Communication device, control method, and program

Abstract

This technology provides a way to appropriately apply Dual Carrier Modulation (DCM) to a Distributed Tone Resource Unit (DRU). [Solution] A communication device compliant with the IEEE 802.11 standard series, comprising a transmission means that modulates and transmits the same data using one first data subcarrier and one second data subcarrier belonging to each of the first and second groups, obtained by dividing the data subcarriers contained in one resource unit in which subcarriers are distributed across a distributed bandwidth into two groups, and then dividing them into two groups.

Description

Technical Field

[0001] The present disclosure relates to a communication device, a control method, and a program.

Background Art

[0002] With the recent increase in the amount of data to be communicated, the development of communication technologies such as wireless LAN (Local Area Network) has been promoted. As the main communication standards for wireless LAN, the IEEE (Institute of Electrical and Electronics Engineers) 802.11 standard series is known. The IEEE 802.11 standard series includes standards such as IEEE 802.11a / b / g / n / ac / ax / be. For further improvement of communication reliability, the development of the IEEE 802.11bn standard is underway as a successor standard to the IEEE 802.11be standard. In the IEEE 802.11 WG (Working Group) that formulates the IEEE 802.11bn standard, in the UHR SG, the goals and scope of consideration of this standard are determined, and in the TGbn, the detailed technical content to be included in this standard is scheduled to be defined. Note that UHR SG is an abbreviation for Ultra High Reliability Study Group. Also, TGbn is an abbreviation for Task Group bn. The name UHR is provided for convenience based on the goals to be achieved by the successor standard and the features that are the highlight of the standard, and it may have another name when the standard formulation is completed. Similarly, the name IEEE 802.11bn may have another name when the standard formulation is completed. On the other hand, this specification and the appended claims are essentially applicable to all successor standards that are successor standards to the 802.11be standard.

[0003] Patent Document 1 discloses communication using OFDMA (Orthogonal Frequency Division Multiple Access) (also called OFDMA communication). In OFDMA communication, an access point (AP) allocates a frequency domain (subchannel) to a station (STA) on a resource unit (RU) basis.

[0004] Here, RU (Router Unit) is a channel division unit used for communication, and an RU contains multiple subcarriers (also called subcarriers or tones). The method of dividing channels into RUs (size and range of RUs) is defined for each frequency bandwidth of 20MHz, 40MHz, 80MHz, 160MHz, and 320MHz. When the multiple subcarriers constituting a single RU are consecutive in the frequency domain, that RU is also called an RRU (Regular RU).

[0005] Patent Document 2 discloses a communication method using a DRU that uses distributed subcarriers as subcarriers constituting a single RU. DRU is an abbreviation for Distributed tone Resource Unit. In this specification and drawings, DRU is also referred to as dRU.

[0006] RRU consists of consecutive subcarriers. In contrast, DRU consists of subcarriers distributed across a wide frequency band. This reduces the transmit power density, making it possible to increase transmit power even in the 6GHz band, where legal regulations on transmit power density are strict. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2023-47755 [Patent Document 2] Special Publication No. 2024-516188 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] Incidentally, the IEEE 802.11ax and IEEE 802.11be standards employ Dual Carrier Modulation (DCM). DCM is a technology that transmits the same data using two subcarriers. This makes it possible to reduce the data error rate through the diversity effect, where the data is combined and decoded at the receiving end.

[0009] However, the mechanism for applying DCM to DRU is not established and has not been clearly defined. Therefore, unless such a mechanism is clarified, it will not be possible to provide the benefits obtained by combining DRU and DCM, such as a reduction in data error rate and an increase in communication distance.

[0010] One aspect of this disclosure, in view of the above, aims to provide a technology for appropriately applying DCM to DRU. [Means for solving the problem]

[0011] A communication device according to one aspect of the present disclosure is a communication device compliant with the IEEE 802.11 standard series, and includes a transmitting means that modulates and transmits the same data using one first data subcarrier and one second data subcarrier belonging to a first group and a second group, respectively, obtained by dividing a data subcarrier contained in a single resource unit in which subcarriers are distributed across a distributed bandwidth into two groups. [Effects of the Invention]

[0012] According to one aspect of this disclosure, DCM can be appropriately applied to DRU. [Brief explanation of the drawing]

[0013] [Figure 1] A diagram showing an example configuration of a wireless communication system according to the embodiment. [Figure 2] A diagram showing an example of the functional configuration of a communication device according to this embodiment. [Figure 3] A diagram showing an example of the hardware configuration of a communication device according to the embodiment. [Figure 4] A diagram illustrating the concepts of DRU and distributed bandwidth. [Figure 5] A diagram illustrating the concept of a PPDU with a bandwidth of 160 MHz. [Figure 6] A figure showing an example of a set of subcarriers modulated based on the same data, according to the embodiment. [Figure 7] A diagram showing an example of a DRU constituting a 20 MHz dispersion bandwidth and the subcarriers constituting each DRU according to an embodiment. [Figure 8] A diagram showing an example of a DRU constituting a 40 MHz dispersed bandwidth and a subcarrier constituting each DRU according to an embodiment. [Figure 9] A diagram showing an example of a DRU constituting an 80 MHz distributed bandwidth and the subcarriers constituting each DRU according to the embodiment. [Modes for carrying out the invention]

