Communication device, control method, and program

Abstract

To make it possible to efficiently control access to a wireless medium of a STA in a wireless LAN.SOLUTION: A communication device sets up a connection with another communication device, receives from another communication device a predetermined radio frame containing information designating frequency resources for another communication device to cause one or more devices to transmit data, and when a first identifier for random access is allocated to the communication device in setting up the connection, acquires a right to transmit data to another communication device by random access and performs communication, on the basis of a sum of a first number of frequency resources associated with the first identifier and a second number of frequency resources associated with a second identifier for random access different from the first identifier, in the predetermined radio frame.SELECTED DRAWING: Figure 7A

Description

[Technical Field]

[0001] The present invention relates to a technique for controlling access to a wireless medium. [Background technology]

[0002] The Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard is known as a communication standard for wireless local area networks (WLANs). The IEEE 802.11ax standard, the latest standard in the IEEE 802.11 series, uses orthogonal frequency division multiple access (OFDMA) to achieve high peak throughput and improved communication speeds under congested conditions. The IEEE 802.11ax standard specifies a mechanism in which an access point (AP) allocates frequency resources to multiple stations (STAs) and causes them to simultaneously transmit data using a frame called a trigger frame (TF). This enables OFDMA-based communication in uplink (UL) communications, in which data is transmitted from the STAs to the AP. Furthermore, Patent Document 1 describes a technology in which the IEEE 802.11ax standard introduces a random access mechanism based on TF, enabling stations, etc., that have resumed sleep mode to quickly transmit data. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2018 / 047570 Summary of the Invention [Problem to be solved by the invention]

[0004] To further improve throughput, a task group has been formed to develop the IEEE802.11be standard as the successor to IEEE802.11ax. This task group is currently studying technologies for achieving low latency while maintaining high efficiency in wireless medium utilization in congested environments for communications for autonomous driving, sensor warnings, machine control, and other purposes. These communications, for example, require the shortest possible time, so they are expected to be transmitted via random access. However, if a large number of STAs communicate via random access, the frequency resources for random access may be insufficient, making it impossible to transmit data quickly. While simply increasing the frequency resources for random access may improve data transmission speeds, this may result in unused frequency resources, resulting in reduced communication efficiency. [Means for solving the problem]

[0005] The present invention provides an efficient technique for controlling access to the wireless medium.

[0006] A communication device according to one embodiment of the present invention has a setting means for setting up a connection with another communication device, a receiving means for receiving from the other communication device a predetermined radio frame including information specifying frequency resources for the other communication device to transmit data to one or more devices, and a communication means for, when a first identifier for random access is assigned to the communication device in setting up the connection, acquiring the right to transmit data to the other communication device by random access based on the sum of a first number of frequency resources associated with the first identifier and a second number of frequency resources associated with a second identifier for random access different from the first identifier in the predetermined radio frame, and performing communication. [Effects of the Invention]

[0007] According to the present invention, access to the wireless medium of STAs in a wireless LAN can be efficiently controlled. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of a wireless communication system. [Figure 2] FIG. 2 illustrates an example of a hardware configuration of a communication device. [Figure 3] FIG. 2 illustrates an example of a functional configuration of a communication device. [Figure 4] FIG. 1 is a diagram illustrating the configuration of a MAC frame format. [Figure 5] A diagram showing an example of the configuration of a UORA Parameter Set element. [Figure 6A] FIG. 10 is a diagram illustrating the configuration of a Trigger Frame. [Figure 6B] FIG. 10 is a diagram illustrating the configuration of a Trigger Frame. [Figure 7A] FIG. 10 is a diagram illustrating an example of a communication flow. [Figure 7B] FIG. 10 is a diagram illustrating an OBO subtraction process. [Figure 8A] FIG. 10 is a diagram illustrating an example of a communication flow. [Figure 8B] FIG. 10 is a diagram illustrating an OBO subtraction process. [Figure 8C] FIG. 10 is a diagram illustrating an OBO subtraction process. [Figure 9A] FIG. 10 is a diagram illustrating an example of a flow of processing executed by an AP. [Figure 9B] FIG. 10 is a diagram illustrating an example of a flow of processing executed by an AP. [Figure 10] FIG. 10 is a diagram illustrating an example of the flow of processing executed by an STA. DETAILED DESCRIPTION OF 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 multiple features are described in the embodiments, not all of these multiple features are necessarily essential to the invention, and multiple features may be combined arbitrarily. Furthermore, in the accompanying drawings, the same reference numerals are used to designate the same or similar components, and redundant explanations will be omitted.

[0010] Please note that this specification uses terms that conform to IEEE802.11ax Draft 8.0, published in October 2020, but these terms may be interpreted as different terms with similar meanings.

[0011] (System Configuration) An example of the configuration of a wireless communication system according to this embodiment will be described with reference to FIG. 1. In this wireless communication system, access points (APs) each constitute a network and communicate with connected stations (STAs) over a wireless LAN conforming to, for example, the IEEE 802.11 standard series. While only one AP (AP 100) is shown in FIG. 1, two or more APs may naturally be present. Although four STAs (STAs 101 to 104) are shown in FIG. 1, more STAs may be present, or the number of STAs may be three or less. Note that the AP and STA merely indicate that they operate as a base station and a terminal, respectively, of a wireless LAN. They may be any communication devices capable of operating as both an AP and a STA, for example. In FIG. 1, the AP 100 manages the BSS 105. BSS is an acronym for Basic Service Set, and refers to a wireless network formed by APs. The AP 100 can connect to other BSSs and external networks via the DS 106. The DS is an acronym for Distribution System. The connection of the DS 106 may be established using a wired line such as Ethernet (registered trademark) or a telephone line. Alternatively, the connection of the DS 106 may be established using a wireless communication line such as LTE (Long Term Evolution) or WiMAX (Worldwide Interoperability for Microwave Access). Alternatively, the connection of the DS 106 may be established by a wireless LAN conforming to the IEEE 802.11 standard. In this case, the wireless channel used for the connection of the DS 106 may be the same as or different from the wireless channel used between the AP 100 and the STA.

[0012] The conventional IEEE 802.11ax standard provides a mechanism for STAs to support TF-based random access. Specifically, the STA has an OFDMA-based BackOff (OBO) counter and decrements the OBO counter by the number of frequency resources (resource units, RUs) for random access in the TF received from the AP. Note that random access RUs include RUs for connected STAs and RUs for unconnected STAs. The STA counts the total number of RUs depending on its own status. When the total number reaches a predetermined value, which is the initial value of the OBO counter, i.e., when the OBO counter reaches 0, the STA acquires access to the random access RU. In this embodiment, this mechanism is enhanced to assign a special identifier for random access to at least some of the STAs. The STA decrements the OBO counter not only when it detects a random access RU corresponding to its own connection status, but also when it detects an RU corresponding to the random access identifier assigned to its own device. This allows a specific STA (which has been assigned a predetermined identifier for random access) to quickly acquire the transmission right in TF-based random access. For example, by assigning a predetermined identifier to a STA that needs to communicate immediately after data generation, the STA can quickly acquire the transmission right for random access.

