.
  • the setup operation will be briefly explained.
  • the beacon management unit 131 of the AP 10 generates a beacon frame.
  • the beacon frame includes, for example, an r-TWT-SP start time and an r-TWT-SP duration.
  • the beacon frame may further include a transmission suppression period.
  • the beacon management unit 131 inputs the beacon frame to the MAC frame processing unit 140.
  • MAC frame processing section 140 inputs the beacon frame to radio signal processing section 150.
  • the wireless signal processing unit 150 generates a beacon signal from the beacon frame, and radiates (transmits) the beacon signal from an antenna.
  • the beacon signal is periodically transmitted at a predetermined period even after step S10. If the service period r-TWT-SP needs to be set at a constant cycle, the beacon signal transmission cycle may be determined in accordance with the service period r-TWT-SP.
  • the beacon management unit 231 of the terminal 20 When the beacon management unit 231 of the terminal 20 receives the beacon frame via the MAC frame processing unit 240, the beacon management unit 231 extracts management information regarding the r-TWT function from the beacon frame and retains the extracted management information to extend the service period. Configure settings. Thereby, the terminal 20 supporting the r-TWT function can recognize the service period r-TWT-SP.
  • step S10 which is the timing before the start of the service period r-TWT-SP, the transmission timing processing unit 133 sets the priority n of each terminal 20.
  • the priority n is, for example, a natural number, and the closer it is to 1, the higher the priority. Further, the initial value of priority n is 1.
  • the assignment of the priority n may be determined according to the priority of the traffic to be exchanged by each terminal 20. Information on traffic to be exchanged by each terminal 20 may be set in advance in the transmission timing processing unit 133 of the AP 10, or may be collected from each terminal 20 at the timing of a setup operation, for example.
  • step S11 the transmission timing processing unit 133 determines whether the current time has reached the r-TWT-SP start time. In step S11, when it is determined that the current time has not reached the r-TWT-SP start time, the process is put on standby. While processing is pending, AP 10 may perform an exchange of data frames with terminal 20. In step S11, when it is determined that the current time has reached the r-TWT-SP start time, the transmission timing processing unit 133 notifies the trigger management unit 132 that the current time has reached the r-TWT-SP start time. do. After that, the process moves to step S12.
  • the trigger management unit 132 performs processing to transmit an RTS frame addressed to the terminal 20 with priority n. Specifically, the trigger management unit 132 generates an RTS frame.
  • the RTS frame in the embodiment includes a Duration field in which the period from the transmission of the RTS signal to the scheduled time of completion of transmission of the trigger frame is stored.
  • the RTS frame in the embodiment includes an RA field in which the MAC address of the terminal 20 with priority n is stored.
  • the scheduled completion time of trigger frame transmission from RTS signal transmission is based on the time required for exchanging the RTS frame, the time required for exchanging the CTS frame, the time required for exchanging the trigger frame, and the delay status collected from each terminal 20. Presumed.
  • the trigger management unit 132 After generating the RTS frame, the trigger management unit 132 inputs the RTS frame to the MAC frame processing unit 140.
  • the MAC frame processing section 140 inputs the RTS frame to the radio signal processing section 150.
  • the radio signal processing unit 150 generates an RTS signal from the RTS frame, and radiates (transmits) the RTS signal from the antenna.
  • RTS frames may be transmitted using the highest priority access category of EDCA.
  • the RTS frame may be transmitted using a frame exchange procedure in which exchange is completed earlier than a frame exchange procedure using EDCA. For example, a frame that waits for SIFS (Short Inter Frame Space) or DIFS (Distributed Inter Frame Space) time without carrier sensing, and then transmits an RTS signal without waiting for random backoff time.
  • SIFS Short Inter Frame Space
  • DIFS Distributed Inter Frame Space
  • step S13 the trigger management unit 132 determines whether a CTS frame has been received from the terminal 20 with priority n during a predetermined period of time.
  • the fixed period may be a fixed period, such as SIFS or DIFS. If it is determined in step S13 that a CTS frame has been received from the terminal 20 with priority n during a predetermined period of time, the process moves to step S14. If it is determined in step S13 that no CTS frame has been received from the terminal 20 with priority n during a predetermined period of time, the process moves to step S17.
  • step S14 the trigger management unit 132 performs processing to transmit a trigger frame to the terminal 20 with priority n.
  • the process moves to step S15.
  • the trigger management unit 132 generates a trigger frame.
  • the trigger frame in an embodiment includes a User Info List field.
  • the AID12 subfield of the User Info List stores the AID of the terminal 20 with priority n.
  • the RU subfield of the User Info List stores information on resources allocated to the terminal 20 with priority n.
