Patent Publication Number: US-2022224462-A1

Title: Communication apparatus that selectively permits spatial reuse parameter based communication, method of controlling communication apparatus, and non-transitory computer-readable storage medium

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to a communication technology for efficiently using a wireless medium. 
     Description of the Related Art 
     In recent years, the IEEE 802.11ax standard intended for efficient use of a wireless medium in an environment where a plurality of communication apparatuses are present has been studied. In this study, introduction of spatial reuse communication using a Spatial Reuse Parameter (SRP) has been studied in order for a plurality of communication apparatuses in a plurality of Basic Service Sets (BSSs) to effectively use the wireless medium (US-2018-0062805). The SRP is information included in a trigger frame transmitted from an access point managing one BSS. In a case where a terminal belonging to another BSS receives the information, performing a transmission process using the information enables efficient use of the wireless medium. 
     For the above-described communication method using the SRP, only uplink communication is assumed as a directionality of communication. That is, the destination of a frame for which transmission is guided by the trigger frame is assumed to be the access point having transmitted the trigger frame. Thus, in a case where communication other than the uplink communication is assumed, for example, in a case where the destination of the frame for which the transmission is guided by the trigger frame is other than the access point, the frame transmitted by the terminal may cause a failure in reception process at the access point. That is, the access point may fail to correctly receive frames destined for the access point because the frames are interfered with by the frame having a destination other than the access point. 
     SUMMARY OF THE INVENTION 
     In light of the above problems, the present disclosure provides a technology for performing communication control in accordance with the directionality of communication. 
     According to one aspect of the present invention, there is provided a communication apparatus which comprises: a transmission unit configured to transmit a frame including frequency band allocation information for communication based on Orthogonal Frequency Division Multiple Access (OFDMA); and a determination unit configured to determine whether to permit or prohibit Spatial Reuse Parameter (SRP) based communication in accordance with a communication partner apparatus of each of a plurality of terminal stations in a network managed by the communication apparatus, wherein in a case where the determination unit determines that the SRP based communication is to be prohibited, the transmission unit transmits the frame including information indicating that the SRP based communication is prohibited. 
     Further features of the present invention will become apparent from the following description of exemplary embodiments (with reference to the attached drawings). 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates an example of a wireless network configuration. 
         FIG. 2A  illustrates an example of a hardware configuration for an access point. 
         FIG. 2B  illustrates an example of a functional configuration of the AP. 
         FIG. 3A  illustrates an overall configuration of a trigger frame. 
         FIG. 3B  illustrates a configuration of a Common Info field. 
         FIG. 3C  illustrates a configuration of a Per User Info field. 
         FIG. 4A  illustrates a configuration of a UL Spatial Reuse field in the trigger frame. 
         FIG. 4B  illustrates the relationship between values of an SRP and meanings of the values. 
         FIG. 5  illustrates an example of a first operation sequence and an example of a second operation sequence. 
         FIG. 6  illustrates an example of a third operation sequence. 
         FIG. 7  is a flowchart illustrating a process performed by an access point. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     Hereinafter, embodiments will be described in detail with reference to the attached drawings. Note, the following embodiments are not intended to limit the scope of the claimed invention. Multiple features are described in the embodiments, but limitation is not made an invention that requires all such features, and multiple such features may be combined as appropriate. Furthermore, in the attached drawings, the same reference numerals are given to the same or similar configurations, and redundant description thereof is omitted. 
     (Wireless Network Configuration) 
       FIG. 1  illustrates an example of a wireless network configuration according to the present embodiment. In  FIG. 1 , a network  100  and a network  110  are illustrated as two Basic Service Set (BSS) networks. A BSS is a base set of wireless networks, and in an infrastructure mode, the BBC is formed and managed by an access point used as a controller. The network  100  is a network with a BSS Identifier value (ID) of 1, and the network  110  is a network with a BSS ID of 2. Note that BSS ID is an identifier of the BSS and, in this case, the address of an access point in a Medium Access Control (MAC) frame configuration is used as the BSS ID, but note that no such limitation is intended. 
