COMMUNICATION DEVICE, COMMUNICATION DEVICE CONTROL METHOD, AND PROGRAM

Abstract

The object is to enable suitable transmission of data using resource units. [Solution] In a communication device that notifies a base station of information regarding the amount of data to be transmitted, receives a trigger frame containing information associating multiple resource units obtained by dividing a frequency channel with AIDs, which are identification information for multiple communication devices, and transmits data to the base station using the resource units associated with the AID of its own device, the information notified to the base station is used to allocate resource units, and if multiple resource units are associated with the AID of its own device, the data is transmitted using those multiple resource units.

Description

[Technical Field]

[0001] The present invention relates to a communication device that communicates using an OFDMA system. [Background technology]

[0002] Communication devices that perform wireless communication in accordance with the IEEE802.11 series are widely used. Communication devices that comply with the IEEE802.11 series use an access method called CSMA / CA (Carrier Sense Multiple Access with Collision Avoidance). CSMA / CA requires that before transmitting a signal, carrier sense be performed to measure the radio wave strength of the frequency channel through which the signal is transmitted. Carrier sense measures the radio wave strength in a 20 MHz wide frequency channel, which is specified in IEEE802.11.

[0003] If the measured radio wave strength does not exceed a predetermined threshold as a result of carrier sensing, a signal is transmitted, and if the measured radio wave strength is equal to or greater than the predetermined threshold, a signal is not transmitted.

[0004] Meanwhile, IEEE is studying IEEE802.11ax as a standard following IEEE802.11ac (Patent Document 1). In IEEE802.11ax, it is being studied that one frequency channel will be further divided into multiple frequency bands, and different devices will be able to communicate simultaneously using each of the multiple frequency bands. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-165676 Summary of the Invention [Problem to be solved by the invention]

[0006] However, when one frequency channel is further divided into a plurality of frequency bands and different devices simultaneously communicate using each of the plurality of frequency bands, there may be cases where only a portion of the frequency bands is used for communication.

[0007] For example, in a system that divides one frequency channel into four frequency bands, there may be a case where only two devices are transmitting data signals at a given time, and in such a case, only two of the four frequency bands may be used.

[0008] In such a case, if the transmission power per unit frequency (transmission power density) of each device is the same as the transmission power density when transmitting signals using the entire frequency band of one frequency channel, the transmission power of the entire frequency channel will be approximately halved.

[0009] Therefore, when another communication device performs carrier sensing in CSMA / CA, the transmission power of the entire frequency channel is low, so it is not possible to measure radio wave strength exceeding a predetermined threshold, and the other communication device may transmit a signal.

[0010] If another communication device transmits a signal, radio interference occurs, resulting in an error. In view of the above problem, it is an object of the present invention to provide a method for suitably transmitting data using resource units. [Means for solving the problem]

[0011] The communication device of the present invention is a communication device that performs communication in accordance with the IEEE802.11 series standard using an OFDMA (Orthogonal Frequency Division Multiple Access) system, and includes a notification means for notifying a base station of information regarding the amount of data transmitted by the communication device, and information from the base station associating a plurality of resource units obtained by dividing a channel of a predetermined frequency bandwidth with AIDs (Association Identifiers) that are identification information for a plurality of communication devices, and a notification means for notifying a base station of information regarding the amount of data transmitted by the communication device, the information being associated ... the information being transmitted by the communication device to the base station. identification and transmitting means for transmitting data to the base station using resource units associated with the AID of the communication device in the trigger frame, wherein the information notified by the notifying means is used for the base station to allocate resource units, and when a plurality of resource units are associated with the AID of the communication device in the trigger frame, the transmitting means transmits data using the plurality of resource units, and when a single resource unit is associated with the AID of the communication device in the trigger frame, the transmitting means transmits data using the single resource unit, and when the communication device reduces the transmission power of the communication device to transmit data, the transmitting means identification When the information used to transmit the first signal is a first value, the first transmission power is used. identification and transmits data at the first transmission power, and the communication device adjusts the transmission power of the communication device. identification The information used to greater than the first value In the case of the second value, when a second transmission power that is greater than the first transmission power is used, identification and transmits data at the second transmission power, and the communication device sets the transmission power of the communication device to identification The information used to greater than the first and second values In the case of the third value, when a third transmission power greater than the first and second transmission powers is used, identification The data is transmitted at the third transmission power. Further, a communication device of the present invention is a communication device that performs communication in accordance with the IEEE802.11 series standard using an OFDMA (Orthogonal Frequency Division Multiple Access) system, and includes an acquisition means for acquiring information on the amount of transmission data of other communication devices participating in a network formed by the communication device, information associating a plurality of resource units obtained by dividing a channel of a predetermined frequency bandwidth with AIDs (Association Identifiers) that are identification information of the plurality of communication devices, and information indicating when the other communication devices should adjust the transmission power of the other communication devices. identification and receiving means for receiving data transmitted from the other communication device using a resource unit associated in the trigger frame with the AID of the other communication device, wherein the information acquired by the acquiring means can be used for allocating the resource unit, and when a plurality of resource units are associated in the trigger frame with the AID of the other communication device, the receiving means receives data transmitted from the other communication device using the plurality of resource units, and when a single resource unit is associated in the trigger frame with the AID of the communication device, the receiving means receives data using the single resource unit, and when the other communication device adjusts the transmission power of the other communication device for the trigger frame to be transmitted to the other communication device. identification Including a first value as information used for transmitting the trigger frame causes the other communication device to perform a transmission process of transmitting data at a first transmission power, and the other communication device sets the transmission power of the other communication device to a value corresponding to the trigger frame transmitted to the other communication device. identification As information used to greater than the first value The inclusion of the second value causes the other communication device to perform a transmission process of transmitting data at a second transmission power that is greater than the first transmission power, and the other communication device sets the transmission power of the other communication device to a value greater than the first transmission power in response to the trigger frame to be transmitted to the other communication device. identificationAs information used to greater than the first and second values The inclusion of the third value is characterized in that it causes the other communication device to perform a transmission process of transmitting data at a third transmission power that is greater than the first and second transmission powers. [Effects of the Invention]