[0014] The embodiments will be described in detail below with reference to the attached drawings. Note that the following embodiments do not limit the scope of the claims. While the embodiments describe multiple features, not all of these features are essential to this disclosure, and the features may be combined in any way. Furthermore, in the attached drawings, identical or similar configurations are given the same reference numerals, and redundant descriptions are omitted.

[0015] <Embodiment> (Network configuration) FIG. 1 is a diagram showing a configuration example of a wireless communication system according to the present embodiment. FIG. 1 shows a configuration example of the network according to the present embodiment. FIG. 1 shows a configuration including one AP (Access Point) 102 and three STAs (Stations) 103, 104, and 105 as (wireless) communication devices that perform wireless LAN communication compliant with the IEEE802.11bn standard. The STA may also be called a non-AP STA.

[0016] As shown in FIG. 1, the network formed by the AP 102 is indicated by a circle 101. The STAs 103-105 can transmit and receive the signals transmitted and received by the AP 102. In the present embodiment, the AP 102 and the STAs 103-105 may be collectively referred to as the communication device 100. Note that the configuration shown in FIG. 1 is an example, and for example, there may be communication devices that perform other wireless LAN communications in a wider area.

[0017] The communication device 100 may be a communication device that performs wireless LAN communication compliant with the IEEE802.11bn standard. Alternatively, the communication device 100 may be a so-called legacy device that complies only with the IEEE802.11a / b / g / n / ac / ax / be standards without complying with the IEEE802.11bn standard.

[0018] The communication device 100 can also be configured to support wireless communication based on other communication standards such as Bluetooth (registered trademark), NFC, and Bluetooth LE (Low Energy). NFC is an abbreviation for Near Field Communication.

[0019] In addition, the communication device 100 can also be configured to support wired communication using an Ethernet (registered trademark) cable or wired communication using an optical fiber.

[0020] In addition, the communication device 100 can also be configured to support cellular wireless communication such as 5G or LTE (Long Term Evolution).

[0021] Specific examples of AP102 include, but are not limited to, wireless LAN routers and personal computers (PCs).

[0022] Specific examples of STA103-105 include, but are not limited to, cameras, tablets, smartphones, PCs, mobile phones, video cameras, smart glasses, and wearable devices such as HMDs (head-mounted displays). Furthermore, STA103-105 may also be IoT devices such as Internet of Things (IoT) sensors, smart locks, and smart sensors. IoT sensors may include accelerometers, light sensors, humidity sensors, etc.

[0023] Furthermore, the communication device 100 may be an information processing device such as a wireless chip capable of performing wireless communication compliant with IEEE 802.11 standards such as the IEEE 802.11bn standard. Alternatively, the communication device 100 may be an information processing device such as a wireless chip that supports the transmission and reception of Physical Layer Protocol Data Units (PPDUs). In this case, the wireless chip can be configured to perform various controls using hardware circuits within it. It is also possible to configure the wireless chip to perform various processes through the cooperation of a processor such as an ASIP, memory, and hardware circuits within it. ASIP is an abbreviation for Application-Specific Instruction Set Processor.

[0024] (AP and STA configuration) Figure 2 is a block diagram showing examples of the functional configurations of AP102 and STA103-105. As an example of its functional configuration, AP102 has an RU allocation unit 201, a frame generation and analysis unit 202, and a frame transmission and reception unit 203, as shown in Figure 2(a). On the other hand, as an example of its functional configuration, STA103-105 has a frame generation and analysis unit 202 and a frame transmission and reception unit 203, as shown in Figure 2(b). In other words, the RU allocation unit 201 is present only in AP102 and not in STA103-105.

[0025] These functions can be realized, for example, by the control unit 302 (described later) executing a program stored in the storage unit 301 (described later), or by the processing function unit in the communication unit 306 (described later). Figure 2 is a diagram illustrating the main functions in this embodiment, and other functions are omitted. For this reason, for example, AP102 and STA103-105 may naturally have functions for establishing a connection between AP and STA and control for communication, as well as functions that communication devices generally have. In addition, the multiple function blocks shown in Figure 2 may be integrated into one function block, or one function block may be divided into multiple function blocks. Also, the names of the function blocks shown in Figure 2 are merely examples and may be changed.

