Communication device, control method, and program

Abstract

To realize highly reliable and low-latency communication.SOLUTION: A communication device transmits or receives a wireless frame that complies with the IEEE 802.11 standard series to another communication device or from another communication device. Here, a Media Access Control (MAC) frame of a wireless frame includes information regarding time-based scheduling of a data frame for a device that has transmitted the wireless frame.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to an information sharing technology for a scheduling function in wireless communication.

Background Art

[0002] As communication standards for wireless LAN (Local Area Network) formulated by IEEE (Institute of Electrical and Electronics Engineers), the IEEE 802.11 standard series is known. The IEEE 802.11 standard series includes IEEE 802.1la / b / g / n / ac / ax standards and the like, and continuously, new standards are being studied to improve peak throughput and frequency utilization efficiency compared to conventional standards. For example, in the IEEE 802.11ax standard, high peak throughput can be obtained by using OFDMA (Orthogonal Frequency Division Multiple Access) or the like (see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, as a new standard, the formulation of the IEEE 802.11be standard is in progress aiming at further improving throughput and frequency utilization efficiency. As one of the targets in this formulation work, the realization of high-reliability and low-latency (Reliable Low-Latency: RLL) communication is there.

[0005] The present invention provides a communication control technology for realizing such high-reliability and low-latency communication.

Means for Solving the Problems

[0006] A communication device according to one aspect of the present invention is: It operates as an access point. A communication device, IEEE 802.11 be Rules In order Compliant wireless frame Send Send The means are provided, and the MAC (Media Access Control) frame of the wireless frame includes, This indicates whether the communication device supports operations to protect access to and reserve wireless resources for the transmission of traffic requiring low latency. information element Includes The operation described above is an operation in which, during a period based on a schedule notified by the communication device, other communication devices prioritize the transmission of the traffic requiring low latency. It is characterized by the following: [Effects of the Invention]

[0007] According to the present invention, highly reliable and low-latency communication can be achieved. [Brief explanation of the drawing]

[0008] [Figure 1] This figure shows an example of the network configuration in this embodiment. [Figure 2] This figure shows an example of the hardware configuration of a communication device. [Figure 3] This figure shows an example of the functional configuration of a communication device. [Figure 4] This diagram shows an example of the processing flow performed by the AP when an STA connection is established. [Figure 5] This diagram shows an example of the data reception processing flow. [Figure 6] This diagram shows an example of the data transmission process flow. [Figure 7] This diagram shows an example of the message flow between AP and STA during DL communication. [Figure 8] This figure shows an example of the message flow between AP and STA during UL communication. [Figure 9] This figure shows an example of the structure of TAS capability information. [Figure 10] This figure shows an example of the structure of TAS capability information. [Figure 11] This diagram explains the settings for TAS capability information. [Figure 12] This diagram explains the settings for TAS capability information. [Figure 13] FIG. is a diagram showing an example of a processing flow when TAS capability information is notified by a Beacon frame. [Figure 14] FIG. is a diagram for explaining an example of a primary channel in the 5 GHz band. [Figure 15] FIG. is a diagram for explaining TAS traffic processing. [Figure 16] FIG. is a diagram for explaining TAS traffic processing.

MODE FOR CARRYING OUT THE INVENTION

[0009] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the invention according to the claims. Although a plurality of features are described in the embodiments, not all of these plurality of features are essential to the invention, and the plurality of features may be arbitrarily combined. Further, in the accompanying drawings, the same or similar configurations are denoted by the same reference numerals, and redundant descriptions are omitted.

[0010] (Network Configuration) FIG. 1 shows a configuration example of the network according to this embodiment. As part of the network in FIG. 1, it includes a wireless communication network (BSS101) in which a wireless communication service is provided by AP102, and a wireless communication network (BSS111) in which a wireless communication service is provided by AP112. Note that AP is an acronym for Access Point, and BSS is an acronym for Basic Service Set. The wireless terminal (STA) can connect to an AP whose communication range is the location where the self-device exists and participate in the BSS provided by that AP. The STA can perform transmission and reception of wireless frames within the joined network. In the example of FIG. 1, since STA103 exists within the communication ranges of both AP102 and AP112, it can connect to either of these APs and participate in either BSS101 or BSS111. Note that an environment in which the communication ranges of such multiple APs overlap is sometimes referred to as an OBSS environment. That is, in this embodiment, STA103 exists in an OBSS environment. Here, it is assumed that STA103 is connected to AP102 and the signal from AP112 can be an interference signal at STA103. Also, since STA113 exists within the communication range of AP112, it can connect to AP112 and participate in BSS111.

[0011] Also, AP102 and AP112 are connected by bridge 104. Between an AP and a bridge, and between a bridge and another bridge, they can be connected by, for example, a wired line. However, a wireless line may be used in at least a part of the section where AP102 and AP112 are connected. With these configurations, one network can be formed in which the wireless network formed by AP102 and AP112 and the wired network composed of bridge 104 and the like are integrated.

[0012] The sensor device 107 is a sensor connected to the network via the bridge 104, and is configured to output environmental data collected by its sensor function to other devices, for example. In this embodiment, the sensor device 107 transmits the collected data to the STA 103 at regular intervals. The remote device 108 is a device connected to the network via the bridge 104 and operates according to remote operation instructions from other devices. The remote device 108 is an end device that requires low-latency data communication via RTA (Real Time Application), such as an industrial robot or a medical surgical robot. In this embodiment, the remote device 108 operates according to remote operation instructions from the STA 103.