[0012] According to the present invention, when a signal is transmitted in a part of a frequency band in a frequency channel including a plurality of frequency bands, the signal can be transmitted suitably. [Brief explanation of the drawings]

[0013] [Figure 1] Network Diagram [Figure 2] Hardware configuration diagram of communication device [Figure 3] Diagram showing the relationship between frequency and RU [Figure 4] Diagram showing the relationship between frequency and RU [Figure 5] Flowchart implemented by the communication device [Figure 6] Flowchart implemented by the communication device [Figure 7] Flowchart realized by base station DETAILED DESCRIPTION OF THE INVENTION

[0014] <Embodiment 1> Fig. 1 shows a communication system according to this embodiment. A base station 110 is an access point conforming to the IEEE 802.11 series, and forms a wireless network 100. In this embodiment, the base station 110 forms the wireless network 100 conforming to IEEE 802.11ax, and performs wireless communication conforming to IEEE 802.11ax. Here, IEEE is an abbreviation for The Institute of Electrical and Electronics Engineers, Inc.

[0015] The communication device 101 is a slave station participating in a wireless network 100 formed by a base station 110. The communication device 101 performs wireless communication in accordance with IEEE802.11ax with the base station 110 in the wireless network 100. Similarly, a plurality of communication devices 102 also participate in the wireless network 100 as slave stations, and perform wireless communication in accordance with IEEE802.11ax with the base station 110.

[0016] The communication device 103 is a legacy terminal that does not support IEEE802.11ax, and performs wireless communication in accordance with at least one of IEEE802.11a, b, g, n, and ac.

[0017] Note that the communication device 103, which is a legacy terminal, communicates using the DSSS or OFDM system, while the communication devices 101, 102 and the base station 110 communicate using the OFDMA system. Therefore, even if the communication device 103 receives signals from the communication devices 101, 102 and the base station 110, it cannot recognize these signals as data signals. Note that DSSS is an abbreviation for Direct Sequence Spread Spectrum. Furthermore, OFDM is an abbreviation for Orthogonal Frequency Division Multiplexing. Furthermore, OFDMA is an abbreviation for Orthogonal Frequency-Division Multiple Access.

[0018] Therefore, the communication device 103, which is a legacy terminal, uses an access method called CSMA / CA (Carrier Sense Multiple Access with Collision Avoidance) to prevent interference.

[0019] Specifically, before transmitting a signal, the communication device 103 performs carrier sensing to measure the radio wave strength of the frequency channel through which the signal is transmitted. In the carrier sensing, the radio wave strength is measured in a 20 MHz width, which is one frequency channel defined by IEEE802.11.

[0020] If the measured radio wave strength does not exceed a predetermined threshold, it is determined that no other communication device is communicating on that frequency channel, and the communication device 103 transmits a signal. On the other hand, if the measured radio wave strength is equal to or greater than the predetermined threshold, it is determined that another communication device is communicating on that frequency channel, and the communication device 103 does not transmit a signal. This prevents interference with other communication devices.

[0021] 2 shows the hardware configuration of the communication device 101. It is assumed that the base station 110 and the other communication devices 102 also have the same hardware configuration.

[0022] The storage unit 201 is configured with memories such as ROM and RAM, and stores various information such as programs for performing various operations described below and communication parameters for wireless communication. Note that, 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 also be used as the storage unit 201. Furthermore, the storage unit 201 may include multiple memories.