[0026] The RU allocation unit 201 determines the multiple access method to be used for communication with STA103-105. Multiple access methods include OFDMA. If the RU allocation unit 201 determines that OFDMA should be used, it determines whether to use RRU or DRU and allocates either RRU or DRU to STA103-105. The RU allocation unit 201 makes these decisions based on the number of STAs connected to AP102, the traffic between one or more connected STAs, the frequency band being used, the distance to the STAs, etc. For example, the RU allocation unit 201 determines that OFDMA should be used if the number of STAs is large (e.g., more than a predetermined number) and the traffic between each STA is small (e.g., less than a predetermined value). Furthermore, the RU allocation unit 201 determines that DRU should be used if the 6GHz band is being used or if the distance to the STAs is long (e.g., more than a predetermined value).

[0027] Furthermore, the RU allocation unit 201 may decide to apply DCM if the STA's communication environment is poor. A poor STA communication environment is, for example, when the STA's communication quality is below a threshold. The STA's communication quality may be represented by at least one of the following parameters: communication distance, interference amount, SNR (Signal-to-Noise Ratio), error rate, etc.

[0028] The frame generation and analysis unit 202 generates frames to be output to the frame transmission / reception unit 203 according to the multiple access scheme determined by the RU allocation unit 201, and analyzes the frames input from the frame transmission / reception unit 203.

[0029] The frame transmission / reception unit 203 encodes the frame input from the frame generation / analysis unit 202 according to the multiple access scheme determined by the RU assignment unit 201, modulates the encoded frame, and transmits the modulated frame as radio waves to the wireless medium. The frame transmission / reception unit 203 also demodulates the radio waves (including frame information) received from the wireless medium, decodes the received frame, and outputs the decoded frame to the frame generation / analysis unit 202. The frame transmission / reception unit 203 is an example of a transmission means, receiving means, transmission / reception means, or communication means.

[0030] Figure 3 shows an example of the hardware configuration of AP102 and STA103-105 (communication device 100).

[0031] AP102 and STA103-105, as an example of their hardware configuration, include a storage unit 301, a control unit 302, a function unit 303, an input unit 304, an output unit 305, a communication unit 306, and a wireless antenna 307.

[0032] The storage unit 301 is composed of one or more memories, such as both ROM and RAM, or either one of them, and stores various information such as programs for performing various operations described later, and communication parameters (setting information) for wireless communication. In addition to memories such as ROM and RAM, storage media such as flexible disks, hard disks, SSDs, optical disks, magneto-optical disks, CD-ROMs, CD-Rs, magnetic tapes, non-volatile memory cards, and DVDs may be used as the storage unit 301. SSD is an abbreviation for Solid State Drive. CD-ROM is an abbreviation for Compact Disc Read Only Memory, CD-R is an abbreviation for Compact Disc Recordable, and DVD is an abbreviation for Digital Versatile Disc.

[0033] The control unit 302 is composed of, for example, one or more processors such as a CPU or MPU, an ASIC (Application-Specific Integrated Circuit), a DSP (Digital Signal Processor), or an FPGA (Field-Programmable Gate Array). CPU is an abbreviation for Central Processing Unit, and MPU is an abbreviation for Micro Processing Unit. The control unit 302 controls the entire device by executing a program stored in the memory unit 301. Alternatively, the control unit 302 may control the device in cooperation with the OS (Operating System) and the program stored in the memory unit 301.

[0034] Furthermore, the control unit 302 controls the functional unit 303 to perform predetermined processes such as imaging, printing, and projection. The functional unit 303 is hardware for the AP or STA to perform predetermined processes. For example, if the AP or STA is a camera, the functional unit 303 is the imaging unit and performs imaging processing. Also, for example, if the AP or STA is a printer, the functional unit 303 is the printing unit and performs printing processing. Also, for example, if the AP or STA is a projector, the functional unit 303 is the projection unit and performs projection processing. The data processed by the functional unit 303 may be data stored in the storage unit 301, or it may be data communicated with other communication devices via the communication unit 306, which will be described later.

[0035] The input unit 304 accepts various operations from the user. The output unit 305 provides various outputs to the user. Here, the output from the output unit 305 includes at least one of the following: display on the screen, audio output from a speaker, vibration output, etc. Note that both the input unit 304 and the output unit 305 may be implemented in a single module, such as a touch panel. Furthermore, the input unit 304 and the output unit 305 may be integrated with the AP or STA, respectively, or they may be separate components.

[0036] The communication unit 306 includes a so-called wireless LAN chip and controls wireless communication compliant with the IEEE 802.11 standard series, IP (Internet Protocol) communication, etc. In this embodiment, the communication unit 306 can perform processing compliant with at least the IEEE 802.11bn standard. The communication unit 306 is a processing device that generates UHR PPDU (Ultra High Reliability Physical layer Protocol Data Unit) as defined in the IEEE 802.11bn standard. The communication unit 306 may also have the function of generating types of PPDU defined in standards prior to the IEEE 802.11bn standard. Furthermore, the communication unit 306 controls the wireless antenna 307 to transmit and receive wireless signals for wireless communication. The communication device 100 communicates content such as image data, document data, and video data with other communication devices via the communication unit 306.