[0013] (Device configuration) Next, an example of the hardware configuration of the communication device (AP and STA) will be described with reference to Fig. 2. The communication device has, as an example of its hardware configuration, a storage unit 201, a control unit 202, a function unit 203, an input unit 204, an output unit 205, a communication unit 206, and an antenna 207.

[0014] The storage unit 201 is configured with one or more memories including both ROM and RAM, and stores various information such as programs for performing various operations described below and communication parameters for wireless communication. ROM is an acronym for Read Only Memory, and RAM is an acronym for Random Access Memory. In addition to memories 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 storage unit 201. Furthermore, the storage unit 201 may be configured to include multiple storage devices such as memories.

[0015] The control unit 202 is configured by, for example, one or more processors such as a CPU or an MPU, an ASIC (Application Specific Integrated Circuit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), etc. Here, CPU is an acronym for Central Processing Unit, and MPU is an acronym for Micro Processing Unit. Note that the control unit 202 may be a multi-core processor. The control unit 202 controls the entire device by executing a program stored in the storage unit 201. Note that the control unit 202 may control the entire device in cooperation with the program stored in the storage unit 201 and an OS (Operating System).

[0016] The control unit 202 also controls the functional unit 203 to perform predetermined processing such as capturing images, printing, and projection. The functional unit 203 is hardware that enables the device to perform predetermined processing. For example, if the device is a camera, the functional unit 203 is an imaging unit that performs imaging processing. For example, if the device is a printer, the functional unit 203 is a printing unit that performs printing processing. For example, if the device is a projector, the functional unit 203 is a projection unit that performs projection processing. Data processed by the functional unit 203 may be data stored in the storage unit 201, or may be data communicated with another AP or STA via the communication unit 206 (described later). The functional unit 203 may include a processing circuit for implementing an AP function or an STA function, and may be configured to perform processing as an AP or STA of a wireless LAN compliant with the IEEE 802.11 standard series based on the control of the control unit 202.

[0017] The input unit 204 receives various operations from the user. The output unit 205 outputs various types of information to the user. Here, the output by the output unit 205 includes, for example, at least one of display on a screen, audio output by a speaker, vibration output, etc. Note that both the input unit 204 and the output unit 205 may be implemented by a single module, such as a touch panel.

[0018] The communication unit 206 controls wireless communication compliant with the IEEE 802.11 standard series and IP communication. The communication unit 206 is a so-called wireless chip and may itself include one or more processors and memories. In this embodiment, the communication unit 206 can execute processing compliant with at least the IEEE 802.11be standard. The communication unit 206 also controls the antenna 207 to transmit and receive wireless signals for wireless communication. The AP and STA communicate content such as image data, document data, and video data with other communication devices via the communication unit 206. The antenna 207 is an antenna capable of transmitting and receiving at least one of the sub-GHz band, the 2.4 GHz band, the 5 GHz band, and the 6 GHz band. Note that the frequency bands (and their combinations) supported by the antenna 207 are not particularly limited. The antenna 207 may be a single antenna or a set of two or more antennas for MIMO (Multi-Input and Multi-Output) transmission and reception. Furthermore, antenna 207 may include two or more antennas (two or more sets) each capable of supporting a different frequency band. Although one communication unit 206 and one antenna 207 are shown in Fig. 2, a plurality of combinations of these may be provided. Furthermore, one or more antennas 207 may be shared by a plurality of communication units 206.

[0019] Next, an example of the functional configuration of the communication device (AP and STA) will be described with reference to Fig. 3. The communication device is configured to include, as its functions, a wireless LAN control unit 301, an OFDMA communication control unit 302, a random access communication control unit 303, a storage control unit 304, and a UI control unit 305. Note that these functional configurations can be realized, for example, by the control unit 202 executing a program stored in the storage unit 201, but are not limited to this, and some or all of these functions may be realized by dedicated hardware.

[0020] The wireless LAN control unit 301 is configured to control a circuit for transmitting and receiving wireless signals to and from other communication devices (e.g., other APs and STAs) in a wireless LAN that conforms to the IEEE 802.11 series of standards. The wireless LAN control unit 301 performs wireless LAN communication control, such as generating and transmitting wireless frames conforming to the IEEE 802.11 series of standards and receiving wireless frames from other communication devices. The OFDMA communication control unit 302 performs communication using OFDMA (Orthogonal Frequency Division Multiple Access), which is introduced in the IEEE 802.11ax standard. For example, the AP may cause multiple STAs to transmit data using a trigger frame (TF) that assigns resource units (RUs) to the multiple STAs using the OFDMA communication control unit 302. The STAs perform uplink communication using the RUs assigned by the OFDMA communication control unit 302. Note that the IEEE 802.11ax standard incorporates the concept of random access, providing RUs for random access, which are used by STAs that acquire the right to use the RUs based on the OBO counter described above. The random access communication control unit 303 executes processing related to this random access in cooperation with the OFDMA communication control unit 302. For example, the AP uses the random access communication control unit 303 to set an RU for random access and to notify the STA of setting information for the initial value of the OBO counter described above. Also, the STA can use the random access communication control unit 303 to set the OBO counter and execute processing such as subtraction processing when receiving a TF.

[0021] The storage control unit 304 is configured to control storage and readout processes of storage devices such as ROM (Read Only Memory) and RAM (Random Access Memory) that store programs executed by the AP or STA and various data. The UI control unit 305 controls a user interface (UI) such as a touch panel or buttons for accepting operations on the AP or STA by a user (not shown) of the AP or STA, and executes processes for acquiring operation information and presenting information to the user. The UI control unit 305 can execute processes for presenting information to the user, such as displaying images or outputting audio.

[0022] (Frame composition) Next, the configuration of a MAC (medium access control) frame 400 of the IEEE802.11 standard and an IE (information element) that is an element of the frame body 410 thereof will be described with reference to FIGS. 4(A) to 4(C).

[0023] FIG. 4A shows an example of the overall configuration of a MAC frame 400. In the MAC frame 400, Frame Control 401 is a field related to overall frame control and is two octets (16 bits) long. The Frame Control 401 has subfields, which will be described in detail later with reference to FIG. 4B. Duration / ID 402 is two octets long, and when the MSB (Most Significant Bit: B15) is "1," the remaining 15 bits indicate the frame length, TXOP, and other time periods in the range of 0 to 32,767 microseconds. Address 403 is a six-octet field in which addresses such as the BSSID, source, and destination are set depending on the MAC frame type (Type 422). Address 404, Address 405, and Address 407 are similar fields, but are set as needed depending on the number of addresses to be indicated. Sequence Control 406 is a two-octet long field set as needed to store information such as the data sequence number.

[0024] QoS Control 408 is a field set with a length of two octets as needed to store information such as a BSR (Buffer Status Report) of a standard earlier than IEEE802.11ax. When a BSR of a standard earlier than IEEE802.11ax is stored, the BSR is represented by two pieces of information. The first piece of information is a 4-bit TID (Traffic Identifier). In the case of the EDCA access method, a value from 0 to 7 indicated by this TID indicates one of four access categories: AC_VO (Voice), AC_VI (Video), AC_BE (Best Effort), or AC_BK (Background). The second piece of information is an 8-bit Queue size. The Queue size is expressed in units of 256 octets and indicates the amount of data remaining in the transmission buffer.