[0023] The control unit 202 is configured with a processor such as a CPU or an MPU, and controls the entire communication device 101 by executing a program stored in the storage unit 201. The control unit 202 may control the entire communication device 101 in cooperation with the program stored in the storage unit 201 and an OS (Operating System). The control unit 202 may also be equipped with multiple processors such as multi-core processors, and the entire communication device 101 may be controlled by the multiple processors.

[0024] Furthermore, the control unit 202 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 communication device 101 to perform predetermined processing. For example, if the communication device 101 is a camera, the functional unit 203 is an imaging unit that performs imaging processing. For example, if the communication device 101 is a printer, the functional unit 203 is a printing unit that performs printing processing. For example, if the communication device 101 is a projector, the functional unit 203 is a projection unit that performs projection processing. The data processed by the functional unit 203 may be data stored in the storage unit 201, or may be data received from another communication device via a communication unit 206 (described later).

[0025] 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 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.

[0026] The communication unit 206 controls wireless communication conforming to the IEEE802.11 series, TCP / IP communication, etc. The communication unit 206 also controls an antenna 207 to transmit and receive wireless signals for wireless communication. The communication device 101 communicates content such as image data, document data, and video data with other communication devices via the communication unit 206.

[0027] Next, a communication method for IEEE802.11ax currently under consideration will be described with reference to FIG. 3. In addition to the conventional method of using an entire frequency channel for communication, the following communication method is being considered for IEEE802.11ax. That is, it is being considered to divide the 20 MHz width that has been used as a single frequency channel into multiple frequency bands, and have different communication devices simultaneously use each of these multiple frequency bands for communication. Here, each of the multiple frequency bands is called an RU (Resource Unit). In this embodiment, it is assumed that one frequency channel 302 (20 MHz width) is divided into four, and each RU 303 has a width of 5 MHz.

[0028] To allow multiple communication devices to use multiple RUs simultaneously, the access point transmits a trigger frame (TF) 301. A trigger frame is a transmission permission for one or multiple communication devices. The trigger frame contains information about the communication device to be assigned to each RU. Specifically, the trigger frame contains a list that associates RUs with AIDs, which are identification information for the communication devices. AID stands for Association Identifier.

[0029] A communication device that has been permitted to transmit by the trigger frame transmits a data frame signal 304 in a designated RU when the SIFS time has elapsed after receiving the trigger frame. Here, SIFS stands for Short Inter Frame Space, and is the minimum waiting time before transmitting a signal. Note that AIFS, DIFS, PIFS, EIFS, etc. may be used instead of SIFS. Note that AIFS stands for Arbitration Inter Frame Space, and DIFS stands for Distributed Inter Frame Space. Also, PIFS stands for Point Inter Frame Space, and EIFS stands for Extended Inter Frame Space. Note that when multiple communication devices transmit data signals, IEEE802.11ax uses OFDMA communication to improve frequency utilization efficiency.

[0030] Furthermore, the transmission power (transmission power density) per unit frequency width of a signal transmitted by each communication device that has permission to transmit is the same as the transmission power density when communicating using an entire frequency channel. Therefore, the transmission power when transmitting a signal using one RU is lower than the transmission power when communicating using an entire frequency channel. As a result, even if, for example, four communication devices each transmit a signal using an RU, the transmission power per frequency channel can be made equivalent to the transmission power when communicating using an entire frequency channel. This makes it possible to prevent the transmission power per frequency channel from becoming too high, for example, causing excessive interference with other networks or exceeding the power limit specified by law.

[0031] IEEE802.11ax also allows communication using multiple frequency channels in parallel. Figure 4 shows a case where communication is performed using four frequency channels. In this case, 16 RUs can be used.

[0032] FIG. 5 shows a flowchart of the flow of processing that is realized when the communication device 101 transmits a data signal by the control unit 202 reading out and executing a program stored in the storage unit 201.

[0033] At least a part of the flowchart shown in FIG. 5 may be realized by hardware. When realizing by hardware, for example, a specific compiler may be used to automatically generate a dedicated circuit on an FPGA from a program for realizing each step. FPGA stands for Field Programmable Gate Array. Alternatively, a gate array circuit may be formed in the same manner as an FPGA and realized as hardware. Alternatively, it may be realized by an ASIC (Application Specific Integrated Circuit).

[0034] First, the communication device 101 waits for a trigger frame from the base station 110 (S501). Upon receiving the trigger frame (Yes in S501), the communication device 101 transmits a data signal after the SIFS time has elapsed (S502). Here, the communication device 101 transmits the data signal in the RU for the communication device 101 specified by the trigger frame.