[0013] In such a network system, it is crucial to ensure that, for example, STA103 can reliably receive data from sensor device 107 at regular intervals, and that remote control instruction signals from STA103 reach remote device 108 with low latency. However, in conventional wireless LANs, the device transmitting data checks that wireless resources are not being used in the surrounding area and transmits signals during periods when wireless resources are not being used. Therefore, communication is not possible if wireless resources are being used by other devices. For this reason, it is necessary to introduce some kind of communication control function to ensure the transmission and reception of signals at regular intervals and to enable low-latency communication. One solution to this is to introduce the Time-Aware Schedule (TAS) method specified in the IEEE 802.1Qbv standard, which enables the proper transmission and reception of predetermined data, such as data with strict latency requirements. The TAS method is a time-aware scheduling method that uses time as a reference to ensure that signals are transmitted and received at regular intervals. In this embodiment, by employing this TAS method in network communication, regular-interval communication and low-latency communication are properly performed. For this purpose, the AP102, STA103, STA113, Bridge 104, and other devices are assumed to support the TAS method. However, the AP112 is assumed to not support this TAS method. Furthermore, devices other than the AP112 are assumed to support the standard (IEEE802.1AS) for synchronization with the same reference clock within the network.

[0014] In the following, predetermined data that is scheduled and transmitted / received using the TAS method is referred to as TAS traffic data. Here, TAS traffic data is packet data that is transmitted and received while considering delay control between end devices. For such transmission and reception control, the network further includes a network management device 105 and a schedule management device 106. The network management device 105 performs delay control for the TAS traffic data. The schedule management device 106 manages the schedule for the TAS traffic of end devices in the network that use the TAS traffic data. AP102 transmits and receives data to and from the network management device 105 via the bridge 104. AP102 also exchanges TAS information with the schedule management device 106, which manages the schedule of the entire network.

[0015] The network management device 105 collects requirements related to time-aware scheduling (TAS) from end devices such as AP 103, sensor device 107, and remote device 108. These requirements specify, for example, which devices will send and receive TAS traffic data, at what time intervals the data will be transmitted, and the magnitude of the acceptable delay. The network management device 105 detects the network topology of the network under its control. Here, the network topology can be the relationship between which devices each device in the network is connected to. Here, "connected" may refer to a state where devices are physically directly connected, or a state where a logical link is established regardless of the physical connection configuration. Based on the collected requirements, the network management device 105 calculates the end-to-end path between end devices for each TAS traffic data transmission and reception to be performed. Then, based on the calculation results, the network management device 105 determines when each device should transmit signals, performs scheduling, and notifies the scheduling result to the scheduling management device 106.

[0016] The schedule management device 106 sends a message containing TAS information to the bridge 104 and AP 102 to set the transmission and reception schedule. The schedule management device 106 also notifies the end devices (STA 103, sensor device 107, remote device 108) of the TAS information. At this time, the end devices (STA 103, sensor device 107, remote device 108) operate as either a talker (data sender) or a listener (data receiver) according to the transmission schedule within the network for TAS traffic. For example, in the end device combination of STA 103 and sensor device 107 considering RTA traffic, STA 103 operates as a listener and sensor device 107 operates as a talker. Details of the message sequence in this case will be described later using Figure 7 as an example of the downlink (DL) communication flow of data communication supporting TAS in BSS 101. Furthermore, in the end device combination that takes into account the RTA traffic of STA103 and remote device 108, the remote device 108 operates as a listener and STA103 operates as a talker. Details of the message sequence in this case will be described later using Figure 8 as an example of the uplink (UL) communication flow of data communication supporting TAS in BSS101.

[0017] The network configuration described above is merely an example and is not limited to the configuration shown in Figure 1. For example, the following discussion can be applied to a network (BSS) that includes a large number of wireless communication devices in a broader area, and to various spatial relationships of wireless communication devices. Furthermore, for example, while the schedule management device 106 sets the transmit and receive schedule, the functions of this schedule management device 106 may be included in network nodes such as AP102, or in some cases in STA103. That is, AP102 or STA103 may determine the transmit and receive schedule for data frames.

[0018] Between devices that support the TAS method, TAS traffic data can be sent and received with precise timing, as will be described later using Figures 15 and 16. Therefore, by setting appropriate communication timing, communication can be performed in a low-latency and, in some cases, highly reliable environment free from interference from other devices. On the other hand, it is naturally assumed that communication devices that do not support the TAS method may exist within the network range. Even if the schedule management device 106 sends a TAS control message to such a communication device that does not support the TAS method, that communication device cannot interpret the message. Therefore, problems such as unexpected behavior may occur.

[0019] In this embodiment, based on the above assumption, a method is provided for notifying each communication device of its capabilities in order to confirm whether or not each communication device supports the TAS method. Specifically, information is notified by adding an information element to the MAC (Media Access Control) header of the wireless frame transmitted by each communication device. Furthermore, by selecting whether or not to use scheduling using the TAS method based on this information, appropriate scheduling can be performed between the transmitting and receiving devices. The configuration and processing flow of the devices that send and receive such notifications, as well as an example of a specific frame configuration, will be described below.

[0020] (Device configuration) Figure 2 shows the hardware configuration of the communication device (AP, STA, and other end devices) according to this embodiment. As an example of its hardware configuration, the communication device includes a storage unit 201, a control unit 202, a functional unit 203, an input unit 204, an output unit 205, a communication unit 206, and an antenna 207.

[0021] The memory unit 201 is composed of, for example, both ROM (Read Only Memory) and RAM (Random Access Memory), or either one of them. The memory unit 201 stores various information, such as programs for performing various operations described later, and communication parameters for wireless communication. In addition to memory such as ROM and RAM, storage media such as flexible disks, hard disks, optical disks, magneto-optical disks, CD-ROMs, CD-Rs, magnetic tapes, non-volatile memory cards, and DVDs may be used as the memory unit 201.

[0022] The control unit 202 is composed of one or more processors, such as a CPU, MPU, ASIC (Application-Specific Integrated Circuit), DSP (Digital Signal Processor), or FPGA (Field-Programmable Gate Array). Here, CPU is an acronym for Central Processing Unit, and MPU is an acronym for Micro Processing Unit. The control unit 202 controls the entire communication device by executing a program stored in the memory unit 201. Alternatively, the control unit 202 may control the entire communication device in cooperation with the OS (Operating System) and the program stored in the memory unit 201.