[0025] HT Control 409 is a field set to a length of four octets as needed. In the IEEE802.11ax standard, setting the first bit to "0" indicates that the frame is for HT (High Throughput: IEEE802.11n). Setting the first two bits to 10 indicates that the frame is for VHT (Very High Throughput: IEEE802.11ac). Setting the first two bits to 11 indicates that the frame is for HE (High Efficiency: IEEE802.11ax). It is not yet decided whether such definitions will be used for EHT (Extremely High Throughput: IEEE802.11be) frames.

[0026] The Frame Body 410 is a field in which data to be transmitted is stored, and its length varies depending on the length of the data. Note that an IE such as that shown in Fig. 4C may be stored as part of the Frame Body 410. The FCS 411 is a Frame Check Sequence, which stores bits for error detection.

[0027] Next, the contents of Frame Control 401 will be outlined using FIG. 4(B). Protocol Version 421 is a 2-bit subfield that indicates the protocol version and is set to "0" for IEEE 802.11 frames. Type 422 is a 2-bit subfield that indicates the frame type, indicating whether the frame is a Management, Control, or Data frame. Subtype 423 is a 4-bit subfield that stores information that further classifies the types of Management, Control, and Data. To DS 424 is a 1-bit subfield that indicates whether the destination of the frame is a Distribution System (DS). From DS 425 is a 1-bit subfield that indicates whether the source of the frame is a DS. More Fragment 426 is a 1-bit subfield that indicates whether the frame is part of a fragment. Retry 427 is a 1-bit subfield that indicates whether the frame is a retransmission of previously transmitted data. Power Management 428 is a 1-bit subfield that indicates whether the STA is in power-saving mode. More Data 429 is a 1-bit subfield that indicates whether there is more data to be transmitted after the data transmitted in the current frame. Protected Frame 430 is a 1-bit subfield that indicates whether the frame is protected by encryption. +HTC 431 is a 1-bit subfield that indicates whether HT Control 409 is included, for example.

[0028] Next, the configuration of the IE included in the Frame Body 410 will be outlined using FIG. 4(C). Here, the configuration of the EHT Capabilities element is particularly shown. Element ID 441 stores the identifier of the IE. The value related to EHT in IEEE 802.11be follows the value of the HE Capabilities element in IEEE 802.11ax, and is set to 255, for example. Length 442 indicates the length of this information element. Element ID Extension 443 stores the identifier of the IE that is set as needed. For example, values ​​corresponding to the EHT Capabilities element related to capability information and the EHT Operation element related to operation information can be newly defined, and these values ​​can be stored in Element ID Extension 443.

[0029] EHT MAC Capabilities Information 444 stores information about MAC layer capabilities. EHT PHY Capabilities Information 445 stores information about physical layer (PHY) capabilities. Supported EHT-MCS And NSS Set 446 stores values ​​indicating the supported modulation and coding scheme (MCS) and number of spatial streams (NSS). PPE (Physical layer Packet Extension) Thresholds 447 is optional information.

[0030] In one example, a field indicating whether or not the EHT MAC Capabilities Information 444 has the capability for random access extended by this embodiment (hereinafter referred to as extended random access) can be defined. This value (or bit) allows capability exchange between the AP and the STA. An AP with this capability can assign a predetermined identifier (AID) for extended random access to the STA, and further indicate the presence of an RU for extended random access in a trigger frame (TF). The AID is an Association ID. A STA with this capability can request the AP to assign an AID for extended random access, and further interpret the TF to identify the RU addressed to the STA. Details of the processing performed by the AP and the STA will be described later.

[0031] Figure 5 shows the structure of the UORA Parameter Set element. UORA is an acronym for Uplink OFDMA based Random Access. This information element can be used to notify setting information related to the initial value of the OBO counter mentioned above. That is, this information element notifies the STA of information for setting the range of values, EOCWmin and EOCWmax, that can be used as the initial value of the OBO counter (this range is called OCW). Note that OCW is an acronym for OFDMA Contention Window, and the "E" in EOCW stands for Exponent. The actual minimum value of OCW, OCWmin, is OCWmin=2 EOCWmin -1, and the maximum value of OCW is OCWmax=2 EOCWmax It is calculated by -1.

[0032] Element ID 501 and Element ID Extension 503 are fields each one octet long that store a value indicating that this information element is a UORA Parameter Set element. Element ID 501 stores the value "255," and Element ID Extension 503 stores the value "37." Length 502 stores a value indicating the length of this information element. OCW Range 504 is a one-octet long field used to notify the above-mentioned EOCWmin and EOCWmax. OCW Range 504 includes an EOCWmin subfield 505 and an EOCWmax subfield 506, each of which is three bits long and indicates the above-mentioned EOCWmin and EOCWmax. The EOCWmin subfield 505 is located in bit positions B0 to B2 of OCW Range 504, and the EOCWmax subfield 506 is located in bit positions B3 to B5 of OCW Range 504. The remaining two bits of the OCW Range 504 are reserved bits (Reserved 507).

[0033] Next, the configuration of the TF 600 will be described using Figures 6A and 6B. The TF is a type of control frame introduced in IEEE 802.11ax and is used to specify the wake-up timing required when multiple STAs simultaneously transmit frames to an access point. The TF also indicates the RU and MCS (modulation and coding scheme) used for frame transmission. Although changes to the TF configuration are being considered for the IEEE 802.11be standard, the following description will be based on the configuration and names of the IEEE 802.11ax standard. Therefore, the frame configuration described here may be changed to the extent that the method according to this embodiment can be realized. For example, some or all of the fields described below may be omitted or replaced with fields with different names, one field may be divided into multiple fields, or multiple fields may be combined into one field.

[0034] In the TF 600 shown in (A), in this embodiment, Frame Control 601 is a field in which a value indicating that the frame is a Trigger Frame of the IEEE 802.11ax standard (or the IEEE 802.11be standard) is entered. The length of Frame Control 601 is 2 octets. Duration 602 is a 2 octet long field. RA 603 is a 6 octet long field in which a Receiver Address is stored. TA 604 is a 6 octet long field in which a Transmitter Address is stored. Common Info 605 is a field indicating information common to multiple terminals that are the destinations of this TF, and is 8 octets or more in length. Details of Common Info 605 will be described later using (B) and (C) of Figure 6A and Figure 6B. Per User Info 606 is a field indicating individual information for the destination of this TF, and is 5 octets or more in length. Details of Per User Info 606 will be described later with reference to (D) of FIG. 6B. Padding 607 is a variable-length padding area used to provide a time allowance to the STA that received this TF. The AP determines this time allowance based on the time (MinTrigProcTime) required for each STA to process the Per User Info 606 related to its own device in the TF. Generally, the AP prepares Padding 607 with a length corresponding to the maximum value of MinTrigProcTime for each of the multiple STAs that are the destinations of the TF. FCS 608 is a Frame Check Sequence added for error detection / correction.