[0035] Then, in parallel with transmitting the data signal, the communication device 101 checks the radio wave strength of the entire frequency channel that the communication device 101 is using to transmit the signal (S503). This check is performed by the communication unit 206 of the communication device 101 receiving while transmitting at the same time, and checking the radio wave strength of the entire frequency channel that the communication device 101 is using to transmit the signal.

[0036] In addition, if the communication unit 206 of the communication device 101 has a separate transmitter and receiver, the transmitter transmits the data signal, and the receiver checks the radio wave strength over the entire frequency channel that the communication device 101 is using to transmit the signal.

[0037] Furthermore, the above radio wave strength check may be limited to the data signals being wirelessly communicated with base station 110, and the radio wave strength check may be performed for the entire frequency channel. This is achieved by calculating the sum of the radio wave strengths of the data signals received at each RU.

[0038] If the result of the check is that the radio wave strength in the entire frequency channel is less than the predetermined threshold (No in S504), the communication device 101 increases the transmission power and transmits the data signal (S505). Here, the communication device 101 increases the power by the amount that the radio wave strength in the entire frequency channel is less than the predetermined threshold, and transmits the data signal.

[0039] The above-mentioned predetermined threshold is the same as the predetermined threshold used by the communication device 103 during carrier sensing.

[0040] If the radio wave strength in the entire frequency channel is below a predetermined threshold, when communication device 103 performs carrier sense, it determines that no other communication devices are communicating on that frequency channel, and communication device 103 transmits a signal. If communication device 103 transmits a signal, it may interfere with the signal transmitted by communication device 101, resulting in an error. Therefore, communication device 101 increases the transmission power of the signal to increase the radio wave strength in the entire frequency channel. This increases the likelihood that communication device 103's carrier sense will determine that another communication device is communicating on that frequency channel, and increases the likelihood that communication device 103 will not transmit a signal. As a result, it is possible to suppress the occurrence of errors due to interference.

[0041] Furthermore, the following two methods are conceivable for the communication device 101 to increase its transmission power. The first method is to increase the transmission power density transmitted in the RU for the communication device 101. The second method is to transmit signals not only in the RU for the communication device 101 but also in other RUs. In this case, the communication device 101 may transmit the same data as in the RU for the communication device 101, or may transmit data different from the RU for the communication device 101, or may transmit dummy data in the other RU.

[0042] The first method increases the transmission power of the data signal, which has the effect of further improving communication quality. The second method can increase transmission power even when there is an upper limit on the transmission power density for transmission from one RU due to hardware limitations or legal restrictions, for example.

[0043] Which of these methods is used may be predetermined, or may be switched depending on the situation. For example, even if the transmission power density is increased within the limits of hardware and legal restrictions, the second method may be used if the radio wave intensity across the entire frequency channel does not meet a predetermined threshold, and the first method may be used otherwise. Furthermore, even when the second method is used, the transmission power density in the RU for the communication device 101 may be increased as appropriate.

[0044] On the other hand, if the radio wave intensity in the entire frequency channel is equal to or greater than the predetermined threshold (Yes in S504), the communication device 101 continues transmitting the data signal without increasing the transmission power (S506).

[0045] When the transmission of the data signal is completed, the communication device 101 receives an Ack, which is an acknowledgment for the data signal, from the base station (S507). Here, the Ack is transmitted using one entire frequency channel. The Ack also serves as an acknowledgment for a data signal transmitted from another communication device 102 via another RU in synchronization with the transmission of the data signal by the communication device 101.

[0046] Thereafter, the process shown in Fig. 5 ends. If data to be transmitted by the communication device 101 occurs, or if data to be transmitted remains, the process returns to the beginning of Fig. 5.

[0047] In S503, instead of checking the radio wave strength over the entire frequency channel, the number of RUs not being used for signal transmission may be determined by checking the usage status of each RU. In this case, in S504, the communication device 101 determines whether the number of RUs not being used for signal transmission is equal to or greater than a predetermined value. Note that the predetermined value is set so that if the number of unused RUs is equal to or greater than the predetermined value, the radio wave strength over the entire frequency channel is less than a predetermined threshold. Therefore, if the number of unused RUs is equal to or greater than the predetermined value, the radio wave strength over the entire frequency channel is equal to or greater than the predetermined threshold.

[0048] If the result of the determination in S504 is that the number of RUs not being used for signal transmission is equal to or greater than a predetermined value, the process proceeds to S505, and if it is less than the predetermined value, the process proceeds to S506. This can also achieve the same effect.

[0049] Furthermore, in this case, in S505, the increase in transmission power may be controlled according to the number of RUs not being used for signal transmission. For example, if it is determined that two of the four RUs are not being used, the transmission power is doubled, and if it is determined that three of the four RUs are not being used, the transmission power is quadrupled. Note that if the transmission power cannot be quadrupled due to hardware or legal restrictions of the communication device 101, the maximum transmission power that satisfies these restrictions may be used.

