Communication device, communication method, and program

Abstract

A communication apparatus according to the present invention that performs communication in compliance with the IEEE 802.11 standard series transmits a wireless frame that includes data repeated on the time axis, wherein: a preamble of the wireless frame includes a U-SIG field and an SIG field corresponding to a prescribed standard; and the SIG field includes information pertaining to repetition of the data.

Description

Communication device, communication method, and program

[0001] The present invention relates to a technology for efficiently notifying information associated with repeated data in a communication method for repeatedly transmitting data.

[0002] The Institute of Electrical and Electronics Engineers (IEEE) 802.11 series of standards is known as a communication standard for wireless LANs (Local Area Networks). The IEEE 802.11 series of standards includes standards such as IEEE 802.11a / b / g / n / ac / ax / be. In formulating the IEEE 802.11be standard and its successor standards, it has been considered to improve communication efficiency and throughput and reduce delays by having multiple access point (AP) devices operate cooperatively.

[0003] In particular, for the IEEE 802.11bn standard, which is being considered as a successor to the IEEE 802.11be standard, discussions are underway on methods for improving communication reliability. The IEEE 802.11bn standard may also be referred to as the Ultra High Reliability (UHR) standard. Patent Document 1 discloses a method for transmitting the same data in parallel via multiple frequency channels as one method for improving communication reliability.

[0004] Japanese Patent Application Laid-Open No. 2021-103805

[0005] The present invention provides a technique for efficiently notifying information associated with repeated data in a communication method in which data is repeatedly transmitted.

[0006] A communication device according to one aspect of the present invention is a communication device that performs communication in accordance with the IEEE 802.11 standard series, and has a transmission means for transmitting a wireless frame including data repeated on a time axis, wherein the Physical Layer (PHY) header of the wireless frame includes a U-SIG field and a SIG field corresponding to a predetermined standard, and the SIG field includes information regarding the repetition of the data.

[0007] According to the present invention, in a communication method for repeatedly transmitting data, it is possible to efficiently notify information associated with the repeated data.

[0008] Fig. 1 is a diagram showing an example of the configuration of a wireless communication system. Fig. 2 is a diagram showing an example of the hardware configuration of a communication device. Fig. 3 is a diagram showing an example of the functional configuration of a communication device. Fig. 4 is a diagram showing a first example of the configuration of a PPDU frame format. Fig. 5 is a diagram showing a first example of the configuration of a PPDU frame format. Fig. 6 is a diagram showing an example of the configuration of a preamble frame format. Fig. 7 is a diagram showing an example of the operation of a communication device when transmitting a PPDU. Fig. 8 is a diagram showing an example of the operation of a communication device when receiving a PPDU. Fig. 9 is a diagram showing a second example of the configuration of a PPDU frame format. Fig. 10 is a diagram showing a third example of the configuration of a PPDU frame format.

[0009] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the invention claimed. 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] (System Configuration) Fig. 1 shows an example configuration of a wireless communication system according to this embodiment. This wireless communication system includes, for example, one access point (AP) 101 and one non-AP station (Non-AP STA, hereinafter referred to as STA) 102. A network 110 formed by the AP 101 indicates the range in which the AP 101 and the STA 102 can communicate. That is, within the range of the network 110, the STA 102 can receive signals transmitted by the AP 101, and signals transmitted by the STA 102 can be received by the AP 101. The AP 101 and the STA 102 are communication devices capable of wireless communication compliant with the IEEE 802.11 series of standards, including the IEEE 802.11bn standard. Note that IEEE stands for Institute of Electrical and Electronics Engineers. The IEEE 802.11bn standard is a successor to the IEEE 802.11be standard, which targets a maximum transmission speed of 46.08 Gbps. The IEEE 802.11bn standard lists high-reliability communication, low-latency communication, and improved throughput during congestion as its main features. The IEEE 802.11bn standard may also be referred to as the UHR standard. UHR may be an abbreviation for Ultra High Reliability. Wireless frames communicated according to the IEEE 802.11bn standard may be referred to as UHR (Ultra High Reliability) PPDUs. PPDU stands for Physical Layer (PHY) Protocol Data Unit. In this embodiment, a wireless frame communicated based on the IEEE 802.11 series standards may be referred to as a PPDU. The PPDU may include a UHR-PPDU. The names IEEE 802.11bn standard and UHR standard were chosen for convenience, taking into account the goals to be achieved when developing these standards and the main features of their development. Therefore, these standards may be given different names once the development of the standards is complete. However, this specification and the accompanying claims are essentially applicable to all standards that may be successors to the IEEE 802.11be standard.

[0011] The IEEE 802.11 series standards may include the IEEE 802.11a / b / g / n / ac / ax / be standards. These standards may be referred to as legacy standards. That is, the AP 101 and the STA 102 may support one or more legacy standards in addition to the IEEE 802.11bn standard. Note that the AP 101 and the STA 102 may also support other communication standards such as Bluetooth (registered trademark), NFC, UWB, ZigBee, and MBOA in addition to the IEEE 802.11 series standards. Note that UWB stands for Ultra Wide Band, and MBOA stands for Multi Band OFDM Alliance. Also, NFC stands for Near Field Communication. UWB includes wireless USB, wireless 1394, WiNET, etc. The AP 101 and the STA 102 may also be compatible with a communication standard for wired communication such as a wired LAN.

[0012] Although FIG. 1 illustrates a state in which one AP 101 and one STA 102 exist, multiple APs 101 and multiple STAs 102 may exist. Furthermore, multiple STAs 102 may be connected to one AP 101, or one STA 102 may be connected to multiple APs 101. The AP 101 may be, but is not limited to, a wireless LAN router or a personal computer (PC). The STA 102 may be, but is not limited to, any electronic device such as a smartphone, tablet, mobile phone, PC, video camera, headset, printer, or display. The AP 101 and the STA 102 may be information processing devices such as wireless chips capable of performing wireless communication compliant with the IEEE 802.11bn standard. In this embodiment, the AP 101 and the STA 102 may be referred to as communication devices 100 without distinction.