  • the trigger management unit 132 inputs the trigger frame to the MAC frame processing unit 140.
  • the MAC frame processing section 140 inputs the trigger frame to the radio signal processing section 150.
  • the wireless signal processing unit 150 generates a trigger signal from the trigger frame, and radiates (transmits) the trigger signal from the antenna.
  • the trigger frame may also be transmitted using the highest priority access category of EDCA.
  • the trigger frame may also be transmitted using a frame exchange procedure in which exchange is completed earlier than a frame exchange procedure using EDCA.
  • step S15 the management unit 130 determines whether or not a data frame has been received from the terminal 20. For example, in step S15, the management unit 130 inquires of, for example, the MAC frame processing unit 140 whether a data frame has been received from the wireless signal processing unit 150. In step S15, the process waits until it is determined that a data frame has been received from the terminal 20. If it is determined in step S15 that a data frame has been received from the terminal 20, the process moves to step S16.
  • step S16 the management unit 130 performs processing for transmitting an acknowledgment (ACK). After that, the process moves to step S17.
  • step S16 the management unit 130 generates an ACK and inputs it to the MAC frame processing unit 140.
  • the MAC frame processing section 140 inputs the ACK to the radio signal processing section 150.
  • the radio signal processing unit 150 radiates (transmits) the ACK from the antenna.
  • the ACK may be generated as a block ACK.
  • step S17 the transmission timing processing unit 133 adds 1 to the value of priority n.
  • step S18 the transmission timing processing unit 133 determines whether the value of priority n exceeds n max .
  • n max is the number of terminals 20 for which priority is set. If it is determined in step S18 that the priority value does not exceed n max , the process returns to step S12. In this case, the RTS frame is transmitted to the terminal 20 with the next priority. If it is determined in step S18 that the value of priority n exceeds n max , the process moves to step S19.
  • step S19 the transmission timing processing unit 133 returns the value of priority n to the initial value of 1. After that, the process returns to step S12. Thereafter, the processes of steps S12-S19 are repeated until the service period r-TWT-SP ends.
  • FIG. 10 is a flowchart showing the terminal operation.
  • FIG. 10 shows the operation of the terminal 20 during the service period r-TWT-SP.
  • the process in FIG. 10 is started when the terminal 20 receives an RTS frame.
  • step S20 the management unit 230 determines whether or not it holds a data frame scheduled to be transmitted during the service period r-TWT-SP. For example, in step S20, the management unit 230 inquires of, for example, the MAC frame processing unit 240 whether there is a data frame scheduled to be transmitted during the service period r-TWT-SP. If it is determined in step S20 that a data frame scheduled to be transmitted is held, the process moves to step S21. If it is determined in step S20 that the data frame scheduled to be transmitted is not held, the process in FIG. 10 ends. In this case, the process of step S21 is not performed, and no CTS frame is transmitted from the terminal 20 to the AP 10.
  • the management unit 230 performs processing to transmit the CTS frame. Specifically, the management unit 230 generates a CTS frame.
  • the CTS frame in the embodiment includes a Duration field in which a period from the transmission of the CTS signal to the scheduled completion time of transmission of the trigger frame is stored. Furthermore, the CTS frame in the embodiment includes an RA field in which the MAC address of the AP 10 is stored.
  • the estimated transmission completion time of the trigger frame from the transmission of the CTS signal is obtained from the information stored in the Duration field of the RTS frame.
  • the management unit 230 inputs the CTS frame to the MAC frame processing unit 240.
  • the MAC frame processing section 240 inputs the CTS frame to the radio signal processing section 250.
  • the radio signal processing unit 250 generates a CTS signal from the CTS frame, and radiates (transmits) the CTS signal from the antenna.
  • the CTS frames are also exchanged in a short time. Therefore, the CTS frame may be transmitted using the highest priority access category of EDCA. Alternatively, the CTS frame may be transmitted using a frame exchange procedure in which exchange is completed earlier than a frame exchange procedure using EDCA.
  • step S22 the management unit 230 determines whether or not a trigger frame addressed to the AP 10 has been received during a predetermined period of time.
  • the fixed period may be a fixed period, such as SIFS or DIFS. Further, whether or not the trigger frame is addressed to the own station can be determined from the AID stored in the AID12 subfield of the User Info List frame.
  • step S22 when it is determined that a trigger frame addressed to the local station has been received from the AP 10 during a predetermined period of time, the process moves to step S23.
  • step S22 when it is determined that the trigger frame addressed to the mobile station has not been received from the AP 10 for a predetermined period of time, the process of FIG. 10 ends.