[0035] Next, details of Common Info 605 will be explained using (B) of FIG. 6A. Trigger Type 611 is a 4-bit subfield, and the type of trigger is specified according to its value, as shown in the table of (C) of FIG. 6B. As shown in the table, for Basic TF, Trigger Type 611 is set to "0". Length 612 is a 12-bit subfield that indicates the duration of the response data to TF. The value set in Length 612 is reflected in the L-SIG field of the physical layer in the frame of the IEEE 802.11 standard series. The information indicated by L-SIG includes the duration of the frame containing that field.

[0036] More TF 613 and CS (Carrier Sense) Required 614 are each a 1-bit subfield. UL BW (Bandwidth) 615 is a 2-bit subfield whose value specifies the frequency bandwidth used in the uplink (UL). For example, if the frequency bandwidth used is 20 MHz, the value of BW 615 is set to 0. GI and HE-LTF Type (Guard Interval and High-Efficiency Long Training Field) 616 is a 2-bit subfield. MU-MIMO LTF Mode 617 and Number of HE-LTF Symbols and Midamble Periocity 618 are 1-bit and 3-bit subfields, respectively. UL STBC (Space Time Block Code) 619 is a 1-bit subfield. LDPC (Low Density Parity Check) Extra Symbol Segment 620 is a 1-bit subfield, located, for example, after UL STBC 619. AP TX Power 621 is a subfield that is 6 bits in length. Pre-FEC Padding Factor Packet 622 and PE Disambiguity 623 are subfields that are 2 bits and 1 bit in length, respectively. UL Spatial Reuse 624 is a subfield that is 16 bits in length. Doppler 625 is a subfield that is 1 bit in length. UL HE-SIG-A Reserved 626 is a subfield that is 9 bits in length. Reserved 627 is a subfield that is 1 bit in length.

[0037] The Trigger Dependent Common Info 628 is a subfield whose length is variable. The Trigger Dependent Common Info 628 can indicate additional information according to the Trigger Type 611.

[0038] The subfields with the above-mentioned HE (High Efficiency) are, as the name suggests, subfields for the IEEE 802.11ax standard. Therefore, in the TF of the IEEE 802.11be standard, the term "EHT" may be used instead of "HE" as the name of the subfield.

[0039] Next, the details of the Per User Info field 606 will be explained using FIG. 6B(D).

[0040] AID12 631 is a 12-bit subfield used to indicate the AID of the destination of this TF. STAs with the same AID value as the value stored in AID12 are the destination of this Per User Info 606, and are permitted to use the RU assigned there for data transmission. A STA can determine whether the RU is addressed to itself by checking whether the LSBs (Least Significant Bits) of AID12 match the AID assigned to itself when connecting. In this case, AID12=0 indicates that the RU is addressed not to a specific terminal but to any STA associated (connected) to the AP. In other words, AID12=0 indicates that the RU indicated by the Per User Info 606 is for random access by STAs connected to the AP. Furthermore, AID12=2045 indicates that the RU indicated by the Per User Info 606 including AID12 is addressed to any STA not connected to the AP. That is, an unconnected STA can transmit data if it acquires the right to transmit by random access in the RU indicated by Per User Info 606 with AID12=2045. Also, AID12=2046 indicates that the RU indicated by Per User Info 606 including that AID12 has not been assigned.

[0041] In this embodiment, some of the AID12 values ​​2008 to 2044 and 2047 to 4094, which are reserved in the IEEE 802.11ax standard, are newly defined as AIDs for extended random access. Hereinafter, this AID for extended random access will be referred to as a G-AID. Note that the same G-AID may be assigned to multiple STAs that should acquire access rights to a random access RU with the same priority, for example. This G-AID may also be referred to as a Group-AID, Enhanced-AID, E-AID, etc. Note that the IEEE 802.11be standard does not currently assign an official name to this AID.

[0042] RU Allocation 632 is an 8-bit subfield indicating the index of the RU allocated by this Per User Info 606. UL FEC Coding Type 633 is a 1-bit subfield indicating the coding type to be used in the radio frame transmitted in response to the TF. UL MCS 634 is a 4-bit subfield indicating the coding scheme to be used in the radio frame transmitted in response to the TF. UL DCM 635 is a 1-bit subfield indicating the Dual Carrier Modulation of the radio frame transmitted in response to the TF. SS Allocation / RA-RU Information 636 indicates the spatial stream of the frame transmitted in response to the TF when AID 12 is not for random access. SS Allocation / RA-RU Information 636 indicates the RA-RU (Random Access Resource Unit) when AID 12 is for random access. SS Allocation / RA-RU Information 636 is a 6-bit subfield. UL Target RSSI 637 is a 7-bit subfield that indicates the received power at the AP of the wireless frame that the AP expects to receive in response to the TF. Reserved 638 is a reserved area. Trigger Dependent User Info 637 is a subfield with a variable number of bits whose content changes depending on the Trigger Type 611.

[0043] (Processing flow) Next, an example of the flow of communication when the extended random access according to this embodiment is used will be described.

[0044] [Processing example 1] An example of the flow of a first communication process will be described with reference to FIG. 7A. In this example, first, the AP 100 performs initial configuration as an access point (S701). In one example, the AP 100 determines the values ​​of the OCW Range (EOCWmin 505 and EOCWmax 506) of the UORA Parameter Set. The AP 100 also determines whether or not to perform communication compatible with the extended random access method. Here, it is assumed that the AP 100 has determined to perform communication compatible with the extended random access method. Then, the AP 100 initializes a G-AID table (S702). The G-AID table is information that associates, for example, STAs (terminals) connected / managed by the AP 100 with G-AIDs for extended random access.

[0045] It is assumed that STA 101 then connects to AP 100 (S703). Here, STA 101 requests allocation of a G-AID, and if AP 100 decides to accept the request, it assigns a G-AID value to STA 101. STA 101 may include G-AID request information in a management frame sent at the time of connection, such as a probe request or an association request, and transmit this to AP 100. AP 100 may also include the G-AID value in an association response and transmit it. To request or assign this G-AID value, a new element for G-AID may be defined in the configuration items of the management frame. It is assumed here that STA 101 is assigned a G-AID value of 2040. The AP 100 updates the G-AID table in response to the assignment of the G-AID value to STA 101 (S704). Thereafter, the AP 100 updates the G-AID table whenever another STA connects, a connected STA is disconnected, or the G-AID of any STA is updated.

[0046] On the other hand, STA 102 is assumed to have connected to AP 100 without making a request for allocation of a G-AID for extended random access (S705). STA 103 is assumed to have made a request for allocation of a G-AID for extended random access, received allocation of a G-AID, and established connection with AP 100 (S706). STA 104 is assumed to remain in an unconnected state.

[0047] The AP 100 periodically transmits a Beacon including, for example, a UORA element (S707). Note that if the AP 100 changes, for example, EOCWmin 505 or EOCWmax 506, it can transmit the updated information in a UORA element. In other words, the periodically transmitted Beacon can notify surrounding STAs of the latest UORA element. If the UORA element in the received Beacon has been updated, the STAs 101 to 104 initialize and update the OBO counters that they each manage independently. For example, the STAs 101 to 104 initialize and update the OBO counters when they receive a UORA element for the first time or when the UORA element is different from the UORA element they received previously. In other words, if there is no change in the UORA element, the OBO counters are not initialized or updated. Note that the STA 104 does not need to initialize its OBO counter because it remains in an unconnected state.