[0013] The communication device 100 may communicate using radio signals in frequency bands such as the 2.4 GHz band, the 3.6 GHz band, the 5 GHz band, the 6 GHz band, and the 45 GHz band and 60 GHz band, which are called millimeter waves. The frequency bands used by the communication device 100 are not limited to these and may be, for example, the Sub 1 GHz band. The communication device 100 may also communicate using bandwidths of 20 MHz, 40 MHz, 80 MHz, 160 MHz, 320 MHz, 540 MHz, 640 MHz, 1080 MHz, and 2160 MHz. The bandwidths used by the communication device 100 are not limited to these and may be, for example, 240 MHz, 4 MHz, etc. The IEEE 802.11 series standards specify a frequency channel using a 20 MHz bandwidth as a basic channel in frequency bands such as the 2.4 GHz, 5 GHz, and 6 GHz bands. This standard also defines multiple available channels in each of the 2.4 GHz, 5 GHz, and 6 GHz frequency bands. This standard allows the communication device 100 to use a channel in combination with an adjacent channel. This use of a channel in combination with an adjacent channel may be referred to as channel bonding.

[0014] The IEEE 802.11 series of standards stipulates an OFDMA function that divides a channel into multiple resource units on the frequency axis and performs multiple access. A resource unit is also called an RU (Resource Unit). OFDMA is an abbreviation for Orthogonal Frequency Division Multiple Access. For example, when multiple STAs 102 are connected to the AP 101, the AP 101 divides a channel used by the AP 101 into multiple resource units and assigns them to each STA 102. As an example, when two STAs 102 are connected to the AP 101, the AP 101 transmits one PPDU using one 20 MHz channel. In this case, the AP 101 arranges two different resource units on the frequency axis within one PPDU. Each resource unit may have a bandwidth of 10 MHz. Furthermore, the resource units may be arranged so as not to overlap with each other on the frequency axis. The AP 101 transmits downlink data to each STA 102 using the resource units allocated to each STA 102. The STA 102 receives data transmitted to the STA 102 in the resource units allocated to the STA 102. For example, the STA 102 may identify the resource units allocated to the STA 102 by referring to information regarding the allocation and assignment of resource units stored in the preamble of the PPDU. In this way, by using the OFDMA function, the AP 101 is able to transmit data to multiple STAs 102 in parallel. Note that when the STA 102 transmits uplink data to the AP 101, the AP 101 first transmits a trigger frame. The trigger frame may indicate information regarding the allocation and assignment of resource units for uplink transmission. That is, the STA 102 may identify the resource units to be used by the STA 102 for uplink transmission by referring to the trigger frame, and transmit the uplink data using the resource units.

[0015] The IEEE 802.11bn standard considers repeated transmission of data. For example, the transmitting communication device 100 copies the original portion of data in one PPDU and repeatedly transmits the data, and the receiving communication device 100 decodes the data using multiple pieces of data, including the copied data, thereby increasing the probability of successful reception. However, constantly transmitting data repeatedly reduces the utilization efficiency of frequency resources. On the other hand, when the transmitting communication device 100 repeatedly transmits data depending on the situation, there is a possibility that the receiving communication device 100 will not be able to properly process the data because there is no way for the receiving communication device 100 to recognize that repetition has occurred or the number of repetitions.

[0016] In consideration of these circumstances, the communication device 100 of this embodiment, when repeatedly transmitting data on the time axis according to the communication conditions, notifies the other communication device that the radio frame contains repeated data. As an example, the communication device 100 may include specific information indicating that the radio frame contains repeated data in the preamble of the radio frame. The communication device 100 may notify the specific information using a Signal (SIG) field corresponding to a predetermined standard included in the preamble, such as a UHR (Ultra High Reliability)-SIG field. Meanwhile, the receiving communication device 100 may determine whether the radio frame contains repeated data and, based on the result, combine and decode multiple data. Furthermore, the communication device 100 may combine multiple received data after weighting them based on their respective received powers. Note that the communication device 100 does not necessarily use all received data for decoding. For example, the communication device 100 may measure the received power, etc., of each received data and combine data exceeding a predetermined threshold. As described above, according to the present embodiment, when transmitting a radio frame including data repeated on a time axis, a means for notifying and specifying information related to the repetition is provided, which allows the communication device 100 to flexibly increase reliability by using data repetition according to the communication situation, etc.

[0017] (Device Configuration) FIG. 2 shows an example of the hardware configuration of the AP 101 and the STA 102 in this embodiment. The AP 101 has 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. Note that there may be multiple antennas. The storage unit 201 is configured with one or more memories such as ROM and RAM, and stores various information such as computer programs for performing various operations described below and communication parameters for wireless communication. ROM and RAM are abbreviations for Read Only Memory and Random Access Memory, respectively. Note that the storage unit 201 may be a memory such as a ROM, RAM, or other storage medium such as a flexible disk, hard disk, optical disk, magneto-optical disk, CD-ROM, CD-R, magnetic tape, non-volatile memory card, or DVD. The storage unit 201 may also be equipped with multiple memories.

[0018] The control unit 202 is configured with one or more processors such as a CPU or an MPU, and controls the entire AP 101 or the STA 102 by executing a computer program stored in the storage unit 201. Note that the control unit 202 may control the entire AP 101 or the STA 102 in cooperation with the computer program stored in the storage unit 201 and an OS (Operating System). The control unit 202 also generates data and signals (wireless frames) to be transmitted in communication with other communication devices.