  • step S23 the MAC frame processing unit 240 inputs a data frame to be exchanged with the AP 10, for example, a low-latency traffic data frame, to the radio signal processing unit 250.
  • the wireless signal processing unit 250 transmits a wireless signal using the access category with the highest priority of EDCA or using a frame exchange procedure in which exchange is completed earlier than a frame exchange procedure using EDCA. After that, the process in FIG. 10 ends.
  • FIG. 11 is a diagram illustrating an example of operation during the service period r-TWT-SP by the system according to the embodiment.
  • FIG. 11 an example of three terminals under the AP is shown.
  • the two terminals are terminals r-TWT STA (1) and r-TWT STA (2), which support r-TWT functionality.
  • the other terminal is a terminal non-r-TWT STA that does not support r-TWT functionality.
  • the priority n is set for the terminals r-TWT STA (1) and r-TWT STA (2).
  • the priority of terminal r-TWT STA (1) is higher than the priority of terminal r-TWT STA (2).
  • a transmission suppression period Quiet is set.
  • the time length of the transmission suppression period Quiet is 1 TU.
  • an RTS frame addressed to the highest priority terminal r-TWT STA (1) is transmitted from the AP in time with the start time of the r-TWT-SP.
  • terminal r-TWT STA (1) holds a data frame, it transmits a CTS frame to the AP immediately after receiving the RTS frame, for example after SIFS has elapsed.
  • the RTS frame is also received by the terminal r-TWT STA (2) and the terminal non-r-TWT STA.
  • the terminal r-TWT STA (2) and the terminal non-r-TWT STA are not addressed to their own stations, the terminal r-TWT STA (2) and the terminal non-r-TWT The STA sets a NAV (Network Allocation Vector) according to the Duration field.
  • the Duration field of the RTS frame stores the value of the period from the transmission of the RTS signal to the scheduled completion time of transmission of the trigger frame. Therefore, for the terminal r-TWT STA (2) and the terminal non-r-TWT STA, the transmission of wireless signals is suppressed from the transmission of the RTS signal until the scheduled completion time of transmission of the trigger frame.
  • the AP transmits a trigger frame to the terminal r-TWT STA (1) immediately after receiving the CTS frame from the terminal r-TWT STA (1), for example after SIFS has passed. Then, the AP waits for the transmission of a data frame from the terminal r-TWT STA (1).
  • the trigger frame is also received by the terminal r-TWT STA (2) and the terminal non-r-TWT STA.
  • the terminal r-TWT STA (2) and the terminal non-r-TWT STA is not a trigger frame addressed to the terminal itself, the terminal r-TWT STA (2) and the terminal non-r-TWT The STA sets the NAV according to the Duration field.
  • terminal r-TWT STA (1) When terminal r-TWT STA (1) receives a trigger frame, it transmits a radio signal including a data frame MSDU (MAC Service Data Unit) according to the resources allocated by the trigger frame. For example, if the SIFS value is set as the transmission start timing, the terminal r-TWT STA (1) transmits the wireless signal after the SIFS has elapsed. The wireless signal is received at the AP, and an acknowledgment (ACK) is returned from the AP. During the transmission of such data frames, the terminal r-TWT STA (1) occupies the channel, so the terminal r-TWT STA (2) and the terminal non-r-TWT STA cannot acquire the transmission right.
  • MSDU MAC Service Data Unit
  • this period is shown as a transmission suppression period (1).
  • the AP transmits an RTS frame addressed to the terminal r-TWT STA (2).
  • terminal r-TWT STA (2) holds a data frame, it transmits a CTS frame to the AP immediately after receiving the RTS frame, for example after SIFS has elapsed.
  • the RTS frame is also received by the terminal r-TWT STA (1) and the terminal non-r-TWT STA.
  • the terminal r-TWT STA (1) and the terminal non-r-TWT STA are not addressed to their own stations, the terminal r-TWT STA (1) and the terminal non-r-TWT The STA sets the NAV according to the Duration field.
  • the AP transmits a trigger frame to the terminal r-TWT STA (2) immediately after receiving the CTS frame from the terminal r-TWT STA (2). Then, the AP waits for the transmission of a data frame from the terminal r-TWT STA (2).
  • the trigger frame is also received by the terminal r-TWT STA (1) and the terminal non-r-TWT STA.
  • the terminal r-TWT STA (1) and the terminal non-r-TWT STA is not a trigger frame addressed to the terminal itself, the terminal r-TWT STA (1) and the terminal non-r-TWT The STA sets the NAV according to the Duration field.