[0048] Thereafter, the AP 100 transmits the TF described with reference to Fig. 6 (S709). Then, in response to receiving the TF, the STAs 101 to 104 execute a subtraction process on the OBO counter.

[0049] This process will be described with reference to FIG. 7B. In the table of FIG. 7B, row 721 indicates the G-AIDs assigned to STA101 to STA104. Here, it is shown that G-AID=2040 is assigned to STA101 and STA103, and no G-AID is assigned to STA102 and STA104. Row 722 indicates the values ​​of the OBO counters held in each of STA101 to STA104 before receiving TF. That is, STA101 to STA103 have OBO=3 when they receive TF, and STA104 has OBO=2 when they receive TF. For simplicity of explanation, it is assumed that the initial values ​​of the OBO counters of STA101 to STA103 are the same. However, these values ​​are determined from the range specified by EOCWmin and EOCWmax, and may be the same or different values. Column 723 shows the AID12 values ​​corresponding to each of the RUs included in the TF received by STA101 to STA104. That is, AID12=0 is associated with RU1, AID12=2040 is associated with RU2 and RU3, and AID12=2045 is associated with RU4. Field 724 shows the RU that was the target of subtraction when the TF was received, and the result of updating the OBO counter by the subtraction.

[0050] In the example of FIG. 7B, as described above, the TF includes one RU with AID12=0, two RUs with AID12=2040, and one RU with AID12=2045. Following the IEEE 802.11ax standard, the RU with AID12=0 indicates an RU for random access for connected STAs, and the RU with AID12=2045 indicates an RU for random access for disconnected STAs. That is, as in the IEEE 802.11ax standard, AID12=0 is used for random access for connected STAs, and AID12=2045 is used for random access for disconnected STAs. In addition, in this embodiment, at least one RU with an AID12 value between 2008 and 2044 and between 2047 and 4094 is designated as an RU for extended random access. Here, AID12=2040 is designated as an RU for extended random access.

[0051] When STAs such as STA101 and STA103 assigned G-AID=2040 for extended random access detect RUs for extended random access that match their own G-AID, they decrement the value of their OBO counter by the number of such RUs. Furthermore, when these STAs detect RUs with AID12=0 that are intended for STAs currently connected, they also decrement the value of their OBO counter by the number of such RUs. That is, in the example of FIG. 7B, STA101 and STA103 decrement the value of their OBO counter by "3," which is the sum of the number of RUs with AID12=0 and the number of RUs with AID12=2040. As a result, STA101 and STA103 acquire the right to transmit data (the right to access the wireless medium). Then, STA101 and STA103 communicate with AP100 (uplink data transmission) using RUs arbitrarily selected from the random access RUs (RU1 to RU3) that were the subject of the decrement process. For example, STA101 may randomly select an RU from RU1 to RU3 and transmit data using RU1. Also, STA103 may randomly select an RU from RU1 to RU3 and transmit data using RU3. Note that if STA101 and STA103 use the same RU as a result of random RU selection, radio frames transmitted from each may collide, as in the conventional random access mechanism. Thus, STA101 and STA103 treat an RU with AID12=0, which can be used by STAs without a G-AID configured, without distinguishing between an RU with AID12=2040 that corresponds to the G-AID configured for the STA itself. However, this is merely an example. While these RUs are not distinguished in the process of decrementing the OBO counter value, a distinction may be made, such as prioritizing the use of an RU with AID12=2040 when selecting an RU to use.

[0052] On the other hand, STA102 has not been assigned a G-AID, so even when it detects RU2 and RU3, it does not decrement the value of the OBO counter, but decrements the OBO counter by 1 using RU1 with AID12=0, which is an RU for random access for connected STAs. Also, STA104 is in an unconnected state, so it decrements the OBO counter by 1 using RU4 with AID12=2045, which is an RU for random access for unconnected STAs. In this way, STA102 and STA104, which have not been assigned a G-AID, perform the same operation as TF-based random access in the conventional IEEE802.11ax standard.

[0053] Returning to the explanation of Fig. 7A, STA101 and STA103 select RU1 and RU3, respectively, and transmit data (UL TB PPDU) as described above (S711, S712). Note that UL TB PPDU is an UpLink Trigger-based Physical layer Protocol Data Unit, which is a PPDU transmitted from a STA to an AP based on a TF. When AP100 successfully receives this data, it transmits a Multi-STA BA (BlockAck) to STA101 and STA103, which are the data transmission sources (S713).

[0054] As described above, in this embodiment, for example, for a STA that needs to quickly acquire access rights to a random access RU, a G-AID, which is an AID for random access, is assigned to the STA. Then, the AP transmits a TF in which an RU corresponding to the G-AID is set, thereby preventing STAs that do not have a G-AID set from decrementing their OBO counters and allowing STAs that have a G-AID set to decrement their OBO counters. As a result, the OBO counter value of the STA that has a G-AID set can quickly reach 0, thereby acquiring access rights to random access resources. In one example, the STA may have a first OBO counter for normal random access and a second OBO counter for the G-AID. For example, by setting the initial value of the G-AID counter to a small value, the STA to which the G-AID is assigned can quickly access the random access RU. In particular, when there are only a few types of G-AIDs, it may be useful to prepare and manage multiple counters like this. On the other hand, if a counter is prepared for each G-AID, the parameter settings for initializing each counter and the management of the counters may become complicated as the number of G-AID types increases. In this case, as described above, it is effective to prepare only one OBO counter and count the total number of first RUs corresponding to the G-AID and second RUs for random access (for connected STAs) that do not correspond to the G-AID. In other words, the above process makes it possible to adjust the ease of obtaining access to the random access RU for each STA without complicating the STA configuration. Furthermore, because it is sufficient to simply add new G-AID handling, it is also possible to minimize the impact when STAs compliant with the IEEE 802.11ax standard are updated to comply with the IEEE 802.11be standard.

[0055] [Processing example 2] Next, an example of a communication flow when multiple G-AIDs for extended random access are used will be described with reference to Figures 8A and 8B. The process of Figure 8A is assumed to be performed after S713 of Figure 7A, for example.

[0056] 8A, first, the connected STA 102 transmits a G-AID allocation request to the AP 100 (S801). For example, the STA 102 transmits the G-AID allocation request to the AP 100 by executing a ReAssociation procedure. Alternatively, the STA 102 may transmit the G-AID allocation request to the AP 100 by executing a newly defined Action frame procedure. The newly defined Action frame procedure may be, for example, an extended procedure of the ADDTS (ADD Traffic Stream) procedure. Alternatively, the STA 102 may transmit the G-AID allocation request to the AP 100 by a procedure using a newly defined HT Control 409 of the MAC frame or a newly defined OMI (Operation Mode Indication) procedure. All of these procedures are performed between an AP and a STA that have extended random access capability.