[0037] The wireless antenna 307 may be physically composed of two or more antennas in order to realize MIMO (Multi-Input and Multi-Output) transmission and reception. The wireless antenna 307 may be configured separately from the communication unit 306, or it may be configured as a single module together with the communication unit 306. The wireless antenna 307 is an antenna capable of communication in the 2.4GHz, 5GHz, 6GHz, 45GHz, and 60GHz bands. In Figure 3, the communication device 100 is shown to have one antenna, but it may have two or more antennas. Alternatively, the communication device 100 may have different antennas for each frequency band.

[0038] In the example shown in Figure 3, the communication device 100 is configured to have only one communication unit 306, but it is also possible to provide a separate communication unit for each of the multiple wireless antennas.

[0039] Furthermore, AP102 and STA103-105 can be any communication device having the configuration shown in Figures 2 and 3, and are not limited to the examples of equipment mentioned above.

[0040] (Concepts of DRU and Distributed Bandwidth) Next, the concepts of DRU and distributed bandwidth will be explained using Figure 4.

[0041] In Figure 4, the PPDU bandwidth 400 is shown. The bandwidth of the PPDU bandwidth 400 can be 20 MHz, 40 MHz, 80 MHz, 160 MHz, or 320 MHz.

[0042] In Figure 4, the distributed bands 401-403 are also shown. The bandwidths of each of the distributed bands 401-403 can be 20 MHz, 40 MHz, or 80 MHz. Alternatively, the bandwidths of the distributed bands 401-403 are not limited to the aforementioned values, but may be integer multiples or fractions of 20 MHz. The bandwidths of the distributed bands 401-403 may all be the same, some may be different, or all may be different.

[0043] A single PPDU bandwidth may contain one or more distributed bandwidths. Figure 4 shows an example where a single PPDU bandwidth 400 contains three distributed bandwidths 401-403. If a single PPDU bandwidth contains only one distributed bandwidth, the bandwidth of the PPDU and the bandwidth of the distributed bandwidth may coincide.

[0044] In Figure 4, for example, if the bandwidth of PPDU bandwidth 400 is 80 MHz, the bandwidths of dispersive bandwidth 401, dispersive bandwidth 402, and dispersive bandwidth 403 can be 20 MHz, 20 MHz, and 40 MHz, respectively.

[0045] A single dispersive bandwidth may contain one or more DRUs. In the case of dispersive bandwidth 401, dispersive bandwidth 401 contains four DRUs: DRU1-DRU4. The subcarriers constituting each DRU are discontinuously arranged throughout the entire dispersive bandwidth 401. That is, from lower frequencies to higher frequencies, the subcarriers of DRU1, DRU2, DRU3, and DRU4 are repeatedly arranged. The subcarriers constituting a DRU may include a data subcarrier and a pilot subcarrier.

[0046] Each dispersion band may include unused subcarriers that do not belong to any DRU. Unused subcarriers may include guard subcarriers, DC (Direct Current) subcarriers, etc. Unused subcarriers may exist between the subcarriers that constitute the DRU.

[0047] Similar to distributed bandwidth 401, distributed bandwidth 402 and distributed bandwidth 403 may also contain one or more DRUs.

[0048] Each dispersive band may contain one or more RRUs. An RRU is a RU first defined in IEEE 802.11ax. The subcarriers constituting an RRU are arranged consecutively on the frequency axis. The subcarriers constituting an RRU may include a data subcarrier and a pilot subcarrier. Even if a dispersive band contains an RRU, it may also contain unused subcarriers that do not belong to any RRU. Unused subcarriers may include guard subcarriers, DC subcarriers, etc. Unused subcarriers may be located between the subcarriers constituting an RRU.

[0049] Furthermore, DRUs and RRUs do not coexist in the same distributed bandwidth. Also, the subcarriers constituting the RU are not dispersed within a distributed bandwidth that includes an RRU. Therefore, a distributed bandwidth that includes an RRU may be referred to by other names such as a subband or normal bandwidth.

[0050] (Concept of a PPDU with a bandwidth of 160MHz) If the bandwidth of the PPDU is 160 MHz or 320 MHz, the relationship between that bandwidth, the dispersion bandwidths that can be placed within that bandwidth, and the DRUs that can be placed within those dispersion bandwidths may be a repetition of the relationship for the 80 MHz bandwidth on the frequency axis.

[0051] Figure 5 shows a conceptual diagram of a PPDU with a bandwidth of 160 MHz. In Figure 5, the PPDU bandwidth 500 is shown. As shown in Figure 5, the bandwidth of the PPDU bandwidth 500 is 160 MHz. In Figure 5, bandwidths 501 and 502, which have a bandwidth of 80 MHz, are also shown. As shown in Figure 5, when the PPDU bandwidth is 160 MHz, the 80 MHz bandwidth is repeated twice on the frequency axis. Note that when the PPDU bandwidth is 320 MHz, the 80 MHz bandwidth is repeated four times on the frequency axis.