  • terminal r-TWT STA (2) When terminal r-TWT STA (2) receives a trigger frame, it transmits a radio signal including a data frame MSDU according to the resources allocated by the trigger frame. The wireless signal is received at the AP, and an ACK is returned from the AP. During the transmission of such data frames, the terminal r-TWT STA (2) occupies the channel, so the terminal r-TWT STA (1) and the terminal non-r-TWT STA cannot acquire the transmission right.
  • this period is shown as a transmission suppression period (2).
  • the AP again sends an RTS frame addressed to the terminal r-TWT STA (1).
  • terminal r-TWT STA (1) does not hold a data frame, so it does not transmit a CTS frame to the AP.
  • the AP transmits an RTS frame addressed to the terminal r-TWT STA (2).
  • terminal r-TWT STA (2) still holds the data frame, so it transmits a CTS frame to the AP.
  • transmission of wireless signals by the terminal non-r-TWT STA is suppressed. In FIG. 11, this period is shown as a transmission suppression period (3).
  • a terminal that does not support the r-TWT function may not be able to recognize the r-TWT-SP start time and r-TWT-SP duration as r-TWT management information, or may not be able to recognize it even if it recognizes it. I ignore it. Therefore, a terminal that does not support the r-TWT function attempts to exchange data frames even if the service period is set by the AP. This will affect the exchange of low-latency traffic during the service period.
  • RTS frames are transmitted to terminals in order of priority, and in response to the RTS frame, a trigger frame is transmitted for granting transmission rights to the terminal that has transmitted the CTS frame.
  • RTS frames are transmitted according to priority immediately after the start of the service period r-TWT-SP and immediately after the exchange of data frames. As a result, low-latency traffic exchange during the service period is performed preferentially. Therefore, each transmission opportunity supporting the r-TWT function is ensured.
  • the AP transmits the RTS frame to the terminal with the next priority.
  • the AP may transmit the RTS frame to the same terminal again. Then, when the CTS frame is not received as a result of transmitting the RTS frame to the same terminal, the RTS frame may be transmitted to the terminal with the next priority.
  • n when n exceeds n max , n returns to the initial value. On the other hand, if n exceeds n max , the process may end at that point.
  • the transmission determination process according to the embodiment and modification described above can also be stored as a program that can be executed by a processor that is a computer.
  • it can be stored and distributed in a storage medium of an external storage device such as a magnetic disk, an optical disk, or a semiconductor memory. Then, the processor reads the program stored in the storage medium of the external storage device, and its operation is controlled by the read program, thereby being able to execute the transmission determination process.
  • the present invention is not limited to the above-described embodiments, and can be variously modified at the implementation stage without departing from the gist thereof.
  • 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 constituent features disclosed. For example, if a problem can be solved and an effect can be obtained even if some constituent features are deleted from all the constituent features shown in the embodiment, the configuration from which these constituent features are deleted can be extracted as an invention.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

La présente invention concerne un point d'accès comprenant une unité de transmission. L'unité de transmission transmet un signal RTS contenant une trame RTS à un terminal immédiatement après le début d'une période de service ou immédiatement après un échange de trames de données effectué pendant la période de service, et transmet un signal de déclenchement contenant une trame de déclenchement au terminal qui a reçu la trame RTS immédiatement après la réception d'une trame CTS en provenance du terminal qui a reçu la trame RTS.
PCT/JP2022/030555 2022-08-10 2022-08-10 Point d'accès WO2024034050A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/JP2022/030555 WO2024034050A1 (fr) 2022-08-10 2022-08-10 Point d'accès

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Application Number Priority Date Filing Date Title
PCT/JP2022/030555 WO2024034050A1 (fr) 2022-08-10 2022-08-10 Point d'accès

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WO2024034050A1 true WO2024034050A1 (fr) 2024-02-15

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Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
CHUNYU HU (FACEBOOK INC.): "Prioritized EDCA channel access - slot management", IEEE DRAFT; 11-20-1046-14-00BE-PRIORITIZED-EDCA-CHANNEL-ACCESS-SLOT-MANAGEMENT, IEEE-SA MENTOR, PISCATAWAY, NJ USA, vol. 802.11 EHT; 802.11be, no. 14, 26 February 2021 (2021-02-26), Piscataway, NJ USA , pages 1 - 22, XP068178883 *
PATRICE NEZOU (CANON): "Low-Latency Triggered TWT", IEEE DRAFT; 11-20-1843-03-00BE-LOW-LATENCY-TRIGGERED-TWT, IEEE-SA MENTOR, PISCATAWAY, NJ USA, vol. 802.11 EHT; 802.11be, no. 3, 20 February 2021 (2021-02-20), Piscataway, NJ USA , pages 1 - 15, XP068178804 *

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