COMMUNICATION DEVICE, COMMUNICATION METHOD, AND COMPUTER-READABLE STORAGE MEDIUM

Abstract

A communication device communicates a physical (PHY) frame including a preamble and a data field. The preamble includes a Legacy Short Training Field (L-STF), a Legacy Long Training Field (L-LTF), a Legacy Signal Field (L-SIG), an EHT (Extremely High Throughput) Signal Field (EHT-SIG-A), an EHT Short Training Field (EHT-STF), and an EHT Long Training Field (EHT-LTF), and the EHT-SIG-A includes at least one subfield indicating that the communication device performs communication in a frequency band more than 160 MHz.

Claims

1. A communication device that transmits a physical (PHY) frame including a preamble and a data field, wherein the preamble includes: a Legacy Short Training Field (L-STF); a Legacy Long Training Field (L-LTF) arranged immediately after the L-STF in the frame; a Legacy Signal Field (L-SIG) arranged immediately after the L-LTF in the frame; an EHT (Extremely High Throughput) Signal Field (EHT-SIG-A) arranged after the L-SIG in the frame; an EHT Short Training Field (EHT-STF) arranged immediately after the EHT-SIG-A in the frame; and an EHT Long Training Field (EHT-LTF) arranged immediately after the EHT-STF in the frame, and the EHT-SIG-A includes at least one subfield indicating that the communication device performs communication in a frequency band more than 160 MHz.

2. The communication device according to claim 1, wherein the number of bits included in the at least one subfield is not less than 3 bits in total.

3. The communication device according to claim 1, wherein the at least one subfield includes a Reserved (reserved field) subfield.

4. A communication device that receives a physical (PHY) frame including a preamble and a data field, wherein the preamble includes: a Legacy Short Training Field (L-STF); a Legacy Long Training Field (L-LTF) arranged immediately after the L-STF in the frame; a Legacy Signal Field (L-SIG) arranged immediately after the L-LTF in the frame; an EHT (Extremely High Throughput) Signal Field (EHT-SIG-A) arranged after the L-SIG in the frame; an EHT Short Training Field (EHT-STF) arranged immediately after the EHT-SIG-A in the frame; and an EHT Long Training Field (EHT-LTF) arranged immediately after the EHT-STF in the frame, and the EHT-SIG-A includes at least one subfield indicating that the communication device performs communication in a frequency band more than 160 MHz.

5. The communication device according to claim 4, wherein the number of bits included in the at least one subfield is not less than 3 bits in total.

6. The communication device according to claim 4, wherein the at least one subfield includes a Reserved (reserved field) subfield.

7. A communication method of transmitting a physical (PHY) frame including a preamble and a data field, wherein the preamble includes: a Legacy Short Training Field (L-STF); a Legacy Long Training Field (L-LTF) arranged immediately after the L-STF in the frame; a Legacy Signal Field (L-SIG) arranged immediately after the L-LTF in the frame; an EHT (Extremely High Throughput) Signal Field (EHT-SIG-A) arranged after the L-SIG in the frame; an EHT Short Training Field (EHT-STF) arranged immediately after the EHT-SIG-A in the frame; and an EHT Long Training Field (EHT-LTF) arranged immediately after the EHT-STF in the frame, and the EHT-SIG-A includes at least one subfield indicating that the communication device performs communication in a frequency band more than 160 MHz.

8. The communication method according to claim 7, wherein the number of bits included in the at least one subfield is not less than 3 bits in total.

9. The communication method according to claim 7, wherein the at least one subfield includes a Reserved (reserved field) subfield.

10. A communication method of receiving a physical (PHY) frame including a preamble and a data field, wherein the preamble includes: a Legacy Short Training Field (L-STF); a Legacy Long Training Field (L-LTF) arranged immediately after the L-STF in the frame; a Legacy Signal Field (L-SIG) arranged immediately after the L-LTF in the frame; an EHT (Extremely High Throughput) Signal Field (EHT-SIG-A) arranged after the L-SIG in the frame; an EHT Short Training Field (EHT-STF) arranged immediately after the EHT-SIG-A in the frame; and an EHT Long Training Field (EHT-LTF) arranged immediately after the EHT-STF in the frame, and the EHT-SIG-A includes at least one subfield indicating that the communication device performs communication in a frequency band more than 160 MHz.

11. The communication method according to claim 10, wherein the number of bits included in the at least one subfield is not less than 3 bits in total.

12. The communication method according to claim 10, wherein the at least one subfield includes a Reserved (reserved field) subfield.

13. A non-transitory computer-readable storage medium that stores a program for causing, when executed by a computer included in a communication device to transmit a physical (PHY) frame including a preamble and a data field, wherein the preamble includes: a Legacy Short Training Field (L-STF); a Legacy Long Training Field (L-LTF) arranged immediately after the L-STF in the frame; a Legacy Signal Field (L-SIG) arranged immediately after the L-LTF in the frame; an EHT (Extremely High Throughput) Signal Field (EHT-SIG-A) arranged after the L-SIG in the frame; an EHT Short Training Field (EHT-STF) arranged immediately after the EHT-SIG-A in the frame; and an EHT Long Training Field (EHT-LTF) arranged immediately after the EHT-STF in the frame, and the EHT-SIG-A includes at least one subfield indicating that the communication device performs communication in a frequency band more than 160 MHz.