[0023] The control unit 202 controls the functional unit 203 to perform predetermined processes such as imaging, printing, and projection. The functional unit 203 is hardware that enables the communication device to perform predetermined processes. For example, if the communication device is a camera, the functional unit 203 is the imaging unit and performs imaging processing. Also, for example, if the communication device is a printer, the functional unit 203 is the printing unit and performs printing processing. Also, for example, if the communication device is a projector, the functional unit 203 is the projection unit and performs projection processing. The data processed by the functional unit 203 may be data stored in the storage unit 201, or data communicated with other communication devices via the communication unit 206, which will be described later.

[0024] The input unit 204 receives various operations from the user. The output unit 205 provides various outputs to the user. Here, the output by the output unit 205 includes at least one of the following: display on the screen, audio output from a speaker, vibration output, etc. Note that both the input unit 204 and the output unit 205 may be implemented in a single module, such as a touch panel. The communication unit 206 controls wireless communication compliant with the IEEE 802.11 standard series and IP communication. In this embodiment, the communication unit 206 can perform processing compliant with at least the IEEE 802.11be standard. The communication unit 206 also controls the antenna 207 to send and receive wireless signals for wireless communication. The communication device communicates content such as image data, document data, and video data with other communication devices via the communication unit 206. The wireless antenna 207 is an antenna capable of receiving either the sub-GHz band, 2.4GHz band, 5GHz band, or 6GHz band. The wireless antenna 207 may be physically composed of one or more antennas in order to achieve MIMO (Multi-Input and Multi-Output) transmission and reception.

[0025] Figure 3 shows an example of the functional configuration related to communication of the TAS of a communication device. The communication device includes, for example, a TAS capability information generation unit 301, a TAS method determination unit 302, a connection processing unit 303, a MAC frame generation unit 304, and a data transmission / reception unit 305. These functional units can be realized, for example, by the control unit 202 executing a program stored in the storage unit 201. However, it is not limited to this, and dedicated hardware corresponding to the functional blocks shown in Figure 3 may be used.

[0026] The TAS capability information generation unit 301 generates capability information (TAS capability information) related to the communication device's TAS and stores it in the storage unit 201. Furthermore, the TAS capability information generation unit 301 can reconfigure the TAS capability information stored in the storage unit 201 or update its contents based on TAS information received from the schedule management device 106. The TAS capability information includes a support ID indicating the scheduling method of the communication device's TAS. The support ID is an identifier corresponding to each of several methods and is used to indicate which of these methods is available. The TAS capability information will be described later with reference to Figures 9 to 12. Note that a communication device may either notify other communication devices of its own capability information or receive capability information from other communication devices. That is, a communication device may only receive capability information from other communication devices and not notify other communication devices of its own capability information.

[0027] The TAS method determination unit 302 determines the TAS method to be used for communication with the communication partner device according to the TAS capability information of the communication partner device. There are generally two types of TAS methods: "shaper" and "policing". Since these methods have different characteristics, the method used is determined based on the differences in characteristics and the intended use (application). The "policing" method reduces delay due to queuing by dropping packets that exceed the limit rate or by changing the priority of packets. The "shaper" method, on the other hand, buffers packets that exceed the limit rate in the I / F queue, which can cause delay. Therefore, for example, in the case of traffic using TCP / UDP port numbers, the method selection may be made to use the "shaper" method for TCP and the "policing" method for UDP. For example, if the only TAS method available to the STA is "shaper", then "shaper" may be adopted, and if the only TAS method available to the STA is "policing", then "policing" may be adopted. Furthermore, if the STA has both "shaper" and "policing" TAS methods available, the TAS method may be determined depending on the application characteristics of the data to be transmitted and received with the STA. For example, the shaper method may be selected for transmitting and receiving data that is periodic but has no delay constraints or does not have strict delay constraints, such as sensor data. Also, if the application is one that requires real-time operation, such as games or industrial robots, and therefore has constraints on data arrival time, the policing method may be selected so that periodic data is transmitted and received with delay control in mind. Note that the shaper method and the policing method are just examples, and other methods may be available. In this case, the TAS method determination unit 302 may select the method to be used from among the multiple available methods, including those other methods.

[0028] TAS capability information can include information about the TAS method according to the application characteristics of the data being transmitted and received. For example, it is notified from the communication device to the other device during connection or communication using a management frame of the IEEE 802.11 standard. Information notification using management frames will be described later with reference to Figure 7. Also, if the number of users (end devices) accommodated in one BSS is large, the overhead for exchanging information to perform low-latency communication may become large. For this reason, the type of TAS method may be changed if the number of STAs accommodated by the AP exceeds a specified number. The communication device may or may not notify the other device of the TAS method determined by the TAS method determination unit 302.

[0029] The connection processing unit 303 performs processing to establish a connection between the STA and the AP. For example, the connection processing unit 303 of the STA sends an Association Request frame to the AP. The connection processing unit 303 of the AP sends an Association Response frame in response to the Association Request frame. The MAC frame generation unit 304 generates a MAC frame containing the TAS capability information generated by the TAS capability information generation unit 301 as needed. The MAC frame here is, for example, a MAC frame in a wireless frame such as a Beacon frame, Probe Request / Response frame, or Association Request / Response frame. The MAC frame may also be a MAC frame in a Reassociation Request / Response frame. The TAS capability information may be stored, for example, in the MAC header. The TAS capability information and TAS scheme information are transmitted using the Capability element, which will be described later using Figures 9 and 11. The data transmission / reception unit 305 transmits and receives TAS traffic data frames that occur periodically at strict timing according to the TAS scheme determined by the TAS scheme determination unit 302. The transmission process of TAS traffic data in the data transmission / reception unit 305 will be described in detail later with reference to Figures 15 and 16.