[0019] Note that CPU is an abbreviation for Central Processing Unit, and MPU is an abbreviation for Micro Processing Unit. The control unit 202 may include multiple processors, such as multi-core processors, and the multiple processors may control the entire AP 101 or STA 102. The control unit 202 also controls the function unit 203 to perform predetermined processes such as wireless communication, image capture, printing, and projection. The function unit 203 is hardware that enables the AP 101 or STA 102 to perform predetermined processes.

[0020] The input unit 204 receives various operations from the user. The output unit 205 outputs various types of information to the user via a monitor screen or a speaker. Here, the output from the output unit 205 may be a display on a monitor screen, an audio output from a speaker, a vibration output, or the like. Note that both the input unit 204 and the output unit 205 may be implemented in a single module, such as a touch panel. The input unit 204 and the output unit 205 may be integrated with the AP 101 or the STA 102, respectively, or may be separate units.

[0021] The communication unit 206 controls wireless communications compliant with the IEEE 802.11bn standard. The communication unit 206 may also control wireless communications compliant with other IEEE 802.11 series standards in addition to the IEEE 802.11bn standard, or wired communications such as a wired LAN. The communication unit 206 controls the antenna 207 to transmit and receive signals for wireless communications generated by the control unit 202. If the AP 101 or the STA 102 supports standards such as the NFC standard or Bluetooth in addition to the IEEE 802.11bn standard, the communication unit 206 may control wireless communications compliant with these communication standards. If the AP 101 or the STA 102 can perform wireless communications compliant with multiple communication standards, the communication unit 206 may be configured to have separate communication units and antennas compatible with each communication standard. The communication device communicates data such as image data, document data, and video data with a counterpart communication device via the communication unit 206. The antenna 207 may be configured as a separate unit from the communication unit 206, or may be configured together with the communication unit 206 as a single module.

[0022] The antenna 207 is an antenna capable of communication in the 2.4 GHz band, 5 GHz band, 6 GHz band, etc. In this embodiment, there may be two or more antennas, and if the communication unit 206 is configured with multiple communication units, there may be an antenna corresponding to each communication unit. Alternatively, there may be a different antenna for each frequency band.

[0023] FIG. 3 shows a block diagram of the functional configuration of the communication device 100 (AP 101 and STA 102) according to this embodiment. The communication device 100 may include a wireless LAN control unit 301, a frame generation unit 302, a frame analysis unit 303, a UI control unit 304, and a storage unit 305. The wireless LAN control unit 301 controls the communication unit 206 and the antenna 207 for transmitting and receiving wireless signals with other wireless LAN devices. For example, the wireless LAN control unit 301 cooperates with the frame generation unit 302 and the frame analysis unit 303 to control wireless frame communication in accordance with the IEEE 802.11 standard series. Note that when the wireless LAN control unit 301 is implemented by the control unit 202, the wireless LAN control unit 301 may determine whether data needs to be repeated on the time axis and the number of repetitions. The wireless LAN control unit 301 may also notify the frame generation unit 302 of information regarding the determined data repetition and instruct the frame generation unit 302 to generate a wireless frame based on that information. The wireless LAN control unit 301 may also perform control to notify the other communication device of specific information for identifying whether or not data is repeated on the time axis, the number of repetitions, etc. The specific information regarding repetition may be, for example, information indicating that repeated data is included in the wireless frame, the number of repetitions included, the total number including the original, and information identifying each piece of repeated data.

[0024] The frame generation unit 302 generates wireless frames including MAC frames such as management frames, control frames, and data frames. MAC frames are also called MAC Protocol Data Units (MPDUs) or Aggregate MAC Protocol Data Units (A-MPDUs). Wireless frames consist of a preamble field and a data field. MAC frames such as management frames, control frames, and data frames are stored in the data field. The content of wireless control by each MAC frame generated by the frame generation unit 302 may be restricted by settings stored in the storage unit 305. The frame generation unit 302 may accept settings from a user via the UI control unit 304. The wireless frames generated by the frame generation unit 302 are sent to the wireless LAN control unit 301 and can be transmitted to the outside via the communication unit 206 or the antenna 207.

[0025] The frame analysis unit 303 analyzes a wireless frame received through cooperation between the communication unit 206, the antenna 207, and the wireless LAN control unit 301. When analyzing a wireless frame, the frame analysis unit 303 can determine the analysis method based on the settings stored in the storage unit 305. The frame analysis unit 303 analyzes the preamble of the received wireless frame and can identify whether or not repetitions are included in the data assigned to its own device, the number of repetitions, etc.

[0026] The UI control unit 304 is configured to include hardware related to a user interface, such as a touch panel or buttons, for accepting operations by a user (not shown) on the AP 101 or the STA 102, and a program for controlling these. The UI control unit 304 also has a function for presenting information, such as displaying images or outputting audio, to the user.

[0027] The storage unit 305 is a storage device that can be configured with a ROM, a RAM, etc., for storing programs and data that the communication device operates on.

[0028] (Frame Format) FIG. 4A shows an example of a PPDU frame format used by the communication device 100 in this embodiment. This PPDU may be a UHR PPDU addressed to one communication device 100. The PPDU may be named something else, such as a UHR MU PPDU. The PPDU may include a preamble 401, original data 402, data 403 and data 404, which are copies of data 402, and a PE 405. The preamble 401 is also called a PHY header or PHY preamble, and includes information necessary for receiving the PPDU, including information regarding the repetition of data on the time axis. Details of the preamble configuration will be described later using FIG. 5. Also, in FIG. 4A, two copies of the data (data 403 and data 404) are generated, and the same data, including the original data 402, is transmitted three times on the time axis. The data may include an MPDU or an A-MPDU. PE 405 is an abbreviation for Packet Extension, and is a field for providing the receiving communication device 100 with a time allowance for the reception processing of the PPDU. Instead of PE, a Signal Extension or Padding field may be stored. The PPDU in FIG. 4A may be transmitted from the AP 101 to the STA 102, or from the STA 102 to the AP 101.