14. A non-transitory computer-readable storage medium that stores a program for causing, when executed by a computer included in a communication device to receive a physical (PHY) frame including a preamble and a data field, wherein the preamble includes: a Legacy Short Training Field (L-STF); a Legacy Long Training Field (L-LTF) arranged immediately after the L-STF in the frame; a Legacy Signal Field (L-SIG) arranged immediately after the L-LTF in the frame; an EHT (Extremely High Throughput) Signal Field (EHT-SIG-A) arranged after the L-SIG in the frame; an EHT Short Training Field (EHT-STF) arranged immediately after the EHT-SIG-A in the frame; and an EHT Long Training Field (EHT-LTF) arranged immediately after the EHT-STF in the frame, and the EHT-SIG-A includes at least one subfield indicating that the communication device performs communication in a frequency band more than 160 MHz.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] FIG. 1 is a view showing an example of the configuration of a network;

[0011] FIG. 2 is a block diagram showing an example of the functional configuration of an AP;

[0012] FIG. 3 is a block diagram showing an example of the hardware configuration of the AP:

[0013] FIG. 4 is a flowchart showing processing executed by the AP;

[0014] FIG. 5 is a sequence chart showing processing executed in a wireless communication network;

[0015] FIG. 6 is a view showing an example of the configuration of frequency bands used for wireless communication;

[0016] FIG. 7 is a view showing an example of the PHY frame structure of an EHT SU PPDU;

[0017] FIG. 8 is a view showing an example of the PHY frame structure of an EHT ER PPDU;

[0018] FIG. 9 is a view showing an example of the PHY frame structure of an EHT MU PPDU; and

[0019] FIG. 10 is a view showing an example of the PHY frame structure of an EHT TB PPDU.

DESCRIPTION OF THE EMBODIMENTS

[0020] Hereinafter, embodiments will be described in detail with reference to the attached drawings. Note, the following embodiments are not intended to limit the scope of the claimed invention. Multiple features are described in the embodiments, but limitation is not made an invention that requires all such features, and multiple such features may be combined as appropriate. Furthermore, in the attached drawings, the same reference numerals are given to the same or similar configurations, and redundant description thereof is omitted.

[0021] (Network Configuration)

[0022] FIG. 1 shows an example of the configuration of a wireless communication network according to this embodiment. This wireless communication network is configured to include one access point (AP 102) and three STAs (STA 103, STA 104, and STA 105) as devices (EHT devices) complying with the IEEE802.11EHT (Extremely High Throughput) standard. Note that it may be understood that EHT is an acronym of Extreme High Throughput. The AP 102 can be considered as one form of an STA because it has the same functions as the STAs 103 to 105 except that it has a relay function. STAs located in a circle 101 representing the area where a signal transmitted from the AP 102 reaches can communicate with the AP 102. The AP 102 communicates with the STAs 103 to 105 in accordance with the wireless communication method of the IEEE802.11 EHT standard. The AP 102 can establish a radio link with each of the STAs 103 to 105 via connection processing such as an association process complying with a standard of the IEEE80211 series.

[0023] Note that the configuration of the wireless communication network shown in FIG. 1 is merely an example for the description and, for example, a network including many EHT devices and legacy devices (communication devices complying with the IEEE802.11a/b/g/n/ax standards) in a wider area may be formed. Also, the arrangement of the communication devices is not limited to that shown in FIG. 1, and the following argument is applicable to various positional relationships of the various kinds of communication devices as well.

[0024] (Configuration of AP)

[0025] FIG. 2 is a block diagram showing the functional configuration of the AP 102. The AP 102 includes, as an example of its functional configuration, a wireless LAN control unit 201, a frame generation unit 202, a signal analysis unit 203, and a UI (User Interface) control unit 204.

[0026] The wireless LAN control unit 201 can be configured to include one or more antennas 205 and circuits configured to transmit/receive a radio signal (radio frame) to/from another wireless LAN device, and a program configured to control these. The wireless LAN control unit 201 executes communication control of the wireless LAN based on a frame generated by the frame generation unit 202 in accordance with the standard of the IEEE802.11 series.

[0027] The frame generation unit 202 generates a frame to be transmitted by the wireless LAN control unit 201 based on the result of analysis performed by the signal analysis unit 203 for a signal received by the wireless LAN control unit 201. The frame generation unit 202 may create a frame without depending on the analysis result of the signal analysis unit 203. The signal analysis unit 203 analyzes a signal received by the wireless LAN control unit 201. The UI control unit 204 accepts an operation by the user (not shown) of the AP 102 on an input unit 304 (FIG. 3), and performs control of transmitting a control signal corresponding to the operation to each constituent element or controls output (including display and the like) for an output unit 305 (FIG. 3).