[0030] (Process flow) Using Figure 4, an example of the processing flow executed by AP102 when STA103 is connected to AP102 will be explained. Similar processing may be performed with other combinations of STA and AP. This processing may be started, for example, when the power of STA103 is turned on. Alternatively, this processing may be started when a user or application instructs STA103 to start data communication in which the TAS method should be used. This processing is implemented, for example, by the control unit 202 of AP102 executing a program stored in the storage unit 201.

[0031] In this process, AP102 first acquires TAS capability information from STA103 (S401). For example, the TAS capability information shown in Figure 9 or Figure 10, described later, is included in the Probe Request frame that STA103 sends before connection and the Association Request frame that it sends when connection is established. AP102 can acquire STA103's TAS capability information by receiving these frames and analyzing their contents. Next, AP102's TAS determination unit 302 determines the TAS method to be used for delay control based on the TAS capability information from STA103 acquired in S401 (S402). Then, AP102 determines whether or not the TAS method determined in S402 can be used (S403). If AP102 determines that the TAS method determined in S402 cannot be used (NO in S403), it notifies STA103 that delay control cannot be performed. In this case, AP102 notifies STA103 of a management frame containing TAS capability information, which includes information (e.g., an ID) indicating that delay control cannot be performed (S406). On the other hand, if AP102 determines that the TAS method determined in S402 can be used (YES in S403), AP102's TAS capability information generation unit 301 notifies STA103 of the TAS method determined in S402. In this case, AP102 notifies STA103 of a management frame containing TAS capability information, which includes a value indicating the TAS method determined in S402 (S404). This value may be, for example, a TAS support ID corresponding to the TAS method. AP102 then stores the TAS capability information included in the management frame and notified to STA103 in S404 or S406 in the storage unit 201 (S405). In this manner, TAS capability information is exchanged between AP and STA.

[0032] Next, using Figure 5, we will explain an example of the data reception process performed by STA103 during communication on the downlink (DL), which is the link through which signals are transmitted from AP102 to STA103. Here, we will explain how TAS traffic data (sensor data, etc.) is handled when a device such as sensor device 107 acts as the talker (transmitter) and STA103 acts as the listener (receiver). For example, TAS traffic data transmitted periodically from sensor device 107 reaches STA103 via bridge 104 and AP102. This process is also applicable to the uplink (UL), which is the link through which signals are transmitted from STA103 to AP102, and similar processing can be performed when AP102 receives data from STA103, for example. In this case, STA103 in the following explanation should be read as AP102.

[0033] When STA103 receives data from AP102 (YES in S501), it determines whether it is operating in a TAS reception mode such as policing or shaping. This determination can be made, for example, by checking the TAS support ID stored in the memory unit 201 in response to STA103 receiving a management frame from AP102. If STA103 is not operating in a TAS reception mode such as policing or shaping (NO in S502), it performs normal data reception processing (S503). On the other hand, if STA103 is operating in TAS reception mode (YES in S502), after data reception processing, it sets and starts a TAS traffic data reception timer at a time interval shorter than the timing of the next TAS traffic data reception (S504).

[0034] Next, STA103 checks the TAS traffic data reception timer to determine if it is time to receive TAS traffic data (S505). If the current time is not the time to receive the next TAS traffic data (NO in S505), STA103 checks if a predetermined time has been reached, such as the time immediately before reception (S508). If this predetermined time has not been reached (NO in S508), STA103 returns to S505 to check the timing to receive TAS traffic data. On the other hand, if the predetermined time has been reached (YES in S508), STA103 performs carrier sense, etc., to check the usage status of the corresponding TAS traffic data reception channel (S509). If STA103 determines that the reception channel is busy (NO in S509), it performs channel access conflict processing (S510) to make the channel available and returns to S505. Furthermore, if the receiving channel is not busy and is available (YES in S509), STA103 reserves the receiving channel for that TAS traffic data by, for example, sending a null packet, since the current time is just before the receiving timing (S511). Then, STA103 returns processing to S505.

[0035] STA103 checks the TAS traffic data reception timer and, if it determines that it is time to receive TAS traffic data (YES in S505), executes the TAS traffic data reception process (S506). Then, STA103 determines whether data communication has ended (S507). If data communication continues (NO in S507), it returns to S501, and if data communication has ended (YES in S507), it terminates the data reception process. In this way, STA103 can receive TAS traffic data from AP102 at a predetermined reception timing (time) in the wireless communication of BSS101.

[0036] Using Figure 6, an example of the data reception process performed by STA103 during uplink (UL) communication will be explained. Here, the handling of TAS traffic data (remote control data, etc.) when STA103 acts as the talker (transmitter) and a device such as remote device 108 acts as the listener (receiver) will be explained. For example, TAS traffic data periodically transmitted from STA103 reaches remote device 108 via AP102 and bridge 104. This process is also applicable to downlink (DL), and similar processing can be performed when AP102 transmits data to STA103, for example. In this case, STA103 in the following explanation should be read as AP102.

[0037] STA103 continuously monitors whether data has been generated for transmission, for example, by receiving a data transmission request from the control application of the remote device 108 implemented in the device (S601). When STA103 detects the generation of data for transmission (YES in S601), it determines whether the device is operating in a TAS transmission mode such as policing or shaping. This determination can be made, for example, by checking the TAS support ID stored in the storage unit 201 in response to STA103 receiving a management frame from AP102. If STA103 is not operating in a TAS transmission mode such as policing or shaping (NO in S602), it performs normal data transmission processing (S603). On the other hand, if STA103 is operating in TAS transmission mode (YES in S602), after the data transmission processing, it sets and starts the TAS traffic data transmission timer at a time interval shorter than the timing of the next TAS traffic data transmission (S604).