[0029] FIG. 4B shows another example of a PPDU frame format used by the communication device 100 in this embodiment. This PPDU is a UHR PPDU addressed to three user communication devices. The PPDU may include a preamble 411 and data (412-417) for each user communication device, transmitted in resource units separated on the frequency axis. The user communication devices may be simply referred to as users. The preamble 411 contains information necessary for receiving the PPDU, including information about the repetition of each user's data on the time axis. Details of the preamble configuration will be described later using FIG. 5. Also in FIG. 4B, two copies of data (data 413 and data 414) are generated for the first user, and the same data, including the original data 412, is transmitted three times on the time axis. Furthermore, no data copies are included for the second user, and only the original data 415 is transmitted. Furthermore, one copy of data (data 417) is generated for the third user, and the same data, including the original data 416, is transmitted twice on the time axis. The PPDU of FIG. 4B may be transmitted from the AP 101 to multiple STAs 102.

[0030] 5 shows an example of a frame format of a PPDU preamble used by the communication device 100 in this embodiment. The preamble may include L-STF 501, L-LTF 502, and L-SIG 503. L-STF and L-LTF are abbreviations for Legacy-Short Training Field and Legacy-Long Training Field, respectively. L-SIG is an abbreviation for Legacy-Signal Field. L-STF 501, L-LTF 502, and L-SIG 503 are arranged at the beginning of the preamble and are fields used to ensure backward compatibility with IEEE 802.11a / b / g / n / ax / be standards, etc. For example, L-STF 501 and L-LTF 502 may be training fields, and L-SIG 503 may be a signal field. L-STF 501 is used for PPDU detection, automatic gain control (also referred to as AGC), timing detection, etc. L-LTF 502 is used for highly accurate synchronization of frequency and time, acquisition of propagation channel information (also referred to as Channel State Information, CSI), etc. L-SIG 503 is used to notify control information including information on the data rate and the frame length of the PPDU. In other words, the receiving communication device 100 may ascertain the timing at which transmission or reception of the PPDU is completed using the notified information on the data rate and the frame length of the PPDU. Note that devices operating in accordance with the IEEE 802.11a / b / g / n / ax / be standards, as well as devices operating in accordance with the IEEE 802.11 standard or its successor standards (including the UHR standard), can decode these fields (legacy fields). Placing the legacy field at the beginning of the PPDU in this way allows devices operating in accordance with legacy standards to receive and decode the PPDU, thereby preventing the PPDU containing the subsequent new field from being regarded as an interference signal. The legacy field may be referred to as a legacy preamble. The preamble may also include an RL-SIG 504. RL-SIG is an abbreviation for Repeated L-SIG.That is, RL-SIG 504 may be a repetition of L-SIG 503, and indicates that the PPDU conforms to the format used in the IEEE 802.11ax standard and later standards.

[0031] The preamble may include a U-SIG 505. U-SIG is an abbreviation for Universal Signal Field. The U-SIG 505 may be a field for notifying control information commonly used in standards subsequent to the IEEE 802.11be standard. The control information included in the U-SIG 505 may differ depending on the standard. For example, the U-SIG 505 may include fields such as a PHY Version Identifier indicating the version of the PHY and a BSS Color indicating a color code used to determine the BSS. For example, a value of 1 in the PHY Version Identifier may indicate that the PPDU is a UHR PPDU. The U-SIG 505 may be located immediately after the legacy preamble or the RL-SIG 504.

[0032] The preamble includes a Signal (SIG) field corresponding to or related to a predetermined standard, and may include, for example, UHR-SIG 506, which is a SIG field corresponding to the UHR standard. UHR-SIG is an abbreviation for Ultra High Reliability Signal Field. UHR-SIG 506 may include control information not placed in U-SIG 505 or control information to be individually notified to each user when performing multi-user transmission. Multi-user transmission is a transmission method that transmits to multiple communication devices in parallel using, for example, OFDMA. Multi-user transmission may be performed using multi-user MIMO (Multiple-Input Multiple-Output) or the like. UHR-SIG 506 may be placed immediately after U-SIG 505. Furthermore, UHR-SIG 506 is a field containing information regarding the repetition of data on the time axis. The name UHR-SIG is a name provided for convenience to identify that this is a SIG field that complies with the IEEE 802.11bn standard. Therefore, a different name may be used. Furthermore, a SIG field that complies with or is related to a predetermined standard may be composed of multiple SIG fields, for example, two SIG fields such as a UHR-SIG-A field and a UHR-SIG-B field, or three or more SIG fields. Furthermore, although a UHR PPDU is used as an example in this embodiment, if the PPDU complies with a predetermined standard other than UHR, UHR-SIG may be replaced with a different name.

[0033] The preamble may include UHR-STF 507 and UHR-LTF 508. UHR-STF and UHR-LTF are abbreviations for Ultra High Reliability Short Training Field and Ultra High Reliability Long Training Field, respectively. UHR-LTF 508 is a training field used for estimating channel information when MIMO or beamforming is used. Multiple UHR-LTFs 508 may be arranged in one preamble. The number of UHR-LTFs 508 to be arranged may be determined based on, for example, the number of antennas used for MIMO and whether beamforming is implemented. For example, up to eight UHR-LTFs 508 may be arranged in the preamble. UHR-STF 507 and UHR-LTF 508 may be placed after UHR-SIG 506 .

[0034] In this embodiment, UHR PPDU is used as an example, but if the PPDU complies with a predetermined standard other than UHR, UHR-LTF and UHR-STF may be replaced with other names.