[0028] FIG. 3 shows the hardware configuration of the AP 102 according to this embodiment. The AP 102 includes, as an example of its hardware configuration, a storage unit 301, a control unit 302, a function unit 303, the input unit 304, the output unit 305, a communication unit 306, and the one or more antennas 205.

[0029] The storage unit 301 is formed by both of a ROM and a RAM or one of them, and stores programs for performing various kinds of operations to be described later and various kinds of information such as communication parameters for wireless communication. Note that other than the memories such as a ROM and a RAM, a storage medium such as a flexible disk, a hard disk, an optical disk, a magnetooptical disk, a CD-ROM, a CD-R, a magnetic tape, a nonvolatile memory card, or a DVD may be used as the storage unit 301.

[0030] The control unit 302 is formed by, for example, a processor such as a CPU or an MPU, an ASIC (Application Specific Integrated Circuit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), or the like. Here, CPU is an acronym of Central Processing Unit, and MPU is an acronym of Micro Processing Unit. The control unit 302 executes the programs stored in the storage unit 301, thereby controlling the entire AP 102. Note that the control unit 302 may control the entire AP 102 by cooperation of the programs stored in the storage unit 301 and an OS (Operating System).

[0031] In addition, the control unit 302 controls the function unit 303 to execute predetermined processing such as image capturing, printing, or projection. The function unit 303 is hardware used by the AP 102 to execute predetermined processing. For example, if the AP 102 is a camera, the function unit 303 is an image capturing unit and performs image capturing processing. For example, if the AP 102 is a printer, the function unit 303 is a printing unit and performs print processing. For example, if the AP 102 is a projector, the function unit 303 is a projection unit and performs projection processing. Data to be processed by the function unit 303 may be data stored in the storage unit 301, or may be data communicated with an STA or another AP via the communication unit 306 to be described later.

[0032] The input unit 304 accepts various kinds of operations from a user. The output unit 305 performs various kinds of outputs for the user. Here, the output by the output unit 305 includes at least one of display on a screen, audio output by a loudspeaker, vibration output, and the like. Note that both the input unit 304 and the output unit 305 may be implemented by one module, like a touch panel.

[0033] The communication unit 206 controls wireless communication complying with the IEEE802.11EHT standard, or controls wireless communication complying with Wi-Fi or IP (Internet Protocol) communication. Also, the communication unit 306 controls the one or more antennas 205 to transmit/receive radio signals for wireless communication. In this case, MIMO (Multi Input Multi Output) communication using spatial streams is possible. The AP 102 communicates contents such as image data, document data, and video data with another communication device via the communication unit 306.

[0034] (Configuration of STA)

[0035] The functional configuration and the hardware configuration of the STAs 103 to 105 are the same as the functional configuration (FIG. 2) and the hardware configuration (FIG. 3) of the AP 102 described above, respectively. That is, each of the STAs 103 to 105 can be configured to include, as its functional configuration, the wireless LAN control unit 201, the frame generation unit 202, the signal analysis unit 203, and the UI control unit 204 and include, as its hardware configuration, the storage unit 301, the control unit 302, the function unit 303, the input unit 304, the output unit 305, the communication unit 306, and the one or more antennas 205.

[0036] (Procedure of Processing)

[0037] Next, the procedure of processing executed by the AP 102 configured as described above and the sequence of processing executed by the wireless communication system shown in FIG. 1 will be described with reference to FIGS. 4 and 5. FIG. 4 is a flowchart showing processing executed by the AP 102. The flowchart shown in FIG. 4 can be implemented when the control unit 302 of the AP 102 executes a control program stored in the storage unit 301 and executes calculation and processing of information and control of each hardware. FIG. 5 shows a sequence chart of processing executed by the wireless communication system.

[0038] Before the description of FIGS. 4 and 5, the configuration of frequency bands used for wireless communication in this embodiment will be described with reference to FIG. 6. FIG. 6 shows an example of the configuration of frequency bands used for wireless communication. In the 2.4 GHz band conventionally used in a wireless LAN, a usable frequency bandwidth is 20 MHz or 40 MHz. Similarly, in the 5 GHz band conventionally used in a wireless LAN, a usable frequency bandwidth is one of 20 MHz, 40 MHz, 80 MHz, and 160 MHz. On the other hand, in a frequency band from 5.925 GHz to 7.125 GHz, which is called a 6 GHz band and includes frequencies recently planned to be newly opened to the wireless LAN, 80 MHz, 160 MHz, and 320 MHz are candidates of usable frequency bandwidths. Note that a frequency band in the 6 GHz band can be used not only in the IEEE802.11EHT standard but also in IEEE802.11x.

[0039] In FIGS. 4 and 5, the AP 102 performs connection processing complying with the standard of the IEEE802.11 series for each of the STAs 103 to 105 (step S401, F501). That is, frames such as Probe Request/Response, Association Request/Response, and Auth (authentication) are transmitted/received between the AP 102 and each of the STAs 103 to 105, thereby establishing a radio link. Next, the AP 102 decides a frequency bandwidth to be used for wireless communication (step S402, F502). The frequency bandwidth can be decided as a bandwidth set in advance in the wireless communication system. Alternatively, the frequency bandwidth may be decided by an operation on the input unit 304 by the user (not shown) of the AP 102.