[0038] Next, STA103 checks the TAS traffic data transmission timer to determine if it is time to transmit TAS traffic data (S605). If the current time is not the time for the next TAS traffic data transmission (NO in S605), STA103 checks if a predetermined time has been reached, such as the time immediately before transmission (S608). If this predetermined time has not been reached (NO in S608), STA103 returns to S605 to check the timing for transmitting TAS traffic data. On the other hand, if the predetermined time has been reached (YES in S608), STA103 performs carrier sense, etc., to check the usage status of the corresponding TAS traffic data transmission channel (S609). If STA103 determines that the transmission channel is busy (NO in S609), it performs channel access conflict processing (S610) to make the channel available and returns to S605. Furthermore, if the transmission channel is not busy and is available (YES in S609), STA103 reserves the transmission channel for the TAS traffic data by, for example, sending a null packet, since the current time is just before the transmission timing (S511). Then, STA103 returns processing to S605.

[0039] STA103 checks the TAS traffic data transmission timer and, if it determines that it is time to transmit TAS traffic data (YES in S605), executes the TAS traffic data transmission process (S606). The TAS traffic data transmission process will be described later using Figures 15 and 16. After that, STA103 determines whether data communication has ended (S607). If data communication continues (NO in S607), it returns to S601, and if data communication has ended (YES in S607), it terminates the data transmission process. In this way, STA103 can transmit TAS traffic data to AP102 at a predetermined transmission timing (time) in the wireless communication of BSS101.

[0040] As described above, STA103 can transmit TAS traffic data to AP102 at predetermined transmission timings. By performing the processes shown in Figures 5 and 6 between STA and AP, TAS traffic data is transmitted periodically at pre-configured times. By operating so that communication takes place at appropriately pre-configured times based on the network topology, unnecessary waiting time is reduced, enabling low-latency communication.

[0041] Next, using Figure 7, an example of the message flow transmitted and received between AP102 and STA103 during downlink (DL) communication will be explained. This process is executed when TAS traffic data from a device such as sensor device 107, which operates as a talker, is received by STA103, which is a listener, via bridge 104 and AP102. First, STA103 performs a scan process to obtain network information from AP102. For example, AP102 broadcasts a Beacon frame (M701) containing network information to devices within the range of BSS101. Here, AP102 may also broadcast a Beacon frame containing capability information for the TAS method, which will be described later, using Figure 9 or Figure 10. STA103 may send a Probe Request frame (M702) to query network information from AP102 and obtain information from AP102. AP102 responds to the Probe Request frame (M702) by sending a Probe Response frame (M703). STA103 can, for example, receive a Beacon frame (M701) transmitted by AP102 and obtain network information of AP102 from that Beacon frame. Alternatively, STA103 may proactively send a Probe Request frame (M702) and receive a Probe Response frame (M703) from AP102 to obtain network information of AP102. In this case, the Beacon frame (M701) and Probe Response frame (M703) will include TAS capability information indicating whether or not AP102 supports the TAS method. If the TAS method is supported, the TAS capability information included in the frame may indicate whether it supports only the policing method, only the shaper method, or both. STA103 can also include its own TAS capability information in the Probe Request frame (M702) and transmit it. Through these processes, STA103 and AP102 can exchange TAS capability information.However, TAS capability information may not be exchanged at this point, but rather in another message such as the Association Request / Response frame described later.

[0042] After scanning, STA103 sends an Association Request frame (M704) to AP102 to connect to BSS101. In response to the Association Request frame (M704), AP102 sends an Association Response frame (M705) to STA103 indicating the connection result from STA103. TAS capability information may be included in the Association Request frame and Association Response frame. Alternatively, STA103 may determine which TAS capability information to include in the Association Request frame based on the TAS capability information of AP102 obtained during the scanning process. For example, when both the shaper method and the policing method are available, STA103 may select the method to use depending on the purpose of communication using the TAS method and notify AP102 that only the selected method is available. For example, if the talker is sensor device 107, STA103, which can use both methods, may send an Association Request frame (M704) to AP102 that includes TAS capability information indicating that its device can only use the shaper method. Alternatively, if the listener is remote device 108, STA103, which can use both methods, may send an Association Request frame (M704) to AP102 that includes TAS capability information indicating that its device can only use the policing method. Similarly, AP102 may determine the TAS capability information to include in the Association Response frame based on the TAS capability information of STA103 included in the Association Request frame. In this way, TAS capability information is exchanged before the connection between AP102 and STA103 is established.

[0043] Subsequently, AP102, after confirming that TAS communication is possible, sends a management frame (M706) to STA103. This management frame contains information indicating, for example, that the shaper method should be used for TAS capability information during DL data communication. This management frame may also contain information indicating, for example, the schedule for when data should be sent and received using the TAS method. Subsequently, STA103, which is the listener, periodically receives TAS traffic data (M707) from the sensor device 107, which is the talker, via AP102. STA103 receives the TAS traffic data (M707) by executing the data reception process, for example, as described in Figure 5. AP102 also transmits the TAS traffic data (M707) by executing the data transmission process, for example, as described in Figure 6.

[0044] Next, using Figure 8, an example of the message flow transmitted and received between AP102 and STA103 during UL communication will be explained. This process is executed, for example, when STA103, acting as a talker, transmits TAS traffic data received by a device such as remote device 108, which acts as a listener, via AP102 and bridge 104. Here, the messages related to the scan process (M701-M703), the messages related to the STA connection process (M704-M705), and the management frame (M706) are the same as in Figure 7. In this case, since the listener is remote device 108, STA103, which can handle both methods, may include TAS capability information indicating that its device can only use the policing method in the Association Request frame and send it to AP102. The management frame (M706) includes information indicating, for example, that the policing method should be used in the TAS capability information during UL data communication. This management frame may also include information indicating, for example, a schedule for when data should be transmitted and received using the TAS method. Subsequently, the talker, STA103, periodically transmits mTAS traffic data (M801) to the listener, remote device 108, via AP102. STA103 transmits the TAS traffic data (M801) by executing the data transmission process described, for example, using Figure 6. AP102, on the other hand, receives the TAS traffic data (M801) by executing the data reception process described, for example, using Figure 5.