[0035] L-STF 501 to UHR-LTF 508 may also be referred to as a PHY preamble or a PHY header. The arrangement of the fields constituting the preamble is not limited to the example of FIG. 5, and may be arranged in a different order. The preamble does not need to include all of the fields shown in FIG. 5, and may include only some of the fields. A field different from the fields shown in FIG. 5 may also be added to the preamble.

[0036] In this embodiment, an example will be described in which the communication device 100 uses UHR-SIG 506 to notify a counterpart communication device of information regarding the repetition of data on the time axis. Note that the information regarding the repetition of data on the time axis may be notified using other information elements or fields. UHR-SIG 506 may include one or more UHR-SIG content channels. Each UHR-SIG content channel may be configured with a Common field 511 and a User Specific Field 512. Each UHR-SIG content channel may include other components and fields. The Common field 511 may include a field such as RU Allocation. RU Allocation indicates the configuration of resource units in the PPDU. The User Specific Field 512 may include multiple User encoding blocks 513. When multiple User encoding blocks are included, each User encoding block 513 corresponds in order to a resource unit included in the PPDU. Information regarding the repetition of data on the time axis may be notified using the User field included in the User encoding block 513. Table 1 shows an example of the configuration of the User encoding block 513.

[0037]

[0038] The User field is a field indicating user information, and includes information specific to the user (STA) shown in Table 2.

[0039]

[0040] One or two User fields can be stored in one User encoding block 513. CRC is used to confirm that information has been received correctly by a cyclic redundancy check. Tails is a field that indicates the end by being set to a value of 0. The arrangement of the fields that make up the User encoding block is not limited to the example in Table 1, and they may be arranged in a different order. Furthermore, the User encoding block does not need to include all of the fields shown in Table 1; it may include only some of the fields, or a field different from the fields shown in Table 1 may be added. The User field includes the following fields: STA-ID, MCS, NSS, Beamformed, Coding, Repetition, and Number of Repetition. STA-ID indicates an identifier that identifies each STA 102. MCS is an abbreviation for Modulation and Coding Scheme, and indicates the modulation and coding method used in communications.

[0041] NSS is an abbreviation for Number of Spatial Streams and indicates the number of spatial streams used in MIMO. Beamformed indicates whether a beamforming steering matrix is ​​used. Coding indicates whether BCC (Block Convolutional Code) or LDPC (Low Density Parity Check) is used. Repetition indicates whether data is repeated on the time axis. For example, a value of 0 for Repetition indicates that no repetition is performed, and a value of 1 indicates that repetition is performed.

[0042] Repetition may be named differently, for example, Replication. Number of Repetition indicates the number of repetitions of data on the time axis. For example, if the value of Number of Repetition is 3, it indicates that three repeated pieces of data are included in the PPDU. That is, in this case, the PPDU includes four identical pieces of data, including the original (source) data and the three replicated repeated pieces of data. In this embodiment, the number of bits of Number of Repetition is 3 bits, but it may be 4 bits or more if a larger number of repetitions is required, or 2 bits or less if a smaller number of repetitions is sufficient. Furthermore, Number of Repetition may be named differently, for example, Number of Replication. If the value of Number of Repetition is 1 or more, the value of Repetition is set to 1. Note that the contents of User Specific Field 512 and the like are merely examples and are not limited to these. For example, MCS may be 5 bits or more. The arrangement of the fields constituting the User field is not limited to the example in Table 2 and may be arranged in a different order. Furthermore, the User field does not need to include all the fields shown in Table 2 and may include only some of the fields. Furthermore, a field different from the fields shown in Table 2 may be added to the User field. Repetition and Number of Repetition may be included in other fields such as Common field 511.

[0043] (Processing Flow) Next, the processing flow executed by the communication device 100 as described above will be described using Figures 6 and 7. Figure 6 shows an example of the operation when the AP 101 transmits a PPDU containing data repeated on the time axis. Figure 7 shows an example of the operation when the STA 102 receives a PPDU containing data repeated on the time axis. Each process shown in the flowcharts of Figures 6 and 7 is executed by the processor of the control unit 202 of the AP 101 or STA 102 executing a computer program stored in the storage unit 201. Some of the processing in Figures 6 and 7, such as transmission, modulation, reception, and decoding, is realized by the processor of the control unit 202 of each communication device, the communication unit 206, and the ASIC, DSP, FPGA, etc. of the control unit 202 working together. Note that when clearly indicating the subject of processing, the functional unit described in Figures 2 and 3 will be used as the subject.

[0044] First, the transmission operation in the communication device 100 will be described using Figure 6. For example, the control unit 202 in the AP 101 performs the transmission operation in cooperation with other functional units. The AP 101 first determines the number of users (the number of STAs 102) to which the PPDU is addressed (S601). For example, when transmitting a PPDU such as that shown in Figure 4A, the number of users is determined to be 1, and when transmitting a PPDU such as that shown in Figure 4B, the number of users is determined to be 3.

[0045] Next, the AP 101 determines whether the User fields of all users to be included in the UHR-SIG of the preamble of the PPDU have been set (S602).

[0046] If the AP 101 determines that the user fields of all users have not been set (NO in S602), it selects a user for whom the user field has not been set (S603). The AP 101 then acquires the communication quality of communication with the selected user (S604). The communication quality may be determined by using the received signal strength indicator (RSSI) or SNR (signal to noise ratio) from the STA 102, or may be determined by receiving feedback from the STA 102 about the received signal power or SNR of the signal from the AP 101.