[0040] Next, the AP 102 decides communication parameters including the frequency bandwidth decided in step S402 or F502, which are included in a radio frame to be transmitted (step S403, F503). Next, the AP 102 transmits data in a form of a radio frame including the decided transmission data communication parameters and data to the STAs 103 to 105 (step S404, F504).

[0041] (Frame Structure)

[0042] FIGS. 7 to 10 show examples of PHY (physical) frame structures of PPDUs defined by the IEEE802.11EHT standard and transmitted in step S404 or F504. Note that PPDU is an abbreviation of Physical Layer (PHY) Protocol Data Unit. FIG. 7 shows an example of the PHY frame structure of an EHT SU PPDU that is a PPDU for single-user (SU) communication (between an AP and a single STA). FIG. 8 shows an example of the PHY frame structure of an EHT ER PPDU that is a PPDU for communication in an extended area (communication distance) (Extended Range). The EHT ER PPDU is used in communication between an AP and a single STA. FIG. 9 shows an example of the PHY frame structure of an EHT MU PPDU that is a PPDU for multi-user (MU) communication (between an AP and a plurality of STAs). FIG. 10 shows an example of the PHY frame structure of an EHT TB (Trigger Based) PPDU having a structure without EHT-SIG-B in the EHT MU PPDU. When the EHT TB is used, EHT-SIG-B is not included because communication resources are allocated to a plurality of STAs using a trigger frame. The EHT TB PPDU is used in communication between an AP and a plurality of STAs.

[0043] Pieces of information commonly included in the PPDUs shown FIGS. 7 to 10 are an STF (Short Training Field), an LTF (Long Term Field), and an SIG (Signal Field). Taking FIG. 7 as an example, the PPDU head portion includes an L (Legacy)-STF 701, an L-LTF 702, and an L-SIG 703 having backward compatibility with the IEEE802.11a/b/g/n/ax standards. The L-STF 701 is used for detection of a PHY frame signal, automatic gain control (AGC), timing detection, or the like. The L-LTF 702 arranged immediately after the L-STF 701 is used for highly accurate frequency/time synchronization, obtainment of propagation channel information (CSI), or the like. The L-SIG 703 arranged immediately after the L-LTF 702 is used for transmitting control information including information such as a data transmission rate and a PHY frame length. A legacy device complying with the IEEE802.11a/b/g/n/ax standards can decode data of the above-described various kinds of legacy fields (the L-STF 701, the L-LTF 702, and the L-SIG 703). The various kinds of legacy fields are similarly included in the PPDUs shown in FIGS. 8 to 10 as well.

[0044] Next to the L-STF 701, the L-LTF 702, and the L-SIG 703 described above, the EHT SU PPDU shown in FIG. 7 includes an RL-SIG 704, an EHT-SIG-A 705, an EHT-STF 706, an EHT-LTF 707, a data field 708, and a Packet extension 709. The RL-SIG 704 may be absent. The EHT-SIG-A 705 is arranged after the L-SIG 703, the EHT-STF 706 is arranged immediately after the EHT-SIG-A 705, and the EHT-LTF 707 is arranged immediately after the EHT-STF 706. Note that the field including the L-STF 701, the L-LTF 702, the L-SIG 703, the RL-SIG 704, the EHT-SIG-A 705, the EHT-STF 706, and the EHT-LTF 707 is called a preamble. The EHT-SIG-A 705 includes Information such as EHT-SIG-A1 and EHT-SIG-A2 necessary for reception of the PPDU. Subfields that form the MT-SIG-A1 and the EHT-SIG-A2 included in the EHT-SIG-A 705 and a description thereof are shown in Table 1 and Table 2.