[0052] (Example of a set of subcarriers modulated based on the same data) Next, we will explain, using Figure 6, how to construct a set of subcarriers modulated based on the same data, that is, a set of subcarriers to which Dual Carrier Modulation (DCM) is applied.

[0053] Figure 6 shows an example of a set of subcarriers modulated based on the same data. In Figure 6, an exemplary dispersed bandwidth 401 is shown.

[0054] A subcarrier pair is composed of two data subcarriers, obtained by dividing a single dispersed bandwidth data subcarrier into two groups: a high-frequency group and a low-frequency group, and selecting one data subcarrier from each group. For example, if one subcarrier is the i-th data subcarrier from the lower frequency group that constitutes the DRU, then the other subcarrier will be the i+(number of data subcarriers constituting the DRU / 2)-th data subcarrier from the lower frequency group. i is a natural number less than (number of data subcarriers / 2)+1. By composing a subcarrier pair with subcarriers that are far apart in frequency, resistance to frequency-selective fading can be strengthened.

[0055] Figures 7, 8, and 9 show examples of DRUs that constitute the 20MHz, 40MHz, and 80MHz dispersion bands, respectively, and the subcarriers that make up each DRU.

[0056] The configuration of the DRU is defined for each dispersion band. Each DRU is assigned an index. In each DRU, the arrangement of subcarriers is indicated using the subcarrier index. The subcarrier index is such that consecutive integers starting from the subcarrier with the lowest frequency are assigned to the subcarriers included in the dispersion band. The index is assigned, for example, as follows. For a 20 MHz bandwidth, the index ranges from -121 to 121; for a 40 MHz bandwidth, the index ranges from -244 to 244; for an 80 MHz bandwidth, the index ranges from -500 to 500; and for a 160 MHz bandwidth, the index ranges from -1012 to 1012.

[0057] Similar to the RRU, the DRU is composed of a plurality of subcarriers, and the number of subcarriers constituting the DRU is the same as that of the RRU. That is, the DRU patterns include 26-tone DRU, 52-tone DRU, 106-tone DRU, 242-tone DRU, and 484-tone DRU. The number of subcarriers of 26-tone DRU, 52-tone DRU, 106-tone DRU, 242-tone DRU, and 484-tone DRU is 26, 52, 106, 242, and 484, respectively.

[0058] [S1, S2, ···] described in FIGS. 5 to 7 indicates that the DRU is composed of subcarriers of the set of indices corresponding to S1, S2, ···. Each of S1 and S2 represents the index of one subcarrier, the set of indices of a plurality of subcarriers, or the set of indices constituting the DRU. Also, [s1:d:s2] described in FIGS. 5 to 7 represents the set of indices of index s1, all indices satisfying index s1 + d (where d is a natural number and s1 + d < s2), and index s2.

[0059] For example, in the case of a 26-tone DRU7 [-120:9:-12,6:9:114] in a 20MHz bandwidth as shown in Figure 7, this DRU is composed of 26 subcarriers. The 26 subcarriers can be represented by the following subcarrier indices: -120, -111, -102, -93, -84, -75, -66, -57, -48, -39, -30, -21, -12, 6, 15, 24, 33, 42, 51, 60, 69, 78, 87, 96, 105, 114. In this case, the subcarrier pairs to which DCM is applied are, for example, (-120 and 6), (-111 and 15), ..., (-12 and 114).

[0060] Furthermore, the 52-tone DRU and 106-tone DRU shown in Figure 7 are based on a combination of 26-tone DRUs. For example, the 52-tone DRU3 in a 20MHz bandwidth consists of 26-tone DRU7 and 26-tone DRU8. In this case, the DRU is composed of 52 subcarriers. The 52 subcarriers, when represented by subcarrier indices, include the following: -120, -116, -111, -107, -102, -98, -93, -89, -84, -80, -75, -71, -66, -62, -57, -53, -48, -44, -39, -35, -30, -26, -21, -17, -12, -8. The 52 subcarriers, when represented by subcarrier indices, further include the following: 6, 10, 15, 19, 24, 28, 33, 37, 42, 46, 51, 55, 60, 64, 69, 73, 78, 82, 87, 91, 96, 100, 105, 109, 114, 118. In this case, the subcarrier pairs to which DCM is applied are, for example, (-120 and 6), (-116 and 10), ..., (-12 and 114), (-8 and 118).

[0061] In this embodiment, the DRU is configured such that the same number of subcarriers as the RRU are regularly arranged across the entire bandwidth. However, the number and arrangement of subcarriers constituting the DRU are not limited to this. For example, the DRU may consist of fewer or more subcarriers than the RRU, or the subcarriers may be arranged irregularly. However, it is necessary to distribute the subcarriers across the entire communication bandwidth and reduce the power density compared to conventional RRUs.