[0050] This makes it possible to suppress the occurrence of errors due to interference with other communication devices by suppressing signal transmissions by other communication devices while taking into consideration the balance with the transmission power when communicating using an entire frequency channel. That is, it is possible to prevent the transmission power in one frequency channel from becoming too high, for example, causing excessive interference with communications on other networks or exceeding the power limit specified by law, and also to prevent interference with other communication devices.

[0051] Furthermore, instead of determining the number of RUs not used for signal transmission, it is also possible to determine the number of RUs used for signal transmission. Even in this case, the same effect can be obtained by appropriately setting a predetermined value and proceeding to S506 if the number of RUs used for signal transmission is equal to or greater than the predetermined value, and proceeding to S505 if the number is less than the predetermined value.

[0052] <Embodiment 2> In the first embodiment, the communication device 101 measures the signal strength and the usage status of the RU in parallel with transmitting the data signal. In the second embodiment, the communication device 101 checks the usage status of the RU based on information included in the trigger frame.

[0053] In the second embodiment, the system configuration and the hardware configuration of each device are the same as those in the first embodiment, so a description thereof will be omitted here.

[0054] FIG. 6 shows a flowchart of the flow of processing that is realized when the communication device 101 transmits a data signal by the control unit 202 reading out and executing a program stored in the storage unit 201.

[0055] First, the communication device 101 waits for a trigger frame from the base station 110 (S601). Upon receiving the trigger frame (Yes in S601), the communication device 101 analyzes the trigger frame and determines the number of RUs to be used for transmitting a data signal (S602). As described in the first embodiment, the trigger frame includes a list in which AIDs, which are identification information of communication devices that are permitted to transmit, are associated with RUs. Therefore, the communication device 101 can determine the number of RUs to be used for transmitting a data signal based on the trigger frame.

[0056] If the number of RUs used to transmit the signal is equal to or greater than the predetermined value (Yes in S603), the communication device 101 transmits the data signal at the same transmission power as in S502 in Fig. 5 (S604). On the other hand, if the number of RUs used to transmit the signal is less than the predetermined value (No in S603), the communication device 101 transmits the data signal at a transmission power higher than the transmission power in S604 (S605).

[0057] For example, if the predetermined value is 3, and it is determined that three of the four RUs are in use and one RU is not in use, transmission is performed at the same transmission power density as when communication is performed using one entire frequency channel. Therefore, the transmission power of communication device 101 is approximately one-fourth of that when communication is performed using one entire frequency channel.

[0058] Furthermore, if it is determined that two of the four RUs are in use and two RUs are not in use, the transmission power density is doubled. Therefore, the transmission power of communication device 101 in this case is double the transmission power in S502.

[0059] Furthermore, if it is determined that one of the four RUs is in use and three RUs are not in use, the transmission power density is quadrupled. Therefore, the transmission power of the communication device 101 in this case is four times the transmission power in S502. Note that if the transmission power cannot be quadrupled due to hardware restrictions or legal restrictions of the communication device 101, the maximum transmission power that satisfies these restrictions may be used.

[0060] When the transmission of the data signal is completed, the communication device 101 receives an Ack, which is an acknowledgement response to the data signal, from the base station (S606). After that, the processing shown in Fig. 6 ends. Note that if data to be transmitted by the communication device 101 occurs or if data to be transmitted remains, the processing returns to the beginning of Fig. 6.

[0061] In this way, the communication device 101 controls the transmission power based on the information included in the trigger frame, and can suppress the occurrence of errors due to interference.

[0062] It is also possible that each communication device uses an RU in an autonomous and distributed manner, and the base station 110 does not specify the device that uses the RU. In such a case, the base station 110 assigns an AID value (e.g., 0) to the trigger frame, indicating that the device that uses the RU is not specified. The base station 110 may not specify the device for all RUs, or may not specify the device for some RUs.

[0063] If the device to be used is not specified for at least some of the RUs, the communication device 101 cannot determine from the trigger frame whether a signal is to be transmitted to the RU for which the device to be used is not specified. Therefore, in such a case, the processing may be switched to perform the processing shown in the first embodiment, and otherwise to perform the processing shown in the second embodiment.

[0064] Furthermore, if the AID information contained in the trigger frame cannot be obtained, the process shown in embodiment 1 is performed, and if not, the process shown in embodiment 2 or the above-mentioned switching process may be performed. Note that cases in which the AID information contained in the trigger frame cannot be obtained may include cases in which the AID information was not contained in the trigger frame in the first place, or cases in which the AID information contained in the trigger frame could not be obtained due to a communication error.

[0065] This allows power control to be performed based on the information in the trigger frame when the RU usage status can be confirmed based on the information included in the trigger frame, and when the usage status cannot be confirmed, power control can be performed based on the measurement results of the radio wave strength and the RU usage status. Therefore, it is possible to perform appropriate power control processing according to the trigger frame.