TABLE-US-00001 TABLE 1 Bit Bit Position Subfield Count Description EHT- B0 Format 1 “1” is set for an EHT PPDU SIG- and an EHT ER PPDU to A1 distinguish them from an EHT TB PPDU. B1 Beam 1 “1” is set if the pre-EHT of Change the PPDU is arranged in a space different from the first symbol of the EHT-LTE or “0” is set if the pre-EHT is mapped similarly to the first symbol. B2 UL/DL 1 This subfield indicates whether the PPDU is for UL or DL, and has the same value as TXVECTOR UPLINK_FLAG. B3-B6 MCS 4 This subfield indicates the value of the Modulation and Coding Scheme. In a case of an EHT SU PPDU, n = 0, 1, 2, . . . , 11 (12 to 15 are reserved). In a case of an EHT ER SU PPDU and Bandwidth = 0, n = 0, 1, 2 (3 to 15 are reserved areas). In a case of an EHT ER SU PPDU and Bandwidth = 1, n = 0 for MCS 0 (1 to 15 are reserved areas). B7 DCM 1 This subfield indicates whether Dual Carrier Modulation is applied to the data field. If “0” is set in the STBC field, “1” is set. (If both the DCM and STBC fields are “1”, neither of them is applied) If DCM is not applied. “0” is set. B8-B13 BSS Color 6 6-bit number for identifying the BSS B14 Reserved 1 Reserved field B15-B18 Spatial 4 This subfield indicates Reuse whether Spatial Reuse is allowed during transmission of this PPDU. The value of Spatial Reuse field encoding shown in the separate table is set. B19-B20 Bandwidth 2 In a case of an EHT SU PPDU: “0” is set for 20 MHz, “1” is set for 40 MHz, “2” is set for 80 MHz, or “3” is set for 160 MHz (80 + 80 MHz). In a case of an EHT ER SU PPDU: “0” is set for 242- tone RU, or “1” is set for upper 106-tone RU of 20 MHz. B21-B22 G1 + LTE 2 This subfield indicates the Size Guard Interval period and the EHT-LTE size. “0” is set for 1 × EHT-LTE and 0.8 μs GI, “1” is set for 2 × EHT-LTE and 0.8 μs GI, “2” is set for 2 × EHT-LTF and 1.6 μs GI, “3” is set if both the DCM and STBC fields are “1” and for 4 × EHT-LTF and 0.8 μs GI, or “3” is set for 4 × EHT-LTF other than the above case and 3.2 μs GI. B23-B25 NSTS And 2 This subfield indicates the Midamble number of space-time Periodicity streams and the midamble period for frame synchronization. If the Doppler field is “0”, “(the number of space-time streams) − 1” is set. If the Doppler field is “1”. B23 and B24 indicate the number of space-time streams. B25 is “0” if the midamble period is 10, or “1” if the midamble period is 20.

TABLE-US-00002 TABLE 2 Bit Bit Position Subfield Count Description EHT- B0-B6 TXOP 1 Transmission Opportunity SIG- If TXOP_DURATION of A2 TXVECTOR is UNSPECIFIED and there is no period infomiation, 127 is set. If TXOP_DURATION of TXVECTOR is smaller than 512, a value smaller than 127 is set to set NAV At this time, if B0 is “0”, FLOOR of TXOP_DURATION/8 (round down) is set in B1 to B6. If B0 is “1”. FLOOR of (TXOP_DURATION − 512)/8 is set in B1 to B6. B7 Coding 1 “0” is set for BCC (Binary Convolutional Code), or “1” is set for LDPC (Low Density Parity Check). B8 LDPC Extra 1 This subfield indicates the Symbol presence/absence of an extra Segment OFDM symbol segment for LDPC. B9 STBC 1 “1” is set in this field if STBC (Space-Time Block Coding) is used and the DCA subfield is “0”, “1” is also set if neither DCM nor STBC is applied, or “0” is set otherwise. B10 Beamformed 1 “1” is set if beamforming steering is applied to the waveform of SU transmission. B11- Pre-FEC 2 “0” is set if the Pre-FEC Padding B12 Padding Factor is 4, “1” is set if the Pre- Factor FEC Padding Factor is 1, “2” is set if the Pre-FEC Padding Factor is 2, or “3” is set if the Pre-FEC Padding Factor is 3. B13- PE 1 Disambigitity field of Packet B14 Disambigitity Extension Reserved 1 Reserved field B15 Doppler 1 “1” is set if either of the following conditions is met: the number of OFDM symbols in the data field is larger than “the value indicated by the midamble period + 1”, and a midamble exists, and the number of OFDM symbols in the data field is equal to or smaller than “the value indicated by the midamble period + 1”, no midamble exists, and the channel changes rapidly. B16- CRC 4 The CRC of the EHT-SIG-A (26 B19 bits of A1 and 16 bits up to B15 of A2, that is, 42 bits in total) field up to here. B20- Tail 6 An area to set “0” to indicate the B25 end portion to a trellis convolution decoder.

[0045] The frequency bandwidth decided in step S402 or F502 is shown in the Bandwidth subfield (B19-B20) in the EHT-SIG-A1 (Table 1). As shown in Table 1, when the value of the Bandwidth subfield is 0, the frequency bandwidth is 20 MHz. When the value is 1, the frequency bandwidth is 40 MHz. When the value is 2, the frequency bandwidth is 80 MHz. When the value is 3, the frequency bandwidth is 160 MHz (80+80 MHz). In this embodiment, 320 MHz is assumed to be used as a frequency bandwidth more than 160 MHz, as described with reference to FIG. 6. On the other hand, since only 2 bits are prepared for the Bandwidth subfield, only four types of frequency bandwidths can be designated. In this embodiment, 1 bit in the Reserved (reserved field) subfield (B14) in the EHT-SIG-A1 (Table 1) and/or the Reserved subfield (B14) in the EHT-SIG-A2 (Table 2) is used. Hence, the frequency bandwidth is designated using a total of 3 or 4 bits including the Bandwidth subfield in the EHT-SIG-A1.