[0062] Furthermore, the bandwidths for communication using DRUs are 20MHz, 40MHz, and 80MHz, and the supported DRU sizes for each of these bandwidths are as follows: For the 20MHz bandwidth, the supported DRU sizes are 26-tone DRU, 52-tone DRU, and 106-tone DRU. For the 40MHz bandwidth, the supported DRU sizes are 26-tone DRU, 52-tone DRU, 106-tone DRU, and 242-tone DRU. For the 80MHz bandwidth, the supported DRU sizes are 52-tone DRU, 106-tone DRU, 242-tone DRU, and 484-tone DRU.

[0063] However, this disclosure is not limited to the foregoing, and a 26-tone DRU may be used in an 80MHz bandwidth, or communication using DRUs may be performed in a 160MHz bandwidth. When a 26-tone DRU is used in an 80MHz bandwidth, the 26-tone DRU can be newly allocated to 37 STAs, so DRU1 to DRU70 will be used as DRU indices.

[0064] Furthermore, the subcarrier to which DCM is applied is modulated with BPSK and coded with BCC or LDPC at a coding rate of 1 / 2. BPSK is an abbreviation for Binary Phase Shift Keying, BCC is an abbreviation for Binary Convolutional Code, and LDPC is an abbreviation for Low Density Parity Check. This makes it possible to provide a combination of modulation and coding schemes that is more noise-resistant than any data rate or MCS that does not apply DCM in the IEEE 802.11 standard series. MCS is an abbreviation for Modulation and Coding Scheme.

[0065] However, other primary modulation schemes and encoding schemes may be applied in DCM. For example, any of MCS0 to 4 may be applied. Alternatively, any of MCS0, 1, 3, and 4 may be applied. Furthermore, for example, a modulation scheme with a modulation level below a predetermined value and an encoding scheme with a coding rate below a predetermined value may be applied. Specifically, modulation schemes and encoding schemes such as QPSK with a coding rate of 1 / 2, 16QAM with a coding rate of 1 / 2, and 16QAM with a coding rate of 3 / 4 may be applied. QPSK is an abbreviation for Quadrature Phase Shift Keying, and QAM is an abbreviation for Quadrature Amplitude Modulation. This allows for a more flexible selection of modulation scheme and encoding scheme combinations depending on the required data rate, the noise environment of the transmission line, etc.

[0066] Furthermore, the number of spatial streams may be limited in DCM. For example, the number of spatial streams may be set to 1 or 2. Also, DCM and STBC (Space-Time Block Coding) do not necessarily have to be applied in combination.

[0067] According to the embodiment described above, on the transmitting side, the data subcarrier contained in one RU (i.e., DRU) in which the subcarrier is distributed across a distributed bandwidth is divided into two groups: a first group and a second group. Then, the same data is modulated and transmitted using one first data subcarrier and one second data subcarrier belonging to each of the first and second groups obtained by this division. On the receiving side, the same data that has been modulated and transmitted using the first and second data subcarriers in this way is received and demodulated. This makes it possible to apply DCM to the DRU, and it becomes possible to achieve a reduction in data error rate, an increase in communication distance, etc., which can be obtained by combining DRU and DCM.

[0068] <Other Embodiments> In the above embodiment, an example was described in which data subcarriers constituting one dispersion band are divided into two groups, consisting of a high-frequency group and a low-frequency group, and one data subcarrier is selected from each group to form a set of subcarriers. However, the disclosure is not limited to this example. For example, data subcarriers constituting one dispersion band may be divided into a group with an odd subcarrier index and a group with an even subcarrier index, and one data subcarrier is selected from each group to form a set of subcarriers.

[0069] In the above embodiment, an example was described in which the set of subcarriers to which DCM is applied is provided as one pattern per DRU. However, the disclosure is not limited to this example. For example, multiple patterns of data subcarrier sets to which DCM is applied may be provided for DRUs consisting of the same subcarriers in the same bandwidth. The AP may also notify the STA of the pattern by deciding which of the multiple patterns to use and sending information about the decided pattern to the STA.

[0070] The above embodiment describes an example in which two groups obtained by splitting the DRU are predetermined. However, the disclosure is not limited to this example. For example, the AP may adaptively or dynamically determine the two groups after splitting, and may notify the STA of the two groups by storing information about the two determined groups in a field (new or existing) related to resource allocation and sending it.

[0071] The above embodiment describes an example in which the same data is modulated and transmitted using one subcarrier selected from each of two groups obtained by dividing the DRU. However, this disclosure is not limited to this example. For example, the same data may be modulated and transmitted using one subcarrier selected from each of three or more groups obtained by dividing the DRU. The three or more groups may be predetermined, or determined adaptively or dynamically. In addition, the sets of data subcarriers when divided into two groups, the sets of data subcarriers when divided into three groups, etc., may be predetermined. In this case, the AP may decide how many groups to use according to the communication quality of the STA, etc., and notify the STA of how many groups to use by transmitting information about the determined number of groups.