[0047] Next, the AP 101 determines whether to repeat the data on the time axis based on the communication quality obtained in S604 (S605). For example, the AP 101 may determine to repeat the data if the communication quality is below a predetermined threshold. For example, the AP 101 may use the communication quality measured in past communications, or may estimate and use the communication quality for future communications. When estimating the communication quality for future communications, an inference result can be obtained by inputting the measured communication quality into a trained model obtained by learning using known supervised learning, deep learning, or the like. In this case, the AP 101 may determine whether to repeat the data based on the probability obtained as the inference result.

[0048] When the AP 101 determines that data repetition is necessary (YES in S605), it sets the Number of Repetition in the User field included in the UHR-SIG of the PPDU preamble to a repetition number of 1 or more according to the communication quality (S606). The AP 101 may determine the number of data repetitions so that the probability of success when decoding using multiple pieces of data exceeds a predetermined threshold. As an example, the AP 101 determines the number of repetitions required for the SNR to exceed a predetermined threshold. Note that the method by which the AP 101 determines the number of data repetitions is not limited to this. For example, the AP 101 may calculate RSSI using a received signal from the STA 102 and determine the number of repetitions required for the total RSSI to exceed a predetermined threshold. In addition, the AP 101 may indicate that repetition is being performed by setting the value of Repetition in the User field included in the UHR-SIG of the PPDU preamble to 1. Next, the AP 101 copies the data to be included in the PPDU from the data of the original MPDU or A-MPDU according to the set number of repetitions (S608).

[0049] When it is determined that data repetition is not necessary (NO in S605), the AP 101 sets the Number of Repetition in the User field included in the UHR-SIG of the PPDU preamble to 0 (S607). In addition, the AP 101 may set the value of Repetition in the User field included in the UHR-SIG of the PPDU preamble to 0 to indicate that no repetition is being performed.

[0050] Next, the AP 101 sets appropriate values ​​for the other fields included in the User field of the selected user (S609). For example, the AP 101 may set the MCS and NSS based on the communication quality acquired in S604. Then, the AP 101 returns to the process of S602 and continues the process of setting the User field for any remaining users who have not set it.

[0051] When the AP 101 determines that the User fields for all users have been set (YES in S602), it uses the frame generation unit 302 to set other fields in the PPDU preamble, generates and transmits a PPDU (S610), and ends the process. The AP 101 can include resource unit allocation in the PPDU using the Common field 511 and User Specific Field 512 of the UHR-SIG in FIG. 5. For example, the resource unit configuration can be stored in the RU Allocation field. The STA 102 to which each resource unit is allocated can be indicated by the User Specific Field 512 following the Common field 511. For example, the User Specific Field 512 may include a Used Field corresponding to each resource unit. When each User field corresponds to each resource unit in turn, the STA ID included in each User field may indicate the STA to which the resource unit is assigned. Then, the AP 101 transmits the generated PPDU using the communication unit 206.

[0052] The process of FIG. 6 may be performed by the STA 102, and when performed by the STA 102, the number of users becomes 1 and a PPDU is transmitted to the AP 101.

[0053] Next, the receiving operation of the communication device 100 will be described using FIG. 7 . For example, the control unit 202 in the STA 102 performs the receiving operation in cooperation with other functional units. The STA 102 receives a PPDU via the communication unit 206 and acquires a PPDU addressed to the STA 102 using the frame analysis unit 303 (S700). For example, the STA 102 may identify a PPDU addressed to the STA 102 by referencing the STA ID of each User field included in the preamble of the received PPDU. The STA 102 then determines whether the received PPDU contains repeated data on the time axis (S701). For example, the STA 102 may determine whether the PPDU contains repeated data based on whether the Repetition value of the User field included in the UHR-SIG in the PPDU preamble is 1 or whether the Number of Repetition value is 1 or greater.

[0054] If STA 102 determines that the PPDU contains repeated data (YES in S701), it acquires the data contained in the PPDU sequentially from the beginning (S702) and performs processing for decoding using the multiple pieces of data. First, STA 102 determines the reception quality of the acquired data (S703). For example, STA 102 measures the RSSI and SNR of the data using the frame analysis unit 303, and may determine that the reception quality is acceptable if the measurement result is equal to or greater than a predetermined threshold. If the reception quality of the data is acceptable (YES in S703), STA 102 stores the data in the storage unit 305 as a combination target (S704). On the other hand, if the reception quality of the data is unacceptable (NO in S703), STA 102 does not include the data in the combination target (S705). In this case, the data is not stored in the storage unit 305. STA 102 may discard the data. The STA 102 determines whether it has acquired the data for the number of repetitions. If it determines that it has not acquired all the data (NO in S707), it returns to S702 to acquire the next data and continue processing. The STA 102 may make this determination based on, for example, whether it has acquired the number of data indicated by the Number of Repetitions in addition to the original data. On the other hand, if it determines that it has acquired the data for the number of repetitions (YES in S707), it decodes the data using the data stored in the storage unit 305 (S708). For example, the STA 102 may combine multiple pieces of data and decode the data. The STA 102 may also combine the received multiple pieces of data after weighting them based on their respective received powers. On the other hand, if it determines in S701 that the received PPDU does not contain repeated data on the time axis (NO in S701), the STA 102 decodes the data independently and stores it in the storage unit 305 (S706).

[0055] In S703 to S705, instead of including data with unacceptable reception quality in the combination, STA 102 may store each piece of data together with its reception quality in storage unit 305. Then, in S708, each piece of data stored in storage unit 305 may be subjected to processing such as weighting and interference removal based on the reception quality before being used for combination. By performing processing based on reception quality before using each piece of data for decoding processing, it becomes possible to effectively utilize received signals.

[0056] The processing in FIG. 7 may be performed by the AP 101, and when performed by the AP 101, the AP 101 receives the PPDU transmitted from the STA 102.