     An access point (AP)  101  is an access point managing the network  100  and supporting IEEE 802.11ax. Similarly, an AP  111  is an access point managing the network  110  and supporting IEEE 802.11ax. According to IEEE 802.11ax, at least a part of a 20-MHz frequency bandwidth may be allocated to one or more stations/terminal stations (STAs) by orthogonal frequency division multiple access (OFDMA). STAs  102 - 1  to  102 - 3  are communication terminals (terminal stations) belonging to the network  100 , and an STA  112 - 1  is a communication terminal belonging to the network  110 . 
     (Configuration of AP) 
       FIG. 2A  illustrates an example of a hardware configuration of an AP  101 . A storage unit  201  is constituted of a memory such as a ROM or a RAM, and stores various types of information such as programs for performing various operations described below and communication parameters for wireless communication. Note that, in addition to a memory such as a ROM, a RAM, or the like, a storage medium such as a flexible disk, a hard disk, an optical disc, a magneto-optical disc, a CD-ROM, a CD-R, a magnetic tape, a non-volatile memory card, or a DVD may be used as the storage unit  201 . Additionally, the storage unit  201  may include a plurality of memories. 
     A control unit  202  is constituted of one or more processors, such as a CPU and an MPU, and controls the AP  101  by executing programs stored in the storage unit  201 . Note that the control unit  202  may control the AP  101  through cooperation between an Operating System (OS) and a program stored in the storage unit  201 . Additionally, the control unit  202  may include a plurality of processors such as a multi-core processor and control the AP  101 . Additionally, the control unit  202  may control a function unit  203  to perform a predetermined process such as access point functions, imaging and printing, and projection. The function unit  203  is hardware for the AP  101  to perform a predetermined process. 
     An input unit  204  accepts various operations from a user. An output unit  205  provides various outputs to the user. Here, the output from the output unit  205  includes at least one of display on a screen, audio output from a speaker, vibration output, and the like. Note that both the input unit  204  and the output unit  205  may be implemented in one module, such as a touch panel. A communication unit  206  controls wireless communication in accordance with IEEE 802.11 series or Wi-Fi, and controls Internet Protocol (IP) communication. For example, the communication unit  206  can perform communication corresponding to IEEE 802.11ax or communication not corresponding to IEEE 802.11ax. The communication unit  206  can control an antenna  207  to transmit and receive wireless signals for wireless communication. 
       FIG. 2B  illustrates an example of a functional configuration of the AP  101 . A transmission unit  211  and a reception unit  212  respectively perform signal transmission processing and signal reception processing via the communication unit  206 . A signal analysis unit  213  performs analysis on a received signal processed by the reception unit  212 . A determination unit  214  determines the directionality (communication partner apparatus) of communication in the network managed by the AP  101  in accordance with an analysis result from the signal analysis unit  213 . A frame generation control unit  215  performs control related to generation of a frame (for example, a trigger frame) transmitted by the AP  101 . 
     (Configuration of Trigger Frame) 
       FIG. 3A  illustrates a configuration of a trigger frame (TF)  300 . The TF is a frame defined by IEEE 802.11ax and used to indicate activation timings and wireless channel (frequency band) information needed for a plurality of STAs to transmit and receive frames. A Frame Control Field  301  is a field common to the IEEE 802.11 series, and in the present embodiment, contains a value indicating the TF for IEEE 802.11ax. A Common Info field  305  indicates information common to a plurality of STAs to which the TF  300  is to be addressed. Details of the Common Info field  305  will be described below using  FIG. 3B . A Per User Info field  306  illustrates individual information for the destination of the TF  300 . Details of the Per User Info field  306  will be described below using  FIG. 3C . Note that descriptions of the fields Duration  302 , Receiver Address (RA)  303 , Transmitter Address (TA)  304 , Padding  307 , and (Frame Check Sequence (FCS)  308  complying with the IEEE 802.11ax standard are omitted. 