[0045] In this way, AP102 and STA103 exchange TAS capability information of their respective devices and can decide whether or not to use the TAS method for subsequent communication, and whether to use the shaper method or the policing method. As a result, by performing the processing described later using Figures 15 and 16, for example, wireless communication can be performed with scheduling according to the time, enabling low-latency communication.

[0046] Next, a first example of TAS capability information will be explained using Figure 9. In this embodiment, the name of this TAS capability information is "TAS capability element," but it is not limited to this. For example, other names such as "TAS Element" may be used. The TAS capability element has a similar structure to other Information Elements defined in the IEEE 802.11 standard. That is, the TAS capability element consists of an Element ID field 901 that identifies the Element, a Length field 902 that indicates the data length of the Element, and Element-specific information. The TAS capability element includes a TAS capability Info field 903 as Element-specific information. The TAS capability element is included in MAC frames such as Beacon frames, Probe Request / Response frames, and Association Request / Response frames. The TAS capability element may also be included in the MAC frame of an Association Request / Response frame. The TAS capability Info field 903 includes information indicating whether the sender of this TAS capability element can use the TAS method and the TAS methods that can be used. This information is represented, for example, by 2 bits. An example of information represented by 2 bits will be described later using Figure 11. Note that, although the TAS capability Info field 903 is described here as having a size of 1 octet (8 bits), it is not limited to this. The field name and bit positions and sizes are not limited to the example in Figure 9, and similar information may be stored with different field names, in different orders, and in different sizes.

[0047] A second example of TAS capability information is explained using Figure 10. This TAS capability element also includes an Element ID field 901 and a Length field 902, similar to the example in Figure 9. Furthermore, this information may be included in the MAC frame of each wireless frame as described above, instead of the information in Figure 9. The TAS capability element in Figure 10 may be the same as the TAS capability element in Figure 9, except for the TAS capability Info field 1001. However, please note that the value stored in the Length field 902 will differ between Figure 9 and Figure 10 because the size of the TAS capability Info field is different. In the example in Figure 10, the TAS capability Info field 1001 consists of information indicating the availability of each TAS method for the primary channel, in addition to the availability of the TAS method. The primary channel is the main channel for supporting multilink technology that uses multiple wireless channels simultaneously, and is used for sending and receiving messages related to the capability information of other wireless links and connection and disconnection. The relationship between the capability information of the TAS method and the primary channel will be explained later using Figure 14. In the following, the primary channel may be referred to as "PCH".

[0048] The TAS support field 1002 contains information indicating whether the sender of this TAS capability element can use the TAS method and which TAS methods are available. This information is represented by 2 bits, for example. An example of information represented by 2 bits will be described later using Figure 11. The PCH1 availability field 1003 to PCH9 availability field 1011 are fields that indicate whether the TAS method can be used for each of the primary channels 1 to 9. The values ​​stored in these fields and what those values ​​indicate will be described later using Figure 12. The Reserve field 1012 is a 5-bit unused area to accommodate future expansions. Here, an example is shown where the TAS capability Info field 1001 is 2 octets (16 bits), but it is not limited to this. For example, similar information may be represented by different field names, different bit positions, or different field sizes. In this embodiment, the element in Figure 10 is named TAS capability element, but it is not limited to this, and other names such as TAS Multi-Link Element may be used.

[0049] Using Figure 11, an example of information from Figure 9 or Figure 10 indicating whether the sender of the information can use the TAS method and which TAS methods can be used will be explained. Note that the information on whether the TAS method can be used and which TAS methods can be used may be collectively referred to as the TAS support status. In Figure 11, the D bit value 1101 represents the 2-bit data bit (D bit) value stored in the TAS capability Info field 903 in Figure 9 and the TAS support field 1002 in Figure 10. Note that the bit sequence indicated by this D bit may be a TAS support ID. The TAS support content 1102 indicates the content corresponding to each TAS support ID. For example, the bit value "00" of the D bit value 1101 indicates that the TAS method is not supported (cannot be used). Also, the bit value "01" of the D bit value 1101 indicates that the TAS method is supported, but only the shaper method can be used. Also, the bit value "10" of the D bit value 1001 indicates that the TAS method is supported, but only the policing method can be used. The bit value "11" for bit value 1001 of D bit indicates that it supports the TAS method and that both the policing method and the shaper method can be used. Note that the setting values ​​for each information element are not limited to this example, and similar information may be represented by different field names or different values.

[0050] Figure 12 shows examples of the values ​​stored in each of the PCH1 availability fields 1003 to PCH9 availability fields 1011 in Figure 10, and their corresponding contents. The PCH1 availability fields 1003 to PCH9 availability fields 1011 store an E bit 1201, which is configured such that the content 1202 it displays differs depending on the combination with the value shown in the TAS support field 1002. For example, if the two bits stored in the TAS support field 1102 represent either the policing method (D bit value "10") or the shaper method (D bit value "01"), the E bit represents whether each TAS method is available. For example, setting the E bit to "1" indicates that the TAS method shown in the D bit value is available, and setting the E bit to "0" indicates that the TAS method shown in the D bit value is unavailable. This is just one example; setting the E bit to "0" may indicate that the TAS method indicated by the D bit value is available, and setting the E bit to "1" may indicate that the TAS method indicated by the D bit value is unavailable. Furthermore, if the two bits stored in the TAS support field 1102 indicate that both the policing method and the shaper method are available (when the D bit value is "11"), one bit of the E bit may specify one of the methods. For example, setting the E bit to "1" specifies the policing method, and setting the E bit to "0" specifies the shaper method. Alternatively, setting the E bit to "0" may specify the policing method, and setting the E bit to "1" may specify the shaper method.