[0072] A storage medium containing program code for software that implements the above-described functions may be supplied to a system or device, and the computer (CPU, MPU) of the system or device may read and execute the program code stored in the storage medium. In this case, the program code read from the storage medium itself implements the functions of the above-described embodiment, and the storage medium containing that program code constitutes the above-described device.

[0073] For supplying program code, storage media such as flexible disks, hard disks, optical disks, magneto-optical disks, CD-ROMs, CD-Rs, magnetic tapes, non-volatile memory cards, ROMs, DVDs, etc., can be used.

[0074] Furthermore, the above-mentioned functions may be realized not only by the computer executing the program code it reads, but also by the operating system running on the computer performing some or all of the actual processing based on the instructions of that program code.

[0075] Furthermore, the program code read from the storage medium is written to the memory of a function expansion board inserted into the computer or a function expansion unit connected to the computer. Then, based on the instructions of that program code, the CPU of the function expansion board or function expansion unit may perform some or all of the actual processing to realize the above-mentioned functions.

[0076] This disclosure can also be implemented by supplying a program that implements one or more of the functions of the embodiments described above to a system or device via a network or storage medium, and by having one or more processors in the computer of that system or device read and execute the program. Furthermore, this disclosure can also be implemented by a circuit (e.g., an ASIC) that implements one or more functions.

[0077] Furthermore, some of the processes described in this disclosure with reference to the flowchart may be implemented in hardware. For example, a dedicated circuit can be automatically generated on the FPGA from a program to implement each step by using a predetermined compiler. Alternatively, a Gate Array circuit may be formed in the same way as the FPGA and implemented in hardware.

[0078] The names of the functional units, messages, parameters, fields, etc., described in the embodiments described above may be changed to other names.

[0079] The order of the processing procedures, sequences, flowcharts, etc., in the embodiments described above is not limited to the specific order presented, and may be rearranged or additional steps may be added, as long as they do not contradict each other.

[0080] Furthermore, the following additional information is disclosed regarding the above embodiments.

[0081] [Note 1] A communication device compliant with the IEEE 802.11 standard series, A communication device having a transmitting means that modulates and transmits the same data using one first data subcarrier and one second data subcarrier belonging to a first group and a second group, respectively, obtained by dividing a data subcarrier contained in a single resource unit in which subcarriers are distributed across a distributed bandwidth into two groups.

[0082] [Note 2] The communication device as described in Appendix 1, wherein the frequency of the subcarrier constituting the second group is higher than the frequency of any of the subcarriers constituting the first group.

[0083] [Note 3] The communication device as described in Appendix 1 or 2, wherein the first data subcarrier and the second data subcarrier are, respectively, the i-th data subcarrier (where i is a natural number less than (number of data subcarriers / 2)+1) and the i+(number of data subcarriers / 2)-th data subcarrier, counting from the lowest frequency of the data subcarriers.

[0084] [Note 4] The same data is modulated using a predetermined modulation scheme in a communication device as described in any of Appendix 1 to 3.

[0085] [Note 5] The communication device described in Appendix 4, wherein the predetermined modulation scheme is the BPSK (Binary Phase Shift Keying) scheme.

[0086] [Note 6] The same data is encoded at a predetermined coding rate in the communication device described in Appendix 4 or 5.

[0087] [Note 7] The communication device described in Appendix 6, wherein the predetermined coding rate is 1 / 2.

[0088] [Note 8] The same data is encoded using BCC (Binary Convolutional Code) or LDPC (Low Density Parity Check) in the communication device described in Appendix 7.

[0089] [Note 9] A communication device compliant with the IEEE 802.11 standard series, A communication device having a receiving means for receiving and modulating the same data that has been modulated and transmitted using one first data subcarrier and one second data subcarrier, each belonging to a first and second group, obtained by dividing a data subcarrier contained in a single resource unit in which subcarriers are distributed across a distributed bandwidth into two groups.

[0090] [Note 10] The communication device as described in Appendix 9, wherein the frequency of the subcarrier constituting the second group is higher than the frequency of any of the subcarriers constituting the first group.

[0091] [Note 11] The communication device according to Appendix 9 or 10, wherein the first data subcarrier and the second data subcarrier are, respectively, the i-th data subcarrier (where i is a natural number less than (number of data subcarriers / 2)+1) and the i+(number of data subcarriers / 2)-th data subcarrier, counting from the lowest frequency of the data subcarriers.

[0092] [Note 12] The same data is modulated using a predetermined modulation scheme in a communication device as described in any of Appendix 9 to 11.