[0046] The EHT-STF 706 next to the EHT-SIG-A 705 is an abbreviation of EHT Short Training Field, and its main object is to improve automatic gain control in MIMO transmission. The EHT-LTF 707 is an abbreviation of EHT Long Training Field and provides a means for estimating a MIMO channel to a receiver. The data field 708 can include MIMO communication data transmitted in the number of SSs (spatial streams) indicated by an NSTS And Midamble Periodicity subfield of the EHT-SIG-A1.

[0047] The EHT ER PPDU shown in FIG. 8 is a PPDU used to extend the communication distance, as described above, and is used in communication between an AP and a single STA. The EHT ER PPDU includes an L-STF 801, an L-LTF 802, an L-SIG 803, an RL-SIG 804, an EHT-SIG-A 805, an EHT-STF 806, an EHT-LTF 807, a data field 808, and a Packet extension 809. The RL-SIG 804 may be absent. The L-LTF 802 is arranged immediately after the L-STF 801, the L-SIG 803 is arranged immediately after the L-LTF 802, the EHT-SIG-A 805 is arranged after the L-SIG 803, the EHT-STF 806 is arranged immediately after the EHT-SIG-A 805, and the EHT-LTF 807 is arranged immediately after the EHT-STF 806. Note that the field including the L-STF 801, the L-LTF 802, the L-SIG 803, the RL-SIG 804, the EHT-SIG-A 805, the EHT-STF 806, and the EHT-LTF 807 is called a preamble. Information included in each field has the same contents as in the EHT SU PPDU shown in FIG. 7, and a description thereof will be omitted. Note that in the EHT-SIG-A 805, the B14 bit of the EHT-SIG-A1 and the B14 bit of the EHT-SIG-A2 are Reserved subfields, as in the EHT SU PPDU shown in FIG. 7. A frequency bandwidth to be used for wireless communication can be set using the subfields as well.

[0048] The EHT MU PPDU shown in FIG. 9 is a PPDU used in communication of MU, as described above. The EHT MU PPDU includes an L-STF 901, an L-LTF 902, an L-SIG 903, an RL-SIG 904, an EHT-SIG-A 905, an EHT-SIG-B 906, an EHT-STF 907, an EHT-LTF 908, a data field 909, and a Packet extension 910. The RL-SIG 904 may be absent. The L-LTF 902 is arranged immediately after the L-STF 901, the L-SIG 903 is arranged immediately after the L-LTF 902, the EHT-SIG-A 905 is arranged after the L-SIG 903, the EHT-SIG-B 906 is arranged immediately after the EHT-SIG-A 905, the EHT-STF 907 is arranged immediately after the EHT-SIG-B 906, and the EHT-LTF 908 is arranged immediately after the EHT-STF 907. Note that the field including the L-STF 901, the L-LTF 902, the L-SIG 903, the RL-SIG 904, the EHT-SIG-A 905, the EHT-SIG-B 906, the EHT-STF 907, and the EHT-LTF 908 is called a preamble.

[0049] The EHT-SIG-A 905 includes Information such as EHT-SIG-A1 and EHT-SIG-A2 necessary for reception of the PPDU. Subfields that form the EHT-SIG-A1 and the EHT-SIG-A2 included in the EHT-SIG-A 705 and a description thereof are shown in Table 3 and Table 4.

TABLE-US-00003 TABLE 3 Bit Bit Position Subfield Count Description EHT- B0 UL/DL 1 This subfield indicates whether the SIG- PPDU is for UL or DL, and has the A1 same value as TX-VECTOR UPLINK_FLAG. B1-B3 SIGB MCS 3 This subfield indicates the MCS of the EHT-SIG-B field. “0” is set for MCS 0, “1” is set for MCS 1, “2” is set for MCS 2, “3”is set for MCS 3, “4” is set for MCS 4, or “5” is set for MCS 5. “6” and “7” are reserved areas. B4 SIGB DCM 1 “1” is set if the HT-SIG-B field is modulated using DCM. B5-B10 BSS Color 6 6-bit number for identifying the BSS B11- Spatial 4 This subfield indicates whether B14 Reuse Spatial Reuse is allowed during transmission of this PPDU. The value of Spatial Reuse field encoding shown in the separate table is set. B15- Bandwidth 3 “0” is set for 20 MHz, “1” is set for B17 40 MHz, or “3” is set for 160 MHz (80 + 80 MHz). When the SIGB Compression field is “0”, “4” is set if only the secondary 20 MHz is puncturing in 80 MHz preamble puncturing, “5” is set if two 20 MHz of the secondary 40 MHz are puncturing in 80 MHz preamble puncturing, “6” is set if only the secondary 20 MHz is puncturing in 160 (pr 80 + 80) MHz preamble puncturing, or “7” is set if only the secondary 40 MHz is puncturing in 160 (or 80 + 80) MHz preamble puncturing. If the SIGH field is “1”, the value between “4” to “7” means “reserved”. B18- Number of 4 When the SIGH Compression field B21 EHT-SIG-B is “0”, this subfield indicates the Symbols or number of OFDMA symbols in the MU-MIMO EHT-SIG-B. Users If the number of OFDM symbols in the EHT-SIG-B is smaller than 16, the number obtained by subtracting 1 from the number of OFDM symbols in the EHT-SIG-B is set. If at least one receiving terminal has set the capability of supporting the number of EHT SIG-B OFDM symbols larger than 16 to “0”, “15” is set to indicate that the minter of OFDM symbols in the EHT-SIG-B is 16, If all the receiving terminals have set the capability of supporting the number of EMT SIG-B OFDM symbols larger than 16 to “0” and the data rate of the EHT-SIG-B is smaller than MCS 4 which does not use DCM, “15” is set to indicate that the number of OFDM symbols in the EHT-SIG-B is equal to or larger than 16. When the SIGB Compression field is “1”, the value set here means the number obtained by subtracting 1 from the number of MU-MIMO users. B22 SIG 1 “1” is set if a Common field exists Compression in the EHT-SIG-B. B23- Gi + LTF 2 This subfield indicates the Guard B24 Size Interval period and the EHT-LTF size. “0” is set for 4 × EHT-LTF and 0.8 μs GI, “1” is set for 2 × EHT-LFF and 0.8 μs GI, “2” is set for 2 × EHT-LTF and 1.6 μs GI, or “3” is for 4 × EHT-LTF and 3.2 μs GI. B25 Doppler 1 “1” is set if either of the following conditions is met: the number of OFDM symbols in the data field is larger than the value indicated by the midamble period + 1”, and a midamble exists, and the number of OFDM symbols in the data field is equal to or smaller than “the value indicated by the midamble period + 1”, no midamble exists, and the channel changes rapidly.