[0051] Here, using Figure 13, an example of the processing flow executed by AP102 when the TAS capability information shown in Figure 10 is broadcast via a Beacon frame will be explained. This processing starts, for example, when the power to AP102 is turned on, or when the TAS-type data collection process is started in AP102. This processing can be implemented, for example, by the control unit 202 of AP102 executing a program stored in the storage unit 201.

[0052] First, AP102 determines whether it is set to include multi-channel TAS information in the Beacon frame, as shown in Figure 10 (S1301). If AP102 determines that it is not set to include multi-channel TAS information in the Beacon frame (NO in S1301), it performs the conventional Beacon frame setting process (S1302). Then, AP102 broadcasts the Beacon frame obtained through the setting process in S1302 within BSS1 (S1306). In this case, AP102 may also transmit a Beacon frame that includes TAS information, for example, as shown in Figure 9.

[0053] If AP102 is configured to include multi-channel TAS information in the Beacon frame (NO in S1301), it determines the usability of each of the multiple PCHs based on the TAS capability information stored in S405 in Figure 4 (S1303). For this purpose, AP102 sends an RTS (Request To Send) message. When STA103 receives an RTS on each PCH, it performs carrier sensing on that PCH. If the PCH is not busy, STA103 sends a CTS (Clear To Send) message to AP102 after the SIFS (Short Inter Frame Space) period has elapsed. AP102 checks whether a CTS has been received on each PCH that sent an RTS, and recognizes the PCHs where reception has been confirmed as usable PCHs. At this time, the TAS capability information generation unit 301 of AP102 recognizes that TAS communication cannot be used for PCHs where reception of a CTS could not be confirmed.

[0054] The TAS capability information generation unit 301 then updates the information regarding the availability of the TAS method for each PCH in the TAS capability information. When AP102 completes the processing in S1303 for all of the available PCHs (YES in S1304), it stores the confirmed TAS capability information in the storage unit 201 and sets the TAS capability information in the Beacon frame (S1305). AP102 then broadcasts the Beacon frame, including the TAS capability information, to BSS101 (S1306). Note that the Beacon frame including the TAS capability information shown in Figure 9 or Figure 10 may be broadcast to multiple PCHs.

[0055] As described above, AP102 can transmit information on multiple PCHs in a Beacon frame. This allows, for example, STA103 to select and use a PCH capable of communication that takes delay control based on TAS capability information. Alternatively, among PCHs with TAS capability information, a PCH with a signal bandwidth of a predetermined width or greater may be selected, or PCHs with larger signal bandwidths may be selected preferentially. Furthermore, among PCHs with TAS capability information, a PCH with a received field strength and signal-to-noise ratio (SNR) of a predetermined value or greater may be selected, or PCHs with good values ​​for these may be selected preferentially. Additionally, among PCHs with TAS capability information, a PCH with a channel transmission capacity calculated from bandwidth and SNR of a predetermined value or greater may be selected, or PCHs with larger capacities may be selected preferentially. Furthermore, among PCHs with TAS capability information, a PCH to be used may be selected based on available channel information estimated from channel usage over a certain period. Other conditions besides these PCH selection conditions may also be used. Moreover, one or more of the above selection conditions may be used in combination.

[0056] Next, Figure 14 will be used to explain PCH1 to PCH9. PCH1 to PCH9 represent multiple PCHs usable in the 5GHz band. For example, PCH1 to PCH9 are frequency channels with channel numbers 36, 44, 52, 60, 100, 108, 116, 124, and 132, respectively, and a bandwidth of 20MHz. Although the 5GHz frequency band has been explained here, similar arguments can be applied to the 2.4GHz and 6GHz frequency bands. Furthermore, the above arguments may be applied to any other frequency channel, not just PCHs.

[0057] Using Figure 15, the Time-Aware Schedule (TAS) traffic data transmission process in the AP and STA according to this embodiment will be explained. As an example, AP102 and STA101 have the configuration shown in Figure 15 for TAS traffic data transmission processing. In the configuration of Figure 15, application 1501 receives TAS method information determined by the TAS method determination unit 302 described above before reaching the state of TAS traffic data communication. Then, application 1501 prepares for a data transmission request from the Mac frame generation unit 304 in order to execute the transmission process according to this TAS method information. Traffic classification function 1503 receives traffic data with priority information added from the Mac frame generation unit 304 and maps time-constrained traffic data to TAS queue (Q0) 1504. In addition, traffic classification function 1503 maps best-effort traffic data other than TAS traffic data to BE queues (Q1-Q4) 1505, respectively. The TAS time gate control function 1502 pauses and resumes the TAS time gate (G0) 1506 and the various BE time gates (G1-G4) 1507, respectively, and controls the output of traffic data accumulated in each queue. The TAS time gate control function 1502 performs control that protects TAS traffic data while avoiding channel access conflicts, for example, as described later.

[0058] Figure 16 illustrates the transmission process of TAS traffic data using multiple time gates (G0-G4). Curve 1601 shows the OPEN / CLOSE state of the TAS time gate (G0) 1506, and curves 1602-1605 show the OPEN / CLOSE state for each of the various BE time gates (G1-G4) 1507. In these curves, "1" indicates OPEN and "0" indicates CLOSE. When a time gate is open, data from the queue corresponding to that time gate can be output through that time gate. Guard time 1606 indicates the time Tg during which transmission of all gates is blocked. This guard time 1606 prevents various BE traffic data from colliding with TAS traffic data. Timing 1607 indicates the timing To during which the TAS time gate (G0) 1506 is periodically opened. Timing To occurs every 1608 cycles. This period 1608 is defined by the interval Tp, which specifies the strict and periodic timing for transmitting data as requested by the TAS traffic data transmission request. Period 1609 is the time interval Tc during which the TAS time gate (G0) 1506 for the TAS queue (Q0) 1504 is opened, and it indicates the period during which TAS traffic data is transmitted at a strict and periodic timing.