[0066] <Embodiment 3> In the first and second embodiments, the communication device 101 checks the signal strength and the RU usage status. In the third embodiment, the base station 110 determines the transmission power of each communication device based on the RU usage status.

[0067] In the third embodiment, the system configuration and the hardware configuration of each device are the same as those in the first embodiment, so a description thereof will be omitted here.

[0068] Figure 7 shows a flowchart of the processing flow that is realized when base station 110 transmits a trigger frame by having control unit 202 of base station 110 read and execute a program stored in memory unit 201 of base station 110.

[0069] 7, the base station 110 receives transmission requests for data signals from the communication devices 101 and 102. Based on the received transmission requests, the base station 110 determines which communication devices will communicate at the same time and allocates RUs to each communication device (S701). Note that the base station 110 may determine which communication devices will communicate at the same time based on the locations and radio wave environments of the communication devices 101 and 102 in addition to the transmission requests.

[0070] Next, the base station 110 determines the transmission power of each communication device based on the number of RUs used by the communication devices communicating at the same time (S702). For example, if two of four RUs are used and two are not, the base station 110 determines the transmission power so that the transmission power density of each communication device is doubled. On the other hand, if one of four RUs is used and three are not, the base station 110 quadruples the transmission power density of each communication device. Therefore, the transmission power in this case is four times the transmission power in S502. Note that if the transmission power cannot be quadrupled due to hardware constraints or legal constraints of the communication device 101, the maximum transmission power that satisfies these constraints may be used.

[0071] In the above example, the transmission power of each communication device is the same, but this is not limiting and the transmission power may be different for each communication device. In this case, the base station 110 determines the transmission power of each communication device so that the radio wave intensity of the entire frequency channel exceeds a predetermined threshold used by the communication device 103 during carrier sensing.

[0072] For example, the base station 110 acquires hardware information of each communication device and determines the transmission power of each communication device based on this information. For example, consider a case where two of the four RUs are used to allow transmission to a device that can increase the transmission power density by four times and a device that cannot increase the transmission power density. In this case, the base station 110 determines to triple the transmission power for the device that can increase the transmission power density by four times, and to single the transmission power density for the device that cannot increase the transmission power density. This satisfies the hardware requirements of each device, while the frequency channels used by the communication device 103 during carrier sense are optimized as a whole. The signal strength can be determined as exceeding a certain threshold.

[0073] Furthermore, for example, the base station 110 may determine each transmission power based on the reception quality of the signal from each communication device. Specifically, the base station 110 determines to increase the transmission power for devices with poor reception quality compared to devices with good reception quality. Even in this case, the base station 110 determines the transmission power for each communication device so that the radio wave strength of the entire frequency channel exceeds a predetermined threshold used by the communication device 103 during carrier sense. Note that the reception quality may be determined using signal strength or the result of channel estimation between the base station 110 and the communication device (e.g., a value obtained by calculating the eigenvalues ​​of a channel matrix). In this way, the reception quality can be improved by increasing the transmission power of devices with poor reception quality, and the radio wave strength of the entire frequency channel can exceed a predetermined threshold used by the communication device 103 during carrier sense.

[0074] Also, for example, the base station 110 may randomly determine the transmission power of each communication device while ensuring that the radio wave intensity of the entire frequency channel exceeds a predetermined threshold used by the communication device 103 during carrier sensing. This allows the power consumption required for data transmission by each communication device to be roughly equalized over a long period of time.

[0075] Next, the base station 110 transmits a trigger frame including the transmission power of each communication device determined in S702 (S703). Note that it is possible not to issue instructions regarding transmission power to devices for which it was determined in S702 not to increase their transmission power. Furthermore, the base station 110 may notify each communication device of the transmission power of each communication device determined in S702 as a signal separate from the trigger frame.

[0076] Then, each communication device that receives the trigger frame transmits a data signal based on the transmission power instructed by the trigger frame.

[0077] This makes it possible to suppress the occurrence of errors due to interference while taking into consideration the balance with the transmission power when communication is performed using one entire frequency channel, without each communication device having to determine its own transmission power.

[0078] In the above-described embodiment, the following two methods are possible for increasing the transmission power of a communication device. The first method is to increase the transmission power density of the RU for that communication device. The second method is to have other RUs transmit signals in addition to the RU for that communication device. In this case, base station 110 specifies which RUs to use for which communication devices. For example, the base station 110 determines which device requests a large amount of transmission data as the device that will transmit signals in other RUs, and instructs that device to use the other RUs as well. The device then transmits data using two RUs. This increases the transmission power of the entire frequency channel and improves data transmission efficiency.