[0093] [Note 13] The communication device described in Appendix 12, wherein the predetermined modulation scheme is the BPSK (Binary Phase Shift Keying) scheme.

[0094] [Note 14] The same data is encoded at a predetermined coding rate in the communication device described in Appendix 12 or 13.

[0095] [Note 15] The communication device described in Appendix 14, wherein the predetermined coding rate is 1 / 2.

[0096] [Note 16] The same data is encoded using BCC (Binary Convolutional Code) or LDPC (Low Density Parity Check) in the communication device described in Appendix 15.

[0097] [Note 17] A control method for communication equipment compliant with the IEEE 802.11 standard series, A control method comprising the step of modulating and transmitting the same data using a first data subcarrier and a second data subcarrier, each belonging to a first group and a second group, obtained by dividing a data subcarrier contained in a single resource unit in which subcarriers are distributed across a distributed bandwidth into two groups.

[0098] [Note 18] A control method for communication equipment compliant with the IEEE 802.11 standard series, A control method comprising the step of receiving and demodulating the same data that has been modulated and transmitted using a first data subcarrier and a second data subcarrier, one each belonging to a first and second group, obtained by dividing a data subcarrier contained in a single resource unit in which subcarriers are distributed across a distributed bandwidth into two groups.

[0099] [Note 19] A program that causes a computer to perform the control method described in Appendix 17 or 18. [Explanation of Symbols]

[0100] 102 Communication equipment (AP) 103, 104, 105 Communication equipment (STA)

Claims

1. A communication device compliant with the IEEE 802.11 standard series, A communication device having a transmitting means that modulates and transmits the same data using one first data subcarrier and one second data subcarrier belonging to a first group and a second group, respectively, obtained by dividing a data subcarrier contained in a single resource unit in which subcarriers are distributed across a distributed bandwidth into two groups.

2. The communication device according to claim 1, wherein the frequency of the subcarrier constituting the second group is higher than the frequency of any of the subcarriers constituting the first group.

3. The communication device according to claim 1, wherein the first data subcarrier and the second data subcarrier are, respectively, the i-th data subcarrier (where i is a natural number less than (number of data subcarriers / 2) + 1) and the i + (number of data subcarriers / 2)-th data subcarrier, counting from the lowest frequency of the data subcarriers.

4. The communication device according to claim 1, wherein the same data is modulated using a predetermined modulation scheme.

5. The communication device according to claim 4, wherein the predetermined modulation scheme is the BPSK (Binary Phase Shift Keying) scheme.

6. The communication device according to claim 4 or 5, wherein the same data is encoded at a predetermined coding rate.

7. The communication device according to claim 6, wherein the predetermined coding rate is 1 / 2.

8. The communication device according to claim 7, wherein the same data is encoded using BCC (Binary Convolutional Code) or LDPC (Low Density Partity Check).

9. A communication device compliant with the IEEE 802.11 standard series, A communication device having a receiving means for receiving and modulating the same data that has been modulated and transmitted using one first data subcarrier and one second data subcarrier belonging to each of the first and second groups, obtained by dividing the data subcarriers contained in a single resource unit in which subcarriers are distributed across a distributed bandwidth into two groups.

10. The communication device according to claim 9, wherein the frequency of the subcarrier constituting the second group is higher than the frequency of any of the subcarriers constituting the first group.

11. The communication device according to claim 9, wherein the first data subcarrier and the second data subcarrier are, respectively, the i-th data subcarrier (where i is a natural number less than (number of data subcarriers / 2) + 1) and the i + (number of data subcarriers / 2)-th data subcarrier, counting from the lowest frequency of the data subcarriers.

12. The communication device according to claim 9, wherein the same data is modulated using a predetermined modulation scheme.

13. The communication device according to claim 12, wherein the predetermined modulation scheme is the BPSK (Binary Phase Shift Keying) scheme.

14. The communication device according to claim 12 or 13, wherein the same data is encoded at a predetermined coding rate.

15. The communication device according to claim 14, wherein the predetermined coding rate is 1 / 2.

16. The communication device according to claim 15, wherein the same data is encoded using BCC (Binary Convolutional Code) or LDPC (Low Density Partity Check).

17. A control method for communication equipment compliant with the IEEE 802.11 standard series, A control method comprising the step of modulating and transmitting the same data using a first data subcarrier and a second data subcarrier, each belonging to a first group and a second group, obtained by dividing a data subcarrier contained in a single resource unit in which subcarriers are distributed across a distributed bandwidth into two groups.

18. A control method for communication equipment compliant with the IEEE 802.11 standard series, A control method comprising the step of receiving and demodulating the same data that has been modulated and transmitted using a first data subcarrier and a second data subcarrier, one each belonging to a first group and a second group, obtained by dividing a data subcarrier contained in a single resource unit in which subcarriers are distributed across a distributed bandwidth into two groups.

19. A program for causing a computer to execute the control method described in claim 17 or 18.

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