[0059] The TAS time gate control function 1502 performs gate control according to the periodically repeated transmission and reception schedule of TAS traffic data. The TAS time gate control function 1502 can close or open each time gate by inputting bit 0 or 1 to each time gate. For example, the TAS time gate control function 1502 can indicate the OPEN / CLOSE status of five time gates G0 to G4 using a 5-bit bit sequence. Each time gate can then extract the bit corresponding to itself from this bit sequence and perform CLOSE / OPEN control. The TAS time gate control function 1502 may also output 1-bit information for each time gate indicating whether that time gate should be closed or open. The state of each time gate for each bit sequence is described below. The bit sequences here represent the OPEN / CLOSE status of each time gate in the order of "G0, G1, G2, G3, G4". The bit sequence "00000" indicates the data block state. This state corresponds to guard time 1606, and all time gates (G0-G4) are closed. The bit sequence "10000" indicates a state where only the TAS time gate (G0) 1506 is open, and this state corresponds to period 1609. The bit sequence "01111" indicates a state where various BE time gates (G1-G4) 1507 are open, and for example, corresponds to the period of period 1608 excluding period 1609 and guard time 1606. In this way, the TAS time gate control function 1502 can control the CLOSE / OPEN of each time gate with a 1-bit indicator.

[0060] In this way, by using time gates (G0-G4), it is possible to process TAS traffic data smoothly while blocking data that should not be transmitted at the precise timing required for transmission.

[0061] The present invention can also be realized by supplying a program that implements one or more of the functions of the above-described embodiments to a system or device via a network or storage medium, and by having one or more processors in the computer of that system or device read and execute the program. It can also be realized by a circuit (e.g., an ASIC) that implements one or more functions.

[0062] The invention is not limited to the embodiments described above, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, claims are attached to disclose the scope of the invention. [Explanation of symbols]

[0063] 101 and 111: BSS, 102 and 112: AP, 103 and 113: STA, 104: Bridge, 105: Network control device, 106: Schedule device, 107: Sensor device, 108: Remote device

Claims

1. A communication device that operates as an access point, It has a transmission means for transmitting wireless frames compliant with the IEEE 802.11be standard, The MAC (Media Access Control) frame of the wireless frame includes an information element indicating whether the communication device supports the operation of protecting access to wireless resources and reserving said wireless resources for the transmission of traffic requiring low latency. The aforementioned operation is an operation in which, during a period based on a schedule notified by the communication device, other communication devices prioritize the transmission of the traffic requiring low latency. A communication device characterized by the following features.

2. The communication device according to claim 1, characterized in that the schedule includes information indicating the start time of the period.

3. The communication device according to claim 1, characterized in that the period is scheduled periodically.

4. The communication device according to claim 1, wherein the information element includes an Element ID field indicating identification information of the information element and a field indicating whether or not the operation is supported.

5. The communication device according to claim 1, characterized in that the wireless frame containing the MAC frame is one of a Beacon frame, a Probe Response frame, an Association Response frame, or an Association Response frame.

6. A control method performed by a communication device operating as an access point, Includes a transmission step that transmits a wireless frame compliant with the IEEE 802.11be standard, The MAC (Media Access Control) frame of the wireless frame includes an information element indicating whether the communication device supports the operation of protecting access to wireless resources and reserving said wireless resources for the transmission of traffic requiring low latency. The aforementioned operation is an operation in which, during a period based on a schedule notified by the communication device, other communication devices prioritize the transmission of the traffic requiring low latency. A control method characterized by the following:

7. A program that causes a computer provided in a communication device operating as an access point to execute a transmission procedure for transmitting wireless frames compliant with the IEEE 802.11be standard, The MAC (Media Access Control) frame of the wireless frame includes an information element indicating whether the communication device supports the operation of protecting access to wireless resources and reserving said wireless resources for the transmission of traffic requiring low latency. The aforementioned operation is an operation in which, during a period based on a schedule notified by the communication device, other communication devices prioritize the transmission of the traffic requiring low latency. A program characterized by the following features.

8. A communication device, It has a receiving means for receiving wireless frames compliant with the IEEE 802.11be standard from an access point. The MAC (Media Access Control) frame of the wireless frame includes an information element indicating whether the access point supports the operation of protecting access to wireless resources and reserving said wireless resources for the transmission of traffic requiring low latency. The operation described above is an operation in which the communication device prioritizes the transmission of the low-latency traffic during a period based on a schedule notified by the access point. A communication device characterized by the following features.

9. The communication device according to claim 8, wherein the schedule includes information indicating the start time of the period.

10. The communication device according to claim 8, characterized in that the period for which the communication device prioritizes transmitting the low-latency traffic is scheduled periodically.

11. The communication device according to claim 8, wherein the information element includes an Element ID field indicating identification information of the information element and a field indicating whether or not the operation is supported.

12. The communication device according to claim 8, characterized in that the wireless frame containing the MAC frame is any of a Beacon frame, a Probe Response frame, an Association Response frame, or a Response frame.

13. A control method performed by a communication device, Includes a receiving step of receiving a wireless frame compliant with the IEEE 802.11be standard from an access point. The MAC (Media Access Control) frame of the wireless frame includes an information element indicating whether the access point supports the operation of protecting access to wireless resources and reserving said wireless resources for the transmission of traffic requiring low latency. The operation described above is an operation in which the communication device prioritizes the transmission of the low-latency traffic during a period based on a schedule notified by the access point. A control method characterized by the following:

14. A program for causing a computer provided in a communication device to execute a receiving procedure for receiving a wireless frame compliant with the IEEE 802.11be standard from an access point, The MAC (Media Access Control) frame of the wireless frame includes an information element indicating whether the access point supports the operation of protecting access to wireless resources and reserving said wireless resources for the transmission of traffic requiring low latency. The operation described above is an operation in which the communication device prioritizes the transmission of the low-latency traffic during a period based on a schedule notified by the access point. A program characterized by the following features.

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