[0079] The method to be used to increase the transmission power of a communication device may be predetermined, or may be switched depending on the situation. For example, even if the transmission power density is increased within the limits of hardware and laws, the second method may be used if the radio wave intensity over the entire frequency channel does not reach a predetermined threshold, and the first method may be used otherwise.

[0080] In the above-described embodiment, the transmission power of each communication device is determined based on the usage status of the RU. However, this is not limited to this. An information processing device other than the base station may determine the communication devices with which the base station 110 will communicate at the same time based on transmission requests from each communication device, allocate RUs to each communication device, and further determine the transmission power. In this case, the content of the determination is notified to the communication devices via the base station 110. This can also achieve the same effect.

[0081] 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. [Explanation of symbols]

[0082] 100 Wireless Networks 101 Communication equipment 102 Communication equipment 103 Communication equipment 110 base station

Claims

1. A communication device that performs communication in accordance with the IEEE 802.11 series standard using an Orthogonal Frequency Division Multiple Access (OFDMA) method, a notification means for notifying a base station of information regarding the amount of data transmitted by the communication device; a receiving means for receiving, from the base station, a trigger frame including information associating a plurality of resource units obtained by dividing a channel of a predetermined frequency bandwidth with AIDs (Association Identifiers) that are identification information of a plurality of communication devices, and information used by the communication devices to specify transmission power of the communication devices; a transmitting means for transmitting data to the base station using a resource unit associated with an AID of the communication device in the trigger frame; Equipped with the information notified by the notifying means can be used for allocating resource units by the base station; the transmitting means, when a plurality of resource units are associated with the AID of the communication device in the trigger frame, transmits data using the plurality of resource units, and when a single resource unit is associated with the AID of the communication device in the trigger frame, transmits data using the single resource unit; The transmission means, when transmitting data, specifies to use a first transmission power when the information used by the communication device to specify the transmission power of the communication device is a first value and transmits the data at the first transmission power; specifies to use a second transmission power that is higher in power than the first transmission power and transmits the data at the second transmission power when the information used by the communication device to specify the transmission power of the communication device is a second value that is larger than the first value; and specifies to use a third transmission power that is higher in power than the first and second transmission powers and transmits the data at the third transmission power when the information used by the communication device to specify the transmission power of the communication device is a third value that is larger than the first and second values.

2. 2. The communication device according to claim 1, wherein the frequency bandwidth of the channel of the predetermined frequency bandwidth is 20 MHz.

3. 3. The communication device according to claim 1, wherein when two resource units are associated with the AID of the communication device, the transmitting means transmits the data using a frequency bandwidth that is twice as large as the frequency bandwidth when one resource unit is associated with the AID of the communication device.

4. 4. The communication device according to claim 1, wherein when two resource units are associated with the AID of the communication device, the transmitting means transmits first data to the base station using a first resource unit of the two resource units, and transmits second data different from the first data to the base station using a second resource unit.

5. 4. The communication device according to claim 1, wherein when two resource units are associated with the AID of the communication device, the transmitting means transmits first data to the base station using a first resource unit of the two resource units, and transmits the first data to the base station using a second resource unit.

6. further comprising: a determination means for analyzing the trigger frame to obtain information regarding the transmission power, and determining the transmission power using the obtained information; The transmitting means transmits a trigger frame associated with the AID of the communication device.

6. The communication device according to claim 1, wherein the data is transmitted to the base station using the resource unit determined by the determination means at the transmission power determined by the determination means.

7. 7. The communication device according to claim 1, wherein a larger number of resource units are allocated to a communication device among the plurality of communication devices that transmits a larger amount of data based on the information notified by the notifying means.

8. 8. The communication device according to claim 1, wherein the communication device is a camera having an image capturing unit for performing an image capturing process, or a printer having a printing unit for performing a print process.

9. A communication device that performs communication in accordance with the IEEE 802.11 series standard using an Orthogonal Frequency Division Multiple Access (OFDMA) method, an acquisition means for acquiring information regarding the amount of data transmitted by other communication devices participating in a network formed by the communication device; a transmitting means for transmitting a trigger frame to the other communication device, the trigger frame including information associating a plurality of resource units obtained by dividing a channel of a predetermined frequency bandwidth with AIDs (Association Identifiers) that are identification information of a plurality of communication devices, and information used by the other communication device to identify the transmission power of the other communication device; a receiving means for receiving data transmitted from the other communication device using a resource unit associated with an AID of the other communication device in the trigger frame; Equipped with the information acquired by the acquisition means is used to allocate the resource units; the receiving means, when a plurality of resource units are associated with the AID of the other communication device in the trigger frame, receives data transmitted from the other communication device using the plurality of resource units, and when a single resource unit is associated with the AID of the communication device in the trigger frame, receives data using the single resource unit; a trigger frame transmitted to the other communication device including a first value as information used by the other communication device to specify the transmission power of the other communication device causes the other communication device to perform a transmission process of transmitting data at a first transmission power; a trigger frame transmitted to the other communication device including a second value greater than the first value as information used by the other communication device to specify the transmission power of the other communication device causes the other communication device to perform a transmission process of transmitting data at a second transmission power greater than the first transmission power; and a trigger frame transmitted to the other communication device including a third value greater than the first and second values ​​as information used by the other communication device to specify the transmission power of the other communication device causes the other communication device to perform a transmission process of transmitting data at a third transmission power greater than the first and second transmission powers.