       FIG. 3B  illustrates a subfield configuration of the Common Info field  305 . A Trigger Type subfield  311  indicates the type of trigger, and in a case where the TF  300  is a Basic Trigger Frame, this subfield is 0. The TF with a Trigger Type  311  of 0 is intended to allocate resource units (RUs) to a plurality of STAs and to activate communication after a Short Inter Frame Space (SIFS) time has elapsed since communication of the TF. Here, RU is an abbreviation for Resource Unit, and indicates an allocation unit of subcarriers (frequency bands) in OFDMA communication. A Length subfield  312  indicates the time (duration) of a frame activated by the TF. The value of the Length subfield  312  is reflected in an L-SIG field for a physical layer in an IEEE 802.11 frame. Here, L-SIG is an abbreviation for Legacy SIGNAL or non-high-throughput SIGNAL. Here, the Length subfield  312  is set and used to indicate the duration of the frame. A Bandwidth (BW) subfield  315  is 0 in a case where an operating channel band is 20 MHz. Descriptions of the following subfields complying with the IEEE 802.11ax standard are omitted: Cascade Indication  313  (also referred to as More TF), Carrier Sense (CS) Required  314 , Guard Interval And Long Training Field (GI And LTF Type)  316 , MU-MIMO LTF Mode  317 , Number of HE LTF Symbols  318 , Space Time Block Code (STBC)  319 , Low Density Parity Check (LDPC), and Extra Symbol Segment  320 . Note that MIMO is an abbreviation for Multiple Input Multiple Output and that HE is an abbreviation for High Efficiency and is used as a modifier meaning high efficiency according to the IEEE 802.11ax standard. An AP TX Power Subfield  321  is a value for transmit power for the TF  300  normalized based on a 20-MHz bandwidth, and a unit of the value is dBm. Details of UL Spatial Reuse  323  will be described below with reference to  FIGS. 4A to 4B . Doppler  324  assumes a value of 0 or 1 in relation to the number of HE-LTF symbols. Descriptions of the subfields Packet Extension  322 , HE-SIG-A Reserved  325 , and Reserved  326  complying with the IEEE 802.11ax standard are omitted. Note that the designation HE-SIG-A is an expression representative of HE-SIG-A1 to HE-SIG-A4. A Trigger Dependent Common Info subfield  327  has a length that is variable (variable length), and indicates additional information in accordance with the value (type of TF) indicated by the Trigger Type subfield  311 . 
       FIG. 3C  illustrates a subfield configuration of the Per User Info field  306 . An Association IDentifier (AID) 12 subfield  328  is an identifier attached, for the purpose of distinction, by the access point to a terminal (STA) connected to the access point. A terminal having the same AID value as the value indicated by the AID12 subfield  328  corresponds to a target terminal of the Per User Info field  306 , and uses an RU allocated in a succeeding RU Allocation subfield  329 . Note that matching of the AID value is determined using 12 Least Significant Bits (LSBs). Additionally, subfield  328 =0 indicates that, instead of a specific terminal, an arbitrary terminal is associated with (connected to) the AP. Additionally, AID12 subfield  328 =2045 indicates that an arbitrary terminal is not associated with the AP. Furthermore, AID12 subfield  328 =2046 indicates that no RU is allocated. The RU Allocation subfield  329  indicates an index of an RU to be allocated. An FEC Coding Type subfield  330  indicates the coding type of TF response data. An MCS subfield  331  indicates a coding scheme used in a TF response frame. Note that MCS is an abbreviation for Modulation and Coding Scheme. A DCM subfield  332  indicates Dual carrier modulation of the TF response frame. An SS Allocation/RA-RU Information subfield  333  is a spatial stream of the TF response frame when the AID of the terminal is neither 0 nor 2045. When the AID of the terminal is 0 or 2045, the subfield indicates a Random Access Resource Unit (RA-RU). A Target Receive Signal Strength Indicator (RSSI) subfield  334  indicates received power at the AP for the TF response frame expected by the AP. Description of a Reserved subfield  335  is omitted. A Trigger Dependent User Info  336  subfield is a subfield, the contents of which vary depending on Trigger Type  311 . 