[0057] When the AP 100 receives a G-AID allocation request from the STA 102, it adjusts the G-AID allocation (S802). For example, the AP 100 can perform at least one of determining whether to allocate a G-AID to the STA 102 and determining how to perform priority control with other STAs. In this example, it is assumed that the AP 100 has decided to allocate a G-AID to the STA 102 and to grant the STA 101 access rights that are more prevalent than those of the STAs 102 and 103. Based on the result of this adjustment, the AP 100 transmits a G-AID allocation response to the STA 102 that includes information indicating the allocated G-AID (S803). This response, for example, assigns the STA 102 a G-AID of 2040 for extended random access. The AP 100 also transmits information indicating the update of the G-AID allocation to the STA 101 (S804). This information includes information indicating that G-AID=2041 will be assigned to STA 101 in addition to G-AID=2040 that has been assigned to STA 101. Here, AP 100 may transmit information indicating both G-AID=2040 and G-AID=2041 to STA 101, or may transmit information indicating G-AID=2041 and information indicating that a G-AID will be additionally assigned to STA 101.

[0058] The AP 100 periodically transmits a Beacon including a UORA element (S805). At this time, if the UORA element is updated, the updated UORA element is notified by a Beacon. Then, the STAs 101 to 104 update their OBO counters (S806). Thereafter, the AP 100 transmits a TF (S807), and the STAs 101 to 104 perform a subtraction process on their OBO counters based on this TF (S808).

[0059] Here, the decrement process of the OBO counter in this processing example will be described with reference to FIG. 8B. As described above, STA 101 is assigned G-AID=2040 and 2041. Therefore, STA 101 performs decrement process of the OBO counter every time it detects an RU associated with AID12=0, 2040, or AID12=2041 in the TF. That is, STA 101 decrements the OBO counter in response to detecting an RU with AID12=0 or 2040, and also decrements the OBO counter when detecting an RU with AID12=2041. On the other hand, STA 102 and STA 103 decrement the OBO counter in response to detecting an RU with AID12=0 or 2040, but do not decrement the OBO counter even when detecting an RU with AID12=2041.

[0060] Here, it is assumed that AP 100 transmits a TF in S807 with AID12 of RU3 set to 2041 as shown in FIG. 8B, as compared with the case of FIG. 7B. STA 101 decrements the OBO counter based on RU1 and RU2 with AID12=0 or 2040, and further decrements the OBO counter based on RU3 with AID12=2041, thereby obtaining access rights to the RU for random access. Meanwhile, STA 102 and STA 103 decrement the OBO counter based on RU1 and RU2 with AID12=0 or 2040, but do not decrement the OBO counter based on RU3 with AID12=2041. Therefore, STA 102 and STA 103 do not obtain access rights to the RU for random access at this stage. Note that the same applies to STA 104 as in the case of FIG. 7B.

[0061] Having obtained the access right, STA 101 selects one RU from RU1 to RU3 and transmits a UL TB PPDU (S809). Then, AP 100 transmits a BA (S810).

[0062] In this manner, in this processing example, by making it possible to set multiple G-AIDs, a specific STA can preferentially acquire access rights to an RU for extended random access. This makes it easier for a first communication that is very sensitive to delays in acquiring access rights to an RU for random access to acquire access rights, for example, between a first communication that is very sensitive to delays in acquiring access rights and a second communication that tolerates a certain degree of sensitivity. In this manner, according to this processing example, it is possible to easily perform prioritization control for acquiring access rights to an RU for random access in accordance with various use cases.

[0063] [Processing example 3] In the processing example 2, for example, the process of assigning G-AIDs 2040 and 2041 to STA 101 has been described, thereby accelerating the decrement of the OBO counter of STA 101 compared to other STAs. In this processing example, instead of assigning multiple G-AIDs, the priority of multiple G-AIDs is set in advance. Then, the STA performs the decrement process of the OBO counter in response to the detection of an RU corresponding to the assigned G-AID, and further performs the decrement process of the OBO counter in response to the detection of an RU corresponding to another G-AID that is lower than the assigned G-AID. For example, a STA assigned G-AID 2041 decrements the OBO counter based on the RU corresponding to G-AID 2041, and also decrements the OBO counter based on the RU corresponding to G-AID 0 or 2040. For example, as shown in FIG. 8C, only G-AID 2041 is assigned to STA 101. 8A, AP 100 notifies STA 101 of only G-AID=2041. STA 101 then manages only G-AID=2041 as the G-AID assigned to itself. Note that information indicating the priority of G-AID values ​​may be notified from the AP to the STA, for example, when a G-AID is assigned for the first time, or may be notified from the AP to the STA when a connection is established, regardless of whether a G-AID has been assigned or not.

[0064] 8C, STA101 performs decrements on the OBO counter based on RU1 with AID12=0 and RU3 with AID12=2041, and further performs decrements on the OBO counter based on RU2 with AID12=2040. That is, STA101 performs decrements on the OBO counter not only based on the RU corresponding to G-AID=2041 assigned to itself, but also based on the RU corresponding to G-AID=2040, which has a lower priority than G-AID=2041. On the other hand, STA102 and STA103 are assigned G-AID=2040, and as a result, do not perform decrements on the OBO counter based on the RU with G-AID=2041, which has a higher priority than the G-AID assigned to them.

[0065] In this example, a G-AID with a larger numerical value has a higher priority than a G-AID with a smaller numerical value, but a G-AID with a smaller numerical value may be prioritized. Furthermore, any prioritization may be performed, such as assigning G-AID=2040 higher priority than G-AID=2042 and 2044, but lower priority than G-AID=2041. This processing example simplifies the process compared to processing example 2, since only one G-AID is assigned to a STA. In particular, the wider the range of numerical values ​​available for use as G-AID, the more easily this processing simplifies the STA configuration by the AP and allows the STA to easily manage the assigned G-AID.

[0066] (Processing flow executed by AP) Next, an example of the flow of processing executed by AP100 will be described with reference to Figures 9A and 9B. This processing can be realized, for example, by the control unit 202 executing a computer program stored in the storage unit 201 of AP100. However, this is just one example, and some or all of the following processing can be executed by dedicated hardware. Furthermore, this processing can be executed, for example, in response to the AP 100 being powered on, or in response to a setting being made such that the AP 100 starts processing for the above-mentioned extended random access.

[0067] First, the AP 100 determines UORA parameters (S901). For example, the AP 100 determines the UORA parameters by accepting a setting operation by the user of the AP 100. Note that, for example, if the setting operation is not performed, the AP 100 may use default values ​​specified in the IEEE 802.11ax standard or the IEEE 802.11be standard as the UORA parameters. Alternatively, the AP 100 may calculate the UORA parameters according to a predetermined rule. Then, the AP 100 initializes a G-AID table. The G-AID table may contain information associating the identifiers of STAs to which G-AIDs have been assigned or information indicating whether a G-AID has been assigned to each STA with the G-AID assigned to the STA.

[0068] After completing the initial settings in S901 and S902, the AP 100 periodically transmits a Beacon at the Beacon transmission timing (YES in S903) (S904). This Beacon includes a UORA element. Note that, as will be the same in the following explanation, the Beacon may not include the UORA element itself, but may include information notifying only information indicating that the UORA has been changed (counter update). In this case, for example, when the AP 100 receives a Probe request from a STA, the AP 100 may notify the STA of the changed parameters by including the changed UORA parameters in a Probe Response or the like to be sent to the STA.