10. 10. The communication device according to claim 9, wherein the predetermined frequency bandwidth channel has a bandwidth of 20 MHz.

11. 11. The communication device according to claim 9, wherein when two resource units are associated with the AID of the other communication device, the receiving means receives the data using a resource unit with a frequency bandwidth twice as large as the frequency bandwidth when one resource unit is associated with the AID of the other communication device.

12. A communication device described in any one of claims 9 to 11, characterized in that the information regarding the transmission power is information indicating the transmission power to be used in transmission power control used by another communication device when transmitting data to the communication device in response to receiving the trigger frame.

13. 13. The communication device according to claim 9, wherein a larger number of resource units are allocated to a communication device among the plurality of communication devices that transmits a larger amount of data based on the information acquired by the acquisition means.

14. 14. The communication device according to claim 9, wherein the communication device is a camera having an image capturing unit for performing an image capturing process, or a printer having a printing unit for performing a print process.

15. A control method for a communication device that performs communication in accordance with the IEEE 802.11 series standard using an Orthogonal Frequency Division Multiple Access (OFDMA) method, comprising: a notification step of notifying a base station of information regarding an amount of data transmitted by the communication device; a receiving step of receiving, from the base station, a trigger frame including information associating a plurality of resource units obtained by dividing a frequency channel with AIDs (Association Identifiers) that are identification information of a plurality of communication devices, and information used by the communication devices to specify transmission power of the communication devices; a transmitting step of transmitting data to the base station using a resource unit associated with the AID of the communication device in the trigger frame; Equipped with The information notified in the notification step can be used for allocating resource units by the base station; In the transmitting step, if a plurality of resource units are associated with the AID of the communication device in the trigger frame, data is transmitted using the plurality of resource units, and if a single resource unit is associated with the AID of the communication device in the trigger frame, data is transmitted using the single resource unit; The transmission step further comprises the steps of: when the information used by the communication device to specify the transmission power of the communication device is a first value, specifying to use a first transmission power and transmitting data at the first transmission power; when the information used by the communication device to specify the transmission power of the communication device is a second value greater than the first value, specifying to use a second transmission power greater than the first transmission power and transmitting data at the second transmission power; and when the information used by the communication device to specify the transmission power of the communication device is a third value greater than the first and second values, specifying to use a third transmission power greater than the first and second transmission powers and transmitting data at the third transmission power.

16. A control method for a communication device that performs communication in accordance with the IEEE 802.11 series standard using an Orthogonal Frequency Division Multiple Access (OFDMA) method, comprising: an acquisition step of acquiring information regarding the amount of data transmitted by other communication devices participating in a network formed by the communication device; a transmitting step of transmitting a trigger frame to the other communication device, the trigger frame including information associating a plurality of resource units obtained by dividing a frequency channel with AIDs (Association Identifiers) that are identification information of a plurality of communication devices, and information used by the other communication device to identify the transmission power of the other communication device; a receiving step of receiving data transmitted from the other communication device using a resource unit associated with the AID of the other communication device in the trigger frame; Equipped with The information acquired in the acquiring step is used to allocate the resource units; In the receiving step, if a plurality of resource units are associated with the AID of the other communication device in the trigger frame, data transmitted from the other communication device is received using the plurality of resource units, and if one resource unit is associated with the AID of the communication device in the trigger frame, the one resource unit is used. The data is received using a control method comprising: including a first value in the trigger frame to be transmitted to the other communication device as information used by the other communication device to specify the transmission power of the other communication device, causing the other communication device to perform a transmission process of transmitting data at a first transmission power; including a second value greater than the first value in the trigger frame to be transmitted to the other communication device as information used by the other communication device to specify the transmission power of the other communication device, causing the other communication device to perform a transmission process of transmitting data at a second transmission power greater than the first transmission power; and including a third value greater than the first and second values ​​in the trigger frame to be transmitted to the other communication device as information used by the other communication device to specify the transmission power of the other communication device, causing the other communication device to perform a transmission process of transmitting data at a third transmission power greater than the first and second transmission powers.

17. A program for causing a computer to operate as the communication device according to any one of claims 1 to 14.

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