       FIG. 4A  illustrates details of a UL Spatial Reuse field  323 , which includes four 4-bit Spatial Reuse 1 to 4 subfields  401  to  404 , respectively. Each Spatial Reuse subfield indicates a value of an SRP.  FIG. 4B  illustrates the values of the SRP and the meanings of the values. As illustrated in  FIG. 4B , a case where an SRP value is 0 (zero) means that, after the transmission of the TF, no Spatial Reuse transmission is permitted (SRP_DISALLOW). Additionally, an SRP value of from 1 to 14 means a numerical value (dBm) obtained by adding the “transmit power for the TF” to the “level of reception interference acceptable by the AP (reception interference value)”. Furthermore, an SRP value of 15 means prohibition of an SRP scheme and an OBSS_PD scheme (SRP_AND_NON_SRG_OBSS_PD_PROHIBITED). Note that OBSS_PD is an abbreviation for Overlapping BSS Packet Detection, and detailed description of the OBSS_PD is omitted. 
     (Description of Operation Sequence) 
     Now, an operation sequence according to the present embodiment in a network configuration illustrated in  FIG. 1  will be described. A communication scheme based on a Spatial Reuse Parameter (SRP) scheme (SRP based communication scheme), which is a prerequisite for the present embodiment, is a spatial reuse communication scheme corresponding to a feature of 802.11ax. More specifically, according to the SRP based communication scheme, in an environment in which a plurality of BSSs use a wireless space in the same frequency band, an access point belonging to one of the BSSs notifies a parameter value (SRP value) relating to an acceptable reception interference level, and terminals belonging to the other BSSs each determine a transmission level based on the value. This scheme enables efficient use of a wireless medium. 
     &lt;Example of First Operation Sequence: SRP Scheme is Permitted&gt; 
       FIG. 5  illustrates a first example of operation sequence. The present operation sequence is a case where the destination of a frame activated by the TF is limited to the access point (uplink communication only). First, AP  101  transmits a TF  501  to activate a UL MU operation in the network  100  with BSSID: 1 managed by the AP  101 . Any of the SRP values as illustrated in  FIG. 4B  is set in the UL Spatial Reuse field  323  in the TF  501 . Note that UL MU is an abbreviation for Up Link Multi User and refers to simultaneous transmissions from a plurality of STAs to the AP. An STA having received the TF  501  transmits the frame after elapse of the SIFS time in a case where an RU is allocated to the STA. In the example in  FIG. 5 , an STA  102 - 1  transmits an HE TB PPDU frame  502  and an STA  102 - 2  transmits an HE TB PPDU frame  503 . The time length of the HE TB PPDU frame is specified by the TF  501  (Length subfield  312  in  FIG. 3B ). Here, TB is an abbreviation for Trigger Based and PPDU is an abbreviation for Physical layer Protocol Data Unit. In other words, the HE TB PPDU frame refers to a frame transmitted and guided by the TF according to IEEE 802.11ax. Note that positions of the HE TB PPDU frame on the vertical axis in  FIG. 5  simulate an RU frequency band used for frame transmission. 
     An STA  112 - 1  in the network  101  with BSSID: 2 network  101  using the same frequency band and channel as those of the network with BSSID: 1 can also receive the TF  501 . Any of the SRP values as illustrated in  FIG. 4B  is set in the UL Spatial Reuse field  323  of the TF  501 , and thus the STA  112 - 1  can recognize the SRP value. At this time, an SRP value of from 1 to 14 allows the STA  112 - 1  to transmit, with conditional transmit power, a Single User (SU) PPDU frame  504  destined for the AP  111 . That is, transmit power is used that has a value smaller than a value obtained by subtracting a reception electric field intensity (Received Signal Strength Indicator (RSSI)) of the RF  501  from the power corresponding to the SRP value (a numerical value (dBm) obtained by adding the “transmit power for the TF” to the “value of reception interference acceptable by the AP (reception interference level)”). For example, as seen in  FIG. 4B , an SRP value of 1 included in the Spatial Reuse 1 subfield  401  of the UL Spatial Reuse field  323  in the TF  501  corresponds to −80 dBm. The STA  112 - 1  transmits the SU PPDU frame  504  at a transmit power value smaller than a value resulting from subtraction of the reception electric field intensity of the RF  501  from −80 dBm. 