[0057] As described above, in this embodiment, the transmitting communication device 100 determines whether to repeat data on the time axis and the number of repetitions based on the communication quality of the channel used by the transmitting communication device 100. Then, the receiving communication device 100 transmits a PPDU to the receiving communication device 100, the PPDU including the repeated data based on the determination and a preamble including information indicating whether the data is repeated and the number of repetitions. The receiving communication device 100 determines whether the data is repeated and the number of repetitions from the preamble of the received PPDU. Then, the receiving communication device 100 decodes the data using the repeated data. This allows the transmitting communication device 100 to flexibly transmit radio frames including repeated data based on the communication quality with the receiving communication device 100, and allows the receiving communication device 100 to decode the data with a higher probability using the repeated data.

[0058] (Modification 1) FIG. 8 shows another example of the frame format of the PPDU used by the communication device 100. In FIG.

[0059] The PPDUs may be UHR PPDUs addressed to one communication device 100. Each PPDU includes a preamble and data, with a copy of the original data 802 included in the first PPDU included in the data 804 of the second PPDU and the data 806 of the third PPDU. Preambles 801, 803, and 805 include information necessary for receiving the PPDU, including information regarding the repetition of data in each PPDU on the time axis. The format of the preamble is as shown in FIG. 5.

[0060] 8 is used, for example, AP 101 may notify STA 102 of whether data is repeated and the number of times the data is repeated, as well as information identifying the order of the repeated data. Table 3 shows an example of the configuration of the User field used when AP 101 notifies STA 102 of whether data is repeated, the number of times the data is repeated, and information identifying the order of each piece of repeated data.

[0061]

[0062] In Table 3, the configuration of the User field in Table 2 is the same as that of the Repetition ID, so a description thereof will be omitted. In the example of Fig. 8, the Repetition of preambles 801, 803, and 805 is set to a value of 1, and the Number of Repetition is set to a value of 2. The Repetition ID is identification information for uniquely identifying data from among the original data and one or more repeated data items repeated on the time axis. For example, the Repetition ID of the User field included in the preamble 801 corresponding to the original data 802 in Fig. 8 may be set to a value of 0. Furthermore, the Repetition ID of the User field included in the preamble 803 corresponding to the first repeated data item 804 in Fig. 8 may be set to a value of 1. The Repetition ID of the User field included in the preamble corresponding to the Nth repeated data may store a value of N. N is an integer equal to or greater than 1. The Repetition ID may be used to manage received data during reception by the STA 102. For example, the STA 102 may store the Repetition ID of the received data in association with its reception quality. When decoding data using multiple pieces of data, the STA 102 may identify the data to be used based on the identifier. For example, the STA 102 may separately store each piece of received data and its reception quality, and create a table that associates the identifier of each piece of data with its reception quality. When decoding data, the STA 102 may identify data corresponding to reception quality equal to or greater than a predetermined threshold based on the table. This configuration may improve the efficiency of management of data stored in the STA 102 and the decoding process. Furthermore, when data is repeatedly transmitted using a PPDU such as that shown in FIG. 8, the Repetition ID included in the preamble can be used to determine the timing of decoding.8, for example, the value of Number of Repetition included in preamble 803 is 2, and the value of Repetition ID included in preamble 803 is 1, so at the time data 804 is received, it can be determined that it is still necessary to wait for subsequent data 806. Thereafter, when the subsequent PPDU is received, the value of Repetition ID included in preamble 805 is 2, which matches the value of Number of Repetition, so it can be determined that reception of all repeated data has ended and that it is time to combine multiple pieces of data and perform decoding processing. The PPDU in FIG. 8 may be transmitted from AP 101 to STA 102, or from STA 102 to AP 101.

[0063] (Variation 2) FIG. 9 shows yet another example of a PPDU frame format used by the communication device 100. This PPDU may be a UHR PPDU addressed to one communication device 100. Each PPDU includes a preamble and data, with the second PPDU 902 and third PPDU 903 being copies of the first PPDU 901. The preamble of each PPDU contains the same content and includes information regarding the repetition of data on the time axis. In this embodiment, the transmitting communication device 100 may duplicate data on a PPDU-by-PPDU basis and transmit the PPDUs repeatedly. The receiving communication device 100 may combine multiple received PPDUs and perform decoding processing. In the example of FIG. 9, the Repetition value included in each preamble of PPDUs 901 to 903 is set to 1, and the Number of Repetition value is set to 2. The PPDU in FIG. 9 may be transmitted from the AP 101 to the STA 102, or from the STA 102 to the AP 101.

[0064] (Variation 3) The transmitting communication device 100 may notify information regarding data repetition using the MCS field included in the User field of the UHR-SIG, instead of notifying repetition information using the Repetition or Number of Repetition of the preamble, etc. Table 4 shows an example of the configuration of the MCS field used when the transmitting communication device 100 notifies the receiving communication device 100 of information regarding data repetition using the MCS field.

[0065]

[0066] Generally, the MCS field is used to notify a combination of a modulation scheme and a coding rate used in communication. In Table 4, in addition to the modulation scheme and the coding rate, an index (UHR-MCS index) is set to indicate the number of repetitions of data included in the PPDU. For example, in Table 4, when the UHR-MCS index is 16, it indicates that the data corresponding to the User field including this MCS field is transmitted as two identical data, consisting of the original data and one repeated data that is a copy of the original data. When the UHR-MCS index is 17, it indicates that two repeated data are transmitted, and when the UHR-MCS index is 18, it indicates that three repeated data are transmitted. DCM stands for Dual Carrier Modulation, and TDM stands for Time Division Modulation. Furthermore, when the UHR-MCS index is 19 to 21, dual carrier modulation, which replicates data on the frequency axis and transmits the same data twice, is combined with data repetition on the time axis. For example, when the MCS index is 19, in addition to dual carrier modulation, one repeated piece of data is transmitted on the time axis, so that the same data is transmitted four times by combining the frequency axis and the time axis. The UHR-MCS index and the correspondence between each parameter in Table 4 are merely examples and are not limited thereto. For example, a parameter set different from the parameter set shown in Table 4 may be associated with each UHR-MCS index shown in Table 4. In this way, by notifying the receiving communication device 100 of information regarding data repetition using the MCS field, it is possible to notify the receiving communication device 100 of information necessary for processing repeated data without making any changes to the previous frame format by adding fields such as Repetition and Number of Repetition.