TABLE-US-00004 TABLE 4 Bit Bit Position Subfield Count Description EHT- B0-B6 TXOP 1 Transmission Opportunity SIG- If TXOP_DURATION of A2 TXVECTOR is UNSPECIFIED and there is no period information, 127 is set. If TXOP_DURATION of TXVECTOR is smaller than 512, a value smaller than 127 is set to set NAV. At this time, if B0 is “0”, FLOOR of TXOP_DURATION/8 (round down) is set in B1 to B6. If B0 is “1”, FLOOR of (TXOP_DURATION − 512)/8 is set in B1 to B6. B7 Reserved 1 Reserved field B8-B10 Number of 3 This subfield indicates the number EHT-LTF of EHT-LTFs. Symbols And “0” is set for one EHT-LTF, “1” is Midamble set for two EHT-LTFs, “2” is set Periodicity for four EHT-LTFs, “3” is set for six EHT-LTFs, or “4” is set for eight EHT-LTFs. When the Doppler field is “1”, B8 and B9 indicate the number of EHT-LTF symbols, and B10 indicates the midamble period. B11 LDPC Extra 1 This subfield indicates the Symbol presence/absence of an extra Segment OFDM symbol segment for LDPC. B12 STBC 1 When the number of users of each RU (Resource Unit) is not larger than 1, “1” is set to indicate that STBC is used for encoding. B13- Pre-FTC 2 “0” is set if the Pre-FEC Padding B14 Padding Factor is 4, “1” is set if the Pre- Factor FEC Padding Factor is 1. “2” is set if the Pre-TEC Padding Factor is 2, or “3” is set if the Pre- FEC Padding Factor is 3. B15 PE 1 Disambiguity field of Packet Disambiguity Extension B16- CRC 4 The CRC of the EHT-SIG-A (26 B19 bits of A1 and 16 bits up to B15 of A2, that is, 42 bits in total) field up to here. B20- Tail 6 An area to set “0” to indicate the B25 end portion to a trellis convolution decoder.

[0050] The EHT-SIG-B 906 includes information such as Common field and User Block field necessary for reception of the PPDU. Subfields that form the Common field and the User Block field included in the EHT-SIG-B 906 and a description thereof are shown in Table 5 and Table 6.

TABLE-US-00005 TABLE 5 Subfield Bit Count Description Common RU N × 8 This subfield indicates RU field Allocation allocation used in the data portion of a frequency axis When N = 1, EHT MU PPDUs of 20 MHz and 40 MHz are allocated. When N = 2, an EHT MU PPDU of 80 MHz is allocated. When N = 4, an EHT MU PPDU of 160 MHz or 80 + 80 MHz is allocated. Center 26- 1 This subfield is used only when tone RU the Bandwidth field of EHT-SIG- A field of an EHT MU PPDU is larger than 1 (if the frequency is equal to or higher than 80 MHz). This subfield indicates whether to use a 26-tone RU at the center. CRC 4 CRC calculation value Tail 4 Trailer bit, which is set to 0.

TABLE-US-00006 TABLE 6 Subfield Bit Count Description User User field N × 21 This subfield indicates Block information for each user. field CRC 4 CRC calculation value Tail 6 Trailer bit, which is set to 0.

[0051] The format of the User field changes depending on whether to do transmission to a plurality of users by OFDMA or MU-MIMO. Table 7 shows a description of the User field in a case of transmission by OFDMA, and Table 8 shows a description of the User field in a case of transmission by MU-MIMO.