     Then, a value resulting from subtracting a loss of the wireless medium between the AP  101  and STA  112 - 1  from the transmit power for the SU PPDU frame  504  is smaller than the acceptable reception interference value. Thus, with the transmission of the SU PPDU frame  504  by the STA  112 - 1  prevented from affecting the reception processing of the AP  101 , the AP  101  can correctly receive frames (HE TB PPDU frames  502  and  503 ) destined for the AP  101 . This corresponds to prevention of the transmission (solid line) of a PPDU frame from STA  112 - 1  from affecting the reception (solid line), at the AP  101 , of an HE TB PPDU frame from STA  102 - 3 . 
     Subsequently, the AP  101  having received the HE TB PPDU frames  502  and  503  returns an MBA frame  505  as a response. MBA is an abbreviation for Multi-STA Block Ack (BA) in which responses to the plurality of STA are configured in one frame. Additionally, the AP  111  having received the SU PPDU frame  504  returns a Block Ack (BA) frame  506  as a response. In this manner, utilizing the SRP scheme allows effective use (reuse) of the wireless medium (space) between the network with BSSID: 1 and the network with BSSID: 2. 
     &lt;Example of Second Operation Sequence: SRP Scheme is Prohibited During Sensing of Start of Direct Communication&gt; 
     The present operation sequence assumes that direct communication between an STA  102 - 1  and an STA  102 - 2  is started. In  FIG. 5 , in which the first operating sequence has been described, after the AP  101  and the AP  111  transmit the MBA frame  505  and the BA frame  506 , respectively, the AP  101  recognizes the start (performance) of the direct communication between the STA  102 - 1  and the STA  102 - 2  (operation  511 ). For example, the AP  101  can recognize the start of the direct communication by detecting signals related to the start of the direct communication and exchanged between the STA  102 - 1  and the STA  102 - 2 , and detecting a signal related to the start of the direct communication via the AP  101 . Note that direct communication refers to direct communication that does not pass through the AP and that is based on Direct Link Setup (DLS) or Tunneled DLS (TDLS) or Wi-Fi direct. Subsequently, the AP  101  transmits the TF. In this case, the AP  101  sets the SRP value in the TF  512  to 0 (zero) or 15. As illustrated in  FIG. 4B , these SRP values mean that the SRP scheme is disallowed. Furthermore, the AP  101  includes, in the TF  512 , RUs for the direct communication between STA  102 - 1  and STA  102 - 2  at TF  512 . 
     The STA  102 - 2  having received the TF  512  recognizes, in the TF  512 , the allocation of the RU for communication with STA  102 - 1  and transmits an HE TB PPDU frame  513  to the STA  102 - 1 . Similarly, the STA  102 - 3  having received the TF  512  recognizes, in the TF  512 , the allocation of the RU for MU UL communication and transmits an HE TB PPDU frame  514  to the AP  101 . On the other hand, the STA  112 - 1  does not perform frame transmission based on the SRP scheme while the HE TB PPDU frames  513  and  514  are being transmitted. 
     The STA  102 - 1  having received the HE TB PPDU frame  513  transmits a BA frame  515  to the STA  102 - 2  as a response. Similarly, the AP  101  having received the HE TB PPDU frame  514  transmits a BA  516  frame to the STA  102 - 3  as a response. These responses (BA frames) are assumed to be based on an OFDMA communication scheme and to utilize the same RU as that used by the HE TB PPDU frame. 
     Thus, in the example of the second operation sequence, unlike in the example of the first operation sequence, the STA  112 - 1  is prevented from performing frame transmission after reception of the TF. This is because the SRP value indicated in the TF  511  indicates prohibition of the frame transmission based on the SRP scheme from being performed by the STAs in the other BSS network. Note that, with reference to  FIG. 5 , communication between two STAs has been described as the direct communication by way of example but that the TF may be configured such that the frame transmission based on the SRP scheme is prohibited also in a case where the direct communication is performed between two or more STAs. 
     &lt;Example of Third Operation Sequence: SRP Scheme is Prohibited when AP Performs Full-Duplex Communication&gt; 
       FIG. 6  illustrates an example of a third operation sequence. In a case where the AP  101  is in a state in which full-duplex communication is executable, the AP  101  controls the communication unit  206  and the antenna  207  to prepare for full-duplex communication (operation  601 ). Note that it is assumed that the STAs  102 - 1  to  102 - 3  can receive a frame from the AP  101  after reception of the TF. 