[0067] The transmitting communication device 100 may transmit a PPDU including repetitions of data by performing operations similar to those described above in the description of FIG. 6. In this example, as described above, the transmitting communication device 100 generates a PPDU including a UHR-MCS index indicating whether data is repeated and the number of data repetitions, instead of Repetition or Number of Repetition. The receiving communication device 100 may obtain each piece of data including repetitions from the received PPDU by performing operations similar to those described above in the description of FIG. 7, and decode the data. When the receiving communication device 100 detects that the value indicated by the UHR-MCS index indicates that repetitions are included, it may combine the multiple pieces of data and decode the data.

[0068] As described above, when a communication device according to the present invention wants to transmit a wireless frame in which data is repeated on a time axis according to the communication conditions to a communication device at a different time, the communication device can notify the communication device of information regarding the repetition. Based on this, the communication device determines whether the received wireless frame contains repeated data, and based on the result, can receive the wireless frame in which data is repeated on a time axis. This allows the communication device to flexibly use data repetition according to the communication conditions, etc., to improve the reliability of communication.

[0069] The present invention can also be realized by supplying a program that realizes one or more of the 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.The present invention can also be realized by a circuit (e.g., an ASIC) that realizes one or more of the functions.

[0070] 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.

[0071] This application claims priority based on Japanese Patent Application No. 2024-116280, filed July 19, 2024, the entire contents of which are incorporated herein by reference.

[0072] 101 AP 102 STA 301 Wireless LAN control unit 302 Frame generation unit 303 Frame analysis unit 304 UI ​​control unit 305 Storage unit

Claims

1. A communications device that performs communications in accordance with the IEEE 802.11 standard series, comprising a transmitting means for transmitting wireless frames containing data repeated on a time axis, wherein the preamble of the wireless frame contains a U-SIG field and a Signal (SIG) field conforming to a predetermined standard, and the SIG field contains information regarding the repetition of the data.

2. The communication device according to claim 1, wherein the SIG field includes a field indicating user information, and the field indicating user information includes information regarding the repetition.

3. A communication device according to claim 1 or 2, characterized in that the information relating to repetition includes information indicating whether or not data is repeated on the time axis.

4. A communication device according to any one of claims 1 to 3, characterized in that the information relating to repetition includes information indicating the number of repetitions of data on the time axis.

5. A communication device according to any one of claims 1 to 4, characterized in that the information relating to repetition includes information for identifying the order of repetition of data on the time axis.

6. A communication device according to claim 2, wherein the field indicating the user information includes a field indicating MCS, and the field indicating MCS includes a value identifying the number of repetitions of data on the time axis.

7. The communication device according to any one of claims 1 to 6, wherein the data is a MAC Protocol Data Unit (MPDU) or an Aggregate MAC Protocol Data Unit (A-MPDU).

8. The communication device according to any one of claims 1 to 6, wherein the data is a PHY Protocol Data Unit (PPDU).

9. A communications device that performs communications in accordance with the IEEE 802.11 standard series, comprising a receiving means for receiving a wireless frame containing data repeated on a time axis, wherein the preamble of the wireless frame contains a U-SIG field and a Signal (SIG) field conforming to a predetermined standard, and the SIG field contains information regarding the repetition of the data.

10. A communication device according to claim 9, wherein the SIG field includes a field indicating user information, and the field indicating user information includes information regarding the repetition of data on the time axis.

11. The communication device according to claim 9 or 10, wherein the information relating to repetition includes information indicating whether or not data is repeated on the time axis.

12. A communication device according to any one of claims 9 to 11, characterized in that the information relating to repetition includes information indicating the number of repetitions of data on the time axis.

13. A communication device according to any one of claims 9 to 12, characterized in that the information relating to repetition includes information identifying the order of repetition of data on the time axis.

14. The communication device according to claim 10, wherein the field indicating the user information includes a field indicating an MCS, and the field indicating the MCS includes a value identifying the number of repetitions of data on the time axis.

15. A communication device according to any one of claims 9 to 14, characterized in that it comprises decoding means for synthesizing at least two pieces of data from among the repeated pieces of data contained in the radio frame received by said receiving means and decoding the data.

16. The communication device according to any one of claims 9 to 15, wherein the data is a MAC Protocol Data Unit (MPDU) or an Aggregate MAC Protocol Data Unit (A-MPDU).

17. The communication device according to any one of claims 9 to 15, wherein the data is a PHY Protocol Data Unit (PPDU).

18. A communication method for a communication device that performs communication in accordance with the IEEE 802.11 standard series, comprising a transmission step of transmitting a wireless frame containing data repeated on a time axis, wherein the preamble of the wireless frame contains a U-SIG field and a Signal (SIG) field conforming to a predetermined standard, and the SIG field contains information regarding the repetition of the data.

19. A communication method in a communication device that performs communication in accordance with the IEEE 802.11 standard series, comprising a receiving step of receiving a wireless frame containing data repeated on a time axis, wherein the preamble of the wireless frame contains a U-SIG field and a Signal (SIG) field conforming to a predetermined standard, and the SIG field contains information regarding the repetition of the data.

20. A program for causing a computer to operate as a communication device according to any one of claims 1 to 8.

21. A program for causing a computer to operate as a communication device according to any one of claims 9 to 17.

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