[0069] Thereafter, when the AP 100 receives a connection request from a STA (YES in S905), it executes connection processing (association processing) with that STA (S906). Note that this procedure is the same as conventional procedures and will not be described in detail here. Also, when a G-AID allocation request is received from a STA (YES in S907), the AP 100 updates the G-AID table (S908) and notifies the STA of the assigned G-AID (S909). Note that the G-AID allocation request and allocation may be performed during the connection processing, as in S703 and S706 of FIG. 7A, or may be performed independently after the connection is established, as in S801 and S803 of FIG. 8A. Also, when there is a STA other than the STA that requested the G-AID allocation that needs to be notified of a change in G-AID (YES in S910), the AP 100 notifies such STA of the G-AID (S911). This process corresponds to, for example, the process of notifying the STA 101 of the newly assigned G-AID from the AP 100 in S804 as a result of the adjustment in S802 in Fig. 8A. The AP 100 may store information indicating the priority of each STA, the type of communication service each STA executes, etc., and adjust and assign a G-AID to each STA based on this information. Furthermore, when the AP 100 receives a connection request or a G-AID update request from a STA, it may execute the connection process at any timing other than the timings of S905 to S911.

[0070] When there is data to be transmitted to each STA via downlink (DL) (YES in S912), the AP 100 transmits the DL data to the target STA (S913) and receives an ACK from the target STA (S914). If the AP 100 does not receive an ACK from the STA to which the DL data is to be transmitted, the AP 100 retransmits the DL data. The DL data may be, for example, data transmitted from another STA and arriving at the AP 100 via the BSS 105 or DS 106, or may be data arriving from a predetermined server on the network. When DL data to be transmitted to each STA occurs, the AP 100 can execute the transmission process for the DL data at any timing other than the timings of S912 to S914.

[0071] When the timing for transmitting the TF arrives (YES in S916), the AP 100 executes processing for transmitting the TF. The timing for transmitting the TF may be, for example, a timing that arrives at a predetermined cycle, a timing based on a predetermined schedule, or a timing when the wireless medium is detected to be in an idle state. In the processing for transmitting the TF, the AP 100 first checks the congestion status of the transmission queue of each STA (S917). For example, the AP 100 may check the congestion status of the transmission queue of each STA by receiving a notification by a BSR (Buffer Status Report) from the STA. The BSR may be notified from the STA by, for example, the QoS Control 408 of the MAC Frame, or may be notified as a response to the TF with TF Type 611=4 transmitted from the AP 100. The congestion status of the transmission queue may also be checked by a method other than the BSR. The AP 100 sets the value of AID 12 to be associated with each RU in the TF based on the G-AID table and the congestion status of the transmission queue (S917). For example, for a STA that is known to have data to be transmitted in S916, the AP 100 prepares an RU that specifies the AID (not for random access) of that STA, and specifies the AID for random access for other RUs. Furthermore, when specifying the AID for random access, the AP 100 also specifies the G-AID so that STAs with high priority (requiring a short time to access the wireless medium) can easily obtain access rights. For example, if there is a G-AID that is assigned only to a STA with high priority, the AP 100 determines to specify that G-AID for some RUs. This G-AID specification is determined using a G-AID table. The AP 100 transmits a TF specifying the AID corresponding to each RU as in S917 (S918), receives a TB PPDU based on the TF from each STA (S919), and, if the reception is successful, transmits an ACK to the source STA (S920). The ACK may be an OFDMA BA or a Multi-STA BA.

[0072] When a disconnection request is received from a STA (YES in S921), the AP 100 executes a disconnection process with the STA (S922). Then, for example, if the G-AID table needs to be updated (G-AID change) based on the disconnection (YES in S923), the AP 100 notifies the STA whose G-AID should be changed of the updated G-AID (S924). Note that when a disconnection request is received from a STA, the AP 100 can execute the disconnection process at any timing other than the timings of S921 to S924.

[0073] Thereafter, if the AP 100 is to terminate its operation as an AP due to, for example, a user operation requesting termination of AP operation (YES in S925), it terminates the process. In this case, the AP 100 performs the process required to disconnect from the connected STA and terminate the AP function. If the AP 100 is to continue its operation as an AP (NO in S925), it returns the process to S903 and continues communication.

[0074] (Processing flow performed by STA) Next, an example of the flow of processing executed by the STAs (STA101 to STA104) will be described with reference to Fig. 10. This processing can be realized, for example, by the control unit 202 executing a computer program stored in the storage unit 201 of the STA. However, this is just one example, and some or all of the following processing may be executed by dedicated hardware. Furthermore, this processing can be executed, for example, when the power of the STA is turned on.

[0075] First, the STA connects to the AP 100, acquires UORA parameters from the AP 100, for example, by a beacon or a probe response, and sets an OBO counter (S1001). The STA then determines and updates the status and attributes of the communications and applications it executes (S1002). Here, the STA identifies and manages the status, such as whether it is performing communications that require real-time performance with strict requirements for access latency, such as the extended random access of this embodiment (whether it is executing such an application). The STA then determines whether to send a G-AID request, depending on whether it is performing strict requirements for access latency (S1003). If the STA determines to send a G-AID request (YES in S1003), it transmits a G-AID assignment request to the AP 100 and receives a response (S1004). If the response includes a G-AID, the STA sets the value as the G-AID assigned to the STA.

[0076] The STA then waits to receive a TF from the AP 100 (S1005). If the STA has not received a TF from the AP 100 (NO in S1005), the STA proceeds to S1014. If the STA receives a TF from the AP 100 (YES in S1005), the STA determines whether an individual RU has been assigned to the STA (S1006). If there is no individual RU assigned to the STA (NO in S1006), the STA determines whether there is an RU for random access that the STA is to subtract (S1007). For example, the STA determines whether the TF includes an RU with AID12=0, or an RU with AID12 corresponding to the G-AID assigned to the STA in S1004 (or a G-AID with a lower priority). If such RUs are included in the TF (YES in S1007), the STA performs a subtraction process of the OBO counter according to the number of such RUs (S1008). If the OBO counter has not reached 0 (NO in S1009), the STA proceeds to S1014. On the other hand, if the OBO counter has reached 0 (YES in S1009), the STA proceeds to S1010. If there is an individual RU addressed to the STA (YES in S1006), the STA performs a setting to use the individual RU addressed to the STA (S1010). Also, if the OBO counter has reached 0 (YES in S1009), the STA performs a setting to use an RU for random access (S1010). This setting is performed based on, for example, each piece of information included in Per User Info 606 of the TF. Then, the STA transmits a TB PPDU to the AP 100 (S1011) and receives an ACK (for example, an OFDMA BA or a Multi-STA BA) from the AP 100 (S1012). After transmitting the data, the AP 100 resets the OBO counter in accordance with the OCW Range (S1013).