     After the operation  601 , the AP  101  transmits a TF  602 . At this time, the AP  101  sets the SRP value to a value meaning that the SRP scheme is disallowed as in the example of the second operation sequence described above. Additionally, for the STA  102 - 1 , the AP  101  includes, in the TF  602 , an RU for downlink communication (communication in a direction from the AP  101  to the STA). Furthermore, for the STA  102 - 2  and the STA  102 - 3 , the AP  101  includes, in the TF  602 , an RU for MU UL communication. After transmitting the TF  602 , the AP  101  transmits an HE TB PPDU frame  603  to the STA  102 - 1 . The STA  102 - 2  having received the TF  602  recognizes, in the TF  602 , the allocation of the RU for MU UL communication and transmits an HE TB PPDU frame  604  to the AP  101 . Similarly, the STA  102 - 3  having received the TF  602  recognizes, in the TF  602 , the allocation of the RU for MU UL communication and transmits an HE TB PPDU frame  605  to the AP  101 . On the other hand, the STA  112 - 1  does not perform the frame transmission based on the SRP scheme while the HE TB PPDU frames  604  and  605  are being transmitted. 
     The STA  102 - 1  having received the HE TB PPDU frame  603  transmits a BA frame  606  as a response destined for the AP  101 . Additionally, the AP  101  having received the HE TB PPDU frames  603  and  604  transmits BA frames  607  and  608  respectively destined for the STA  102 - 2  and the STA  102 - 3 . Note that  FIG. 6  illustrates a configuration in which the AP  101  transmits the HE TB PPDU frame to the single STA, but in a case of transmitting a data frame to a plurality of STAs, the AP  101  transmits frames in an HE MU PPDU format. 
     Note that, although not illustrated, in an example of an operation sequence corresponding to a combination of the examples of the second and third operation sequences, the TF may be configured such that the AP  101  also prohibits the SRP scheme in a case where the direct communication between a plurality of STA is started and where the AP  101  performs full-duplex communication. 
     Additionally, the AP  101  and the STAs  102 - 1  to  102 - 3  recognize information (operation capability and operation information) indicating that full-duplex communication is enabled (UL communication and DL communication are enabled), through a capability exchange procedure executed when the AP  101  connects to each STA. 
     Incidentally,  FIG. 1  illustrates a case in which the TF from the AP  101  fails to reach the AP  111 . This is because the present embodiment relates to operation of the STA having received the TF (i.e. STA  112 - 1 ) from the AP managing other BSS network (i.e. AP  101 ). In  FIG. 1 , in a case where the AP  111  or any STA (not illustrated) in the network  110  receives the TF from the AP  101 , the use or non-use of the SRP scheme may be controlled for these STAs as is the case with the STA  112 - 1 . 
     &lt;Processing of AP  101 &gt; 
       FIG. 7  illustrates a flowchart of a trigger frame transmission process executed by the AP  101 . The process in the present flowchart is implemented, for example, by the control unit  202  of the AP  101  by executing a program stored in the storage unit  201 . 
     First, in S 701 , the AP  101  checks each STA connected to the AP  101  for a transmission buffer state. For example, the transmission buffer state can be checked by the signal analysis unit  213  by analyzing Buffer Status Reports (BSRs) from the STA  102 - 1  to  102 - 3  received by the reception unit  212  of the AP  101 . The transmission buffer state may include the amount of data to be transmitted by each STA, the type of access category, a residence time in the buffer, etc. 
     Then, in S 702 , the signal analysis unit  213  of the AP  101  checks the data destined for each STA. For example, the signal analysis unit  213  checks for data directed from any STA in the network  100  to the same network  100  via the AP  101 , or data directed from any STA outside the network  100 , which is not illustrated, to any STA in the network  100 . Furthermore, in S 703 , the AP  101  checks whether the direct communication is started between two or more STAs in the network  100 . At this stage, the AP  101  recognizes a communication request that includes a communication partner apparatus (communication directionality) in the network  100  managed by the AP  101 . Note that the user may set, via the input unit  204 , the information related to the connection partner apparatus (directionality of communication) such that the AP  101  recognizes the information. 