TABLE-US-00007 TABLE 7 Bit Bit Position Subfield Count Description User B0-B10 STA-ID 11 This subfield indicates the ID field of an STA or an STA group that is the receiver of the RU of an EHT MU PPDU. B11-B13 NSTS 3 This subfield indicates the number of Space-time streams B14 Tx 1 When transmission Beamforming Beamforming is used, “1” is set. When transmission Beamforming is not used, “0” is set. B15-B18 MCS 4 This subfield indicates the value of Modulation and Coding Scheme B19 DCM 1 This subfield indicates whether Dual Carrier Modulation is applied to the data field. B20 Coding 1 When BCC (Binary Convolutional Code) is used, “0” is set. When LDPC (Low Density Parity Check) is used, “1” is set.

TABLE-US-00008 TABLE 8 Bit Bit Position Subfield Count Description User B0-B10 STA-ID 11 This subtield indicates the field ID of an STA or an STA group that is the receiver of the RU of an EHT MU PPDU B11-B14 Spatial 4 This subfield indicates the Configuration number of Spatial Streams of an STA in MU-MIMO Allocation B15-B18 MCS 4 This subfield indicates the value of Modulation and Coding Scheme B19 Reserved 1 Reserved field B20 Coding 1 When BCC (Binary Convolutional Code) is used, “0” is set. When LDPC (Low Density Parity Check) is used, is set.

[0052] In the EHT MU PPDU, the frequency bandwidth to be used for wireless communication can be set using the Reserved subfield (B7) in the EHT-SIG-A2 (Table 4) in addition to the 3-bit Reserved subfield (B15-B17) in the EHT-SIG-A1 (Table 3).

[0053] The EHT TB PPDU shown in FIG. 10 is a PPDU having a structure without EHT-SIG-B in the EHT MU PPDU, as described above. If the EHT TB PPDU is used, allocation of communication resources to a plurality of STAs is done using a trigger frame. The EHT TB PPDU includes an L-STF 1001, an L-LTF 1002, an L-SIG 1003, an RL-SIG 1004, an EHT-SIG-A 1005, an EHT-STF 1006, an EHT-LTF 1007, a data field 1008, and a Packet extension 1009. The RL-SIG 1004 may be absent. The L-LTF 1002 is arranged immediately after the L-STF 1001, the L-SIG 903 is arranged immediately after the L-LTF 1002, the EHT-SIG-A 1005 is arranged after the L-SIG 1003, the EHT-STF 1006 is arranged immediately after the EHT-SIG-A 1005, and the EHT-LTF 1007 is arranged immediately after the EHT-STF 1006. Note that the field including the L-STF 1001, the L-LTF 1002, the L-SIG 1003, the RL-SIG 1004, the EHT-SIG-A 1005, the EHT-STF 1006, and the EHT-LTF 1007 is called a preamble.

[0054] A detailed description of subfields that form an EHT-SIG-A1 and an EHT-SIG-A2 of the EHT-SIG-A 1005 of the EHT TB PPDU will be omitted. The B23 bit of the EHT-SIG-A1 and the B7-B15 bits of the EHT-SIG-A2 are Reserved subfields. Hence, the frequency bandwidth to be used for wireless communication can be set using these subfields as well.

[0055] In the above-described way, every PPDU used in the IEEE802.11EHT standard can ensure a field of 3 bits or more in the EHT-SIG-A for designation of a frequency bandwidth and designate a frequency bandwidth more than 160 MHz.

[0056] Note that FIGS. 7 to 10 show frame structures having backward compatibility with the IEEE802.11a/b/g/n/ax standards. If backward compatibility need not be ensured, the fields of the L-STF and the L-LTF may be omitted. Instead, the EHT-STF and the EHT-LTF may be inserted.

[0057] According to the present invention, it is possible to notify, in a preamble, that communication is performed in a frequency bandwidth more than 160 MHz.

Other Embodiments

[0058] Embodiment(s) of the present invention can also be realized by a computer of a system or apparatus that reads out and executes computer executable instructions (e.g., one or more programs) recorded on a storage medium (which may also be referred to more fully as a ‘non-transitory computer-readable storage medium’) to perform the functions of one or more of the above-described embodiment(s) and/or that includes one or more circuits (e.g., application specific integrated circuit (ASIC)) for performing the functions of one or more of the above-described embodiment(s), and by a method performed by the computer of the system or apparatus by, for example, reading out and executing the computer executable instructions from the storage medium to perform the functions of one or more of the above-described embodiment(s) and/or controlling the one or more circuits to perform the functions of one or more of the above-described embodiment(s). The computer may comprise one or more processors (e.g., central processing unit (CPU), micro processing unit (MPU)) and may include a network of separate computers or separate processors to read out and execute the computer executable instructions. The computer executable instructions may be provided to the computer, for example, from a network or the storage medium. The storage medium may include, for example, one or more of a hard disk, a random-access memory (RAM), a read only memory (ROM), a storage of distributed computing systems, an optical disk (such as a compact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD)™), a flash memory device, a memory card, and the like.

[0059] While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.