[0077] In S1014, the STA determines whether access to the wireless medium is possible using EDCA (Enhanced Distributed Channel Access). If the STA determines that access is not possible using EDCA (NO in S1014), the process proceeds to S1017. On the other hand, if the STA determines that access is possible using EDCA (YES in S1014), the STA transmits an SU (Single User) PPDU to the AP 100 (S1015) and receives an ACK (or BA) from the AP 100 (S1016). Thereafter, if the STA receives DL data from the AP 100 (YES in S1017), it transmits an ACK (or BA) to the AP 100 (S1018). Then, if the STA terminates its operation as an STA because, for example, a user operation has requested that the STA terminate its operation (YES in S1019), the process ends. In this case, the STA performs the processes required for disconnecting from the AP to which it is connected and for terminating its function as an STA. If the STA continues its operation (NO in S1019), the process returns to S1002 and the STA continues communication.

[0078] As described above, in this embodiment, the first STA, which has a small tolerance for access delay to the wireless medium, decrements the OBO counter faster than the second STA, which has a relatively large tolerance. This reduces the time it takes for the first STA to access the wireless medium. Furthermore, since access to the wireless medium can be adjusted for each STA without using multiple OBO counters, it is possible to provide flexible access control while preventing an increase in the impact on the device configuration.

[0079] The present invention can also be realized by supplying a program that realizes one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program. It can also be realized by a circuit (e.g., ASIC) that realizes one or more functions.

[0080] The invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0081] 301: Wireless LAN control unit, 303: Random access communication control unit

Claims

1. A communication device, a setting means for setting up a connection with another communication device; a receiving means for receiving a predetermined radio frame from the other communication device, the predetermined radio frame including information specifying a frequency resource for the other communication device to transmit data to one or more devices; a communication means for, when a first identifier for random access is assigned to the communication device in the connection setup, acquiring a right to transmit data to the other communication device by random access based on a sum of a first number of frequency resources associated with the first identifier and a second number of frequency resources associated with a second identifier for random access different from the first identifier in the predetermined radio frame, and performing communication; A communication device comprising:

2. 2. The communication device according to claim 1, wherein said communication means acquires said transmission right when said sum reaches a predetermined value.

3. 3. The communication device according to claim 2, wherein, when a random access identifier is not assigned to the communication device in the connection setup, the communication means acquires the transmission right based on the second number reaching the predetermined value, regardless of the first number.

4. 2. The communication device according to claim 1, wherein, when a third identifier for random access different from the first identifier and the second identifier is further assigned to the communication device in addition to the first identifier during the connection setup, the communication means acquires the transmission right when a value obtained by adding the sum to a third number of frequency resources associated with the third identifier reaches a predetermined value in the specified radio frame.

5. 5. The communication device according to claim 4, wherein when the communication device is assigned the first identifier but not the third identifier, the communication means acquires the transmission right when the sum of the first number and the second number reaches the predetermined value, regardless of the third number.

6. 2. The communication device according to claim 1, wherein, when the first identifier is assigned to the communication device in the connection setup and a third identifier having a lower priority than the first identifier is present, the communication means acquires the transmission right when a value obtained by adding the sum to a third number of frequency resources associated with the third identifier reaches a predetermined value in the specified radio frame.

7. 7. The communication device according to claim 6, wherein when the first identifier is assigned to the communication device in the connection setup and a fourth identifier having a higher priority than the first identifier exists, the communication means acquires the transmission right based on the sum, regardless of a fourth number of frequency resources associated with the fourth identifier.

8. 8. The communication device according to claim 2, wherein the communication means has a counter that performs a subtraction process using the predetermined value as an initial value for random access.

9. 9. The communication device according to claim 1, wherein the setting means receives the assignment of the first identifier from the other communication device by making a request to the other communication device when establishing or during the connection.

10. A communication device, a setting means for performing setting including assigning a first identifier for random access to a first other communication device that is to be given priority in acquiring the right to transmit data by random access; a generating means for generating a predetermined radio frame including information specifying a frequency resource for transmitting data to another device, the predetermined radio frame specifying a frequency resource for random access associated with the first identifier for which a first number is counted by the first other communication device to acquire the right to transmit data, and a frequency resource for random access associated with a second identifier different from the first identifier for which the first number is counted by the first other communication device and a second number is counted by a second other communication device to which the first identifier is not assigned to acquire the right to transmit data; a transmitting means for transmitting the predetermined radio frame; and The first other communication device acquires the right to transmit data in a frequency resource for random access based on the first number, and the second other communication device acquires the right to transmit data in a frequency resource for random access based on the second number.

11. the setting means further assigns a third identifier for random access to the first other communication device; the generating means generates the predetermined radio frame, further specifying a frequency resource for random access associated with the third identifier in which the first number is counted by the first other communication device to acquire the right to transmit data.

11. The communication device according to claim 10.

12. 12. The communication device according to claim 11, wherein a third other communication device that is assigned the first identifier but not the third identifier does not count the third number for the frequency resources for random access associated with the third identifier, and a third other communication device that is assigned the first identifier but not the third identifier counts the third number for the frequency resources for random access associated with the first identifier and the frequency resources for random access associated with the second identifier, and the third other communication device acquires the right to transmit data in the frequency resources for random access based on the third number.

13. the first identifier is set to have a higher priority than a third identifier for random access; the generating means generates the predetermined radio frame, further specifying a frequency resource for random access associated with the third identifier, in which the first number is counted by the first other communication device to which the first identifier is assigned in order to acquire the right to transmit data.

11. The communication device according to claim 10.

14. the first identifier is set to have a lower priority than a fourth identifier for random access; the generating means generates the predetermined radio frame further specifying a frequency resource for random access associated with the fourth identifier, in which a third number is counted by a third other communication device to which the fourth identifier is assigned for the purpose of acquiring a right to transmit data, but the first number is not counted by the first other communication device for the purpose of acquiring a right to transmit data.

14. The communication device according to claim 13.

15. 15. The communication device according to claim 1, wherein the communication device is a station conforming to the IEEE 802.11 standard.

16. 16. The communication device according to claim 15, wherein the predetermined radio frame is a trigger frame, and the frequency resource is a resource unit.

17. A control method performed by a communication device, comprising: Setting up a connection with another communication device; receiving a predetermined radio frame from the other communication device, the predetermined radio frame including information specifying frequency resources for the other communication device to transmit data to one or more devices; when a first identifier for random access is assigned to the communication device in the connection setup, acquiring a right to transmit data to the other communication device by random access based on a sum of a first number of frequency resources associated with the first identifier and a second number of frequency resources associated with a second identifier for random access different from the first identifier in the predetermined radio frame, and performing communication; A control method comprising:

18. A control method performed by a communication device, comprising: performing a setting including assigning a first identifier for random access to a first other communication device that is to be given priority in acquiring the right to transmit data by random access; generating a predetermined radio frame including information specifying frequency resources for transmitting data to other devices, the predetermined radio frame specifying a frequency resource for random access associated with the first identifier, in which a first number is counted by the first other communication device to acquire the right to transmit data, and a frequency resource for random access associated with a second identifier different from the first identifier, in which the first number is counted by the first other communication device and a second number is counted by a second other communication device to which the first identifier is not assigned, in order to acquire the right to transmit data; transmitting the predetermined radio frame; and a first other communication device acquiring the right to transmit data in a frequency resource for random access based on the first number, and a second other communication device acquiring the right to transmit data in a frequency resource for random access based on the second number.

19. A program for causing a computer to function as the communication device according to any one of claims 1 to 16.

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