     Subsequently, in S 704 , the determination unit  214  of the AP  101  determines the communication partner apparatus (the directionality of communication) of each STA in the network  100  based on check statuses in S 702  and S 703  and determines whether the communication guided (activated) by the TF is to be only the UL communication to the AP  101 . In a case where only the UL communication to the AP  101  is determined to be performed, the process proceeds to S 705 . In S 705 , the frame generation control unit  215  determines an acceptable reception interference value (reception interference level) at the AP  101 . Furthermore, in S 706 , the frame generation control unit  215  determines the value of the transmit power for the TF to be transmitted. The communication unit  206  performs a transmission process using the determined transmit power. In S 707 , the frame generation control unit  215  calculates a numerical value obtained by adding the determined TF transmit power to the determined acceptable reception interference value, determines the SRP value from a relationship table illustrated in  FIG. 4B , and creates a TF configured with the SRP value. Thereafter, the transmission unit  211  transmits the created TF. 
     In a case where communication other than the UL communication to the AP  101  is also determined in S 704  to be performed, the process proceeds to S 708 . In S 708 , the determination unit  214  determines whether to perform transmission from the AP  101  using the transmitted TF as a trigger, i.e., whether the directionality of communication includes downlink communication from the AP  101  to the STA. In a case where the downlink communication is performed, the process proceeds to S 709  and otherwise the process proceeds to S 710 . In S 709 , the control unit  202  prepares for full-duplex communication. In S 710 , the frame generation control unit  215  creates a TF with the SRP scheme prohibited, and the transmission unit  211  transmits the created TF. Here, as illustrated in  FIG. 4B , the prohibition corresponds to setting the SRP value to 0 (SRP_DISALLOW) or 15 (SRP_AND_NON_SRG_OBSS_PD_PROHIBITED). 
     In a case where the flowchart illustrated in  FIG. 7  is associated with the examples of the first to third operation sequences described above, the example of the first operation sequence corresponds to the process proceeding from S 704  to S 707 , the example of the second operation sequence corresponds to the process proceeding from S 708  to S 710 , and the example of the third operation sequence corresponds to the process proceeding from S 708  to S 709  and the subsequent steps. 
     As described above, in a case where the directionality of communication in the network managed by the AP includes communication other than the uplink communication, that is, the destination of the frame guided by the TF includes a terminal (communication apparatus) other than the AP having transmitted the TF, control is provided such that no communication other than the SRP based communication is performed. Such operation enables the use of the SRP scheme to be appropriately controlled when the wireless medium is shared by APs and STAs belonging to a plurality of BSS networks, allowing exertion of an effect that facilitates efficient use of the wireless media. Additionally, the throughput of the overall system is improved. 
     Note that the embodiment described above is not limited to IEEE 802.11ax, and is similarly applicable to IEEE 802.11 series standards such as IEEE 802.11 Extremely/Extreme High Throughput (EHT). 
     OTHER EMBODIMENTS 
     Embodiment(s) of the present invention can also be realized by a computer of a system or apparatus that reads out and executes computer executable instructions (e.g., one or more programs) recorded on a storage medium (which may also be referred to more fully as a ‘non-transitory computer-readable storage medium’) to perform the functions of one or more of the above-described embodiment(s) and/or that includes one or more circuits (e.g., application specific integrated circuit (ASIC)) for performing the functions of one or more of the above-described embodiment(s), and by a method performed by the computer of the system or apparatus by, for example, reading out and executing the computer executable instructions from the storage medium to perform the functions of one or more of the above-described embodiment(s) and/or controlling the one or more circuits to perform the functions of one or more of the above-described embodiment(s). The computer may comprise one or more processors (e.g., central processing unit (CPU), micro processing unit (MPU)) and may include a network of separate computers or separate processors to read out and execute the computer executable instructions. The computer executable instructions may be provided to the computer, for example, from a network or the storage medium. The storage medium may include, for example, one or more of a hard disk, a random-access memory (RAM), a read only memory (ROM), a storage of distributed computing systems, an optical disk (such as a compact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD)™), a flash memory device, a memory card, and the like. 
     While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions. 
     This application claims the benefit of Japanese Patent Application No. 2019-033029, filed on Feb. 26, 2019, which is hereby incorporated by reference herein in its entirety.